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Johann Gottlieb Fichte transformed Kant’s critical idealism into absolute idealism by eliminating Kant’s ‘things-in-themselves’ (external reality) and making the self, or the ego, the ultimate reality. Fichte maintained that the world is created by an absolute ego, which is conscious first of itself and only later of non-self, or the otherness of the world. The human will, a partial manifestation of self, gives human beings freedom to act. Friedrich Wilhelm Joseph von Schelling moved still further toward absolute idealism by construing objects or things as the works of the imagination and Nature as an all-embracing being, spiritual in character. Schelling became the leading philosopher of the movement known as romanticism, which in contrast to the Enlightenment placed its faith in feeling and the creative imagination rather than in reason. The romantic view of the divinity of nature influenced the American transcendentalist movement, led by poet and essayist Ralph Waldo Emerson.
German philosopher Georg Wilhelm Friedrich Hegel proposed that truth is reached by a continuing dialectic, in which a concept (thesis) always gives rise to its opposite (antithesis), and the interaction between these two leads and the creation of a new concept (synthesis). Hegel employed this dialectical method in such works as Phenomenology of the Mind (1807) to explain history and the evolution of ideas.
The most powerful philosophical mind of the 19th century was the German philosopher Georg Wilhelm Friedrich Hegel, whose system of absolute idealism, although influenced greatly by Kant and Schelling, was based on a new conception of logic and philosophical method. Hegel believed that absolute truth, or reality, existed and that the human mind can know it. This is so because ‘whatever is real is rational,’ according to Hegel. He conceived the subject matter of philosophy to be reality as a whole, a reality that he referred to as Absolute Spirit, or cosmic reason. The world of human experience, whether subjective or objective, he viewed as the manifestation of Absolute Spirit.
In his effort to develop an all-encompassing philosophical system, German philosopher Georg Wilhelm Friedrich Hegel wrote on topics ranging from logic and history to art and literature. He considered art to be one of the supreme developments of spiritual and absolute knowledge, surpassed only by religion and philosophy. In this excerpt from Introductory Lectures on Aesthetics, which was based on lectures that Hegel delivered between 1820 and 1829, Hegel discussed the relationship of poetry to other arts, particularly music, and explained that poetry was one mode of expressing the ‘Idea of beauty’ that Hegel believed resided in all art forms. For Hegel, poetry was ‘the universal realization of the art of the mind.’
Philosophy’s task, according to Hegel, is to chart the development of Absolute Spirit from abstract, undifferentiated being into more and more concrete reality. Hegel believed this development occurs by a dialectical process—that is, a process through which conflicting ideas become resolved—which consists of a series of stages that occur in triads (sets of three). Each triad involves (1) an initial state (or thesis), which might be an idea or a movement; (2) its opposite state (or antithesis); and (3) a higher state, or synthesis, that combines elements from the two opposites into a new and superior arrangement. The synthesis then becomes the thesis of the next triad in an unending progress toward the ideal.
Hegel argued that this dialectical logic applies to all knowledge, including science and history. His discussion of history was particularly influential, especially because it supported the political and social philosophy later developed by Karl Marx. According to Hegel human history demonstrates the dialectical development of Absolute Spirit, which can be observed by studying conflicts and wars and the rise and fall of civilizations. He maintained that political states are real entities, the manifestation of Spirit in the world, and participants of history. In every epoch a particular state is the bearer or agent of spiritual advance, and it thereby gathers to itself power. Because the dialectic means opposition and conflict, war must be expected, and it has value as evidence of the health of a state.
Hegel’s philosophy stimulated interest in history by representing it as a deeper penetration into reality than the natural sciences provide. His conception of the national state as the highest social embodiment of the Absolute Spirit was for some time believed to be a main source of 20th-century totalitarianism, although Hegel himself advocated a large measure of individual freedom.
German philosopher Arthur Schopenhauer considered the will as the basic reality and the source of human unhappiness, beliefs he set forth in 1819 in his major work, The World as Will and Idea. Only through reason and resignation can human beings overcome the striving and desires of the will and achieve happiness.
German philosophers of the 19th century who came after Hegel rejected Hegel’s faith in reason and progress. Arthur Schopenhauer in The World as Will and Idea (1819) argued that existence is fundamentally irrational and an expression of a blind, meaningless force—the human will, which encompasses the will to live, the will to reproduce, and so forth. Will, however, entails continuous striving and results in disappointment and suffering. Schopenhauer offered two avenues of escape from irrational will: through the contemplation of art, which enables one to endure the tragedy of life, and through the renunciation of will and of the striving for happiness.
Schopenhauer on the Suffering of the World
German philosopher Arthur Schopenhauer developed a philosophy of pessimism that focused on the nature of the ‘will,’, a term Schopenhauer used to mean both a person’s individual desires as well as the overall essence of being alive. Schopenhauer believed that although ‘will’ was essential to life, it was also the source of endless striving and discontent. In this excerpt from Parerga und Paralipomena (1851, translated as Essays and Aphorisms), Schopenhauer contemplated the role of suffering in human life, and argued that pain was an inescapable part of life. Schopenauer’s acceptance of human suffering reflected the influence of both Christian and Indian Buddhist religious traditions.
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Schopenhauer was one of the first Western philosophers to be influenced by Indian philosophy, which was then appearing in Europe in translation. The influence of Buddhist thought, for example, appears in his sense that the world is full of evil and suffering which can be overcome only through resignation and renunciation. Schopenhauer’s own view that an irrational force lies at the center of life subsequently influenced voluntaristic psychology, a school of psychology that emphasized the causes for our choices; sociological studies that examine nonrational factors affecting people; and cultural attitudes that play down the value of reason in life.
During the 19th century, Friedrich Nietzsche, in a return to the classical ideals of ancient Greece, attacked Christianity and moral philosophy. According to Nietzsche, the ideals of Christianity and moral philosophy were ‘slave moralities’ that sought to restrict individuals of talent and vision from rising above the masses. He acclaimed the ‘will to power’ and praised the creative accomplishments of great individuals.
German philosopher Friedrich Nietzsche continued the revolt against reason initiated by the romantic movement, but he scornfully repudiated Schopenhauer’s negative, resigned attitude. Instead, Nietzsche affirmed the value of vitality, strength, and the supremacy of an existence that is purely egoistic. He also scorned the Christian and democratic ideas of the equal worth of human beings, maintaining that it is up to a few aristocrats to refuse to subordinate themselves to a state or cause, and thereby achieve self-realization and greatness. For Nietzsche the power to be strong was the greatest value in life. Although Nietzsche valued geniuses over dictators, his beliefs helped bolster the ideas of the National Socialists (Nazis) who gained control of Germany in the 1930s.
One of the most controversial works of 19th-century philosophy, Thus Spake Zarathustra (1883-1885) articulated German philosopher Friedrich Nietzsche’s theory of the Übermensch, a term translated as ‘Superman’ or ‘Overman.’ The Superman was an individual who overcame what Nietzsche termed the ‘slave morality’ of traditional values, and lived according to his own morality. Nietzsche also advanced his idea that ‘God is dead,’ or that traditional morality was no longer relevant in people’s lives. In this passage, the sage Zarathustra came down from the mountain where he had spent the last ten years alone to preach to the people.
Nineteenth-century Danish philosopher S ren Kierkegaard helped found existentialism and explored the inherent paradoxes in Christianity. In his book Fear and Trembling, Kierkegaard discussed Genesis 22, in which God commanded Abraham to kill his only son, Isaac. Abraham was prepared to heed God’s unreasonable request, and Kierkegaard regard’s Abraham’s ‘leap of faith’ in this matter as the essence of religion.
Danish philosopher S ren Kierkegaard developed another distinctive philosophy of life. Kierkegaard’s ideas, which were not appreciated until a century after their appearance, were literary, religious, and self-revealing rather than systematic in character. They stressed the importance of experiences that the intellectual mind judges as absurd, including the experiences of angst (‘anxiety’) and ‘fear and trembling.’ (The latter phrase is the title of one of his books.) Such experiences, in his view, lead first to despair and eventually to religious faith. Kierkegaard discussed this process in terms of the religious person who is commanded by God to sacrifice his own most cherished treasures, as in the example of Abraham and the sacrifice of Isaac in the Old Testament. Although Abraham cannot understand this absurd request from God, he decides to obey his commitment to God. Through such terrible experiences, Kierkegaard claimed, we learn that humanity’s relationship to God is absolute and all else relative. What is most significant in a person’s life, Kierkegaard concluded, are the decisions made in such ethical crises?
Danish religious philosopher S ren Kierkegaard rejected the all-encompassing, analytical philosophical systems of such 19th-century thinkers as German philosopher G. W. F. Hegel. Instead, Kierkegaard focused on the choices the individual must make in all aspects of his or her life, especially the choice to maintain religious faith. In Fear and Trembling (1846; trans. 1941), Kierkegaard explored the concept of faith through an examination of the biblical story of Abraham and Isaac, in which God demanded that Abraham demonstrate his faith by sacrificing his son.
Kierkegaard’s ideas came to have importance in the 20th century. The concepts of existence, dread, the absurd, and decision were influential in Germany, France, and English-speaking countries. The condition of humankind during an epoch with two world wars gave these ideas a new relevance; the philosophers who developed them founded the movement now known as existentialism.
In the 18th century British philosopher Jeremy Bentham founded the ethical, legal, and political doctrine of utilitarianism, which states that correct actions are those that result in the greatest happiness for the greatest number of people. For Bentham, happiness is precisely quantifiable and reducible to units of pleasure, less units of pain. Bentham was strongly opposed to then-dominant theories of natural rights, in which human beings are believed to possess certain inherent and unalterable social requirements.
Jeremy Bentham and John Stuart Mill, both economists as well as philosophers, dominated philosophy in England during the 19th century. Bentham originated the ethical principle of utilitarianism—that what is useful is good—and Mill developed and refined the doctrine. The utilitarians argued for an ethical principle that would be superior to the self-interest of the individual, just as Kant had established a rational principle of moral law superior to individual desire, by which people’s conduct ought to be governed. The utilitarians based their principle on the theory that everyone desires his or her own happiness, which people have to find that happiness in society, and that consequently we all have an interest in the general happiness. They took the position that whatever produces the greatest happiness for the greatest number of people is what is most useful for all. This is the meaning of the principle of utility, or benefit, from which utilitarianism takes its name.
English philosopher-economist John Stuart Mill was one of the most important thinkers of the 19th century. The son of English philosopher James Mill, he refined and elaborated on the work of his father and of English philosopher-economist Jeremy Bentham in his book Utilitarianism (1863). Utilitarian philosophers argued that all decisions could be made according to the principal of the greatest ‘utility,’ or benefit, to the greatest number of people. In this section from the end of the work, Mill discussed the issue of criminal punishment and examined how it related to concepts of justice and fairness and to the doctrine of utility.
In evaluating happiness, Bentham believed it possible to measure quantitatively the pleasures resulting from each action—the pleasures of oneself and the pleasure of others - and thus to decide in any instance what promoted the greatest amount of happiness. Mill partly abandoned that idea and maintained that one should consider the quality, or type, of pleasure as well as the quantity. Mill applied utilitarian principles to social justice, and the principle of utility influenced legislation that brought about social and economic reforms in Great Britain.
British philosopher and economist John Stuart Mill, though a leading proponent of utilitarianism during the 19th century, came to understand that utilitarian thought was flawed because it failed to take account of people’s emotions. He became outspoken on the subject of equality for women, an unpopular cause at the time. His essay The Subjection of Women (1869) sought to shift the law and public perceptions in order to free women from what was effectively slavery, and to allow them to live as individuals.
British philosopher and economist Jeremy Bentham (1748-1832) was the originator of the doctrine known as utilitarianism. He declared that in order to come into accord with the laws of nature, government and citizens should act to increase the overall happiness of the community. The utilitarian principles of Bentham and others who shared his beliefs, including British philosopher-economists James Mill (1773-1836) and his son, John Stuart Mill (1806-1873), helped to bring about social and political reform in Britain.
Karl Marx, along with Friedrich Engels, defined communism. Their most famous work was the Communist Manifesto (1848), in which they argued that the working class should rebel and build a Communist society.
The most influential achievement in political philosophy during the 19th century was the development of Marxism, the German political philosopher created the system known as Marxism, and his collaborator Friedrich Engels accepted the basic form of Hegel’s dialectic of history, but they made crucial modifications. For them history was a matter of the development not of Absolute Spirit but of the material conditions governing humanity’s economic existence. In their view, later known as historical materialism, the history of society is a history of class struggle in which the ruling class uses religion and other traditions and institutions, as well as its economic power, to reinforce its domination over the working classes. Human culture, according to Marx, is dependent on economic (material) conditions and serves economic ends. Religion, he concluded, is ‘the opiate of the masses’ that serves the political end of suppressing mass revolution. Marxism is a theory of revolution, of history, of economics, and of politics, and it served as the ideology for Communism. Although he was a philosopher Marx had disdain for merely theoretical intellectual work, stating, ‘The philosophers have only interpreted the world in different ways; the point is to change it.’
Many Socialist and Communist tracts were published in the early and mid-19th century, but the succinct expression of Socialist ideas and the dramatic rhetoric helped make The Communist Manifesto (1848) the central text of modern Socialism. In this excerpt from Part I, German political philosopher Karl Marx advanced the idea that the history of society is the history of struggle between the oppressed and their oppressors. Marx based the Manifesto in part on a draft prepared by German revolutionary political economist Friedrich Engels.
Marx’s view of human history is both profoundly pessimistic and profoundly optimistic. Its pessimism lies in his belief that history reflects the oppression of the many by a small minority, who thereby secure economic and political power. It is optimistic on two counts. First, Marx believed that technical innovations bring about new ways of meeting human needs and make it increasingly possible for people to satisfy their deepest wants and to develop and perfect their individual capacities. Second, Marx claimed to have proved that the long history of oppression would soon end when the masses rise up and usher in a revolution that will create a classless utopian society. The first idea enabled Marx to bring attention in the modern era to Aristotle’s idealistic conception of human flourishing, which called upon people to develop and manifest many different abilities, including intellectual, artistic, and physical skills. The second idea motivated much radical activity during the 20th century, including the Russian Revolutions of 1917, the Communist victory in China in 1949, and the Cuban Revolution of 1959.
American psychologist and philosopher William James helped to popularize the philosophy of pragmatism with his book Pragmatism: A New Name for Old Ways of Thinking (1907). Influenced by a theory of meaning and verification developed for scientific hypotheses by American philosopher C. S. Peirce, James held that truth is what works, or has good experimental results. In a related theory, James argued the existence of God is partly verifiable because many people derive benefits from believing.
Toward the end of the 19th century, pragmatism became the most vital school of thought within American philosophy. It continued the empiricist tradition of grounding knowledge on experience and stressing the inductive procedures of experimental science. The pragmatists believed in the progress of human knowledge and that ideas are tools whose validity and significance are established as people adapt and test them in physical and social settings. For pragmatists, ideas demonstrate their value insofar as they enrich human experience.
At the turn of the century, American psychologist and philosopher William James gave a series of lectures on religion at Scotland’s University of Edinburgh. In the 20 lectures he delivered between 1901 and 1902, published together as The Varieties of Religious Experience (1902), James discussed such topics as the existence of God, religious conversions, and immortality. In his lectures on mysticism, excerpted here, James defined the characteristics of a mystical experience—a state of consciousness in which God is directly experienced. He also quoted accounts of mystical experiences as given by important religious figures from many different religious traditions.
The three most important American philosophers of the pragmatic movement were Charles Sanders Peirce, who founded pragmatism and gave the movement its name; psychologist and religious thinker William James; and psychologist and educator John Dewey. Their work continued into the 20th century. Peirce formulated a pragmatic theory of knowledge and advocated ‘laboratory philosophy’ whereby researchers investigate and clarify the kinds of knowledge that can be gained either through everyday experience or through scientific inquiry. By limiting the realm of meaningful questions to those that concern possible experience, Peirce hoped to introduce scientific logic into metaphysics. He advanced a theory of truth that defined truth as that which and ideal community of researchers could agree upon. Peirce concluded that many traditional philosophical concepts have no practical use and thus are meaningless.
Whereas Peirce sought to determine the meaning of terms and ideas and thereby make metaphysics a precise and pragmatic discipline, James and Dewey applied the principles of pragmatism in developing a comprehensive philosophy. Like Peirce, James maintained that the meaning of ideas lies in their practical consequences. If an idea has no practical uses, then it is meaningless. James focused on the power of true ideas to offer individuals, rather than scientific researchers, practical guidance in handling problems that arise in everyday experience. Truth, according to James, resides in those experiences that enable people to successfully navigate the challenges and demands of the world.
American philosopher, educator, and psychologist John Dewey reformed educational theory and practice in the United States by making learn more diverse and participatory. He tested his educational principles at the famous Laboratory School, and called the Dewey School, in Chicago. Dewey’s theories were developed while he was at the University of Chicago, from 1894 to 1904.
Dewey emphasized the cooperative process in which human beings, as intelligent and social beings, create and revise ideas about the world. One such process was scientific inquiry; another was participation in just and democratic social and political communities. Dewey concluded that science and democracy are the only sure guides for intelligent behaviour. His progressive social philosophy communicates a vision of a world in which science, education, and social reform demonstrate the benefits of pragmatic ideas for human life.
A diversity of methods, interests, and styles of argumentation marked 20th-century philosophy and proved both fruitful and destructive. This diversity, and the divisions that arose, proved fruitful as new topics arose and new ways developed for discussing these topics philosophically. It proved destructive, however, as philosophers wrote increasingly for a narrow audience and often ignored or derided philosophical styles different from their own.
In the decades following World War II (1939-1945), significant divisions arose between so-called continental philosophers, who worked on the European continent, and philosophers in the United States, the United Kingdom, and Australia. Deconstruction and other postmodern theories followed existentialism and phenomenology on the continent, whereas the Americans, Britons, and Australians worked in the analytic tradition. In the final decades of the century, the divisions between continental and analytic philosophy eased as interest moved away from the old disputes, and more and more philosophers became interested in exploring common roots of the two traditions in the history of Western philosophy.
German philosopher Edmund Husserl is considered the founder of phenomenology. This 20th-century philosophical movement is dedicated to the description of phenomena as they present themselves through perception to the conscious mind.
German philosopher Edmund Husserl founded the 20th-century movement of phenomenology. Husserl said that philosophers must attempt to describe and analyze phenomena as they occur, setting aside such considerations as whether the phenomena are objective or subjective. He emphasized careful observation and interpretation of our conscious perceptions of things. First, we must attend to what we are conscious of, observing our perceptions far more carefully and intensely than we do in everyday life. Second, we must reflect upon these observations and interpret them without preconceptions. Husserl maintained that we arrive at meaning and the key to solving philosophical problems through a logical analysis of the data that emerges from such a ‘phenomenological study’ of the contents of the mind.
German philosopher Martin Heidegger was instrumental in the development of the 20th-century philosophical school of existential phenomenology, which examines the relationship between phenomena and individual consciousness. His inquiries into the meaning of ‘authentic’ or ‘inauthentic’ existence greatly influenced a broad range of thinkers, including French existentialist Jean-Paul Sartre. Author Michael Inwood explores Heidegger’s key concept of Dasein, or ‘being,’ which was first expounded in his major work Being and Time (1927).
French philosopher Maurice Merleau-Ponty and German philosopher Martin Heidegger further developed phenomenology and its emphasis on pure description. For Merleau-Ponty, however, all perceptual experience carries with it a reference to something beyond and independent of our perception of it. Heidegger, too, sought to return to what he claimed had become unfamiliar—Sein (German for ‘being’ or ‘existence’).
French philosopher and author Simone de Beauvoir often addressed existential themes such as the necessity of being responsible for oneself. Two of her best-known works were nonfiction: The Second Sex, a study of women in society, published in 1949; and The Coming of Age, a condemnation of society’s attitude toward the aged, published in 1970. She is shown here in a Parisian café with fellow French existentialist and writer Jean-Paul Sartre. He was her close companion for almost 60 years.
Heidegger was also a key figure in the 20th-century movement known as existentialism. Existentialists focused on the personal: on individual existence, subjectivity, and choice. Two central existential doctrines claim that there is no fixed human essence structuring our lives and that our choices are never determined by anything except our own free will. In making choices in life, we determine our individual selves. These doctrines imply that human beings have enormous freedom. Existentialists maintained that the human ability to make free choices is so great that it overwhelms many individuals, who experience a ‘flight from freedom’ by falsely treating religion, science, or other external factors as constraints and limits on individual freedom. In addition to Heidegger the main existentialist thinkers include French feminist philosopher Simone de Beauvoir and her companion, the philosopher, novelist, and playwright Jean-Paul Sartre.
In the early 20th century British mathematician and philosopher Bertrand Russell, along with British mathematician and philosopher Alfred North Whitehead, attempted to demonstrate that mathematics and numbers can be understood as groups of concepts, or classes. Russell and Whitehead tried to show that mathematics is closely related to logic and, in turn, that ordinary sentences can be logically analyzed using mathematical symbols for words and phrases. This idea resulted in a new symbolic language, used by Russell in a field he termed philosophical logic, in which philosophical propositions were reformulated and examined according to his symbolic logic.
Analytic philosophy rose to prominence in the United Kingdom after the end of World War I (1914-1918). This movement heralded a linguistic shift according to which the philosophical study of language became the central task of philosophy. Many analytic philosophers concluded that a number of issues prominent in the history of philosophy are unimportant or even meaningless because they arose when philosophers misunderstood or misused language. Analytic philosophy is based upon the assumption that the careful analysis of language and concepts can clear up these problems and confusions. The key figures at the beginning of the movement were British philosopher and mathematician Bertrand Russell and Austrian-born British philosopher Ludwig Wittgenstein.
Russell, strongly influenced by the precision of mathematics, wished to construct a logical language that would reflect the nature of the world. He argued that what he called the ‘surface grammar’ of everyday language masks a true ‘logical grammar,’ knowledge of which is essential for understanding the true meaning of statements. Russell and many philosophers influenced by him asserted that complex statements can be reduced to simple components; if their logic does not permit such reduction, then the statements are meaningless.
Russell’s view was central to the development of the so-called Vienna Circle, a group of analytic philosophers active from about 1920 to 1950, who were led by Rudolf Carnap and Moritz Schlick. The members of the Vienna Circle were scientists or mathematicians as well as philosophers, and they originated the movement known as logical positivism. They believed that the clarification of meaning is the task of philosophy, and that all meaningful statements are either scientifically verifiable statements about the world or else logical tautologies (self-evident propositions). According to the logical positivists the discovery of new facts belongs to science, and metaphysics—the construction of comprehensive truths about reality - is a pretentious pseudo-science.
Wittgenstein, who studied with Russell at Cambridge University, was perhaps the most important analytic philosopher. Like Russell, he distrusted ordinary language. In his Tractatus Logico-Philosophicus (1921) Wittgenstein stated that ‘philosophy aims at the logical clarification of thoughts.’ Philosophy’s function, he believed, is to monitor the use of language by reducing complex statements to their elementary components and by rebuffing all attempts to misuse words in creating the illusion of philosophical depth. ‘What can be said at all can be said clearly, and what we cannot talk about, but we must consign to silence.’ The Tractatus made important contributions to the philosophy of language, logic, and the philosophy of mathematics. The account of language in Wittgenstein’s later work was much richer and more sophisticated than that in the Tractatus. However, Wittgenstein never abandoned his radical early views on the nature of philosophy.
Austrian-born philosopher Ludwig Wittgenstein was one of the most influential thinkers of the 20th century. With his fundamental work, Tractatus Logico-philosophicus, published in 1921, he became a central figure in the movement known as analytic and linguistic philosophy.
As the analytic movement developed, different ideas emerged about how philosophical analysis should proceed. A group called constructivists was inspired by Russell, the early writings of Wittgenstein, and the logical positivists. The solutions to philosophical problems, the constructivists argued, lie in using tools of logic to create more precise technical vocabularies. Two leading representatives of this movement were the American philosopher’s Nelson Goodman and W. V. Quine. Quine saw language and logic as themselves embodying theories about reality, rather than consisting of theory-neutral tools of analysis. By contrast, the descriptivists maintained that philosophical analysis should focus on the careful study of the everyday usage of crucial terms. This group was inspired by the 20th-century British philosophers G. E. Moore, Gilbert Ryle, and John Austin.
German philosopher Rudolf Carnap attempted to introduce the methodology and precision of mathematics into the study of philosophy. This approach is now known as logical positivism or logical empiricism.
Although the radical formulations of analytic philosophy from the first half of the 20th century no longer hold sway, analytic philosophy continues to flourish. Many contemporary philosophers have adopted ideas, methods, or values from the movement, including the Americans Donald Davidson, Hilary Putnam, and Saul Kripke. Analytic philosophy also has widely influenced the training and practices of philosophers today. On the one hand, its influence has led to a renewed commitment to clarity, concision, incisiveness, and depth in philosophical thinking and writing. On the other hand, it has also caused many philosophers to embrace difficult and obscure technical language to such an extent that their ideas are accessible to only a small community of specialists.
French philosopher Michel Foucault became world famous for his research into the shifting patterns of power in society. In 1970 he was elected to France’s highest academic post, the Coll ge de France.
Inaccessible ideas and impenetrable prose also characterize many postmodern philosophical texts, although the difficulties in this case are often intentional and reflect specific postmodern claims about the nature of language and meaning. The literal meaning of postmodernism is ‘after modernism,’ and in many ways postmodernism constitutes an attack on modernist claims about the existence of truth and value—claims that stem from the European Enlightenment of the 18th century. In disputing past assumptions postmodernist generally display a preoccupation with the inadequacy of language as a mode of communication. Among the major postmodern theorists are French philosopher’s Jacques Derrida and Michel Foucault, and psychoanalyst Jacques Lacan.
Derrida originated the philosophical method of deconstruction, a system of analysis that assumes a text has no single, fixed meaning, both because of the inadequacy of language to express the author’s original intention and because a reader’s understanding of the text is culturally conditioned—that is, influenced by the culture in which the reader lives. Thus texts have many possible legitimate interpretations brought about by the ‘play’ of language. Derrida stresses the philosophical importance of pun, metaphor, ambiguity, and other playful aspects of language traditionally disregarded in philosophy. His method of deconstruction involves close and careful readings of central texts of Western philosophy that bring to light some of the conflicting forces within the text and that highlight the devices the text uses to claim legitimacy and truth for itself, many of which may lie beyond the intention of its author. Although some of Derrida’s ideas about language resemble views held by the analytic philosophers Wittgenstein, Quine, and Davidson, many philosophers schooled in the analytic tradition have dismissed Derrida’s work as destructive of philosophy.
Algerian-born French philosopher Jacques Derrida challenged established ideas on the analysis of texts during the 1960s and 1970s. His deconstructivist approach to reading a text opens it up to many different interpretations, each of which, he argued, is legitimate within its context.
Foucault created a searing critique of the ideals of the Enlightenment, such as reason and truth. Like Derrida, Foucault used close readings of historical texts to challenge assumptions, demonstrating how ideas about human nature and society, which we assume to be permanent truths, have changed over time. From an array of historical texts Foucault created ‘philosophical anthropologies’ that reveal the evolution of concepts such as reason, madness, responsibility, punishment, and power. By examining the origins of these concepts, he maintained, we see that attitudes and assumptions that today seem natural or even inevitable are historical phenomena dependent upon time and place. He further claimed that the historical development of these ideas demonstrates that seemingly humane and liberal Enlightenment ideals are in reality coercive and destructive.
Lacan agreed with Derrida and Foucault about the need to overturn crucial cultural and philosophical assumptions, but he arrived at this conclusion by a different method altogether. Influenced by Swiss linguist Ferdinand de Saussure and the psychoanalytic theories of Sigmund Freud, Lacan claimed that the unconscious portion of the mind operates with structures and rules analogous to those of a language. He used this claim to criticize both psychoanalytic theory and philosophy. On the one hand, he believed that concepts from linguistics could clarify and correct Freud’s picture of the mind and provide the field of psychoanalysis with greater philosophical depth. On the other hand, he maintained that applying psychoanalytic methods and theories to linguistics would radically revise traditional philosophical views of language and reason.
Feminist philosophers also challenge basic principles of traditional Western philosophy, investigating how philosophical inquiry would change if women conducted it and if it incorporated women’s experiences as well as their viewpoints. In interpreting the history of Western philosophy, feminists study texts by male philosophers for their depiction of women, masculine values, and biases toward men. Feminist philosophers also write about women’s experiences of subjectivity, their relationship to their bodies, and feminist concepts of language, knowledge, and nature. They explore connections between feminism in philosophy and other emerging feminist disciplines, such as feminist legal theory, feminist theology, and ecological feminism. Central to feminist philosophy is the concept of the oppression of women who live in patriarchal (male-controlled) societies; much of the work of feminist philosophers has gone into understanding patriarchy and developing alternatives to it. Prominent feminist philosophers include French postmodern philosopher’s Luce Irigaray and Hél ne Cixous and American philosopher of law Catharine MacKinnon.
Environmental philosophy is concerned with issues that arise when human beings interact with the environment. For instance, is a transformation of society necessary for the survival of living organisms and the environment? How is the exploitation of nature related to the subjugation of women and other oppressed humans? How can the philosophical study of the environment guide and inspire effective environmental activism? Most environmental philosophers seek to apply philosophical methods and ideas in collaboration with academics and activists working in the environmental sciences, theology, and feminism.
Two figures who played a prominent role in founding environmental philosophy are Norwegian philosopher Arne Naess and American naturalist, conservationist, and philosopher Aldo Leopold. Naess founded the so-called deep-ecology movement in the 1970s. The movement distinguishes between shallow ecology, which view’s nature in terms of its value to human beings, and deep ecology, which values nature independently of its usefulness to humanity. Leopold, in his influential book A Sand County Almanac (1949), called for the extension of ethical concern to include all life on Earth, not just human life. Other contemporary environmental philosophers include American ecological theologian Thomas Berry and American ecological feminist Karen Warren.
British political philosopher Isaiah Berlin is best known as a proponent of secular liberalism. In his book Four Essays on Liberty, Berlin advocates ‘negative’ liberty—that is, freedom from restrictions on the individual.
According to liberalism the chief goods (benefits) of government and society are personal and political freedoms, such as freedom of speech, freedom of association, and freedom of conscience (belief). Many liberal theorists view the freedom to make moral choices as the most important freedom; they argue that political and social systems should be organized to allow individuals the freedom to pursue their own ideas about ‘the good life.’ Communitarians respond that granting individuals this extreme freedom of choice ultimately limits human experience by undermining shared communal values. They claim that by ignoring the importance of community, liberalism disregards humanity’s social nature.
Prominent Communitarians include Scottish philosopher Alasdair MacIntyre and American philosopher Michael Sandel. Important liberal theorists include British philosopher Isaiah Berlin and American philosopher’s Ronald Dworkin and John Rawls. Rawls is the author of A Theory of Justice (1971), considered being the most significant work of political philosophy in the 20th century. In this book, he presents the idea of ‘justice as fairness,’ a principle that promotes the equal distribution of the benefits and burdens of society among individuals. Any advantages that society confers should benefit those who are most disadvantaged, Rawls believes. From this and other principles he has developed theories about political and social relations within liberal democracies and between those democracies and certain illiberal states. Rawls’s ideas remain a major inspiration for much current work in political philosophy.
The advent of new medical and reproductive technologies in recent years has complicated how ethical decisions are made in medical research and practice. This slide show highlights some of the most prominent issues in medical ethics: assisted reproductive technologies, human fetal tissue transplantation, cloning, and abortion.
Although most contemporary philosophy is highly technical and inaccessible to nonspecialists, some contemporary philosophers concern themselves with practical questions and strive to influence today’s culture. Practitioners of feminist philosophy, environmental philosophy, and some areas of contemporary political philosophy seek to use the tools of philosophy to resolve current issues directly related to peoples’ lives. Nowhere have philosophers more enthusiastically embraced practical relevance than in contemporary applied ethics, a field that has developed since the 1960s. Most of the questions applied ethicists raise concern the general theme ‘How should we live and die?’—a question central to ancient Greek philosophy.
Separate areas of specialization, such as biomedical ethics and business ethics, have emerged within applied ethics. Biomedical ethics deals with questions arising from the life sciences and human health care, and has two subspecialties: bioethics and medical ethics. Bioethicists study the ethical implications of advances in genetics and biotechnology, such as genetic testing, genetic privacy, cloning, and new reproductive technologies. For example, they consider the consequences for individuals who learn they have inherited a fatal genetic disease, or the consequences of technology that enables parents to choose the sex of a baby. Bioethicists then offer advice to legislators, researchers, and physicians active in these areas. Specialists in medical ethics offer advice to physicians, other health care personnel, and patients on a wide variety of issues, including abortion, euthanasia, fertility treatments, medical confidentiality, and the allocation of scarce medical resources. Much of the work in medical ethics directly affects the everyday practice of medicine, and most nursing students and medical students now take courses in this field.
Business ethicists bring ethical theories and techniques to bear on moral issues that arise in business. For example, what are the responsibilities of corporations to their employees, their customers, their shareholders, and the environment? Most business students take courses in business ethics, and many large corporations regularly consult with specialists in the field. Business ethicists also address larger topics, such as the ethics of globalization and the moral justification of various economic systems, such as capitalism and socialism.
Cognition, belongs of an act or process of knowing. Cognition includes attention, perception, memory, reasoning, judgment, imagining, thinking, and speech. Attempts to explain the way in which cognition works are as old as philosophy itself; the term, in fact, comes from the writings of Plato and Aristotle. With the advent of psychology as a discipline separate from philosophy, cognition has been investigated from several viewpoints.
An entire field—cognitive psychology—has arisen since the 1950s. It studies cognition mainly from the standpoint of information handling. Parallels are stressed between the functions of the human brain and the computer concepts such as the coding, storing, retrieving, and buffering of information. The actual physiology of cognition is of little interest to cognitive psychologists, but their theoretical models of cognition have deepened understanding of memory, psycholinguistics, and the development of intelligence.
Social psychologists since the mid-1960s have written extensively on the topic of cognitive consistency—that is, the tendency of a person's beliefs and actions to be logically consistent with one another. When cognitive dissonance, or the lack of such consistency, arises, the person unconsciously seeks to restore consistency by changing his or her behaviour, beliefs, or perceptions. The manner in which a particular individual classifies cognitions in order to impose order has been termed cognitive style.
Philosophers use the characteristics of inward accessibility, subjectivity, intentionality, goal-directedness, creativity and freedom, and consciousness to distinguish mental phenomena from physical phenomena.
Perhaps the most important characteristic of mental phenomena is that they are inwardly accessible, or available to us through introspection. We each know our own minds—our sensations, thoughts, memories, desires, and fantasies—in a direct sense, by internal reflection. We also know our mental states and mental events in a way that no one else can. In other words, we have privileged access to our own mental states.
Certain mental phenomena, those we generally call experiences, have a subjective nature—that is, they have certain characteristics we become aware of when we reflect. For instance, there is ‘something it is like’ to feel pain, or have an itch, or see something red. These characteristics are subjective in that they are accessible to the subject of the experience, the person who has the experience, but not to others.
Other mental phenomena, which we broadly refer to as thoughts, have a characteristic philosophers call intentionality. Intentional thoughts are about other thoughts or objects, which are represented as having certain properties or as being related to one another in a certain way. The belief that California is west of Nevada, for example, is about California and Nevada and represents the former as being west of the latter. Although we have privileged access to our intentional states, many of them do not seem to have a subjective nature, at least not in the way that experiences do.
A number of mental phenomena appear to be connected to one another as elements in an intelligent, goal-directed system. The system works as follows: First, our sense organs are stimulated by events in our environment; next, by virtue of these stimulations, we perceive things about the external world; finally, we use this information, as well as information we have remembered or inferred, to guide our actions in ways that further our goals. Goal-directedness seems to accompany only mental phenomena.
Another important characteristic of mind, especially of human minds, is the capacity for choice and imagination. Rather than automatically converting past influences into future actions, individual minds are capable of exhibiting creativity and freedom. For instance, we can imagine things we have not experienced and can act in ways that no one expects or could predict.
Scientists have long considered the nature of consciousness without producing a fully satisfactory definition. In the early 20th century American philosopher and psychologist William James suggested that consciousness is a mental process involving both attention to external stimuli and short-term memory. Later scientific explorations of consciousness mostly expanded upon James’s work. In this article from a 1997 special issue of Scientific American, Nobel laureate Francis Crick, who helped determine the structure of DNA, and fellow biophysicist Christof Koch explain how experiments on vision might deepen our understanding of consciousness.
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Mental phenomena are conscious, and consciousness may be the closest term we have for describing what is special about mental phenomena. Minds are sometimes referred to as consciousness, yet it is difficult to describe exactly what consciousness is. Although consciousness is closely related to inward accessibility and subjectivity, these very characteristics seem to hinder us in reaching an objective scientific understanding of it.
Although philosophers have written about mental phenomena since ancient times, the philosophy of mind did not garner much attention until the work of French philosopher René Descartes in the 17th century. Descartes’s work represented a turning point in thinking about mind by making a strong distinction between bodies and minds, or the physical and the mental. This duality between mind and body, known as Cartesian dualism, has posed significant problems for philosophy ever since.
Descartes believed there are two basic kinds of things in the world, a belief known as substance dualism. For Descartes, the principles of existence for these two groups of things—bodies and minds—are completely different from one another: Bodies exist by being extended in space, while minds exist by being conscious. According to Descartes, nothing can be done to give a body thought and consciousness. No matter how we shape a body or combine it with other bodies, we cannot turn the body into a mind, a thing that is conscious, because being conscious is not a way of being extended.
For Descartes, a person consists of a human body and a human mind causally interacting with one another. For example, the intentions of a human may cause that person’s limbs to move. In this way, the mind can affect the body. In addition, the sense organs of a human may be affected by light, pressure, or sound, external sources which in turn affect the brain, affecting mental states. Thus the body may affect the mind. Exactly how mind can affect body, and vice versa, is a central issue in the philosophy of mind, and is known as the mind-body problem. According to Descartes, this interaction of mind and body is peculiarly intimate. Unlike the interaction between a pilot and his ship, the connection between mind and body more closely resembles two substances that have been thoroughly mixed together.
In response to the mind-body problem arising from Descartes’s theory of substance dualism, a number of philosophers have advocated various forms of substance monism, the doctrine that there is ultimately just one kind of thing in reality. In the 18th century, Irish philosopher George Berkeley claimed there were no material objects in the world, only minds and their ideas. Berkeley thought that talk about physical objects was simply a way of organizing the flow of experience. Near the turn of the 20th century, American psychologist and philosopher William James proposed another form of substance monism. James claimed that experience is the basic stuff from which both bodies and minds are constructed.
Most philosophers of mind today are substance monists of a third type: They are materialists who believe that everything in the world is basically material, or a physical object. Among materialists, there is still considerable disagreement about the status of mental properties, which are conceived as properties of bodies or brains. Materialists who are property dualists’ believe that mental properties are an additional kind of property or attribute, not reducible to physical properties. Property dualists have the problem of explaining how such properties can fit into the world envisaged by modern physical science, according to which there are physical explanations for all things.
Materialists who are property monists believe that there is ultimately only one type of property, although they disagree on whether or not mental properties exist in material form. Some property monists, known as reductive materialists, hold that mental properties exist simply as a subset of relatively complex and nonbasic physical properties of the brain. Reductive materialists have the problem of explaining how the physical states of the brain can be inwardly accessible and have a subjective character, as mental states do. Other property monists, known as eliminative materialists, consider the whole category of mental properties to be a mistake. According to them, mental properties should be treated as discredited postulates of an outmoded theory. Eliminative materialism is difficult for most people to accept, since we seem to have direct knowledge of our own mental phenomena by introspection and because we use the general principles we understand about mental phenomena to predict and explain the behaviour of others.
Philosophy of mind concerns itself with a number of specialized problems. In addition to the mind-body problem, important issues include those of personal identity, immortality, and artificial intelligence.
During much of Western history, the mind has been identified with the soul as presented in Christian theology. According to Christianity, the soul is the source of a person’s identity and is usually regarded as immaterial; thus it is capable of enduring after the death of the body. Descartes’s conception of the mind as a separate, nonmaterial substance fits well with this understanding of the soul. In Descartes’s view, we are aware of our bodies only as the cause of sensations and other mental phenomena. Consequently our personal essence is composed more fundamentally of mind and the preservation of the mind after death would constitute our continued existence.
The mind conceived by materialist forms of substance monism does not fit as neatly with this traditional concept of the soul. With materialism, once a physical body is destroyed, nothing enduring remains. Some philosophers think that a concept of personal identity can be constructed that permits the possibility of life after death without appealing to separate immaterial substances. Following in the tradition of 17th-century British philosopher John Locke, these philosophers propose that a person consists of a stream of mental events linked by memory. It is these links of memory, rather than a single underlying substance, that provides the unity of a single consciousness through time. Immortality is conceivable if we think of these memory links as connecting a later consciousness in heaven with an earlier one on earth.
Garry Kasparov became the youngest world champion in chess history at the age of 22. Since that time in 1985 Kasparov has continued to be rated and recognized as the best chess player in the world. In the 1990s Kasparov competed in two highly publicized matches against Deep Blue, a supercomputer designed to play chess. In 1999 Kasparov challenged chess enthusiasts everywhere in an Internet project called ‘Kasparov Vs. The World.’ In September 1999 was favoured by an interview, Kasparov discusses taking on the world, Deep Blue, and his future challengers in chess.
The field of artificial intelligence also raises interesting questions for the philosophy of mind. People have designed machines that mimic or model many aspects of human intelligence, and there are robots currently in use whose behaviour is described in terms of goals, beliefs, and perceptions. Such machines are capable of behaviour that, were it exhibited by a human being, would surely be taken to be free and creative. As an example, in 1996 an IBM computer named Deep Blue won a chess game against Russian world champion Garry Kasparov under international match regulations. Moreover, it is possible to design robots that have some sort of privileged access to their internal states. Philosophers disagree over whether such robots truly think or simply appear to think and whether such robots should be considered to be conscious.
John Locke (1632-1704), English philosopher, who founded the school of empiricism. His essay concerning, An Essay Concerning Human Understanding
English philosopher John Locke explained his theory of empiricism, a philosophical doctrine holding that all knowledge is based on experience, in An Essay Concerning Human Understanding (1690). Locke believed the human mind to be a blank slate at birth that gathered all its information from its surroundings—starting with simple ideas and combining these simple ideas into more complex ones. His theory greatly influenced education in Great Britain and the United States. Locke believed that education should begin in early childhood and should proceed gradually as the child learns increasingly complex ideas.
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Locke was born in the village of Wrington, Somerset, on August 29, 1632. He was educated at the University of Oxford and lectured on Greek, rhetoric, and moral philosophy at Oxford from 1661 to 1664. In 1667 Locke began his association with the English statesman Anthony Ashley Cooper, 1st earl of Shaftesbury, to whom Locke was friend, adviser, and physician. Shaftesbury secured for Locke a series of minor government appointments. In 1669, in one of his official capacities, Locke wrote a constitution for the proprietors of the Carolina Colony in North America, but it was never put into effect. In 1675, after the liberal Shaftesbury had fallen from favour, Locke went to France. In 1679 he returned to England, but in view of his opposition to the Roman Catholicism favoured by the English monarchy at that time, he soon found it expedient to return to the Continent. From 1683 to 1688 he lived in Holland, and following the so-called Glorious Revolution of 1688 and the restoration of Protestantism to favour, Locke returned once more to England. The new king, William III, appointed Locke to the Board of Trade in 1696, a position from which he resigned because of ill health in 1700. He died in Oates on October 28, 1704.
The ideas of 17th-century English philosopher and political theorist John Locke greatly influenced modern philosophy and political thought. Locke, who is best known for establishing the philosophical doctrine of empiricism, was criticized for his ‘atheistic’ proposition that morality is nate within human beings. However, Locke was a religious man, and the influence of his faith was overlooked by his contemporaries and subsequent readers. Author John Dunn explores the influence of Locke’s Anglican beliefs on works such as An Essay Concerning Human Understanding (1690).
Locke's empiricism emphasizes the importance of the experience of the senses in pursuit of knowledge rather than intuitive speculation or deduction. The empiricist doctrine was first expounded by the English philosopher and statesman Francis Bacon early in the 17th century, but Locke gave it systematic expression in his Essay Concerning Human Understanding (1690). He regarded the mind of a person at birth as a tabula rasa, a blank slate upon which experience imprinted knowledge, and did not believe in intuition or theories of innate conceptions. Locke also held that all persons are born good, independent, and equal.
English philosopher John Locke anonymously published his Treatises on Government (1690) the same year as his famous Essay Concerning Human Understanding. In the Second Treatise, Locke described his concept of a ‘civil government.’ Locke excluded absolute monarchy from his definition of civil society, because he believed that the people must consent to be ruled. This argument later influenced the authors of the Declaration of Independence and the Constitution of the United States.
Locke's views, in his Two Treatises of Government (1690), attacked the theory of divine right of kings and the nature of the state as conceived by the English philosopher and political theorist Thomas Hobbes. In brief, Locke argued that sovereignty did not reside in the state but with the people, and that the state is supreme, but only if it is bound by civil and what he called ‘natural’ law. Many of Locke's political ideas, such as those relating to natural rights, property rights, the duty of the government to protect these rights, and the rule of the majority, were later embodied in the US Constitution.
Locke further held that revolution was not only a right but often an obligation, and he advocated a system of checks and balances in government. He also believed in religious freedom and in the separation of church and state.
Locke's influence in modern philosophy has been profound and, with his application of empirical analysis to ethics, politics, and religion, he remains one of the most important and controversial philosophers of all time. Among his other works are Some Thoughts Concerning Education (1693) and The Reasonableness of Christianity (1695). Empiricism, in philosophy, a doctrine that affirms that all knowledge is based on experience, and denies the possibility of spontaneous ideas or a priori thought. Until the 20th century the term empiricism was applied to the view held chiefly by the English philosophers of the 17th, 18th, and 19th centuries. Of these the English philosopher John Locke was the first to give it systematic expression, although his compatriot, the philosopher Francis Bacon, had anticipated some of its characteristic conclusions. The philosophy opposed to empiricism is rationalism, represented by such thinkers as the French philosopher René Descartes; the Dutch philosopher Baruch Spinoza; and the 17th- and 18th-century German philosophers Gottfried Wilhelm Leibniz and Christian von Wolff. Rationalists assert that the mind is capable of recognizing reality by means of the reason, a faculty that exists independent of experience. Immanuel Kant, the German philosopher, attempted a compromise between empiricism and rationalism, restricting knowledge to the domain of experience, and thus agreeing with the empiricists, but attributing to the mind a function in incorporating sensations into the structure of experience. This structure could be known a priori without resorting to empirical methods, and in this respect Kant agreed with the rationalists.
In recent years the term empiricism has taken on a more flexible meaning, and now is used in connection with any philosophical system that finds all of its materials in experience. In the United States, William James called his own philosophy radical empiricism, and John Dewey coined the term immediate empiricism for his view of experience. The term empirical laws is applied to those laws that express relationships observed to exist among phenomena, without implying the explanation or cause
Pragmatism calls for ideas and theories to be tested in practice, by assessing whether acting upon the idea or theory produces desirable or undesirable results. According to pragmatists, all claims about truth, knowledge, morality, and politics must be tested in this way. Pragmatism has been critical of traditional Western philosophy, especially the notion that there are absolute truths and absolute values. Although pragmatism was popular for a time in France, England, and Italy, most observers believe that it encapsulates an American faith in know-how and practicality and an equally American distrust of abstract theories and ideologies.
American psychologist and philosopher William James helped to popularize the philosophy of pragmatism with his book Pragmatism: A New Name for Old Ways of Thinking (1907). Influenced by a theory of meaning and verification developed for scientific hypotheses by American philosopher C. S. Peirce, James held that truth is what works, or has good experimental results. In a related theory, James argued the existence of God is partly verifiable because many people derive benefits from believing.
The Association for International Conciliation first published William James’s pacifist statement, ‘The Moral Equivalent of War,’ in 1910. James, a highly respected philosopher and psychologist, was one of the founders of pragmatism—a philosophical movement holding that ideas and theories must be tested in practice to assess their worth. James hoped to find a way to convince men with a long-standing history of pride and glory in war to evolve beyond the need for bloodshed and to develop other avenues for conflict resolution. Spelling and grammar represent standards of the time.
Pragmatists regard all theories and institutions as tentative hypotheses and solutions. For this reason they believed that efforts to improve society, through such means as education or politics, must be geared toward problem solving and must be ongoing. Through their emphasis on connecting theory to practice, pragmatist thinkers attempted to transform all areas of philosophy, from metaphysics to ethics and political philosophy.
Pragmatism sought a middle ground between traditional ideas about the nature of reality and radical theories of nihilism and irrationalism, which had become popular in Europe in the late 19th century. Traditional metaphysics assumed that the world has a fixed, intelligible structure and that human beings can know absolute or objective truths about the world and about what constitutes moral behaviour. Nihilism and irrationalism, on the other hand, denied those very assumptions and their certitude. Pragmatists today still try to steer a middle course between contemporary offshoots of these two extremes.
The ideas of the pragmatists were considered revolutionary when they first appeared. To some critics, pragmatism’s refusal to affirm any absolutes carried negative implications for society. For example, pragmatists do not believe that a single absolute idea of goodness or justice exists, but rather than these concepts are changeable and depend on the context in which they are being discussed. The absence of these absolutes, critics feared, could result in a decline in moral standards. The pragmatists’ denial of absolutes, moreover, challenged the foundations of religion, government, and schools of thought. As a result, pragmatism influenced developments in psychology, sociology, education, semiotics (the study of signs and symbols), and scientific method, as well as philosophy, cultural criticism, and social reform movements. Various political groups have also drawn on the assumptions of pragmatism, from the progressive movements of the early 20th century to later experiments in social reform.
Pragmatism is best understood in its historical and cultural context. It arose during the late 19th century, a period of rapid scientific advancement typified by the theories of British biologist Charles Darwin, whose theories suggested to many thinkers that humanity and society are in a perpetual state of progress. During this same period a decline in traditional religious beliefs and values accompanied the industrialization and material progress of the time. In consequence it became necessary to rethink fundamental ideas about values, religion, science, community, and individuality.
The three most important pragmatists are American philosophers Charles Sanders Peirce, William James, and John Dewey. Peirce was primarily interested in scientific method and mathematics; his objective was to infuse scientific thinking into philosophy and society, and he believed that human comprehension of reality was becoming ever greater and that human communities were becoming increasingly progressive. Peirce developed pragmatism as a theory of meaning - in particular, the meaning of concepts used in science. The meaning of the concept ‘brittle,’ for example, is given by the observed consequences or properties that objects called ‘brittle’ exhibit. For Peirce, the only rational way to increase knowledge was to form mental habits that would test ideas through observation, experimentation, or what he called inquiry. Many philosophers known as logical positivists, a group of philosophers who have been influenced by Peirce, believed that our evolving species was fated to get ever closer to Truth. Logical positivists emphasize the importance of scientific verification, rejecting the assertion of positivism that personal experience is the basis of true knowledge.
James moved pragmatism in directions that Peirce strongly disliked. He generalized Peirce’s doctrines to encompass all concepts, beliefs, and actions; he also applied pragmatist ideas to truth as well as to meaning. James was primarily interested in showing how systems of morality, religion, and faith could be defended in a scientific civilization. He argued that sentiment, as well as logic, is crucial to rationality and that the great issues of life—morality and religious belief, for example—are leaps of faith. As such, they depend upon what he called ‘the will to believe’ and not merely on scientific evidence, which can never tell us what to do or what is worthwhile. Critics charged James with relativism (the belief that values depend on specific situations) and with crass expediency for proposing that if an idea or action works the way one intends, it must be right. But James can more accurately be described as a pluralist—someone who believes the world to be far too complex for any one philosophy to explain everything.
Dewey’s philosophy can be described as a version of philosophical naturalism, which regards human experience, intelligence, and communities as ever-evolving mechanisms. Using their experience and intelligence, Dewey believed, human beings can solve problems, including social problems, through inquiry. For Dewey, naturalism led to the idea of a democratic society that allows all members to acquire social intelligence and progress both as individuals and as communities. Dewey held that traditional ideas about knowledge, truth, and values, in which absolutes are assumed, are incompatible with a broadly Darwinian world view in which individuals and society are progressing. In consequence, he felt that these traditional ideas must be discarded or revised. Indeed, for pragmatists, everything people know and do depend on a historical context and is thus tentative rather than absolute.
Many followers and critics of Dewey believe he advocated elitism and social engineering in his philosophical stance. Others think of him as a kind of romantic humanist. Both tendencies are evident in Dewey’s writings, although he aspired to synthesize the two realms.
The pragmatist tradition was revitalized in the 1980s by American philosopher Richard Rorty, who has faced similar charges of elitism for his belief in the relativism of values and his emphasis on the role of the individual in attaining knowledge. Interest has renewed in the classic pragmatists—Pierce, James, and Dewey - as an alternative to Rorty’s interpretation of the tradition.
In an ever changing world, pragmatism has many benefits. It defends social experimentation as a means of improving society, accepts pluralism, and rejects dead dogmas. But a philosophy that offers no final answers or absolutes and that appears vague as a result of trying to harmonize opposites may also be unsatisfactory to some.
Even do, that, Linguistics, is the scientific study of language. It encompasses the description of languages, the study of their origin, and the analysis of how children acquire language and how people learn languages other than their own. Linguistics is also concerned with relationships between languages and with the ways languages change over time. Linguists may study language as a thought process and seek a theory that accounts for the universal human capacity to produce and understand language. Some linguists examine language within a cultural context. By observing talk, they try to determine what a person needs to know in order to speak appropriately in different settings, such as the workplace, among friends, or among family. Other linguists focus on what happens when speakers from different language and cultural backgrounds interact. Linguists may also concentrate on how to help people learn another language, using what they know about the learner’s first language and about the language being acquired.
Although there are many ways of studying language, most approaches belong to one of the two main branches of linguistics: descriptive linguistics and comparative linguistics.
Descriptive linguistics is the study and analysis of spoken language. The techniques of descriptive linguistics were devised by German American anthropologist Franz Boas and American linguist and anthropologist Edward Sapir in the early 1900s to record and analyze Native American languages. Descriptive linguistics begins with what a linguist hears native speakers say. By listening to native speakers, the linguist gathered a body of data and analyses it in order to identify distinctive sounds, called phonemes. Individual phonemes, such as /p/ and /b/, are established on the grounds that substitution of one for the other changes the meaning of a word. After identifying the entire inventory of sounds in a language, the linguist looks at how these sounds combine to create morphemes, or units of sound that carry meaning, such as the words push and bush. Morphemes may be individual words such as push; root words, such as berry in blueberry; or prefixes (pre- in preview) and suffixes (-ness in openness).
The linguist’s next step is to see how morphemes combine into sentences, obeying both the dictionary meaning of the morpheme and the grammatical rules of the sentence. In the sentence ‘She pushed the bush,’ the morpheme she, a pronoun, is the subject; push, a transitive verb, is the verb; the, a definite article, is the determiner; and bush, a noun, is the object. Knowing the function of the morphemes in the sentence enables the linguist to describe the grammar of the language. The scientific procedures of phonemics (finding phonemes), morphology (discovering morphemes), and syntax (describing the order of morphemes and their function) provide descriptive linguists with a way to write down grammars of languages never before written down or analyzed. In this way they can begin to study and understand these languages.
Comparative linguistics is the study and analysis, by means of written records, of the origins and relatedness of different languages. In 1786 Sir William Jones, a British scholar, asserted that Sanskrit, Greek, and Latin were related to one another and had descended from a common source. He based this assertion on observations of similarities in sounds and meanings among the three languages. For example, the Sanskrit word bhratar for ‘brother’ resembles the Latin word frater, the Greek word phrater, (and the English word brother).
Other scholars went on to compare Icelandic with Scandinavian languages, and Germanic languages with Sanskrit, Greek, and Latin. The correspondences among languages, known as genetic relationships, came to be represented on what comparative linguists refer to as family trees. Family trees established by comparative linguists include the Indo-European, relating Sanskrit, Greek, Latin, German, English, and other Asian and European languages; the Algonquian, relating Fox, Cree, Menomini, Ojibwa, and other Native North American languages; and the Bantu, relating Swahili, Xhosa, Zulu, Kikuyu, and other African languages.
Comparative linguists also look for similarities in the way words are formed in different languages. Latin and English, for example, change the form of a word to express different meanings, as when the English verb go changes to go and gone to express a past action. Chinese, on the other hand, has no such inflected forms; the verb remains the same while other words indicate the time (as in ‘go store tomorrow’). In Swahili, prefixes, suffixes, and infixes (additions in the body of the word) combine with a root word to change its meaning. For example, a single word might express when something was done, by whom, to whom, and in what manner.
Some comparative linguists reconstruct hypothetical ancestral languages known as proto-languages, which they use to demonstrate relatedness among contemporary languages. A proto-language is not intended to depict a real language, however, and does not represent the speech of ancestors of people speaking modern languages. Unfortunately, some groups have mistakenly used such reconstructions in efforts to demonstrate the ancestral homeland of a people.
Comparative linguists have suggested that certain basic words in a language do not change over time, because people are reluctant to introduce new words for such constants as arm, eye, or mother. These words are termed culture free. By comparing lists of culture-free words in languages within a family, linguists can derive the percentage of related words and use a formula to figure out when the languages separated from one another.
By the 1960s comparativists were no longer satisfied with focusing on origins, migrations, and the family tree method. They challenged as unrealistic the notion that an earlier language could remain sufficiently isolated for other languages to be derived exclusively from it over a period of time. Today comparativists seek to understand the more complicated reality of language history, taking language contact into account. They are concerned with universal characteristics of language and with comparisons of grammars and structures.
The field of linguistics both borrows from and lends its own theories and methods to other disciplines. The many subfields of linguistics have expanded our understanding of languages. Linguistic theories and methods are also used in other fields of study. These overlapping interests have led to the creation of several cross-disciplinary fields.
Sociolinguistics is the study of patterns and variations in language within a society or community. It focuses on the way people use language to express social class, group status, gender, or ethnicity, and it looks at how they make choices about the form of language they use. It also examines the way people use language to negotiate their role in society and to achieve positions of power. For example, sociolinguistic studies have found that the way a New Yorker pronounces the phoneme /r/ in an expression such as ‘fourth floor’ can indicate the person’s social class. According to one study, people aspiring to move from the lower middle class to the upper middle class attach prestige to pronouncing the /r/. Sometimes they even overcorrect their speech, pronouncing an /r/ where those whom they wish to copy may not.
Some sociolinguists believe that analyzing such variables as the use of a particular phoneme can predict the direction of language change. Change, they say, moves toward the variable associated with power, prestige, or other quality having high social value. Other sociolinguists focus on what happens when speakers of different languages interact. This approach to language change emphasizes the way languages mix rather than the direction of change within a community. The goal of sociolinguistics is to understand communicative competence—what people need to know to use the appropriate language for a given social setting.
Psycholinguistics merges the fields of psychology and linguistics to study how people process language and how language use is related to underlying mental processes. Studies of children’s language acquisition and of second-language acquisition are psycholinguistic in nature. Psycholinguists work to develop models for how language is processed and understood, using evidence from studies of what happens when these processes go awry. They also study language disorders such as aphasia (impairment of the ability to use or comprehend words) and dyslexia (impairment of the ability to make out written language).
Computational linguistics involves the use of computers to compile linguistic data, analyze languages, translate from one language to another, and develop and test models of language processing. Linguists use computers and large samples of actual language to analyze the relatedness and the structure of languages and to look for patterns and similarities. Computers also aid in stylistic studies, information retrieval, various forms of textual analysis, and the construction of dictionaries and concordances. Applying computers to language studies has resulted in machine translation systems and machines that recognize and produce speech and text. Such machines facilitate communication with humans, including those who are perceptually or linguistically impaired.
Applied linguistics employs linguistic theory and methods in teaching and in research on learning a second language. Linguists look at the errors people make as they learn another language and at their strategies for communicating in the new language at different degrees of competence. In seeking to understand what happens in the mind of the learner, applied linguists recognize that motivation, attitude, learning style, and personality affect how well a person learns another language.
Anthropological linguistics, also known as linguistic anthropology, uses linguistic approaches to analyze culture. Anthropological linguists examine the relationship between a culture and its language, but the way cultures and languages have changed over time, and how different cultures and languages are related to one another. For example, the present English use of family and given names arose in the late 13th and early 14th centuries when the laws concerning registration, tenure, and inheritance of property were changed.
Philosophical linguistics examines the philosophy of language. Philosophers of language search for the grammatical principles and tendencies that all human languages share. Among the concerns of linguistic philosophers is the range of possible word order combinations throughout the world. One finding is that 95 percent of the world’s languages use a subject-verb-object (SVO) order as English does (‘She pushed the bush’) Only 5 percent use a subject-object-verb (SOV) order or verb-subject-object (VSO) order.
Neurolinguistics is the study of how language is processed and represented in the brain. Neurolinguists seek to identify the parts of the brain involved with the production and understanding of language and to determine where the components of language (phonemes, morphemes, and structure or syntax) are stored. In doing so, they make use of techniques for analyzing the structure of the brain and the effects of brain damage on language.
Speculation about language goes back thousands of years. Ancient Greek philosophers speculated on the origins of language and the relationship between objects and their names. They also discussed the rules that govern language, or grammar, and by the 3rd century Bc they had begun grouping words into parts of speech and devising names for different forms of verbs and nouns.
In India religion provided the motivation for the study of language nearly 2500 years ago. Hindu priests noted that the language they spoke had changed since the compilation of their ancient sacred texts, the Vedas, starting about 1000 Bc. They believed that for certain religious ceremonies based upon the Vedas to succeed, they needed to reproduce the language of the Vedas precisely. Panini, an Indian grammarian who lived about 400 Bc, produced the earliest work describing the rules of Sanskrit, the ancient language of India.
The Romans used Greek grammars as models for their own, adding commentary on Latin style and usage. Statesman and orator Marcus Tullius Cicero wrote on rhetoric and style in the 1st century Bc. Later grammarians Aelius Donatus (4th century ad) and Priscian (6th century ad) produced detailed Latin grammars. Roman works served as textbooks and standards for the study of language for more than 1000 years.
It was not until the end of the 18th century that language was researched and studied in a scientific way. During the 17th and 18th centuries, modern languages, such as French and English, replaced Latin as the means of universal communication in the West. This occurrence, along with developments in printing, meant that many more texts became available. At about this time, the study of phonetics, or the sounds of a language, began. Such investigations led to comparisons of sounds in different languages; in the late 18th century the observation of correspondences among Sanskrit, Latin, and Greek gave birth to the field of Indo-European linguistics.
During the 19th century, European linguists focused on philology, or the historical analysis and comparison of languages. They studied written texts and looked for changes over time or for relationships between one language and another.
American linguist, writer, teacher, and political activist Noam Chomsky is considered the founder of transformational-generative linguistic analysis, which revolutionized the field of linguistics. This system of linguistics treats grammar as a theory of language—that is, Chomsky believes that in addition to the rules of grammar specific to individual languages, there are universal rules common to all languages that indicate that the ability to form and understand language is innate to all human beings. Chomsky also is well known for his political activism—he opposed United States involvement in Vietnam in the 1960s and 1970s and has written various books and articles and delivered many lectures in an attempt to educate and empower people on various political and social issues.
In the early 20th century, linguistics expanded to include the study of unwritten languages. In the United States linguists and anthropologists began to study the rapidly disappearing spoken languages of Native North Americans. Because many of these languages were unwritten, researchers could not use historical analysis in their studies. In their pioneering research on these languages, anthropologists Franz Boas and Edward Sapir developed the techniques of descriptive linguistics and theorized on the ways in which language shapes our perceptions of the world.
An important outgrowth of descriptive linguistics is a theory known as structuralism, which assumes that language is a system with a highly organized structure. Structuralism began with publication of the work of Swiss linguist Ferdinand de Saussure in Cours de linguistique générale (1916; Course in General Linguistics, 1959). This work, compiled by Saussure’s students after his death, is considered the foundation of the modern field of linguistics. Saussure made a distinction between actual speech, and spoken language, and the knowledge underlying speech that speakers share about what is grammatical. Speech, he said, represents instances of grammar, and the linguist’s task is to find the underlying rules of a particular language from examples found in speech. To the structuralist, grammar is a set of relationships that account for speech, rather than a set of instances of speech, as it is to the descriptivist.
Once linguists began to study language as a set of abstract rules that somehow account for speech, other scholars began to take an interest in the field. They drew analogies between language and other forms of human behaviour, based on the belief that a shared structure underlies many aspects of a culture. Anthropologists, for example, became interested in a structuralist approach to the interpretation of kinship systems and analysis of myth and religion. American linguist Leonard Bloomfield promoted structuralism in the United States.
Saussure’s ideas also influenced European linguistics, most notably in France and Czechoslovakia (now the Czech Republic). In 1926 Czech linguist Vilem Mathesius founded the Linguistic Circle of Prague, a group that expanded the focus of the field to include the context of language use. The Prague circle developed the field of phonology, or the study of sounds, and demonstrated that universal features of sounds in the languages of the world interrelate in a systematic way. Linguistic analysis, they said, should focus on the distinctiveness of sounds rather than on the ways they combine. Where descriptivists tried to locate and describe individual phonemes, such as /b/ and /p/, the Prague linguists stressed the features of these phonemes and their interrelationships in different languages. In English, for example, the voice distinguishes between the similar sounds of /b/ and /p/, but these are not distinct phonemes in a number of other languages. An Arabic speaker might pronounce the cities Pompei and Bombay the same way.
As linguistics developed in the 20th century, the notion became prevalent that language is more than speech—specifically, that it is an abstract system of interrelationships shared by members of a speech community. Structural linguistics led linguists to look at the rules and the patterns of behaviour shared by such communities. Whereas structural linguists saw the basis of language in the social structure, other linguists looked at language as a mental process.
The 1957 publication of Syntactic Structures by American linguist Noam Chomsky initiated what many view as a scientific revolution in linguistics. Chomsky sought a theory that would account for both linguistic structure and the creativity of language - the fact that we can create entirely original sentences and understand sentences never before uttered. He proposed that all people have an innate ability to acquire language. The task of the linguist, he claimed, is to describe this universal human ability, known as language competence, with a grammar from which the grammars of all languages could be derived. The linguist would develop this grammar by looking at the rules children use in hearing and speaking their first language. He termed the resulting model, or grammar, a transformational-generative grammar, referring to the transformations (or rules) that generate (or account for) language. Certain rules, Chomsky asserted, are shared by all languages and form part of a universal grammar, while others are language specific and associated with particular speech communities. Since the 1960s much of the development in the field of linguistics has been a reaction to or against Chomsky’s theories.
At the end of the 20th century, linguists used the term grammar primarily to refer to a subconscious linguistic system that enables people to produce and comprehend an unlimited number of utterances. Grammar thus accounts for our linguistic competence. Observations about the actual language we use, or language performance, are used to theorize about this invisible mechanism known as grammar.
The orientation toward the scientific study of language led by Chomsky has had an impact on nongenerative linguists as well. Comparative and historically oriented linguists are looking for the various ways linguistic universals show up in individual languages. Psycholinguists, interested in language acquisition, are investigating the notion that an ideal speaker-hearer is the origin of the acquisition process. Sociolinguists are examining the rules that underlie the choice of language variants, or codes, and allow for switching from one code to another. Some linguists are studying language performance - the way people use language - to see how it reveals a cognitive ability shared by all human beings. Others seek to understand animal communication within such a framework. What mental processes enable chimpanzees to make signs and communicate with one another and how do these processes differ from those of humans?
Semantics (Greek semantikos, ‘significant’), the study of the meaning of linguistic signs — that is, words, expressions, and sentences. Scholars of semantics try to answer such questions as ‘What is the meaning of (the word) X?’ They do this by studying what signs are, as well as how signs possess significance—that is, how they are intended by speakers, how they designate (make reference to things and ideas), and how they are interpreted by hearers. The goal of semantics is to match the meanings of signs - what they stand for - with the process of assigning those meanings.
Semantics is studied from philosophical (pure) and linguistic (descriptive and theoretical) approaches, plus an approach known as general semantics. Philosophers look at the behaviour that goes with the process of meaning. Linguists study the elements or features of meaning as they are related in a linguistic system. General semanticists concentrate on meaning as influencing what people think and do.
These semantic approaches also have broader application. Anthropologists, through descriptive semantics, study what people categorize as culturally important. Psychologists draw on theoretical semantic studies that attempt to describe the mental process of understanding and to identify how people acquire meaning (as well as sound and structure) in language. Animal behaviourists research how and what other species communicate. Exponents of general semantics examine the different values (or connotations) of signs that supposedly mean the same thing (such as ‘the victor at Jena’ and ‘the loser at Waterloo,’ both referring to Napoleon). Also in a general-semantics vein, literary critics have been influenced by studies differentiating literary language from ordinary language and describing how literary metaphors evoke feelings and attitudes.
In the late 19th century Michel Jules Alfred Breal, a French philologist, proposed a ‘science of significations’ that would investigate how sense is attached to expressions and other signs. In 1910 the British philosophers Alfred North Whitehead and Bertrand Russell published Principia Mathematica, which strongly influenced the Vienna Circle, a group of philosophers who developed the rigorous philosophical approach known as logical positivism.
German philosopher Rudolf Carnap attempted to introduce the methodology and precision of mathematics into the study of philosophy. This approach is now known as logical positivism or logical empiricism.
One of the leading figures of the Vienna Circle, the German philosopher Rudolf Carnap, made a major contribution to philosophical semantics by developing symbolic logic, a system for analyzing signs and what they designate. In logical positivism, meaning is a relationship between words and things, and its study is empirically based: Because language, ideally, is a direct reflection of reality, signs match things and facts. In symbolic logic, however, mathematical notation is used to state what signs designate and to do so more clearly and precisely than is possible in ordinary language. Symbolic logic is thus itself a language, specifically, a metalanguage (formal technical language) used to talk about an object language (the language that is the object of a given semantic study).
An object language has a speaker (for example, a French woman) using expressions (such as la plume rouge) to designate a meaning (in this case, to indicate a definite pen—plume—of the collour red—rouge). The full description of an object language in symbols is called the semiotic of that language. A language's semiotic has the following aspects: (1) a semantic aspect, in which signs (words, expressions, sentences) are given specific designations; (2) a pragmatic aspect, in which the contextual relations between speakers and signs are indicated; and (3) a syntactic aspect, in which formal relations among the elements within signs (for example, among the sounds in a sentence) are indicated.
An interpreted language in symbolic logic is an object language together with rules of meaning that link signs and designations. Each interpreted sign has a truth condition—a condition that must be met in order for the sign to be true. A sign's meaning is what the sign designates when its truth condition is satisfied. For example, the expression or sign ‘the moon is a sphere’ is understood by someone who knows English; however, although it is understood, it may or may not be true. The expression is true if the thing it is extended to—the moon—is in fact spherical. To determine the sign's truth value, one must look at the moon for oneself.
The symbolic logic of logical positivist philosophy thus represents an attempt to get at meaning by way of the empirical verifiability of signs—by whether the truth of the sign can be confirmed by observing something in the real world. This attempt at understanding meaning has been only moderately successful. The Austrian-British philosopher Ludwig Wittgenstein rejected it in favour of his ‘ordinary language’ philosophy, in which he asserted that thought is based on everyday language. Not all signs designate things in the world, he pointed out, nor can all signs be associated with truth values. In his approach to philosophical semantics, the rules of meaning are disclosed in how speech is used.
From ordinary-language philosophy has evolved the current theory of speech-act semantics. The British philosopher J. L. Austin claimed that, by speaking, a person performs an act, or does something (such as state, predict, or warn), and that meaning is found in what an expression does, in the act it performs. The American philosopher John R. Searle extended Austin's ideas, emphasizing the need to relate the functions of signs or expressions to their social context. Searle asserted that speech encompasses at least three kinds of acts: (1) locutionary acts, in which things are said with a certain sense or reference (as in ‘the moon is a sphere’); (2) illocutionary acts, in which such acts as promising or commanding are performed by means of speaking; and (3) perlocutionary acts, in which the speaker, by speaking, does something to someone else (for example, angers, consoles, or persuades someone). The speaker's intentions are conveyed by the illocutionary force that is given to the signs—that is, by the actions implicit in what is said. To be successfully meant, however, the signs must also be appropriate, sincere, consistent with the speaker's general beliefs and conduct, and recognizable as meaningful by the hearer.
What has developed in philosophical semantics, then, is a distinction between truth-based semantics and speech-act semantics. Some critics of speech-act theory believe that it deals primarily with meaning in communication (as opposed to meaning in language) and thus is part of the pragmatic aspect of a language's semiotic—that it relates to signs and to the knowledge of the world shared by speakers and hearers, rather than relating to signs and their designations (semantic aspect) or to formal relations among signs (syntactic aspect). These scholars hold that semantics should be restricted to assigning interpretations to signs alone—independent of a speaker and hearer.
Researchers in descriptive semantics examine what signs mean in particular languages. They aim, for instance, to identify what constitutes nouns or noun phrases and verbs or verb phrases. For some languages, such as English, this is done with subject-predicate analysis. For languages without clear-cut distinctions between nouns, verbs, and prepositions, it is possible to say what the signs mean by analyzing the structure of what are called propositions. In such an analysis, a sign is seen as an operator that combines with one or more arguments (also signs) - often nominal arguments (noun phrases)—or relates nominal arguments to other elements in the expression (such as prepositional phrases or adverbial phrases). For example, in the expression ‘Bill gives Mary the book,’‘gives’ is an operator that relates the arguments ‘Bill,’‘Mary,’ and ‘the book.’
Whether using subject-predicate analysis or propositional analysis, descriptive semanticists establish expression classes (classes of items that can substitute for one another within a sign) and classes of items within the conventional parts of speech (such as nouns and verbs). The resulting classes are thus defined in terms of syntax, and they also have semantic roles; that is, the items in these classes perform specific grammatical functions, and in so doing they establish meaning by predicating, referring, making distinctions among entities, relations, or actions. For example, ‘kiss’ belongs to an expression class with other items such as ‘hit’ and ‘see,’ as well as to the conventional part of speech ‘verb,’ in which it is part of a subclass of operators requiring two arguments (an actor and a receiver). In ‘Mary kissed John,’ the syntactic role of ‘kiss’ is to relate two nominal arguments (‘Mary’ and ‘John’), whereas its semantic role is to identify a type of action. Unfortunately for descriptive semantics, however, it is not always possible to find a one-to-one correlation of syntactic classes with semantic roles. For instance, ‘John’ has the same semantic role—to identify a person—in the following two sentences: ‘John is easy to please’ and ‘John is eager to please.’ The syntactic role of ‘John’ in the two sentences, however, is different: In the first, ‘John’ is the receiver of an action; in the second, ‘John’ is the actor.
Linguistic semantics is also used by anthropologists called ethnoscientists to conduct formal semantic analysis (componential analysis) to determine how expressed signs—usually single words as vocabulary items called lexemes—in a language are related to the perceptions and thoughts of the people who speak the language. Componential analysis tests the idea that linguistic categories influence or determine how people view the world; this idea is called the Whorf hypothesis after the American anthropological linguist Benjamin Lee Whorf, who proposed it. In componential analysis, lexemes that have a common range of meaning constitute a semantic domain. Such a domain is characterized by the distinctive semantic features (components) that differentiate individual lexemes in the domain from one another, and also by features shared by all the lexemes in the domain. Such componential analysis points out, for example, that in the domain ‘seat’ in English, the lexemes ‘chair,’‘sofa,’‘loveseat,’ and ‘bench’ can be distinguished from one another according to how many people are accommodated and whether a back support is included. At the same time all these lexemes share the common component, or feature, of meaning ‘something on which to sit.’
Linguists pursuing such componential analysis hope to identify a universal set of such semantic features, from which are drawn the different sets of features that characterize different languages. This idea of universal semantic features has been applied to the analysis of systems of myth and kinship in various cultures by the French anthropologist Claude Lévi-Strauss. He showed that people organize their societies and interpret their place in these societies in ways that, despite apparent differences, have remarkable underlying similarities.
Linguists concerned with theoretical semantics are looking for a general theory of meaning in language. To such linguists, known as transformational-generative grammarians, meaning is part of the linguistic knowledge or competence that all humans possess. A generative grammar as a model of linguistic competence has a phonological (sound-system), a syntactic, and a semantic component. The semantic component, as part of a generative theory of meaning, is envisioned as a system of rules that govern how interpretable signs are interpreted and determine that other signs (such as ‘Colourless green ideas sleep furiously’), although grammatical expressions, are meaningless—semantically blocked. The rules must also account for how a sentence such as ‘They passed the port at midnight’ can have at least two interpretations.
Generative semantics grew out of proposals to explain a speaker's ability to produce and understand new expressions where grammar or syntax fails. Its goal is to explain why and how, for example, a person understands at first hearing that the sentence ‘Colourless green ideas sleep furiously’ has no meaning, even though it follows the rules of English grammar; or how, in hearing a sentence with two possible interpretations (such as ‘They passed the port at midnight’), one decides which meaning applies.
In generative semantics, the idea developed that all information needed to semantically interpret a sign (usually a sentence) is contained in the sentence's underlying grammatical or syntactic deep structure. The deep structure of a sentence involves lexemes (understood as words or vocabulary items composed of bundles of semantic features selected from the proposed universal set of semantic features). On the sentence's surface (that is, when it is spoken) these lexemes will appear as nouns, verbs, adjectives, and other parts of speech—that is, as vocabulary items. When the sentence is formulated by the speaker, semantic roles (such as subject, object, predicate) are assigned to the lexemes; the listener hears the spoken sentence and interprets the semantic features that are meant.
Whether deep structure and semantic interpretation are distinct from one another is a matter of controversy. Most generative linguists agree, however, that a grammar should generate the set of semantically well-formed expressions that are possible in a given language, and that the grammar should associate a semantic interpretation with each expression.
Another subject of debate is whether semantic interpretation should be understood as syntactically based (that is, coming from a sentence's deep structure); or whether it should be seen as semantically based. According to Noam Chomsky, an American scholar who is particularly influential in this field, it is possible—in a syntactically based theory—for surface structure and deep structure jointly to determine the semantic interpretation of an expression.
The focus of general semantics is how people evaluate words and how that evaluation influences their behaviour. Begun by the Polish American linguist Alfred Korzybski and long associated with the American semanticist and politician S. I. Hayakawa, general semantics has been used in efforts to make people aware of dangers inherent in treating words as more than symbols. It has been extremely popular with writers who use language to influence people's ideas. In their work, these writers use general-semantics guidelines for avoiding loose generalizations, rigid attitudes, inappropriate finality, and imprecision. Some philosophers and linguists, however, have criticized general semantics as lacking scientific rigour, and the approach has declined in popularity.
Also, have to Artificial Intelligence (AI), a term that in its broadest sense would indicate the ability of an artifact to perform the same kinds of functions that characterize human thought. The possibility of developing some such artifact has intrigued human beings since ancient times. With the growth of modern science, the search for AI has taken two major directions: psychological and physiological research into the nature of human thought, and the technological development of increasingly sophisticated computing systems.
In the latter sense, the term AI has been applied to computer systems and programs capable of performing tasks more complex than straightforward programming, although still far from the realm of actual thought. The most important fields of research in this area are information processing, pattern recognition, game-playing computers, and applied fields such as medical diagnosis. Current research in information processing deals with programs that enable a computer to understand written or spoken information and to produce summaries, answer specific questions, or redistribute information to users interested in specific areas of this information. Essential to such programs is the ability of the system to generate grammatically correct sentences and to establish linkages between words, ideas, and associations with other ideas. Research has shown that whereas the logic of language structure—its syntax—submits to programming, the problem of meaning, or semantics, lies far deeper, in the direction of true AI.
In medicine, programs have been developed that analyze the disease symptoms, medical history, and laboratory test results of a patient, and then suggest a diagnosis to the physician. The diagnostic program is an example of so-called expert systems—programs designed to perform tasks in specialized areas as a human would. Expert systems take computers a step beyond straightforward programming, being based on a technique called rule-based inference, in which preestablished rule systems are used to process the data. Despite their sophistication, systems still do not approach the complexity of true intelligent thought.
Many scientists remain doubtful that true AI can ever be developed. The operation of the human mind is still little understood, and computer design may remain essentially incapable of analogously duplicating those unknown, complex processes. Various routes are being used in the effort to reach the goal of true AI. One approach is to apply the concept of parallel processing—interlinked and concurrent computer operations. Another is to create networks of experimental computer chips, called silicon neurons, that mimic data-processing functions of brain cells. Using analog technology, the transistors in these chips emulate nerve-cell membranes in order to operate at the speed of neurons.
The capturing of Mind, are the mental activities and memory of a person. The mind includes both conscious thoughts and unconscious activity such as dreaming. The human identity can be viewed as being made of mind and body. Many philosophies and religions also recognize another aspect of identity, the soul.
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
　
No simple, agreed-upon definition of consciousness exists. Attempted definitions tend to be tautological (for example, consciousness defined as awareness) or merely descriptive (for example, consciousness described as sensations, thoughts, or feelings). Despite this problem of definition, the subject of consciousness has had a remarkable history. At one time the primary subject matter of psychology, consciousness as an area of study suffered an almost total demise, later reemerging to become a topic of current interest.
French thinker René Descartes applied rigorous scientific methods of deduction to his exploration of philosophical questions. Descartes is probably best known for his pioneering work in philosophical skepticism. Author Tom Sorell examines the concepts behind Descartes’s work Meditationes de Prima Philosophia (1641; Meditations on First Philosophy), focusing on its unconventional use of logic and the reactions it aroused.
Most of the philosophical discussions of consciousness arose from the mind-body issues posed by the French philosopher and mathematician René Descartes in the 17th century. Descartes asked: Is the mind, or consciousness, independent of matter? Is consciousness extended (physical) or unextended (nonphysical)? Is consciousness determinative, or is it determined? English philosophers such as John Locke equated consciousness with physical sensations and the information they provide, whereas European philosophers such as Gottfried Wilhelm Leibniz and Immanuel Kant gave a more central and active role to consciousness.
The philosopher who most directly influenced subsequent exploration of the subject of consciousness was the 19th-century German educator Johann Friedrich Herbart, who wrote that ideas had quality and intensity and that they may inhibit or facilitate one another. Thus, ideas may pass from ‘states of reality’ (consciousness) to ‘states of tendency’ (unconsciousness), with the dividing line between the two states being described as the threshold of consciousness. This formulation of Herbart clearly presages the development, by the German psychologist and physiologist Gustav Theodor Fechner, of the psychophysical measurement of sensation thresholds, and the later development by Sigmund Freud of the concept of the unconscious.
The experimental analysis of consciousness dates from 1879, when the German psychologist Wilhelm Max Wundt started his research laboratory. For Wundt, the task of psychology was the study of the structure of consciousness, which extended well beyond sensations and included feelings, images, memory, attention, duration, and movement. Because early interest focused on the content and dynamics of consciousness, it is not surprising that the central methodology of such studies was introspection; that is, subjects reported on the mental contents of their own consciousness. This introspective approach was developed most fully by the American psychologist Edward Bradford Titchener at Cornell University. Setting his task as that of describing the structure of the mind, Titchener attempted to detail, from introspective self-reports, the dimensions of the elements of consciousness. For example, taste was ‘dimensionalized’ into four basic categories: sweet, sour, salt, and bitter. This approach was known as structuralism.
By the 1920s, however, a remarkable revolution had occurred in psychology that was to essentially remove considerations of consciousness from psychological research for some 50 years: Behaviourism captured the field of psychology. The main initiator of this movement was the American psychologist John Broadus Watson. In a 1913 article, Watson stated, ‘I believe that we can write a psychology and never use the terms consciousness, mental states, mind . . . imagery and the like.’ Psychologists then turned almost exclusively to behaviour, as described in terms of stimulus and response, and consciousness was totally bypassed as a subject. A survey of eight leading introductory psychology texts published between 1930 and the 1950s found no mention of the topic of consciousness in five texts, and in two it was treated as a historical curiosity.
Beginning in the late 1950s, however, interest in the subject of consciousness returned, specifically in those subjects and techniques relating to altered states of consciousness: sleep and dreams, meditation, biofeedback, hypnosis, and drug-induced states. Much of the surge in sleep and dream research was directly fuelled by a discovery relevant to the nature of consciousness. A physiological indicator of the dream state was found: At roughly 90-minute intervals, the eyes of sleepers were observed to move rapidly, and at the same time the sleepers' brain waves would show a pattern resembling the waking state. When people were awakened during these periods of rapid eye movement, they almost always reported dreams, whereas if awakened at other times they did not. This and other research clearly indicated that sleep, once considered a passive state, was instead an active state of consciousness.
During the 1960s, an increased search for ‘higher levels’ of consciousness through meditation resulted in a growing interest in the practices of Zen Buddhism and Yoga from Eastern cultures. A full flowering of this movement in the United States was seen in the development of training programs, such as Transcendental Meditation, that were self-directed procedures of physical relaxation and focused attention. Biofeedback techniques also were developed to bring body systems involving factors such as blood pressure or temperature under voluntary control by providing feedback from the body, so that subjects could learn to control their responses. For example, researchers found that persons could control their brain-wave patterns to some extent, particularly the so-called alpha rhythms generally associated with a relaxed, meditative state. This finding was especially relevant to those interested in consciousness and meditation, and a number of ‘alpha training’ programs emerged.
Another subject that led to increased interest in altered states of consciousness was hypnosis, which involves a transfer of conscious control from the subject to another person. Hypnotism has had a long and intricate history in medicine and folklore and has been intensively studied by psychologists. Much has become known about the hypnotic state, relative to individual suggestibility and personality traits; the subject has now largely been demythologized, and the limitations of the hypnotic state are fairly well known. Despite the increasing use of hypnosis, however, much remains to be learned about this unusual state of focused attention.
Finally, many people in the 1960s experimented with the psychoactive drugs known as hallucinogens, which produce disorders of consciousness. The most prominent of these drugs are lysergic acid diethylamide, or LSD; mescaline Peyote; and psilocybin; the latter two have long been associated with religious ceremonies in various cultures. LSD, because of its radical thought-modifying properties, was initially explored for its so-called mind-expanding potential and for its psychotomimetic effects (imitating psychoses). Little positive use, however, has been found for these drugs, and their use is highly restricted.
Scientists have long since considered the nature of consciousness without producing a fully satisfactory definition. In the early 20th century American philosopher and psychologist William James suggested that consciousness is a mental process involving both attention to external stimuli and short-term memory. Later scientific explorations of consciousness mostly expanded upon James’s work. In this article from a 1997 special issue of Scientific American, Nobel laureate Francis Crick, who helped determine the structure of DNA, and fellow biophysicist Christof Koch explain how experiments on vision might deepen our understanding of consciousness.
As the concept of a direct, simple linkage between environment and behaviour became unsatisfactory in recent decades, the interest in altered states of consciousness may be taken as a visible sign of renewed interest in the topic of consciousness. That persons are active and intervening participants in their behaviour has become increasingly clear. Environments, rewards, and punishments are not simply defined by their physical character. Memories are organized, not simply stored in the Memory. An entirely new area called cognitive psychology has emerged that centres on these concerns. In the study of children, increased attention is being paid to how they understand, or perceive, the world at different ages. In the field of animal behaviour, researchers increasingly emphasize the inherent characteristics resulting from the way a species has been shaped to respond adaptively to the environment. Humanistic psychologists, with a concern for self-actualization and growth, have emerged after a long period of silence. Throughout the development of clinical and industrial psychology, the conscious states of persons in terms of their current feelings and thoughts were of obvious importance. The role of consciousness, however, was often de-emphasised in favour of unconscious needs and motivations. Trends can be seen, however, toward a new emphasis on the nature of states of consciousness.
There is to be said that Dreaming, our form of mental activity, different from waking thought, that occurs during sleep. The nature of dream activity has been characterized by many clinical and laboratory studies. These studies show that dreams are more perceptual than conceptual: Things are seen and heard rather than thought. In terms of the senses, visual experience is present in almost all dreams; auditory experience in 40 to 50 percent; and touch, taste, smell, and pain in a relatively small percentage. A considerable amount of emotion is commonly present—usually a single, stark emotion such as fear, anger, or joy rather than the modulated emotions that occur in the waking state. Most dreams are in the form of interrupted stories, made up partly of memories, with frequent shifts of scene.
This broad characterization includes a great variety of dream experiences. Many dreams collected in sleep laboratories are rather ordinary, but most people have at least some bizarre dreams. At the start of the 20th century Sigmund Freud proposed that a mental process quite different from that used in the waking state dominates the dreaming mind. He described this ‘primary process’ as characterized by more primitive mechanisms, by rapid shifts in energy and emotions, and by a good deal of sexual and aggressive content derived from childhood.
From the pharaohs of ancient Egypt to the 20th century Austrian psychoanalyst Sigmund Freud, human beings have tried to decipher the meaning of dreams. In the early 1980s two prominent scientists proposed that dreams are essentially meaningless and represent the brain’s method of forgetting useless information. In a 1997 Scientific American article, however, researcher Jonathan Winson suggests that dreams may play a key part in the development of memories and in the formation of survival strategies.
Research in recent years has clarified many of these aspects of dreaming, but what may be of greatest significance has been the discovery of a biology of dreaming. Starting with the work of American sleep researchers Eugene Aserinsky and Nathaniel Kleitman in 1953, studies have shown that a dream does not consist of fleeting imagery that occurs while a person awakens from sleep, but instead a dream takes place during a biological state of its own.
Thus, two clearly distinguishable states of sleep exist. The first state, called S-synchronized sleep, or NREM-sleep (non-rapid-eye-movement sleep), occupies most of the sleep period and is associated with a relatively low pulse and blood pressure, little activation of the autonomic nervous system, and few or no reports of dreaming. The second type of sleep, known as D-sleep (dreaming, or desynchronized, sleep), or REM-sleep (rapid-eye-movement sleep), occurs cyclically during the sleep period and is characterized by activation of the autonomic nervous system, rapid eye movements, and frequent dream reports. Typically, a person has four or five periods of D-sleep during the night, whether the dreams are remembered often, rarely, or not at all; they occur at intervals of about 90 minutes and altogether constitute about 25 percent of the night’s sleep (as much as 50 percent in a newborn child). Evidence indicates that a dream period usually lasts from 5 to 20 minutes.
Such stimuli as sounds and touches impinging on a dreamer can be incorporated into a dream if they occur during a D-period. These stimuli, however, do not initiate a D-period if one is not already in progress, so that, at least in such cases, dreams do not protect sleep in the way that Freud suggested. Although mental activity may be reported during NREM-sleep, these are usually short, fragmented, thought like experiences.
　
It is likely that other animals dream. Mammals, including dogs, cats, and monkeys, have D-sleep periods like those of humans. During D-sleep they also show intense activity in a region of the brain called the visual cortex. In humans this brain activity corresponds to visual sensations. One study observed monkeys that were trained to push a lever whenever they saw a picture on a screen. At different times during their sleep the monkeys suddenly began to push the lever as if responding to an observed image.
Ancient cultures believed that dreams were spiritual in origin, often foretelling the future. Aristotle believed that dreams originated from within the dreamer, arising from the heart. Modern dream research has focused on two general interpretations of dream content. In one view, dreams have no inherent meaning but are simply a process by which the brain integrates new information into memories. In the other view, dreams contain real meaning symbolized in a picture language that is distinct from conscious logical thought.
The recounting of dreams has been used widely as part of clinical treatment. If dreams express important wishes, fears, concerns, and worries of the dreamer, the study and analysis of dreams can help reveal previously unknown aspects of a person’s mental functioning.
The Collective Unconscious, in psychology, is a shared pool of memories, ideas, and modes of thought. According to Swiss psychiatrist Carl Jung, it comes from the life experience of one's ancestors and from the entire human race. The collective unconscious coexists with the personal unconscious, which contains the material of individual experience, and may be regarded as an immense depository of ancient wisdom.
Primal experiences are represented in the collective unconscious by archetypes, symbolic pictures, or personifications that appear in dreams and are the common elements in myths, fairy tales, and religious literature. Examples include the serpent, the sphinx, the Great Mother, the anima (representing the nature of woman), and the mandala (representing balanced wholeness, human or divine
Unconscious or unconsciousness, in psychology, hypothetical region of the mind containing wishes, memories, fears, feelings, and ideas that are prevented from expression in conscious awareness. They manifest themselves, instead, by their influence on conscious processes and, most strikingly, by such anomalous phenomena as dreams and neurotic symptoms. Not all mental activity of which the subject is unaware belongs to the unconscious; for example, thoughts that may be made conscious by a new focusing of attention are termed fore conscious or preconscious.
The concept of the unconscious was first developed in the period from 1895 to 1900 by Sigmund Freud, who theorized that it consists of survivals of feelings experienced during infantile life, including both instinctual drives or libido and their modifications by the development of the superego. According to the Swiss psychoanalyst Carl Jung, the unconscious also consists of a racial unconscious that contains certain inherited, universal, archaic fantasies belonging to what Jung termed the collective unconscious.
Epistemology is concerned with the definition of knowledge and related concepts, the sources and criteria of knowledge, the kinds of knowledge possible and the degree to which each is certain, and the exact relation between the one who knows and the object known.
Thirteenth-century Italian philosopher and theologian Saint Thomas Aquinas attempted to synthesize Christian belief with a broad range of human knowledge, embracing diverse sources such as Greek philosopher Aristotle and Islamic and Jewish scholars. His thought exerted lasting influence on the development of Christian theology and Western philosophy. Author Anthony Kenny examines the complexities of Aquinas’s concepts of substance and accident.
In the 5th century Bc, the Greek Sophists questioned the possibility of reliable and objective knowledge. Thus, a leading Sophist, Gorgias, argued that nothing really exists, that if anything did exist it could not be known, and that if knowledge were possible, it could not be communicated. Another prominent Sophist, Protagoras, maintained that no person's opinions can be said to be more correct than another's, because each is the sole judge of his or her own experience. Plato, following his illustrious teacher Socrates, tried to answer the Sophists by postulating the existence of a world of unchanging and invisible forms, or ideas, about which it is possible to have exact and certain knowledge. The things one sees and touches, they maintained, are imperfect copies of the pure forms studied in mathematics and philosophy. Accordingly, only the abstract reasoning of these disciplines yields genuine knowledge, whereas reliance on sense perception produces vague and inconsistent opinions. They concluded that philosophical contemplation of the unseen world of forms is the highest goal of human life.
Aristotle followed Plato in regarding abstract knowledge as superior to any other, but disagreed with him as to the proper method of achieving it. Aristotle maintained that almost all knowledge is derived from experience. Knowledge is gained either directly, by abstracting the defining traits of a species, or indirectly, by deducing new facts from those already known, in accordance with the rules of logic. Careful observation and strict adherence to the rules of logic, which were first set down in systematic form by Aristotle, would help guard against the pitfalls the Sophists had exposed. The Stoic and Epicurean schools agreed with Aristotle that knowledge originates in sense perception, but against both Aristotle and Plato they maintained that philosophy is to be valued as a practical guide to life, rather than as an end in itself.
After many centuries of declining interest in rational and scientific knowledge, the Scholastic philosopher Saint Thomas Aquinas and other philosophers of the Middle Ages helped to restore confidence in reason and experience, blending rational methods with faith into a unified system of beliefs. Aquinas followed Aristotle in regarding perception as the starting point and logic as the intellectual procedure for arriving at reliable knowledge of nature, but he considered faith in scriptural authority as the main source of religious belief.
The 17th century French scientist and mathematician René Descartes was also one of the most influential thinkers in Western philosophy. Descartes stressed the importance of skepticism in thought and proposed the idea that existence had a dual nature: one physical, the other mental. The latter concept, known as Cartesian dualism, continues to engage philosophers today. This passage from Discourse on Method (first published in his Philosophical Essays in 1637) contains a summary of his thesis, which includes the celebrated phrase ‘I think, therefore I am.’
From the 17th to the late 19th century, the main issue in epistemology was reasoning versus sense perception in acquiring knowledge. For the rationalists, of whom the French philosopher René Descartes, the Dutch philosopher Baruch Spinoza, and the German philosopher Gottfried Wilhelm Leibniz were the leaders, the main source and final test of knowledge was deductive reasoning based on self-evident principles, or axioms. For the empiricists, beginning with the English philosophers Francis Bacon and John Locke, the main source and final test of knowledge was sense perception.
French thinker René Descartes applied rigorous scientific methods of deduction to his exploration of philosophical questions. Descartes is probably best known for his pioneering work in philosophical skepticism. Author Tom Sorell examines the concepts behind Descartes’s work Meditationes de Prima Philosophia (1641; Meditations on First Philosophy), focusing on its unconventional use of logic and the reactions it aroused.
Bacon inaugurated the new era of modern science by criticizing the medieval reliance on tradition and authority and also by setting down new rules of scientific method, including the first set of rules of inductive logic ever formulated. Locke attacked the rationalist belief that the principles of knowledge are intuitively self-evident, arguing that all knowledge is derived from experience, either from experience of the external world, which stamps sensations on the mind, or from internal experience, in which the mind reflects on its own activities. Human knowledge of external physical objects, he claimed, is always subject to the errors of the senses, and he concluded that one cannot have absolutely certain knowledge of the physical world.
Irish-born philosopher and clergyman George Berkeley (1685-1753) argued that everything that human beings conceive of exists as an idea in a mind, a philosophical focus which is known as idealism. Berkeley reasoned that because one cannot control one’s thoughts, they must come directly from a larger mind: that of God. In this excerpt from his Treatise Concerning the Principles of Human Knowledge, written in 1710, Berkeley explained why he believed that it is ‘impossible … that there should be any such thing as an outward object.’
The Irish philosopher George Berkeley agreed with Locke that knowledge comes through ideas, but he denied Locke's belief that a distinction can be made between ideas and objects. The British philosopher David Hume continued the empiricist tradition, but he did not accept Berkeley's conclusion that knowledge was of ideas only. He divided all knowledge into two kinds: knowledge of relations of ideas—that is, the knowledge found in mathematics and logic, which is exact and certain but provides no information about the world; and knowledge of matters of fact—that is, the knowledge derived from sense perception. Hume argued that most knowledge of matters of fact depends upon cause and effect, and since no logical connection exists between any given cause and its effect, one cannot hope to know any future matter of fact with certainty. Thus, the most reliable laws of science might not remain true—a conclusion that had a revolutionary impact on philosophy.
Irish philosopher and clergyman George Berkeley set out to challenge what he saw as the atheism and skepticism inherent in the prevailing philosophy of the early 18th century. His initial publications, which asserted that no objects or matter existed outside the human mind, were met with disdain by the London intelligentsia of the day. Berkeley aimed to explain his ‘Immaterialism’ theory, part of the school of thought known as idealism, to a more general audience in Three Dialogues between Hylas and Philonous (1713). This passage is from the close of the third dialogue.
The German philosopher Immanuel Kant tried to solve the crisis precipitated by Locke and brought to a climax by Hume; his proposed solution combined elements of rationalism with elements of empiricism. He agreed with the rationalists that one can have exact and certain knowledge, but he followed the empiricists in holding that such knowledge is more informative about the structure of thought than about the world outside of thought. He distinguished three kinds of knowledge: analytical a priori, which is exact and certain but uninformative, because it makes clear only what is contained in definitions; synthetic a posteriori, which conveys information about the world learned from experience, but is subject to the errors of the senses; and synthetic a priori, which is discovered by pure intuition and is both exact and certain, for it expresses the necessary conditions that the mind imposes on all objects of experience. Mathematics and philosophy, according to Kant, provide this last. Since the time of Kant, one of the most frequently argued questions in philosophy has been whether or not such a thing as synthetic a priori knowledge really exists.
During the 19th century, the German philosopher Georg Wilhelm Friedrich Hegel revived the rationalist claim that absolutely certain knowledge of reality can be obtained by equating the processes of thought, of nature, and of history. Hegel inspired an interest in history and a historical approach to knowledge that was further emphasized by Herbert Spencer in Britain and by the German school of historicism. Spencer and the French philosopher Auguste Comte brought attention to the importance of sociology as a branch of knowledge, and both extended the principles of empiricism to the study of society.
The American school of pragmatism, founded by the philosophers Charles Sanders Peirce, William James, and John Dewey at the turn of this century, carried empiricism further by maintaining that knowledge is an instrument of action and that all beliefs should be judged by their usefulness as rules for predicting experiences.
In the early 20th century, epistemological problems were discussed thoroughly, and subtle shades of difference grew into rival schools of thought. Special attention was given to the relation between the act of perceiving something, the object directly perceived, and the thing that can be said to be known as a result of the perception. The phenomenalists contended that the objects of knowledge are the same as the objects perceived. The neorealists argued that one has direct perceptions of physical objects or parts of physical objects, rather than of one's own mental states. The critical realists took a middle position, holding that although one perceives only sensory data such as colours and sounds, these stand for physical objects and provide knowledge thereof.
A method for dealing with the problem of clarifying the relation between the act of knowing and the object known was developed by the German philosopher Edmund Husserl. He outlined an elaborate procedure that he called phenomenology, by which one is said to be able to distinguish the way things appear to be from the way one thinks they really are, thus gaining a more precise understanding of the conceptual foundations of knowledge.
During the second quarter of the 20th century, two schools of thought emerged, each indebted to the Austrian philosopher Ludwig Wittgenstein. The first of these schools, logical empiricism, or logical positivism, had its origins in Vienna, Austria, but it soon spread to England and the United States. The logical empiricists insisted that there is only one kind of knowledge: scientific knowledge; that any valid knowledge claim must be verifiable in experience; and hence that much that had passed for philosophy was neither true nor false but literally meaningless. Finally, following Hume and Kant, a clear distinction must be maintained between analytic and synthetic statements. The so-called verifiability criterion of meaning has undergone changes as a result of discussions among the logical empiricists themselves, as well as their critics, but has not been discarded. More recently, the sharp distinction between the analytic and the synthetic has been attacked by a number of philosophers, chiefly by American philosopher W. V. O. Quine, whose overall approach is in the pragmatic tradition.
The latter of these recent schools of thought, generally referred to as linguistic analysis, or ordinary language philosophy, seems to break with traditional epistemology. The linguistic analysts undertake to examine the actual way key epistemological terms are used—terms such as knowledge, perception, and probability—and to formulate definitive rules for their use in order to avoid verbal confusion. British philosopher John Langshaw Austin argued, for example, that to say a statement was true added nothing to the statement except a promise by the speaker or writer. Austin does not consider truth a quality or property attaching to statements or utterances.
Learning, is an acquiring of knowledge or developing the ability to perform new behaviours. It is common to think of learning as something that takes place in school, but much of human learning occurs outside the classroom, and people continue to learn throughout their lives.
Even before they enter school, young children learn to walk, to talk, and to use their hands to manipulate toys, food, and other objects. They use all of their senses to learn about the sights, sounds, tastes, and smells in their environments. They learn how to interact with their parents, siblings, friends, and other people important to their world. When they enter school, children learn basic academic subjects such as reading, writing, and mathematics. They also continue to learn a great deal outside the classroom. They learn which behaviours are likely to be rewarded and which are likely to be punished. They learn social skills for interacting with other children. After they finish school, people must learn to adapt to the many major changes that affect their lives, such as getting married, raising children, and finding and keeping a job.
Because learning continues throughout our lives and affects almost everything we do, the study of learning is important in many different fields. Teachers need to understand the best ways to educate children. Psychologists, social workers, criminologists, and other human-service workers need to understand how certain experiences change people’s behaviours. Employers, politicians, and advertisers make use of the principles of learning to influence the behaviour of workers, voters, and consumers.
Learning is closely related to memory, which is the storage of information in the brain. Psychologists who study memory are interested in how the brain stores knowledge, where this storage takes place, and how the brain later retrieves knowledge when we need it. In contrast, psychologists who study learning are more interested in behaviour and how behaviour changes as a result of a person’s experiences.
There are many forms of learning, ranging from simple to complex. Simple forms of learning involve a single stimulus. A stimulus is anything perceptible to the senses, such as a sight, sound, smell, touch, or taste. In a form of learning known as classical conditioning, people learn to associate two stimuli that occur in sequence, such as lightning followed by thunder. In operant conditioning, people learn by forming an association between a behaviour and its consequences (reward or punishment). People and animals can also learn by observation—that is, by watching others perform behaviours. More complex forms of learning include learning languages, concepts, and motor skills.
Habituation, one of the simplest types of learning, is the tendency to become familiar with a stimulus after repeated exposure to it. A common example of habituation occurs in the orienting response, in which a person’s attention is captured by a loud or sudden stimulus. For example, a person who moves to a house on a busy street may initially be distracted (an orienting response) every time a loud vehicle drives by. After living in the house for some time, however, the person will no longer be distracted by the street noise - the person becomes habituated to it and the orienting response disappears.
Despite its simplicity, habituation is a very useful type of learning. Because our environments are full of sights and sounds, we would waste a tremendous amount of time and energy if we paid attention to every stimulus each time we encountered it. Habituation allows us to ignore repetitive, unimportant stimuli. Habituation occurs in nearly all organisms, from human beings to animals with very simple nervous systems. Even some one-celled organisms will habituate to a light, sound, or chemical stimulus that is presented repeatedly.
Sensitization, another simple form of learning, is the increase that occurs in an organism’s responsiveness to stimuli following an especially intense or irritating stimulus. For example, a sea snail that receives a strong electric shock will afterward withdraw its gill more strongly than usual in response to a simple touch. Depending on the intensity and duration of the original stimulus, the period of increased responsiveness can last from several seconds to several days.
Classical conditioning is a type of learning in which an animal’s natural response to one object or sensory stimulus transfers to another stimulus. This illustration shows how a dog can learn to salivate to the sound of a tuning fork, and an experiment first carried out in the early 1900s by Russian physiologist Ivan Pavlov. For conditioning to occur, the pairing of the food with the tuning fork (step 3 in the illustration) must be repeated many times, so that the dog eventually learns to associate the two items.
Another form of learning is classical conditioning, in which a reflexive or automatic response transfers from one stimulus to another. For instance, a person who has had painful experiences at the dentist’s office may become fearful at just the sight of the dentist’s office building. Fear, a natural response to a painful stimulus, has transferred to a different stimulus, the sight of a building. Most psychologists believe that classical conditioning occurs when a person forms a mental association between two stimuli, so that encountering one stimulus makes the person think of the other. People tend to form these mental associations between events and stimuli that occur closely together in space or time.
Russian physiologist Ivan Pavlov discovered a major type of learning, classical conditioning, by accident while conducting experiments on digestion in the early 1900s. He devoted the rest of his life to discovering the underlying principles of classical conditioning.
Classical conditioning was discovered by accident in the early 1900's by Russian physiologist Ivan Pavlov. Pavlov was studying how saliva aids the digestive process. He would give a dog some food and measure the amount of saliva the dog produced while it ate the meal. After the dog had gone through this procedure a few times, however, it would begin to salivate before receiving any food. Pavlov reasoned that some new stimulus, such as the experimenter in his white coat, had become associated with the food and produced the response of salivation in the dog. Pavlov spent the rest of his life studying this basic type of associative learning, which is now called classical conditioning or Pavlovian conditioning.
The conditioning process usually follows the same general procedure. Suppose a psychologist wants to condition a dog to salivate at the sound of a bell. Before conditioning, an unconditioned stimulus (food in the mouth) automatically produces an unconditioned response (salivation) in the dog. The term unconditioned indicates that there is an unlearned, or inborn, connection between the stimulus and the response. During conditioning, the experimenter rings a bell and then gives food to the dog. The bell is called the neutral stimulus because it does not initially produce any salivation response in the dog. As the experimenter repeats the bell-food association over and over again, however, the bell alone eventually causes the dog to salivate. The dog has learned to associate the bell with the food. The bell has become a conditioned stimulus, and the dog’s salivation to the sound of the bell is called a conditioned response.
Following his initial discovery, Pavlov spent more than three decades studying the processes underlying classical conditioning. He and his associates identified four main processes: acquisition, extinction, generalization, and discrimination.
The acquisition phase is the initial learning of the conditioned response—for example, the dog learning to salivate at the sound of the bell. Several factors can affect the speed of conditioning during the acquisition phase. The most important factors are the order and timing of the stimuli. Conditioning occurs most quickly when the conditioned stimulus (the bell) precedes the unconditioned stimulus (the food) by about half a second. Conditioning takes longer and the response is weaker when there is a long delay between the presentation of the conditioned stimulus and the unconditioned stimulus. If the conditioned stimulus follows the unconditioned stimulus—for example, if the dog receives the food before the bell is rung—conditioning seldom occurs.
Once learned, a conditioned response is not necessarily permanent. The term extinction is used to describe the elimination of the conditioned response by repeatedly presenting the conditioned stimulus without the unconditioned stimulus. If a dog has learned to salivate at the sound of a bell, an experimenter can gradually extinguish the dog’s response by repeatedly ringing the bell without presenting food afterward. Extinction does not mean, however, that the dog has simply unlearned or forgotten the association between the bell and the food. After extinction, if the experimenter lets a few hours pass and then rings the bell again, the dog will usually salivate at the sound of the bell once again. The reappearance of an extinguished response after some time has passed is called spontaneous recovery.
After an animal has learned a conditioned response to one stimulus, it may also respond to similar stimuli without further training. If a child is bitten by a large black dog, the child may fear not only that dog, but other large dogs. This phenomenon is called generalization. Less similar stimuli will usually produce less generalization. For example, the child may show little fear of smaller dogs.
The opposite of generalization is discrimination, in which an individual learns to produce a conditioned response to one stimulus but not to another stimulus that is similar. For example, a child may show a fear response to freely roaming dogs, but may show no fear when a dog is on a leash or confined to a pen.
After studying classical conditioning in dogs and other animals, psychologists became interested in how this type of learning might apply to human behaviour. In an infamous 1921 experiment, American psychologist John B. Watson and his research assistant Rosalie Rayner conditioned a baby named Albert to fear a small white rat by pairing the sight of the rat with a loud noise. Although their experiment was ethically questionable, it showed for the first time that humans can learn to fear seemingly unimportant stimuli when the stimuli are associated with unpleasant experiences. The experiment also suggested that classical conditioning accounts for some cases of phobias, which are irrational or excessive fears of specific objects or situations. Psychologists now know that classical conditioning explains many emotional responses—such as happiness, excitement, anger, and anxiety - that people have to specific stimuli. For example, a child who experiences excitement on a roller coaster may learn to feel excited just at the sight of a roller coaster. For an adult who finds a letter from a close friend in the mailbox, the mere sight of the return address on the envelope may elicit feelings of joy and warmth.
Psychologists use classical conditioning procedures to treat phobias and other unwanted behaviours, such as alcoholism and addictions. To treat phobias of specific objects, the therapist gradually and repeatedly presents the feared object to the patient while the patient relaxes. Through extinction, the patient loses his or her fear of the object. In one treatment for alcoholism, patients drink an alcoholic beverage and then ingest a drug that produces nausea. Eventually they feel nauseous at the sight or smell of alcohol and stop drinking it. The effectiveness of these therapies varies depending on the individual and on the problem behaviour.
Modern theories of classical conditioning depart from Pavlov’s theory in several ways. Whereas Pavlov’s theory stated that the conditioned and unconditioned stimuli should elicit the same type of response, modern theories acknowledge that the conditioned and unconditioned responses frequently differ. In some cases, especially when the unconditioned stimulus is a drug, the conditioned stimulus elicits the opposite response. Modern research has also shown that conditioning does not always require a close pairing of the two stimuli. In taste-aversion learning, people can develop disgust for a specific food if they become sick after eating it, even if the illness begins several hours after eating.
Psychologists today also recognize that classical conditioning does not automatically occur whenever two stimuli are repeatedly paired. For instance, suppose that an experimenter conditions a dog to salivate to a light by repeatedly pairing the light with food. Next, the experimenter repeatedly pairs both the light and a tone with food. When the experimenter presents the tone by itself, the dog will show little or no conditioned response (salivation), because the tone provides no new information. The light already allows the dog to predict that food will be coming. This phenomenon, discovered by American psychologist Leon Kamin in 1968, is called blocking because prior conditioning blocks new conditioning.
One of the most widespread and important types of learning is operant conditioning, which involves increasing a behaviour by following it with a reward, or decreasing a behaviour by following it with punishment. For example, if a mother starts giving a boy his favourite snack every day that he cleans up his room, before long the boy may spend some time each day cleaning his room in anticipation of the snack. In this example, the boy’s room-cleaning behaviour increases because it is followed by a reward or reinforcer.
Unlike classical conditioning, in which the conditioned and unconditioned stimuli are presented regardless of what the learner does, operant conditioning requires action on the part of the learner. The boy in the above example will not get his snack unless he first cleans up his room. The term operant conditioning refers to the fact that the learner must operate, or perform a certain behaviour, before receiving a reward or punishment.
In the late 19th century American psychologist Edward L. Thorndike conducted some of the first experiments on animal learning. Thorndike formulated the law of effect, which states that behaviours that are followed by pleasant consequences will be more likely to be repeated in the future.
Some of the earliest scientific research on operant conditioning was conducted by American psychologist Edward L. Thorndike at the end of the 19th century. Thorndike’s research subjects included cats, dogs, and chickens. To see how animals learn new behaviours, Thorndike used a small chamber that he called a puzzle box. He would place an animal in the puzzle box, and if it performed the correct response (such as pulling a rope, pressing a lever, or stepping on a platform), the door would swing open and the animal would be rewarded with some food located just outside the cage. The first time an animal entered the puzzle box, but it usually took a long time to make the response required to open the door. Eventually, however, it would make the appropriate response by accident and receive its reward: escape and food. As Thorndike placed the same animal in the puzzle box again and again, it would make the correct response more and more quickly. Soon it would take the animal just a few seconds to earn its reward.
Based on these experiments, Thorndike developed a principle he called the law of effect. This law states that behaviours that are followed by pleasant consequences will be strengthened, and will be more likely to occur in the future. Conversely, behaviours that are followed by unpleasant consequences will be weakened, and will be less likely to be repeated in the future. Thorndike’s law of effect is another way of describing what modern psychologists now call operant conditioning.
American psychologist B. F. Skinner designed an apparatus, now called a Skinner box, that allowed him to formulate important principles of animal learning. An animal placed inside the box is rewarded with a small bit of food each time it makes the desired response, such as pressing a lever or pecking a key. A device outside the box records the animal’s responses.
American psychologist B. F. Skinner became one of the most famous psychologists in history for his pioneering research on operant conditioning. In fact, he coined the term operant conditioning. Beginning in the 1930s, Skinner spent several decades studying the behaviour of animals—usually rats or pigeons—in chambers that became known as Skinner boxes. Like Thorndike’s puzzle box, the Skinner box was a barren chamber in which an animal could earn food by making simple responses, such as pressing a lever or a circular response key. A device attached to the box recorded the animal’s responses. The Skinner box differed from the puzzle box in three main ways: (1) upon making the desired response, the animal received food but did not escape from the chamber; (2) the box delivered only a small amount of food for each response, so that many reinforcers could be delivered in a single test session; and (3) the operant response required very little effort, so an animal could make hundreds or thousands of responses per hour. Because of these changes, Skinner could collect much more data, and he could observe how changing the pattern of food delivery affected the speed and pattern of an animal’s behaviour.
American psychologist B. F. Skinner became famous for his pioneering research on learning and behaviour. During his 60-year career, Skinner discovered important principles of operant conditioning, a type of learning that involves reinforcement and punishment. A strict behaviourist, Skinner believed that operant conditioning could explain even the most complex of human behaviours.
Skinner became famous not just for his research with animals, but also for his controversial claim that the principles of learning he discovered using the Skinner box also applied to the behaviour of people in everyday life. Skinner acknowledged that many factors influence human behaviour, including heredity, basic types of learning such as classical conditioning, and complex learned behaviours such as language. However, he maintained that rewards and punishments control the great majority of human behaviours, and that the principles of operant conditioning can explain these behaviours.
Operant conditioning, pioneered by American psychologist B. F. Skinner, is the process of shaping behaviour by means of reinforcement and punishment. This illustration shows how a mouse can learn to manoeuver through a maze. The mouse is rewarded with food when it reaches the first turn in the maze (A). Once the first behaviour becomes ingrained, the mouse is not rewarded until it makes the second turn (B). After many times through the maze, the mouse must reach the end of the maze to receive its reward ©.
In a career spanning more than 60 years, Skinner identified a number of basic principles of operant conditioning that explain how people learn new behaviours or change existing behaviours. The main principles are reinforcement, punishment, shaping, extinction, discrimination, and generalization.
In operant conditioning, reinforcement refers to any process that strengthens a particular behaviour—that is, increases the chances that the behaviour will occur again. There are two general categories of reinforcement, positive and negative. The experiments of Thorndike and Skinner illustrate positive reinforcement, a method of strengthening behaviour by following it with a pleasant stimulus. Positive reinforcement is a powerful method for controlling the behaviour of both animals and people. For people, positive reinforcers include basic items such as food, drink, sex, and physical comfort. Other positive reinforcers include material possessions, money, friendship, love, praise, attention, and success in one’s career.
Depending on the circumstances, positive reinforcement can strengthen either desirable or undesirable behaviours. Children may work hard at home or at school because of the praise they receive from parents and teachers for good performance. However, they may also disrupt a class, try dangerous stunts, or start smoking because these behaviours lead to attention and approval from their peers. One of the most common reinforcers of human behaviour is money. Most adults spend many hours each week working at their jobs because of the paychecks they receive in return. For certain individuals, money can also reinforce undesirable behaviours, such as burglary, selling illegal drugs, and cheating on one’s taxes.
Negative reinforcement is a method of strengthening a behaviour by following it with the removal or omission of an unpleasant stimulus. There are two types of negative reinforcement: escape and avoidance. In escape, performing a particular behaviour leads to the removal of an unpleasant stimulus. For example, if a person with a headache tries a new pain reliever and the headache quickly disappears, this person will probably use the medication again the next time a headache occurs. In avoidance, people perform a behaviour to avoid unpleasant consequences. For example, drivers may take side streets to avoid congested intersections, citizens may pay their taxes to avoid fines and penalties, and students may do their homework to avoid detention.
Gamblers at a casino in Atlantic City, New Jersey, try their luck at the slot machines. Because slot machines pay off on a variable-ratio schedule - that is, after an unpredictable number of tries—the gamblers drop in coins at a steady rate.
A reinforcement schedule is a rule that specifies the timing and frequency of reinforcers. In his early experiments on operant conditioning, Skinner rewarded animals with food every time they made the desired response—a schedule known as continuous reinforcement. Skinner soon tried rewarding only some instances of the desired response and not others—a schedule known as partial reinforcement. To his surprise, he found that animals showed entirely different behaviour patterns.
Skinner and other psychologists found that partial reinforcement schedules are often more effective at strengthening behaviour than continuous reinforcement schedules, for two reasons. First, they usually produce more responding, at a faster rate. Second, a behaviour learned through a partial reinforcement schedule has greater resistance to extinction—if the rewards for the behaviour are discontinued. The behaviour will persist for a longer period of time before stopping. One reason extinction is slower after partial reinforcement is that the learner has become accustomed to making responses without receiving a reinforcer each time. There are four main types of partial reinforcement schedules: fixed-ratio, variable-ratio, fixed-interval, and variable-interval. Each produces a distinctly different pattern of behaviour.
On a fixed-ratio schedule, individuals receive a reinforcer each time they make a fixed number of responses. For example, a factory worker may earn a certain amount of money for every 100 items assembled. This type of schedule usually produces a stop-and-go pattern of responding: The individual works steadily until receiving one reinforcer, then takes a break, then works steadily until receiving another reinforcer, and so on.
On a variable-ratio schedule, individuals must also make a number of responses before receiving a reinforcer, but the number is variable and unpredictable. Slot machines, roulette wheels, and other forms of gambling are examples of variable-ratio schedules. Behaviours reinforced on these schedules tend to occur at a rapid, steady rate, with few pauses. Thus, many people will drop coins into a slot machine over and over again on the chance of winning the jackpot, which serves as the reinforcer.
On a fixed-interval schedule, individuals receive reinforcement for their response only after a fixed amount of time elapses. For example, in a laboratory experiment with a fixed-interval one-minute schedule, at least one minute must elapse between the deliveries of the reinforcer. Any responses that occur before one minute has passed have no effect. On these schedules, animals usually do not respond at the beginning of the interval, but they respond faster and faster as the time for reinforcement approaches. Fixed-interval schedules rarely occur outside the laboratory, but one close approximation is the clock-watching behaviour of students during a class. Students watch the clock only occasionally at the start of a class period, but they watch more and more as the end of the period gets nearer.
Variable-interval schedules also require the passage of time before providing reinforcement, but the amount of time is variable and unpredictable. Behaviour on these schedules tends to be steady, but slower than on ratio schedules. For example, a person trying to call someone whose phone line is busy may redial every few minutes until the call gets through.
Whereas reinforcement strengthens behaviour, punishment weakens it, reducing the chances that the behaviour will occur again. As with reinforcement, there are two kinds of punishment, positive and negative. Positive punishment involves reducing a behaviour by delivering an unpleasant stimulus if the behaviour occurs. Parents use positive punishment when they spank, scold, or shout at children for bad behaviour. Societies use positive punishment when they fine or imprison people who break the law. Negative punishment, also called omission, involves reducing a behaviour by removing a pleasant stimulus if the behaviour occurs. Parents’ tactics of grounding teenagers or taking away various privileges because of bad behaviour are examples of negative punishment.
Considerable controversy exists about whether punishment is an effective way of reducing or eliminating unwanted behaviours. Careful laboratory experiments have shown that, when used properly, punishment can be a powerful and effective method for reducing behaviour. Nevertheless, it has several disadvantages. When people are severely punished, they may become angry, aggressive, or have other negative emotional reactions. They may try to hide the evidence of their misbehaviour or escape from the situation, as when a punished child runs away from home. In addition, punishment may eliminate desirable behaviours along with undesirable ones. For example, a child who is scolded for making an error in the classroom may not raise his or her hand again. For these and other reasons, many psychologists recommend that punishment be used to control behaviour only when there is no realistic alternative.
A killer whale jumps out of a pool at Marine World, a theme park in Vallejo, California. Through shaping, a type of operant conditioning, a trainer can teach killer whales and other animals behaviours they have never performed before. Shaping uses rewards to gradually guide an animal toward a desired behaviour. In this case, the desired behaviour is touching the ball above the water, and the reward for the killer whale is fish.
Shaping is a reinforcement technique that is used to teach animals or people behaviours that they have never performed before. In this method, the teacher begins by reinforcing a response the learner can perform easily, and then gradually requires more and more difficult responses. For example, to teach a rat to press a lever that is over its head, the trainer can first reward any upward head movement, then an upward movement of at least one inch, then two inches, and so on, until the rat reaches the lever. Psychologists have used shaping to teach children with severe mental retardation to speak by first rewarding any sounds they make, and then gradually requiring sounds that more and more closely resemble the words of the teacher. Animal trainers at circuses and theme parks use shaping to teach elephants to stand on one leg, tigers to balance on a ball, dogs to do backward flips, and killer whales and dolphins to jump through hoops.
As in classical conditioning, responses learned in operant conditioning are not always permanent. In operant conditioning, extinction is the elimination of a learned behaviour by discontinuing the reinforcer of that behaviour. If a rat has learned to press a lever because it receives food for doing so, its lever-pressing will decrease and eventually disappear if food is no longer delivered. With people, withholding the reinforcer may eliminate some unwanted behaviours. For instance, parents often reinforce temper tantrums in young children by giving them attention. If parents simply ignore the child’s tantrums rather than reward them with attention, the number of tantrums should gradually decrease.
Generalization and discrimination occur in operant conditioning in much the same way that they do in classical conditioning. In generalization, people perform a behaviour learned in one situation in other, similar situations. For example, a man who is rewarded with laughter when he tells certain jokes at a bar may tell the same jokes at restaurants, parties, or wedding receptions. Discrimination is learning that a behaviour will be reinforced in one situation but not in another. The man may learn that telling his jokes in church or at a serious business meeting will not make people laugh. Discriminative stimuli signal that a behaviour is likely to be reinforced. The man may learn to tell jokes only when he is at a loud, festive occasion (the discriminative stimulus). Learning when a behaviour will and will not be reinforced is an important part of operant conditioning.
Operant conditioning techniques have practical applications in many areas of human life. Parents who understand the basic principles of operant conditioning can reinforce their children’s appropriate behaviours and punish inappropriate ones, and they can use generalization and discrimination techniques to teach which behaviours are appropriate in particular situations. In the classroom, many teachers reinforce good academic performance with small rewards or privileges. Companies have used lotteries to improve attendance, productivity, and job safety among their employees.
Psychologists known as behaviour therapists use the learning principles of operant conditioning to treat children or adults with behaviour problems or psychological disorders. Behaviour therapists use shaping techniques to teach basic job skills to adults with mental retardation. Therapists use reinforcement techniques to teach self-care skills to people with severe mental illnesses, such as schizophrenia, and use punishment and extinction to reduce aggressive and antisocial behaviours by these individuals. Psychologists also use operant conditioning techniques to treat stuttering, sexual disorders, marital problems, drug addictions, impulsive spending, eating disorders, and many other behavioural problems.
People learn much of what they know simply by observing others. Here a child learns to use a lawnmower by observing his father’s behaviour and imitating it with a toy lawnmower.
Although classical and operant conditioning are important types of learning, people learn a large portion of what they know through observation. Learning by observation differs from classical and operant conditioning because it does not require direct personal experience with stimuli, reinforcers, or punishers. Learning by observation involves simply watching the behaviour of another person, called a model, and later imitating the model’s behaviour.
Both children and adults learn a great deal through observation and imitation. Young children learn language, social skills, habits, fears, and many other everyday behaviours by observing their parents and older children. Many people learn academic, athletic, and musical skills by observing and then imitating a teacher. According to Canadian-American psychologist Albert Bandura, a pioneer in the study of observational learning, this type of learning plays an important role in a child’s personality development. Bandura found evidence that children learn traits such as industriousness, honesty, self-control, aggressiveness, and impulsiveness in part by imitating parents, other family members, and friends.
Psychologists once thought that only human beings could learn by observation. They now know that many kinds of animals—including birds, cats, dogs, rodents, and primates—can learn by observing other members of their species. Young animals can learn food preferences, fears, and survival skills by observing their parents. Adult animals can learn new behaviours or solutions to simple problems by observing other animals.
In the early 1960s Bandura and other researchers conducted a classic set of experiments that demonstrated the power of observational learning. In one experiment, a preschool child worked on a drawing while a television set showed an adult behaving aggressively toward a large inflated Bobo doll (a clown doll that bounces back up when knocked down). The adult pummelled the doll with a mallet, kicked it, flung it in the air, sat on it, and beat it in the face, while yelling such remarks as ‘Sock him in the nose . . . Kick him . . . Pow!’ The child was then left in another room filled with interesting toys, including a Bobo doll. The experimenters observed the child through one-way glass. Compared with children who witnessed a nonviolent adult model and those not exposed to any model, children who witnessed the aggressive display were much more likely to show aggressive behaviours toward the Bobo doll, and they often imitated the model's exact behaviours and hostile words.
In a variant of the original experiment, Bandura and colleagues examined the effect of observed consequences on learning. They showed four-year-old children one of three films of an adult acting violently toward a Bobo doll. In one version of the film, the adult was praised for his or her aggressive behaviour and given soda and candies. In another version, the adult was scolded, spanked, and warned not to behave that way again. In a third version, the adult was neither rewarded nor punished. After viewing the film, each child was left alone in a room that contained a Bobo doll and other toys. Many children imitated the adult’s violent behaviours, but children who saw the adult punished imitated the behaviours less often than children who saw the other films. However, when the researchers promised the children a reward if they could copy the adult’s behaviour, all three groups of children showed large and equal amounts of violent behaviour toward the Bobo doll.
Bandura concluded that even those children who did not see the adult model receive a reward had learned through observation, but these children (especially those who saw the model being punished) would not display what they had learned until they expected a reward for doing so. The term latent learning describes cases in which an individual learns a new behaviour but does not perform this behaviour until there is the possibility of obtaining a reward.
According to Bandura’s influential theory of imitation, also called social learning theory, four factors are necessary for a person to learn through observation and then imitate a behaviour: attention, retention, reproduction, and motivation. First, the learner must pay attention to the crucial details of the model’s behaviour. A young girl watching her father bake a cake will not be able to imitate this behaviour successfully unless she pays attention to many important details—ingredients, quantities, oven temperature, baking time, and so on. The second factor is retention - the learner must be able to retain all of this information in memory until it is time to use it. If the person forgets important details, he or she will not be able to successfully imitate the behaviour. Third, the learner must have the physical skills and coordination needed for reproduction of the behaviour. The young girl must have enough strength and dexterity to mix the ingredients, pour the batter, and so on, in order to bake a cake on her own. Finally, the learner must have the motivation to imitate the model. That is, learners are more likely to imitate a behaviour if they expect it to lead to some type of reward or reinforcement. If learners expect that imitating the behaviour will not lead to reward or might lead to punishment, they are less likely to imitate the behaviour.
An alternative to Bandura’s theory is the theory of generalized imitation. This theory states that people will imitate the behaviours of others if the situation is similar to cases in which their imitation was reinforced in the past. For example, when a young child imitates the behaviour of a parent or an older sibling, this imitation is often reinforced with smiles, praise, or other forms of approval. Similarly, when children imitate the behaviours of friends, sports stars, or celebrities, this imitation may be reinforced—by the approval of their peers, if not their parents. Through the process of generalization, the child will start to imitate these models in other situations. Whereas Bandura’s theory emphasizes the imitator’s thought processes and motivation, the theory of generalized imitation relies on two basic principles of operant conditioning—reinforcement and generalization.
Many factors determine whether or not a person will imitate a model. As already shown, children are more likely to imitate a model when the model’s behaviour has been reinforced than when it has been punished. More important, however, are the expected consequences to the learner. A person will imitate a punished behaviour if he or she thinks that imitation will produce some type of reinforcement.
The characteristics of the model also influence the likelihood of imitation. Studies have shown that children are more likely to imitate adults who are pleasant and attentive to them than those who are not. In addition, children more often imitate adults who have substantial influence over their lives, such as parents and teachers, and those who seem admired and successful, such as celebrities and athletes. Both children and adults are more likely to imitate models who are similar to them in sex, age, and background. For this reason, when behaviour therapists use modelling to teach new behaviours or skills, they try to use models who are similar to the learners.
In modern society, television provides many powerful models for children and abundant opportunities for observational learning. Many parents are concerned about the behaviours their children can observe on TV. Many television programs include depictions of sex, violence, drug and alcohol use, and vulgar language—behaviours that most parents do not want their children to imitate. Studies have found that by early adolescence, the average American child has watched thousands of dramatized murders and countless other acts of violence on television.
For many years, psychologists have debated the question of whether watching violence on television has detrimental effects on children. A number of experiments, both inside and outside the laboratory, have found evidence that viewing television violence is related to increased aggression in children. Some psychologists have criticized this research, maintaining that the evidence is inconclusive. Most psychologists now believe, however, that watching violence on television can sometimes lead to increased aggressiveness in children.
The effects of television on children’s behaviours are not all negative. Educational programs such as ‘Sesame Street’ give children the opportunity to learn letters of the alphabet, words, numbers, and social skills. Such programs also show people who solve problems and resolve differences through cooperation and discussion rather than through aggression and hostility.
Although psychologists who study learning have focused the most attention on classical conditioning, operant conditioning, and observational learning, they have also studied other types of learning, including language learning, learning by listening and reading, concept formation, and the learning of motor skills. These types of learning still involve the principles of conditioning and observational learning, but they are worth considering separately because of their importance in everyday life.
Learning to speak and understand a language is one of the most complex types of learning, yet all normal children master this skill in the first few years of their lives. The familiar principles of shaping, reinforcement, generalization, discrimination, and observational learning all play a role in a child’s language learning. However, in the 1950s American linguist Noam Chomsky proposed that these basic principles of learning cannot explain how children learn to speak so well and so rapidly. Chomsky theorized that humans have a unique and inborn capacity to extract word meanings, sentence structure, and grammatical rules from the complex stream of sounds they hear. Although Chomsky’s theory is controversial, it has received some support from scientific evidence that specific parts of the human brain are essential for language. When these areas of the brain are damaged, a person loses the ability to speak or comprehend language.
Because people communicate through language, they can learn vast amounts of information by listening to others and by reading. Learning through the spoken or written word is similar to observational learning, because it allows people to learn not simply from their own experiences, but also from the experiences of others. For example, by listening to a parent or instructor, children can learn to avoid busy streets and to cross the street at crosswalks without first experiencing any positive or negative consequences. By listening to and observing others, children can learn skills such as tying a shoelace, swinging a baseball bat, or paddling a canoe. Listening to the teacher and reading are essential parts of most classroom learning.
Much of what we read and hear is quickly forgotten. Learning new information requires that we retain the information in memory and later be able to retrieve it. The process of forming long-term memories is complex, depending on the nature of the original information and on how much a person rehearses or reviews the information.
Concept formation occurs when people learn to classify different objects as members of a single category. For example, a child may know that a mouse, a dog, and a whale are all animals, despite their great differences in size and appearance. Concept formation is important because it helps us identify stimuli we have never encountered before. Thus, a child who sees an antelope for the first time will probably know that it is an animal. Even young children learn a large number of such concepts, including food, games, flowers, cars, and houses. Although language plays an important role in how people learn concepts, the ability to speak is not essential for concept formation. Experiments with birds and chimpanzees have shown that these animals can form concepts.
A motor skill is the ability to perform a coordinated set of physical movements. Examples of motor skills include handwriting, typing, playing a musical instrument, driving a car, and most sports skills. Learning a motor skill is usually a gradual process that requires practice and feedback. Learners need feedback from a teacher or coach to tell them which movements they are performing well and which need improvement. While learning a new motor skill, the learner should direct full attention to the task. Some motor skills, if learned well, can be performed automatically. For example, a skilled typist can type quickly and accurately without thinking about every keystroke.
Early in the 20th century, some psychologists believed that it might be possible to develop a single, general theory that could explain all instances of learning. For instance, the so-called one-factor theory proposed that reinforcement was the single factor that controlled whether learning would or would not occur. However, latent learning and similar phenomena contradicted this theory by showing that learning could occur without reinforcement.
In recent years, psychologists have abandoned attempts to develop a single, all-purpose theory of learning. Instead, they have developed smaller and more specialized theories. Some theories focus on classical conditioning, some on operant conditioning, some on observational learning, and some on other specific forms of learning. The major debates in learning theory concern which theories best describe these more specific areas of learning.
In studying learning, psychologists follow two main theoretical approaches: the behavioural approach and the cognitive approach. Recall that learning is acquiring knowledge or developing the ability to perform new behaviours. Behavioural psychologists focus on the change that takes place in an individual’s behaviour. Cognitive psychologists prefer to study the change in an individual’s knowledge, emphasizing mental processes such as thinking, memory, and problem solving. Many psychologists combine elements of both approaches to explain learning.
American psychologist John B. Watson believed psychologists should study observable behaviour instead of speculating about a person’s inner thoughts and feelings. Watson’s approach, which he termed behaviourism in the early 1910s, dominated psychology for the first half of the 20th century.
The term behaviourism was first used by John B. Watson in the early 1910s. Later, B. F. Skinner expanded and popularized the behavioural approach. The essential characteristic of the behavioural approach to learning is that events in the environment are understood to predict a person’s behaviour, not thoughts, feelings, or other events that take place inside the person. Strict behaviourists believe that it is dangerous and unscientific to treat thoughts and feelings as the causes of a person’s behaviour, because no one can see another person’s thoughts or feelings. Behaviourists maintain that human learning can be explained by examining the stimuli, reinforcers, and punishments that a person experiences. According to behaviourists, reinforcement and punishment, along with other basic principles such as generalization and discrimination, can explain even the most advanced types of human learning, such as learning to read or to solve complex problems.
Unlike behaviourists, cognitive psychologists believe that it is essential to study an individual’s thoughts and expectations in order to understand the learning process. In 1930 American psychologist Edward C. Tolman investigated cognitive processes in learning by studying how rats learn their way through a maze. He found evidence that rats formed a ‘cognitive map’ (a mental map) of the maze early in the experiment, but did not display their learning until they received reinforcement for completing the maze - a phenomenon he termed latent learning. Tolman’s experiment suggested that learning is more than just the strengthening of responses through reinforcement.
Modern cognitive psychologists believe that learning involves complex mental processes, including memory, attention, language, concept formation, and problem solving. They study how people process information and form mental representations of people, objects, and events.
During the first half of the 20th century, behaviourism was the dominant theoretical approach in the field of learning. Since the 1950s, however, cognitive psychology has steadily gained in popularity, and now more psychologists favour a cognitive approach than a strict behavioural approach. Cognitive psychologists and behaviourists will continue to debate the merits of their different positions, but in many ways these two approaches have different strengths that complement each other. With its emphasis on memory and complex thought processes, the cognitive approach appears well suited for investigating the most sophisticated types of human learning, such as reasoning, problem solving, and creativity. The behavioural approach, which emphasizes basic principles of conditioning, reinforcement, and punishment, can provide explanations of why people behave the way they do and how they choose between different possible courses of action.
A variety of factors determine an individual’s ability to learn and the speed of learning. Four important factors are the individual’s age, motivation, prior experience, and intelligence. In addition, certain developmental and learning disorders can impair a person’s ability to learn.
Animals and people of all ages are capable of the most common types of learning—habituation, classical conditioning, and operant conditioning. As children grow, they become capable of learning more and more sophisticated types of information. Swiss developmental psychologist Jean Piaget theorized that children go through four different stages of cognitive development. In the sensorimotor stage (from birth to about 2 years of age), infants use their senses to learn about their bodies and about objects in their immediate environments. In the preoperational stage (about 2 to 7 years of age), children can think about objects and events that are not present, but their thinking is primitive and self-centred, and they have difficulty seeing the world from another person’s point of view. In the concrete operational stage (about 7 to 11 years of age), children learn general rules about the physical world, such as the fact that the amount of water remains the same if it is poured between containers of different shapes. Finally, in the formal operational stage (ages 11 and up), children become capable of logical and abstract thinking.
Adults continue to learn new knowledge and skills throughout their lives. For example, most adults can successfully learn a foreign language, although children usually can achieve fluency more easily. If older adults remain healthy, their learning ability generally does not decline with age. Age-related illnesses that involve a deterioration of mental functioning, such as Alzheimer’s disease, can severely reduce a person’s ability to learn.
Learning is usually most efficient and rapid when the learner is motivated and attentive. Behavioural studies with both animals and people have shown that one effective way to maintain the learner’s motivation is to deliver strong and immediate reinforcers for correct responses. However, other research has indicated that very high levels of motivation are not ideal. Psychologists believe an intermediate level of motivation is best for many learning tasks. If a person’s level of motivation is too low, he or she may give up quickly. At the other extreme, a very high level of motivation may cause such stress and distraction that the learner cannot focus on the task.
How well a person learns a new task may depend heavily on the person’s previous experience with similar tasks. Just as a response can transfer from one stimulus to another through the process of generalization, people can learn new behaviours more quickly if the behaviours are similar to those they can already perform. This phenomenon is called positive transfer. Someone who has learned to drive one car, for example, will be able to drive other cars, even though the feel and handling of the cars will differ. In cases of negative transfer, however, a person’s prior experience can interfere with learning something new. For instance, after memorizing one shopping list, it may be more difficult to memorize a different shopping list.
Psychologists have long known that people differ individually in their level of intelligence, and thus in their ability to learn and understand. Scientists have engaged in heated debates about the definition and nature of intelligence. In the 1980s American psychologist Howard Gardner proposed that there are many different forms of intelligence, including linguistic, logical-mathematical, musical, and interpersonal intelligence. A person may easily learn skills in some categories but have difficulty learning in others. A variety of disorders can interfere with a person’s ability to learn new skills and behaviours. Learning and developmental disorders usually first appear in childhood and often persist into adulthood. Children with attention-deficit hyperactivity disorder (ADHD) may not be able to sit still long enough to focus on specific tasks. Children with autism typically have difficulty speaking, understanding language, and interacting with people. People with mental retardation, characterized primarily by very low intelligence, may have trouble mastering basic living tasks and academic skills. Children with learning or developmental disorders often receive special education tailored to their individual needs and abilities.
Wittgenstein’s philosophical life may be divided into two distinct phases: an early period, represented by the Tractatus, and a later period, represented by the Philosophical Investigations. Throughout most of his life, however, Wittgenstein consistently viewed philosophy as linguistic or conceptual analysis. In the Tractatus he argued that ‘philosophy aims at the logical clarification of thoughts.’ In the Philosophical Investigations, however, he maintained that ‘philosophy is a battle against the bewitchment of our intelligence by means of language.’
Language, Wittgenstein argued in the Tractatus, is composed of complex propositions that can be analyzed into less complex propositions until one arrives at simple or elementary propositions. Correspondingly, the world is composed of complex facts that can be analyzed into less complex facts until one arrives at simple, or atomic, facts. The world is the totality of these facts. According to Wittgenstein’s picture theory of meaning, it is the nature of elementary propositions logically to picture atomic facts, or ‘states of affairs.’ He claimed that the nature of language required elementary propositions, and his theory of meaning required that there be atomic facts pictured by the elementary propositions. On this analysis, only propositions that picture facts - the propositions of science - are considered cognitively meaningful. Metaphysical and ethical statements are not meaningful assertions. The logical positivists associated with the Vienna Circle were greatly influenced by this conclusion.
Wittgenstein came to believe, however, that the narrow view of language reflected in the Tractatus was mistaken. In the Philosophical Investigations he argued that if one actually looks to see how language is used, the variety of linguistic usage becomes clear. Words are like tools, and just as tools serve different functions, so linguistic expressions serve many functions. Although some propositions are used to picture facts, others are used to command, question, pray, thank, curse, and so on. This recognition of linguistic flexibility and variety led to Wittgenstein’s concept of a language game and to the conclusion that people play different language games. The scientist, for example, is involved in a different language game than the theologian. Moreover, the meaning of a proposition must be understood in terms of its context, that is, in terms of the rules of the game of which that proposition is a part. The key to the resolution of philosophical puzzles is the therapeutic process of examining and describing language in use.
Again, Phenomenology, the 20th-century philosophical movement dedicated to describing the structures of experience as they present themselves to consciousness, without recourse to theory, deduction, or assumptions from other disciplines such as the natural sciences.
German philosopher Edmund Husserl is considered the founder of phenomenology. This 20th-century philosophical movement is dedicated to the description of phenomena as they present themselves through perception to the conscious mind.
The founder of phenomenology, German philosopher Edmund Husserl, introduced the term in his book Ideen zu einer reinen Phänomenolgie und phänomenologischen Philosophie (1913; Ideas: A General Introduction to Pure Phenomenology,1931). Early followers of Husserl such as German philosopher Max Scheler, influenced by his previous book, Logische Untersuchungen (two volumes, 1900 and 1901; Logical Investigations, 1970), claimed that the task of phenomenology is to study essences, such as the essence of emotions. Although Husserl himself never gave up his early interest in essences, he later held that only the essences of certain special conscious structures are the proper object of phenomenology. As formulated by Husserl after 1910, phenomenology is the study of the structures of consciousness that enable consciousness to refer to objects outside itself. This study requires reflection on the content of the mind to the exclusion of everything else. Husserl called this type of reflection the phenomenological reduction. Because the mind can be directed toward nonexistent as well as real objects, Husserl noted that phenomenological reflection does not presuppose that anything exists, but rather amounts to a ‘bracketing of existence’—that is, setting aside the question of the real existence of the contemplated object.
What Husserl discovered when he contemplated the content of his mind were such acts as remembering, desiring, and perceiving, in addition to the abstract content of these acts, which Husserl called meanings. These meanings, he claimed, enabled an act to be directed toward an object under a certain aspect; and such directedness, called intentionality, he held to be the essence of consciousness. Transcendental phenomenology, according to Husserl, was the study of the basic components of the meanings that make intentionality possible. Later, in Méditations cartésiennes (1931; Cartesian Meditations, 1960), he introduced genetic phenomenology, which he defined as the study of how these meanings are built up in the course of experience.
Phenomenology attempts to describe reality in terms of pure experience by suspending all beliefs and assumptions about the world. Though first defined as descriptive psychology, phenomenology attempts philosophical rather than psychological investigations into the nature of human beings. Influenced by his colleague Edmund Husserl (known as the founder of phenomenology), German philosopher Martin Heidegger published Sein und Zeit (Being and Time) in 1927, an effort to describe the phenomenon of being by considering the full scope of existence.
All phenomenologists follow Husserl in attempting to use pure description. Thus, they all subscribe to Husserl's slogan ‘To the things themselves.’ They differ among themselves, however, as to whether the phenomenological reduction can be performed, and as to what is manifest to the philosopher giving a pure description of experience. German philosopher Martin Heidegger, Husserl's colleague and most brilliant critic, claimed that phenomenology should make manifest what is hidden in ordinary, everyday experience. He thus attempted in Sein und Zeit (1927; Being and Time, 1962) to describe what he called the structure of everydayness, or being-in-the-world, which he found to be an interconnected system of equipment, social roles, and purposes.
German philosopher Martin Heidegger was instrumental in the development of the 20th-century philosophical school of existential phenomenology, which examines the relationship between phenomena and individual consciousness. His inquiries into the meaning of ‘authentic’ or ‘inauthentic’ existence greatly influenced a broad range of thinkers, including French existentialist Jean-Paul Sartre. Author Michael Inwood explores Heidegger’s key concept of Dasein, or ‘being,’ which was first expounded in his major work Being and Time (1927).
Because, for Heidegger, one is what one does in the world, a phenomenological reduction to one's own private experience is impossible; and because human action consists of a direct grasp of objects, it is not necessary to posit a special mental entity called a meaning to account for intentionality. For Heidegger, being thrown into the world among things in the act of realizing projects is a more fundamental kind of intentionality than that revealed in merely staring at or thinking about objects, and it is this more fundamental intentionality that makes possible the directedness analyzed by Husserl.
In the mid-1900s, French existentialist Paul Sartre attempted to adapt Heidegger's phenomenology to the philosophy of consciousness, in effect returning to the approach of Husserl. Sartre agreed with Husserl that consciousness is always directed at objects but criticized his claim that such directedness is possible only by means of special mental entities called meanings. The French philosopher Maurice Merleau-Ponty rejected Sartre's view that phenomenological description reveals human beings to be pure, isolated, and free consciousness. He stressed the role of the active, involved body in all human knowledge, thus generalizing Heidegger's insights to include the analysis of perception. Like Heidegger and Sartre, Merleau-Ponty is an existential phenomenologists, in that he denies the possibility of bracketing existence.
Phenomenology has had a pervasive influence on 20th-century thought. Phenomenological versions of theology, sociology, psychology, psychiatry, and literary criticism have been developed, and phenomenology remains one of the most important schools of contemporary philosophy.
Metaphysics is customarily divided into ontology, which deals with the question of how many fundamentally distinct sorts of entities compose the universe, and metaphysics proper, which is concerned with describing the most general traits of reality. These general traits together define reality and would presumably characterize any universe whatever. Because these traits are not peculiar to this universe, but are common to all possible universes, metaphysics may be conducted at the highest level of abstraction. Ontology, by contrast, because it investigates the ultimate divisions within this universe, is more closely related to the physical world of human experience.
The term metaphysics is believed to have originated in Rome about 70 Bc, with the Greek Peripatetic philosopher Andronicus of Rhodes (flourished 1st century Bc) in his edition of the works of Aristotle. In the arrangement of Aristotle's works by Andronicus, the treatise originally called First Philosophy, or Theology, followed the treatise Physics. Hence, the First Philosophy came to be known as meta (ta) physica, or ‘following (the) Physics,’ later shortened to Metaphysics. The word took on the connotation, in popular usage, of matters transcending material reality. In the philosophic sense, however, particularly as opposed to the use of the word by occultists, metaphysics applies to all reality and is distinguished from other forms of inquiry by its generality.
The subjects treated in Aristotle's Metaphysics (substance, causality, the nature of being, and the existence of God) fixed the content of metaphysical speculation for centuries. Among the medieval Scholastic philosophers, metaphysics was known as the ‘transphysical science’ on the assumption that, by means of it, the scholar philosophically could make the transition from the physical world to a world beyond sense perception. The 13th-century Scholastic philosopher and theologian St. Thomas Aquinas declared that the cognition of God, through a causal study of finite sensible beings, was the aim of metaphysics. With the rise of scientific study in the 16th century the reconciliation of science and faith in God became an increasingly important problem.
Irish-born philosopher and clergyman George Berkeley (1685-1753) argued that everything that human beings conceive of exists as an idea in a mind, a philosophical focus which is known as idealism. Berkeley reasoned that because one cannot control one’s thoughts, they must come directly from a larger mind: that of God. In this excerpt from his Treatise Concerning the Principles of Human Knowledge, written in 1710, Berkeley explained why he believed that it is ‘impossible … that there should be any such thing as an outward object.’
Before the time of the German philosopher Immanuel Kant metaphysics was characterized by a tendency to construct theories on the basis of a priori knowledge, that is, knowledge derived from reason alone, in contradistinction to a posteriori knowledge, which is gained by reference to the facts of experience. From a priori knowledge were deduced general propositions that were held to be true of all things. The method of inquiry based on a priori principles is known as rationalistic. This method may be subdivided into monism, which holds that the universe is made up of a single fundamental substance; dualism, the belief in two such substances; and pluralism, which proposes the existence of many fundamental substances.
The monists, agreeing that only one basic substance exists, differ in their descriptions of its principal characteristics. Thus, in idealistic monism the substance is believed to be purely mental; in materialistic monism it is held to be purely physical, and in neutral monism it is considered neither exclusively mental nor solely physical. The idealistic position was held by the Irish philosopher George Berkeley, the materialistic by the English philosopher Thomas Hobbes, and the neutral by the Dutch philosopher Baruch Spinoza. The latter expounded a pantheistic view of reality in which the universe is identical with God and everything contains God's substance.
Irish philosopher and clergyman George Berkeley set out to challenge what he saw as the atheism and skepticism inherent in the prevailing philosophy of the early 18th century. His initial publications, which asserted that no objects or matter existed outside the human mind, were met with disdain by the London intelligentsia of the day. Berkeley aimed to explain his ‘Immaterialism’ theory, part of the school of thought known as idealism, to a more general audience in Three Dialogues between Hylas and Philonous (1713). This passage is from the close of the third dialogue.
The most famous exponent of dualism was the French philosopher René Descartes, who maintained that body and mind are radically different entities and that they are the only fundamental substances in the universe. Dualism, however, does not show how these basic entities are connected.
In the work of the German philosopher Gottfried Wilhelm Leibniz, the universe is held to consist of an infinite number of distinct substances, or monads. This view is pluralistic in the sense that it proposes the existence of many separate entities, and it is monistic in its assertion that each monad reflects within itself the entire universe.
Other philosophers have held that knowledge of reality is not derived from a priori principles, but is obtained only from experience. This type of metaphysics is called empiricism. Still another school of philosophy has maintained that, although an ultimate reality does exist, it is altogether inaccessible to human knowledge, which is necessarily subjective because it is confined to states of mind. Knowledge is therefore not a representation of external reality, but merely a reflection of human perceptions. This view is known as skepticism or agnosticism in respect to the soul and the reality of God.
The 18th-century German philosopher Immanuel Kant published his influential work The Critique of Pure Reason in 1781. Three years later, he expanded on his study of the modes of thinking with an essay entitled ‘What is Enlightenment?’ In this 1784 essay, Kant challenged readers to ‘dare to know,’ arguing that it was not only a civic but also a moral duty to exercise the fundamental freedoms of thought and expression.
Several major viewpoints were combined in the work of Kant, who developed a distinctive critical philosophy called transcendentalism. His philosophy is agnostic in that it denies the possibility of a strict knowledge of ultimate reality; it is empirical in that it affirms that all knowledge arises from experience and is true of objects of actual and possible experience; and it is rationalistic in that it maintains the a priori character of the structural principles of this empirical knowledge.
These principles are held to be necessary and universal in their application to experience, for in Kant's view the mind furnishes the archetypal forms and categories (space, time, causality, substance, and relation) to its sensations, and these categories are logically anterior to experience, although manifested only in experience. Their logical anteriority to experience makes these categories or structural principles transcendental; they transcend all experience, both actual and possible. Although these principles determine all experience, they do not in any way affect the nature of things in themselves. The knowledge of which these principles are the necessary conditions must not be considered, therefore, as constituting a revelation of things as they are in themselves. This knowledge concerns things only insofar as they appear to human perception or as they can be apprehended by the senses. The argument by which Kant sought to fix the limits of human knowledge within the framework of experience and to demonstrate the inability of the human mind to penetrate beyond experience strictly by knowledge to the realm of ultimate reality constitutes the critical feature of his philosophy, giving the key word to the titles of his three leading treatises, Critique of Pure Reason, Critique of Practical Reason, and Critique of Judgment. In the system propounded in these works, Kant sought also to reconcile science and religion in a world of two levels, comprising noumena, objects conceived by reason although not perceived by the senses, and phenomena, things as they appear to the senses and are accessible to material study. He maintained that, because God, freedom, and human immortality are noumenal realities, these concepts are understood through moral faith rather than through scientific knowledge. With the continuous development of science, the expansion of metaphysics to include scientific knowledge and methods became one of the major objectives of metaphysicians.
Some of Kant's most distinguished followers, notably Johann Gottlieb Fichte, Friedrich Schelling, Georg Wilhelm Friedrich Hegel, and Friedrich Schleiermacher, negated Kant's criticism in their elaborations of his transcendental metaphysics by denying the Kantian conception of the thing-in-itself. They thus developed an absolute idealism in opposition to Kant's critical transcendentalism.
Since the formation of the hypothesis of absolute idealism, the development of metaphysics has resulted in as many types of metaphysical theory as existed in pre-Kantian philosophy, despite Kant's contention that he had fixed definitely the limits of philosophical speculation. Notable among these later metaphysical theories are radical empiricism, or pragmatism, a native American form of metaphysics expounded by Charles Sanders Peirce, developed by William James, and adapted as instrumentalism by John Dewey; voluntarism, the foremost exponents of which are the German philosopher Arthur Schopenhauer and the American philosopher Josiah Royce; phenomenalism, as it is exemplified in the writings of the French philosopher Auguste Comte and the British philosopher Herbert Spencer; emergent evolution, or creative evolution, originated by the French philosopher Henri Bergson; and the philosophy of the organism, elaborated by the British mathematician and philosopher Alfred North Whitehead. The salient doctrines of pragmatism are that the chief function of thought is to guide action, that the meaning of concepts is to be sought in their practical applications, and that truth should be tested by the practical effects of belief; according to instrumentalism, ideas are instruments of action, and their truth is determined by their role in human experience. In the theory of voluntarism the will is postulated as the supreme manifestation of reality. The exponents of phenomenalism, who are sometimes called positivists, contend that everything can be analyzed in terms of actual or possible occurrences, or phenomena, and that anything that cannot be analyzed in this manner cannot be understood. In emergent or creative evolution, the evolutionary process is characterized as spontaneous and unpredictable rather than mechanistically determined. The philosophy of the organism combines an evolutionary stress on constant process with a metaphysical theory of God, the eternal objects, and creativity.
In the 20th century the validity of metaphysical thinking has been disputed by the logical positivists and by the so-called dialectical materialism of the Marxists. The basic principle maintained by the logical positivists is the verifiability theory of meaning. According to this theory a sentence has factual meaning only if it meets the test of observation. Logical positivists argue that metaphysical expressions such as ‘Nothing exists except material particles’ and ‘Everything is part of one all-encompassing spirit’ cannot be tested empirically. Therefore, according to the verifiability theory of meaning, these expressions have no factual cognitive meaning, although they can have an emotive meaning relevant to human hopes and feelings.
The dialectical materialists assert that the mind is conditioned by and reflects material reality. Therefore, speculations that conceive of constructs of the mind as having any other than material reality are themselves unreal and can result only in delusion. To these assertions metaphysicians reply by denying the adequacy of the verifiability theory of meaning and of material perception as the standard of reality. Both logical positivism and dialectical materialism, they argue, conceal metaphysical assumptions, for example, that everything is observable or at least connected with something observable and that the mind has no distinctive life of its own. In the philosophical movement known as existentialism, thinkers have contended that the questions of the nature of being and of the individual's relationship to it are extremely important and meaningful in terms of human life. The investigation of these questions is therefore considered valid whether or not its results can be verified objectively.
Since the 1950's the problems of systematic analytical metaphysics have been studied in Britain by Stuart Newton Hampshire and Peter Frederick Strawson, the former concerned, in the manner of Spinoza, with the relationship between thought and action, and the latter, in the manner of Kant, with describing the major categories of experience as they are embedded in language. In the US metaphysics has been pursued much in the spirit of positivism by Wilfred Stalker Sellars and Willard Van Orman Quine. Sellars has sought to express metaphysical questions in linguistic terms, and Quine has attempted to determine whether the structure of language commits the philosopher to asserting the existence of any entities whatever and, if so, what kind. In these new formulations the issues of metaphysics and ontology remain vital.
Martin Heidegger (1889-1976), German philosopher, who developed existential phenomenology and is widely regarded as the most original and influential 20th-century philosopher.
　
German philosopher Martin Heidegger greatly influenced the modern philosophy movements of phenomenology and existentialism. According to Heidegger, humankind has fallen into a crisis by taking a narrow, technological approach to the world and by ignoring the larger question of existence. People, if they wish to live authentically, must broaden their perspectives. Instead of taking their existence for granted, people should view themselves as part of Being (Heidegger's term for that which underlies all existence).
Heidegger was born in Messkirch, Baden. He studied Roman Catholic theology and then philosophy at the University of Freiburg, where he was an assistant to Edmund Husserl, the founder of phenomenology. Heidegger began teaching at Freiburg in 1915. From 1923 to 1928 he taught at Marburg University. He then returned to Freiburg in 1928, inheriting Husserl's position as professor of philosophy. Because of his public support of Adolf Hitler and the Nazi Party in 1933 and 1934, Heidegger's professional activities were restricted in 1945, and controversy surrounded his university standing until his retirement in 1959.
German philosopher Martin Heidegger was instrumental in the development of the 20th-century philosophical school of existential phenomenology, which examines the relationship between phenomena and individual consciousness. His inquiries into the meaning of ‘authentic’ or ‘inauthentic’ existence greatly influenced a broad range of thinkers, including French existentialist Jean-Paul Sartre. Author Michael Inwood explores Heidegger’s key concept of Dasein, or ‘being,’ which was first expounded in his major work Being and Time (1927).
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Besides Husserl, Heidegger was especially influenced by the pre-Socratics, by Danish philosopher S ren Kierkegaard, and by German philosopher Friedrich Nietzsche. In developing his theories, Heidegger rejected traditional philosophic terminology in favour of an individual interpretation of the works of past thinkers. He applied original meanings and etymologies to individual words and expressions, and coined hundreds of new, complex words. In his most important and influential work, Sein und Zeit (Being and Time, 1927), Heidegger was concerned with what he considered the essential philosophical question: What is it, to be? This led to the question of what kind of ‘being’ human beings have. They are, he said, thrown into a world that they have not made but that consists of potentially useful things, including cultural as well as natural objects. Because these objects come to humanity from the past and are used in the present for the sake of future goals, Heidegger posited a fundamental relation between the mode of being of objects, of humanity, and of the structure of time.
The individual is, however, always in danger of being submerged in the world of objects, everyday routine, and the conventional, shallow behaviour of the crowd. The feeling of dread (Angst) brings the individual to a confrontation with death and the ultimate meaninglessness of life, but only in this confrontation can an authentic sense of Being and of freedom be attained.
After 1930, Heidegger turned, in such works as Einführung in die Metaphysik (An Introduction to Metaphysics, 1953), to the interpretation of particular Western conceptions of being. He felt that, in contrast to the reverent ancient Greek conception of being, modern technological society has fostered a purely manipulative attitude that has deprived Being and human life of meaning—a condition he called nihilism. Humanity has forgotten its true vocation and must recover the deeper understanding of Being (achieved by the early Greeks and lost by subsequent philosophers) to be receptive to new understandings of Being.
Heidegger's original treatment of such themes as human finitude, death, nothingness, and authenticity led many observers to associate him with existentialism, and his work had a crucial influence on French existentialist Jean-Paul Sartre. Heidegger, however, eventually repudiated existentialist interpretations of his work. His thought directly influenced the work of French philosophers Michel Foucault and Jacques Derrida and of German sociologist Jurgen Habermas. Since the 1960s his influence has spread beyond continental Europe and has had an increasing impact on philosophy in English-speaking countries worldwide.
Jean-Paul Sartre, in 1940-41 he was imprisoned by the Germans; after his release, he taught in Neuilly, France, and later in Paris, and was active in the French Resistance. The German authorities, unaware of his underground activities, permitted the production of his antiauthoritarian play The Flies (1943; trans. 1946) and the publication of his major philosophic work Being and Nothingness (1943; trans. 1953). Sartre gave up teaching in 1945 and founded the political and literary magazine Les Temps Modernes, of which he became editor in chief. Sartre was active after 1947 as an independent Socialist, critical of both the USSR and the United States in the so-called cold war years. Later, he supported Soviet positions but still frequently criticized Soviet policies. Most of his writing of the 1950s deals with literary and political problems. Sartre rejected the 1964 Nobel Prize in literature, explaining that to accept such an award would compromise his integrity as a writer.
Sartre's philosophic works combine the phenomenology of the German philosopher Edmund Husserl, the metaphysics of the German philosophers Georg Wilhelm Friedrich Hegel and Martin Heidegger, and the social theory of Karl Marx into a single view called existentialism. This view, which relates philosophical theory to life, literature, psychology, and political action, stimulated so much popular interest that existentialism became a worldwide movement.
In his early philosophic work, Being and Nothingness, Sartre conceived humans as beings who create their own world by rebelling against authority and by accepting personal responsibility for their actions, unaided by society, traditional morality, or religious faith. Distinguishing between human existence and the nonhuman world, he maintained that human existence is characterized by nothingness, that is, by the capacity to negate and rebel. His theory of existential psychoanalysis asserted the inescapable responsibility of all individuals for their own decisions and made the recognition of one's absolute freedom of choice the necessary condition for authentic human existence. His plays and novels express the belief that freedom and acceptance of personal responsibility are the main values in life and that individuals must rely on their creative powers rather than on social or religious authority.
In his later philosophic work Critique of Dialectical Reason (1960; trans. 1976), Sartre's emphasis shifted from existentialist freedom and subjectivity to Marxist social determinism. Sartre argued that the influence of modern society over the individual is so great as to produce serialization, by which he meant loss of self. Individual power and freedom can only be regained through group revolutionary action. Despite this exhortation to revolutionary political activity, Sartre himself did not join the Communist Party, thus retaining the freedom to criticize the Soviet invasions of Hungary in 1956 and Czechoslovakia in 1968. He died in Paris, April 15, 1980.
Sartre's other works include the novels Nausea (1938; trans. 1949) and the unfinished series Les chemins de la liberté (The Roads of Liberty), comprising The Age of Reason (1945; trans. 1947), The Reprieve (1945; trans. 1947), and Troubled Sleep (1949; trans. 1951); the biography of the controversial French writer Jean Genet, Saint Genet, Actor and Martyr (1952; trans. 1952); the plays No Exit (1944; trans. 1946), The Respectful Prostitute (1946; trans. 1947), and The Condemned of Altona (1959; trans. 1961); his autobiography, The Words (1964; trans. 1964); and a biography of the French author Gustave Flaubert (3 volumes, 1971-72).
Because of the diversity of positions associated with existentialism, the term is impossible to define precisely. Certain themes common to virtually all existentialist writers can, however, be identified. The term itself suggests one major theme: the stress on concrete individual existence and, consequently, on subjectivity, individual freedom, and choice.
Most philosophers since Plato have held that the highest ethical good is the same for everyone; insofar as one approaches moral perfection, one resembles other morally perfect individuals. The 19th-century Danish philosopher S ren Kierkegaard, who was the first writer to call himself existential, reacted against this tradition by insisting that the highest good for the individual is to find his or her own unique vocation. As he wrote in his journal, ‘I must find a truth that is true for me . . . the idea for which I can live or die.’ Other existentialist writers have echoed Kierkegaard's belief that one must choose one's own way without the aid of universal, objective standards. Against the traditional view that moral choice involves an objective judgment of right and wrong, existentialists have argued that no objective, rational basis can be found for moral decisions. The 19th-century German philosopher Friedrich Nietzsche further contended that the individual must decide which situations are to count as moral situations.
All existentialists have followed Kierkegaard in stressing the importance of passionate individual action in deciding questions of both morality and truth. They have insisted, accordingly, that personal experience and acting on one's own convictions are essential in arriving at the truth. Thus, the understanding of a situation by someone involved in that situation is superior to that of a detached, objective observer. This emphasis on the perspective of the individual agent has also made existentialists suspicious of systematic reasoning. Kierkegaard, Nietzsche, and other existentialist writers have been deliberately unsystematic in the exposition of their philosophies, preferring to express themselves in aphorisms, dialogues, parables, and other literary forms. Despite their antirationalist position, however, most existentialists cannot be said to be irrationalists in the sense of denying all validity to rational thought. They have held that rational clarity is desirable wherever possible, but that the most important questions in life are not accessible to reason or science. Furthermore, they have argued that even science is not as rational as is commonly supposed. Nietzsche, for instance, asserted that the scientific assumption of an orderly universe is for the most part a useful fiction.
Perhaps the most prominent theme in existentialist writing is that of choice. Humanity's primary distinction, in the view of most existentialists, is the freedom to choose. Existentialists have held that human beings do not have a fixed nature, or essence, as other animals and plants do; each human being makes choices that create his or her own nature. In the formulation of the 20th-century French philosopher Jean-Paul Sartre, existence precedes essence. Choice is therefore central to human existence, and it is inescapable; even the refusal to choose is a choice. Freedom of choice entails commitment and responsibility. Because individuals are free to choose their own path, existentialists have argued, they must accept the risk and responsibility of following their commitment wherever it leads.
Kierkegaard held that it is spiritually crucial to recognize that one experiences not only a fear of specific objects but also a feeling of general apprehension, which he called dread. He interpreted it as God's way of calling each individual to make a commitment to a personally valid way of life. The word anxiety (German Angst) has a similarly crucial role in the work of the 20th-century German philosopher Martin Heidegger; anxiety leads to the individual's confrontation with nothingness and with the impossibility of finding ultimate justification for the choices he or she must make. In the philosophy of Sartre, the word nausea is used for the individual's recognition of the pure contingency of the universe, and the word anguish is used for the recognition of the total freedom of choice that confronts the individual at every moment.
Existentialism as a distinct philosophical and literary movement belongs to the 19th and 20th centuries, but elements of existentialism can be found in the thought (and life) of Socrates, in the Bible, and in the work of many premodern philosophers and writers.
The first to anticipate the major concerns of modern existentialism was the 17th-century French philosopher Blaise Pascal. Pascal rejected the rigorous rationalism of his contemporary René Descartes, asserting, in his Pensées (1670), that a systematic philosophy that presumes to explain God and humanity is a form of pride. Like later existentialist writers, he saw human life in terms of paradoxes: The human self, which combines mind and body, is itself a paradox and contradiction.
Nineteenth-century Danish philosopher S ren Kierkegaard played a major role in the development of existentialist thought. Kierkegaard criticized the popular systematic method of rational philosophy advocated by German Georg Wilhelm Friedrich Hegel. He emphasized the absurdity inherent in human life and questioned how any systematic philosophy could apply to the ambiguous human condition. In Kierkegaard’s deliberately unsystematic works, he explained that each individual should attempt an intense examination of his or her own existence.
Kierkegaard, generally regarded as the founder of modern existentialism, reacted against the systematic absolute idealism of the 19th-century German philosopher Georg Wilhelm Friedrich Hegel, who claimed to have worked out a total rational understanding of humanity and history. Kierkegaard, on the contrary, stressed the ambiguity and absurdity of the human situation. The individual's response to this situation must be to live a totally committed life, and this commitment can only be understood by the individual who has made it. The individual therefore must always be prepared to defy the norms of society for the sake of the higher authority of a personally valid way of life. Kierkegaard ultimately advocated a ‘leap of faith’ into a Christian way of life, which, although incomprehensible and full of risk, was the only commitment he believed could save the individual from despair.
Danish religious philosopher S ren Kierkegaard rejected the all-encompassing, analytical philosophical systems of such 19th-century thinkers as German philosopher G. W. F. Hegel. Instead, Kierkegaard focused on the choices the individual must make in all aspects of his or her life, especially the choice to maintain religious faith. In Fear and Trembling (1846; trans. 1941), Kierkegaard explored the concept of faith through an examination of the biblical story of Abraham and Isaac, in which God demanded that Abraham demonstrate his faith by sacrificing his son.
One of the most controversial works of 19th-century philosophy, Thus Spake Zarathustra (1883-1885) articulated German philosopher Friedrich Nietzsche’s theory of the Übermensch, a term translated as ‘Superman’ or ‘Overman.’ The Superman was an individual who overcame what Nietzsche termed the ‘slave morality’ of traditional values, and lived according to his own morality. Nietzsche also advanced his idea that ‘God is dead,’ or that traditional morality was no longer relevant in people’s lives. In this passage, the sage Zarathustra came down from the mountain where he had spent the last ten years alone to preach to the people.
Nietzsche, who was not acquainted with the work of Kierkegaard, influenced subsequent existentialist thought through his criticism of traditional metaphysical and moral assumptions and through his espousal of tragic pessimism and the life-affirming individual will that opposes itself to the moral conformity of the majority. In contrast to Kierkegaard, whose attack on conventional morality led him to advocate a radically individualistic Christianity, Nietzsche proclaimed the ‘death of God’ and went on to reject the entire Judeo-Christian moral tradition in favour of a heroic pagan ideal.
The modern philosophy movements of phenomenology and existentialism have been greatly influenced by the thought of German philosopher Martin Heidegger. According to Heidegger, humankind has fallen into a crisis by taking a narrow, technological approach to the world and by ignoring the larger question of existence. People, if they wish to live authentically, must broaden their perspectives. Instead of taking their existence for granted, people should view themselves as part of Being (Heidegger's term for that which underlies all existence).
Heidegger, like Pascal and Kierkegaard, reacted against an attempt to put philosophy on a conclusive rationalistic basis—in this case the phenomenology of the 20th-century German philosopher Edmund Husserl. Heidegger argued that humanity finds itself in an incomprehensible, indifferent world. Human beings can never hope to understand why they are here; instead, each individual must choose a goal and follow it with passionate conviction, aware of the certainty of death and the ultimate meaninglessness of one's life. Heidegger contributed to existentialist thought an original emphasis on being and ontology, as well as on language.
Twentieth-century French intellectual Jean-Paul Sartre helped to develop existential philosophy through his writings, novels, and plays. Much of Sartre’s work focuses on the dilemma of choice faced by free individuals and on the challenge of creating meaning by acting responsibly in an indifferent world. In stating that ‘man is condemned to be free,’ Sartre reminds us of the responsibility that accompanies human decisions.
Sartre first gave the term existentialism general currency by using it for his own philosophy and by becoming the leading figure of a distinct movement in France that became internationally influential after World War II. Sartre's philosophy is explicitly atheistic and pessimistic; he declared that human beings require a rational basis for their lives but are unable to achieve one, and thus human life is a ‘futile passion.’ Sartre nevertheless insisted that his existentialism is a form of humanism, and he strongly emphasized human freedom, choice, and responsibility. He eventually tried to reconcile these existentialist concepts with a Marxist analysis of society and history.
Although existentialist thought encompasses the uncompromising atheism of Nietzsche and Sartre and the agnosticism of Heidegger, its origin in the intensely religious philosophies of Pascal and Kierkegaard foreshadowed its profound influence on 20th-century theology. The 20th-century German philosopher Karl Jaspers, although he rejected explicit religious doctrines, influenced contemporary theology through his preoccupation with transcendence and the limits of human experience. The German Protestant theologians Paul Tillich and Rudolf Bultmann, the French Roman Catholic theologian Gabriel Marcel, the Russian Orthodox philosopher Nikolay Berdyayev, and the German Jewish philosopher Martin Buber inherited many of Kierkegaard's concerns, especially that a personal sense of authenticity and commitment is essential to religious faith.
Renowned as one of the most important writers in world history, 19th-century Russian author Fyodor Dostoyevsky wrote psychologically intense novels which probed the motivations and moral justifications for his characters’ actions. Dostoyevsky commonly addressed themes such as the struggle between good and evil within the human soul and the idea of salvation through suffering. The Brothers Karamazov (1879-1880), generally considered Dostoyevsky’s best work, interlaces religious exploration with the story of a family’s violent quarrels over a woman and a disputed inheritance.
Twentieth-century writer and philosopher Albert Camus examined what he considered the tragic inability of human beings to understand and transcend their intolerable conditions. In his work Camus presented an absurd and seemingly unreasonable world in which some people futilely struggle to find meaning and rationality while others simply refuse to care. For example, the main character of The Stranger (1942) kills a man on a beach for no reason and accepts his arrest and punishment with dispassion. In contrast, in The Plague (1947), Camus introduces characters who act with courage in the face of absurdity.
A number of existentialist philosophers used literary forms to convey their thought, and existentialism has been as vital and as extensive a movement in literature as in philosophy. The 19th-century Russian novelist Fyodor Dostoyevsky is probably the greatest existentialist literary figure. In Notes from the Underground (1864), the alienated antihero rages against the optimistic assumptions of rationalist humanism. The view of human nature that emerges in this and other novels of Dostoyevsky is that it is unpredictable and perversely self-destructive; only Christian love can save humanity from itself, but such love cannot be understood philosophically. As the character Alyosha says in The Brothers Karamazov (1879-80), ‘We must love life more than the meaning of it.’
The opening lines of Russian novelist Fyodor Dostoyevsky’s Notes from Underground (1864) —‘I am a sick man . . . I am a spiteful man’ - are among the most famous in 19th-century literature. Published five years after his release from prison and involuntary military service in Siberia, Notes from Underground is a sign of Dostoyevsky’s rejection of the radical social thinking he had embraced in his youth. The unnamed narrator is antagonistic in tone, questioning the reader’s sense of morality as well as the foundations of rational thinking. In this excerpt from the beginning of the novel, the narrator describes himself, derisively referring to himself as an ‘overly conscious’ intellectual.
In the 20th century, the novels of the Austrian Jewish writer Franz Kafka, such as The Trial (1925; trans. 1937) and The Castle (1926; trans. 1930), present isolated men confronting vast, elusive, menacing bureaucracies; Kafka's themes of anxiety, guilt, and solitude reflect the influence of Kierkegaard, Dostoyevsky, and Nietzsche. The influence of Nietzsche is also discernible in the novels of the French writers André Malraux and in the plays of Sartre. The work of the French writer Albert Camus is usually associated with existentialism because of the prominence in it of such themes as the apparent absurdity and futility of life, the indifference of the universe, and the necessity of engagement in a just cause. Existentialist themes are also reflected in the theatre of the absurd, notably in the plays of Samuel Beckett and Eug ne Ionesco. In the United States, the influence of existentialism on literature has been more indirect and diffuse, but traces of Kierkegaard's thought can be found in the novels of Walker Percy and John Updike, and various existentialist themes are apparent in the work of such diverse writers as Norman Mailer, John Barth, and Arthur Miller.
Alan Turing (1912-1954), British mathematician, who did pioneering work in computer theory. He was born in London and educated at Cambridge and Princeton universities. In 1936, while he was still a graduate student, Turing published a paper called ‘On Computable Numbers,’ which introduced the concept of a theoretical computing device now known as a Turing machine. The concept of this machine, which could theoretically perform any mathematical calculation, was important in the development of the digital computer. Turing also extended his mathematical work to the study of artificial intelligence and biological forms. He proposed a method called the Turing test, to determine whether machines could have the ability to think. During World War II (1939-1945), Turing worked as a cryptographer for the British Foreign Office. In 1951 Turing was named a Fellow of the Royal Society and in 1952 he began to publish his work on the mathematical aspects of pattern and form development in living organisms. He apparently committed suicide in 1954 , probably in reaction to medical treatments he was forced to receive in order to ‘cure’ him of homosexuality.
Automata Theory, a concept that describes how machines mimic human behaviour. The theory proposes that human physical functions and behaviour can be simulated by a mechanical or computer-controlled device. Applications of automata theory have included imitating human comprehension and reasoning skills using computer programs, duplicating the function of muscles and tendons by hydraulic systems or electric motors, and reproducing sensory organs by electronic sensors such as smoke detectors.
The concept of automata, or manlike machines, has historically been associated with any self-operating machine, such as watches or clockwork songbirds driven by tiny springs and gears. But in the late 20th century, the science of robotics (the development of computer-controlled devices that move and manipulate objects) has replaced automata as it relates to replicating motion based on human anatomy. Modern theories of automata currently focus on reproducing human thought patterns and problem-solving abilities using artificial intelligence and other advanced computer-science techniques.
Automata date to ancient times. During the Han dynasty (3rd century BC), a mechanical orchestra was constructed for the Chinese Emperor. The 13th-century English philosopher and scientist Roger Bacon is credited with creating an artificial talking head, and in the 17th century French philosopher and mathematician René Descartes reportedly built a female automaton as a travelling companion. In the 18th and 19th centuries, intricate machines were constructed that imitated some human actions, such as limb movement, but these devices were little more than sophisticated windup toys.
Mimicry of human mental abilities did not begin until the advent of electronics and mathematical logic structures. In the mid-20th century, the British mathematician Alan Turing designed a theoretical machine to process equations without human direction. The machine (now known as a Turing machine), in concept resembled an automatic typewriter that used symbols for math and logic instead of letters. Turing intended the device to be used as a ‘universal machine’ that could be programmed to duplicate the function of any other existing machine. Turing's machine was the theoretical precursor to the modern digital computer.
In the 1940s and 1950s American researchers Warren McCulloch and Walter Pitts at the Massachusetts Institute of Technology developed artificial neurons, or neural networks, to theoretically bridge the structure of the human brain and the still-to-be-invented modern computer. The human brain has about 1 trillion nerve cells, or neurons, each of which is connected to several other neurons. This allows neurons to transmit information along different pathways, depending on the stimulation they receive. McCulloch and Pitts theorized that this same mode of information transmission, an interconnected network, might be reproduced with electronic components. Artificial neural networks have been shown to have the capacity to learn from their experiences and enhance their computational performance.
In 1956 American social scientist and Nobel laureate Herbert Simon and American physicist and computer scientist Allan Newell at Carnegie Mellon University in Pennsylvania devised a program called Logic Theorist that simulated human thinking on computers, although at first the program was simply written on index cards due to the scarcity of computers. Newell and Simon later created a modified version of the program called the General Problem Solver (GPS). The GPS was unique in that it was programmed to achieve a goal and then find the means to reach that goal—as opposed to starting from a problem or question and working toward an eventual solution. The GPS process involved backward thinking, going from the final solution to the present state. Using computers from the Rand Corporation to test GPS, Simon and Newell found that in some cases GPS did act as if it were capable of human reasoning. This was one of the first breakthroughs in the computer-science field that would later be known as artificial intelligence.
The first artificial intelligence conference occurred at Dartmouth College in New Hampshire in 1956. This conference inspired researchers to undertake projects that emulated human behaviour in the areas of reasoning, language comprehension, and communications. In addition to Newell and Simon, computer scientists and mathematicians Claude Shannon, Marvin Minsky, and John McCarthy laid the groundwork for creating ‘thinking’ machines from computers. Contemporary fields of interest resulting from early artificial intelligence research include expert systems, cellular automata, and artificial life.
Expert systems are computer software programs that mimic the expertise of human specialists. Expert systems have two components, a knowledge base that provides rules and data and an inference engine that enables the expert system to form conclusions. For example, an expert system that diagnoses blood disease in a patient would require a knowledge base that included data on physiology, blood pathogens, disease symptoms, and treatment options. The inference engine searches through the knowledge base and concludes which possible disease or diseases the patient has and then suggests various treatments based on that diagnosis.
Cellular automata originated in the theoretical work of American mathematician John von Neumann in the 1950s. His theory treated pieces of data like biological cells. In living organisms, individual cells are affected by the death or malfunction of the cells around them. Applying this metaphor to computational problems, for example a stock market simulation, a particular stock will fluctuate in response to economic factors just as a cell will react to an injury. Using cellular automata, stock performance is simulated on a computer that treats stock like biological entities. Outside forces are applied, such as rising and falling interest rates, and financial analysts try to predict how individual stocks will perform.
Plants and animals evolve in response to their environment and to threats such as predators, disease, and competing species. Artificial life, developed primarily by Chris Langton at the University of Michigan in the 1980s, allows data to evolve within a computer simulation. As in evolution, data that have the strongest set of attributes thrive, while incomplete or lesser data die. A practical application of artificial life would be to model the long-term growth of a business. A fledgling company could be allowed to evolve in the confines of a computerized simulation of the marketplace. Weaknesses in the company's plans would become evident when certain factors are introduced into the business model, similar to disease or predators in the real world. Changes could subsequently be made to the basic structure of the business model to help strengthen the business's resistance to these outside factors. As a result, better business plans could be developed without risk.
A number of automata technologies have been introduced into contemporary use. Voice recognition gives a computer the ability to understand spoken instructions. Natural language enables a computer to understand conversation in the same way that humans understand it—that is, in context, with minor eccentricities, and with incomplete sentence structure. Machine vision allows computers and computer-controlled robots to identify objects using cameras. Expert systems partially mimic human reasoning. Neural nets replicate a human's ability to identify patterns, which is useful for various types of recognition, such as facial features.
But automata progress has been limited by programming techniques. Prior to the 1980s, almost all programming was done by structures designed for numerical processes such as calculating the sum of two numbers. New symbolic processes that use programming language, such as LISP, PROLOG, and C++, use symbolic logic, in which symbols represent the laws of reasoning. These languages and advances in programming techniques have stimulated new interest in automata theory.
Despite these advances, modern computer technology is not expected to take automata beyond the realm of theory for many years. This is due in part to the limitations of speed, storage, and application development of computer technology. In addition, a more definitive view of what actually constitutes human behaviour and intelligence is needed. This latter obstacle is especially difficult to overcome since progress in the medical and psychological sciences constantly changes existing beliefs about the human mind and body.
The history of computing began with an analog machine. In 1623 German scientist Wilhelm Schikard invented a machine that used 11 complete and 6 incomplete sprocketed wheels that could add, and with the aid of logarithm tables, multiply and divide.
French philosopher, mathematician, and physicist Blaise Pascal invented a machine in 1642 that added and subtracted, automatically carrying and borrowing digits from column to column. Pascal built 50 copies of his machine, but most served as curiosities in parlours of the wealthy. Seventeenth-century German mathematician Gottfried Leibniz designed a special gearing system to enable multiplication on Pascal’s machine.
In the early 19th century French inventor Joseph-Marie Jacquard devised a specialized type of computer: a silk loom. Jacquard’s loom used punched cards to program patterns that helped the loom create woven fabrics. Although Jacquard was rewarded and admired by French emperor Napoleon I for his work, he fled for his life from the city of Lyon pursued by weavers who feared their jobs were in jeopardy due to Jacquard’s invention. The loom prevailed, however: When Jacquard died, more than 30,000 of his looms existed in Lyon. The looms are still used today, especially in the manufacture of fine furniture fabrics.
American physicist John Atanasoff built the first rudimentary electronic computer in the late 1930s and early 1940s, although for several decades afterward credit for the first electronic computer went to the scientists who assembled the Electronic Numerical Integrator and Computer (ENIAC) for the United States military by 1945. Danish physicist Allan Mackintosh recounts in a Scientific American article how Atanasoff first conceived of the design principles that are still used in present-day computers.
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Another early mechanical computer was the Difference Engine, designed in the early 1820s by British mathematician and scientist Charles Babbage. Although never completed by Babbage, the Difference Engine was intended to be a machine with a 20-decimal capacity that could solve mathematical problems. Babbage also made plans for another machine, the Analytical Engine, considered the mechanical precursor of the modern computer. The Analytical Engine was designed to perform all arithmetic operations efficiently; however, Babbage’s lack of political skills kept him from obtaining the approval and funds to build it.
Augusta Ada Byron, countess of Lovelace, was a personal friend and student of Babbage. She was the daughter of the famous poet Lord Byron and one of only a few woman mathematicians of her time. She prepared extensive notes concerning Babbage’s ideas and the Analytical Engine. Lovelace’s conceptual programs for the machine led to the naming of a programming language (Ada) in her honour. Although the Analytical Engine was never built, its key concepts, such as the capacity to store instructions, the use of punched cards as a primitive memory, and the ability to print, can be found in many modern computers.
Herman Hollerith, an American inventor, used an idea similar to Jacquard’s loom when he combined the use of punched cards with devices that created and electronically read the cards. Hollerith’s tabulator was used for the 1890 US census, and it made the computational time three to four times shorter than the time previously needed for hand counts. Hollerith’s Tabulating Machine Company eventually merged with two companies to form the Computing-Tabulating-Recording Company. In 1924 the company changed its name to International Business Machines (IBM).
In 1936 British mathematician Alan Turing proposed the idea of a machine that could process equations without human direction. The machine (now known as a Turing machine) resembled an automatic typewriter that used symbols for math and logic instead of letters. Turing intended the device to be a ‘universal machine’ that could be used to duplicate or represent the function of any other existing machine. Turing’s machine was the theoretical precursor to the modern digital computer. The Turing machine model is still used by modern computational theorists.
In the 1930's American mathematician Howard Aiken developed the Mark I calculating machine, which was built by IBM. This electronic calculating machine used relays and electromagnetic components to replace mechanical components. In later machines, Aiken used vacuum tubes and solid state transistors (tiny electrical switches) to manipulate the binary numbers. Aiken also introduced computers to universities by establishing the first computer science program at Harvard University in Cambridge, Massachusetts. Aiken obsessively mistrusted the concept of storing a program within the computer, insisting that the integrity of the machine could be maintained only through a strict separation of program instructions from data. His computer had to read instructions from punched cards, which could be stored away from the computer. He also urged the National Bureau of Standards not to support the development of computers, insisting that there would never be a need for more than five or six of them nationwide.
At the Institute for Advanced Study in Princeton, New Jersey, Hungarian-American mathematician John von Neumann developed one of the first computers used to solve problems in mathematics, meteorology, economics, and hydrodynamics. Von Neumann's 1945 design for the Electronic Discrete Variable Automatic Computer (EDVAC)—in stark contrast to the designs of Aiken, his contemporary—was the first electronic computer design to incorporate a program stored entirely within its memory. This machine led to several others, and some with clever names like ILLIAC, JOHNNIAC, and MANIAC.
American physicist John Mauchly proposed the electronic digital computer called ENIAC, the Electronic Numerical Integrator And Computer. He helped build it along with American engineer John Presper Eckert, Jr., at the Moore School of Engineering at the University of Pennsylvania in Philadelphia. ENIAC was operational in 1945 and introduced to the public in 1946. It is regarded as the first successful, general digital computer. It occupied 167 sq. m (1,800 sq. ft), weighed more than 27,000 kg (60,000 lb), and contained more than 18,000 vacuum tubes. Roughly 2,000 of the computer’s vacuum tubes were replaced each month by a team of six technicians. Many of ENIAC’s first tasks were for military purposes, such as calculating ballistic firing tables and designing atomic weapons. Since ENIAC was initially not a stored program machine, it had to be reprogrammed for each task.
The first commercially available electronic computer, UNIVAC I, was also the first computer to handle both numeric and textual information. Designed by John Presper Eckert, Jr., and John Mauchly, whose corporation subsequently passed to Remington Rand, the implementation of the machine marked the beginning of the computer era. Here, a UNIVAC computer is shown in action. The central computer is in the background, and in the foreground is the supervisory control panel. Remington Rand delivered the first UNIVAC machine to the US Bureau of Census in 1951.
Eckert and Mauchly eventually formed their own company, which was then bought by the Rand Corporation. They produced the Universal Automatic Computer (UNIVAC), which was used for a broader variety of commercial applications. The first UNIVAC was delivered to the United States Census Bureau in 1951. By 1957, there were 46 UNIVACs in use.
Between 1937 and 1939, while teaching at Iowa State College, American physicist John Vincent Atanasoff built a prototype computing device called the Atanasoff-Berry Computer, or ABC, with the help of his assistant, Clifford Berry. Atanasoff developed the concepts that were later used in the design of the ENIAC. Atanasoff’s device was the first computer to separate data processing from memory, but it is not clear whether a functional version was ever built. Atanasoff did not receive credit for his contributions until 1973, when a lawsuit regarding the patent on ENIAC was settled.
A close-up on a smoke detector’s circuit board reveals its components, which include transistors, resistors, capacitors, diodes, and inductors. Rounded silver containers house the transistors that make the circuit work. Transistors are capable of serving many functions, such as amplifier, switch, and oscillator. Each transistor consists of a small piece of silicon that has been ‘doped,’ or treated with impurity atoms, to create n-type and p-type semiconductors. Invented in 1940, transistors are a fundamental component in nearly all modern electronic devices.
In 1948, at Bell Telephone Laboratories, American physicists Walter Houser Brattain, John Bardeen, and William Bradford Shockley developed the transistor, a device that can act as an electric switch. The transistor had a tremendous impact on computer design, replacing costly, energy-inefficient, and unreliable vacuum tubes.
In the late 1960s integrated circuits (tiny transistors and other electrical components arranged on a single chip of silicon) replaced individual transistors in computers. Integrated circuits resulted from the simultaneous, independent work of Jack Kilby at Texas Instruments and Robert Noyce of the Fairchild Semiconductor Corporation in the late 1950s. As integrated circuits became miniaturized, more components could be designed into a single computer circuit. In the 1970s refinements in integrated circuit technology led to the development of the modern microprocessor, integrated circuits that contained thousands of transistors. Modern microprocessors can contain more than 40 million transistors.
Manufacturers used integrated circuit technology to build smaller and cheaper computers. The first of these so-called personal computers (PCs)—the Altair 8800—appeared in 1975, sold by Micro Instrumentation Telemetry Systems (MITS). The Altair used an 8-bit Intel 8080 microprocessor, had 256 bytes of RAM, received input through switches on the front panel, and displayed output on rows of light-emitting diodes (LEDs). Refinements in the PC continued with the inclusion of video displays, better storage devices, and CPUs with more computational abilities. Graphical user interfaces were first designed by the Xerox Corporation, then later used successfully by Apple Computer, Inc. Today the development of sophisticated operating systems such as Windows, the Mac OS, and Linux enables computer users to run programs and manipulate data in ways that were unimaginable in the mid-20th century.
Several researchers claim the ‘record’ for the largest single calculation ever performed. One large single calculation was accomplished by physicists at IBM in 1995. They solved one million trillion mathematical subproblems by continuously running 448 computers for two years. Their analysis demonstrated the existence of a previously hypothetical subatomic particle called a glueball. Japan, Italy, and the United States are collaborating to develop new supercomputers that will run these types of calculations 100 times faster.
In 1996 IBM challenged Garry Kasparov, the reigning world chess champion, to a chess match with a supercomputer called Deep Blue. The computer had the ability to compute more than 100 million chess positions per second. In a 1997 rematch Deep Blue defeated Kasparov, becoming the first computer to win a match against a reigning world chess champion with regulation time controls. Many experts predict these types of parallel processing machines will soon surpass human chess playing ability, and some speculate that massive calculating power will one day replace intelligence. Deep Blue serves as a prototype for future computers that will be required to solve complex problems. At issue, however, is whether a computer can be developed with the ability to learn to solve problems on its own, rather than one programmed to solve a specific set of tasks.
In 1965 semiconductor pioneer Gordon Moore predicted that the number of transistors contained on a computer chip would double every year. This is now known as Moore’s Law, and it has proven to be somewhat accurate. The number of transistors and the computational speed of microprocessors currently doubles approximately every 18 months. Components continue to shrink in size and are becoming faster, cheaper, and more versatile.
With their increasing power and versatility, computers simplify day-to-day life. Unfortunately, as computer use becomes more widespread, so do the opportunities for misuse. Computer hackers - people who illegally gain access to computer systems—often violate privacy and can tamper with or destroy records. Programs called viruses or worms can replicate and spread from computer to computer, erasing information or causing malfunctions. Other individuals have used computers to electronically embezzle funds and alter credit histories. New ethical issues also have arisen, such as how to regulate material on the Internet and the World Wide Web. Long-standing issues, such as privacy and freedom of expression, are being reexamined in light of the digital revolution. Individuals, companies, and governments are working to solve these problems through informed conversation, compromise, better computer security, and regulatory legislation.
Computers will become more advanced and they will also become easier to use. Improved speech recognition will make the operation of a computer easier. Virtual reality, the technology of interacting with a computer using all of the human senses, will also contribute to better human and computer interfaces. Standards for virtual-reality program languages—for example, Virtual Reality Modelling language (VRML)—are currently in use or are being developed for the World Wide Web.
Other, exotic models of computation are being developed, including biological computing that uses living organisms, molecular computing that uses molecules with particular properties, and computing that uses deoxyribonucleic acid (DNA), the basic unit of heredity, to store data and carry out operations. These are examples of possible future computational platforms that, so far, are limited in abilities or are strictly theoretical. Scientists investigate them because of the physical limitations of miniaturizing circuits embedded in silicon. There are also limitations related to heat generated by even the tiniest of transistors.
Intriguing breakthroughs occurred in the area of quantum computing in the late 1990s. Quantum computers under development use components of a chloroform molecule (a combination of chlorine and hydrogen atoms) and a variation of a medical procedure called magnetic resonance imaging (MRI) to compute at a molecular level. Scientists use a branch of physics called quantum mechanics, which describes the behaviour of subatomic particles (particles that make up atoms), as the basis for quantum computing. Quantum computers may one day be thousands to millions of times faster than current computers, because they take advantage of the laws that govern the behaviour of subatomic particles. These laws allow quantum computers to examine all possible answers to a query simultaneously. Future uses of quantum computers could include code breaking and large database queries. Theorists of chemistry, computer science, mathematics, and physics are now working to determine the possibilities and limitations of quantum computing.
Communications between computer users and networks will benefit from new technologies such as broadband communication systems that can carry significantly more data faster or more conveniently to and from the vast interconnected databases that continue to grow in number and type.
Binary logic was first proposed by 19th-century British logician and mathematician George Boole, who in 1847 invented a two-valued system of algebra that represented logical relationships and operations. This system of algebra, called Boolean Algebra, was used by German engineer Konrad Zuse in the 1930s for his Z1 calculating machine. It was also used in the design of the first digital computer in the late 1930's by American physicist John Atanasoff and his graduate student Clifford Berry. During 1944 and 1945 Hungarian-born American mathematician John von Neumann suggested using the binary arithmetic system for storing programs in computers. In the 1930s and 1940s British mathematician Alan Turing and American mathematician Claude Shannon also recognized how binary logic was well suited to the development of digital computers.
The first large-scale digital computers were pioneered in the 1940s. Von Neumann completed the EDVAC (Electronic Discrete Variable Automatic Computer) at the Institute of Advanced Study in Princeton in 1945. Engineers John Eckert and John Mauchly built ENIAC (Electronic Numerical Integrator and Calculator), which began operation at the University of Pennsylvania in 1946. As increasingly complex computers are built, the field of artificial intelligence has drawn attention. Researchers in this field attempt to develop computer systems that can mimic human thought processes.
A child prodigy, American mathematician Norbert Wiener earned his Ph.D. from Harvard University at the age of 18. Wiener contributed to many areas of mathematics and science, but he became famous for developing the field of science called cybernetics. Interdisciplinary in nature, cybernetics is concerned with communication and control systems in living organisms, machines, and organizations.
Mathematician Norbert Wiener, working at the Massachusetts Institute of Technology (MIT), also became interested in automatic computing and developed the field known as cybernetics. Cybernetics grew out of Wiener’s work on increasing the accuracy of bombsights during World War II. From this came a broader investigation of how information can be translated into improved performance. Cybernetics is now applied to communication and control systems in living organisms.
Computers have exercised an enormous influence on mathematics and its applications. As ever more complex computers are developed, their applications proliferate. Computers have given great impetus to areas of mathematics such as numerical analysis and finite mathematics. Computer science has suggested new areas for mathematical investigation, such as the study of algorithms. Computers also have become powerful tools in areas as diverse as number theory, differential equations, and abstract algebra. In addition, the computer has made possible the solution of several long-standing problems in mathematics, such as the four-colour theorem first proposed in the mid-19th century.
The four-colour theorem stated that four colours are sufficient to colour any map, given that any two countries with a contiguous boundary require different colours. Mathematicians at the University of Illinois finally confirmed the theorem in 1976 by means of a large-scale computer that reduced the number of possible maps to slightly less than 2,000. The program they wrote ran thousands of lines in length and took more than 1,200 hours to run. Many mathematicians, however, do not accept the result as a proof because it has not been checked. Verification by hand would require far too many human hours. Some mathematicians object to the solution’s lack of elegance. This complaint has been paraphrased, ‘a good mathematical proof is like a poem - this is a telephone directory.’
Hilbert inaugurated the 20th century by proposing 23 problems that he expected to occupy mathematicians for the next 100 years. A number of these problems, such as the Riemann hypothesis about prime numbers, remain unsolved in the early 21st century. Hilbert claimed, ‘If I were to awaken after having slept for a thousand years, my first question would be: Has the Riemann hypothesis been proven?’
The existence of old problems, along with new problems that continually arise, ensures that mathematics research will remain challenging and vital through the 21st century. Influenced by Hilbert, the Clay Mathematics Institute at Harvard University announced the Millennium Prize in 2000 for solutions to mathematics problems that have long resisted solution. Among the seven problems is the Riemann hypothesis. An award of $1 million awaits the mathematician who solves any of these problems.