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Alfred Jules Ayer

Alfred Jules Ayer

Alfred Jules Ayer (1910-1989) was a leading philosopher of the 20th century who rigorously attacked metaphysics. His major work was Language, Truth and Logic.

Alfred Jules Ayer was born in 1910. He was educated at Eton and Oxford University. After his graduation from Oxford, he studied at the University of Vienna, concentrating on the philosophy of Logical Positivism. From 1933 to 1940 he was lecturer in philosophy at Christ Church (College), Oxford. During World War II he served in the Welsh Guards and was also engaged in military intelligence. In 1945, he returned to Oxford where he became a fellow and Dean of Wadham College. In the following year, he became Grote Professor of the Philosophy of Mind and Logic at University College, London. In 1959, he returned to Oxford, where he became Wykeham Professor of Logic, a position he held until his retirement in 1978. He was elected a fellow of the British Academy in 1952 and honorary fellow of Wadham College, Oxford, in 1957. Among his many awards, Ayer received an honorary doctorate from Brussels University in 1962 and was knighted in 1970. He was also an honorary member of the American Academy of Arts and Sciences and chevalier of the Legion d'Honneur.

Contributions to Philosophy

Ayer's books include: Bertrand Russell: Philosopher of the Century (Contribution), 1967; British Empirical Philosophers (editor with Raymond Winch), (1952); The Central Questions of Philosophy (1973); The Concept of a Person (1963); The Foundations of Empirical Knowledge (1940); Freedom and Morality and Other Essays (1984); Hume (1980); Language, Truth and Logic (1956); Logical Positivism (editor), (1960); Metaphysics and Common Sense (1970); The Origins of Pragmatism: Studies in the Philosophy of Charles Sanders Peirce and William James (1968); Philosophical Essays (1954); Philosophy in the Twentieth Century (1982); Probability and Evidence (1972); The Problem of Knowledge (1956); The Revolution in Philosophy (Contribution), (1956); and Russell and Moore; The Analytical Heritage (1971).

Language, Truth and Logicis one of Ayer's most important books and may be considered as one of the most influential philosophical works of the 20th century. In the second edition (1946), Ayer clarified some of his ideas and replied to his critics, but essentially his philosophical position remained the same. He called his philosophy "logical empiricism," a variation of logical positivism, the philosophical orientation he learned in Vienna. He was largely influenced by the thought of the 20th century philosophers Bertrand Russell and Ludwig Wittgenstein and by the earlier empiricism of George Berkeley and David Hume.

The book is a milestone in the development of philosophical thought in the 20th century. The implications of Ayer's "logical empiricism" would be felt by many branches of the discipline of philosophy, especially metaphysics, ethics, and philosophy of religion, and also logic, mathematics, and the philosophy of science. Although Ayer acknowledged the influences upon his philosophical perspective, he remained an independent thinker, accepting no position uncritically.

Ayer asserted that the criterion of meaning is found in the "verification principle": "We say that a sentence is factually significant to any given person if, and only if, he knows how to verify the proposition which it purports to express—that is, if he knows what observations would lead him, under certain conditions, to accept the proposition as being true, or reject it as being false." (Language, Truth and Logic). The a priori statements of logic and mathematics do not claim to provide factual content. Those statements can be said to be true only because of the conventions which govern the use of the symbols that make up the statements.

Ayer was known in the 20th century for his rigorous attack on metaphysics and as the main representative of the British empirical tradition. Genuine statements are either logical or empirical. Metaphysical statements do not purport to express either logical truths or empirical hypotheses. For that reason, metaphysical statements are pseudo-statements and do not have any meaning. The metaphysician had been tied to the attempt to construct a deductive system of the universe from "first principles." These first principles, Ayer argued, can never be derived from experience. They are merely hypotheses. As a priori principles, they are hypotheses only, and therefore are tautologies and notcertain empirical knowledge.

Theology, as a special branch of metaphysics which attempts to gain knowledge that transcends the limits of experience (for example, the affirmation of the existence of God) is not only false but it too has no meaning. Value statements in ethics and aesthetics are also meaningless, not genuine statements, and can be understood as emotive utterances of an imperative character.

Ayer therefore discovered for philosophy a function in the 20th century. Once the traditional tasks of philosophy have been discarded, philosophy can be seen as an intellectual discipline which endeavors to clarify the problems of science. Philosophy is, therefore, finally identical with the logic of science.

In Language, Truth and Logic Ayer argued that it is the task of the philosopher to give a correct definition of material things in terms of sensation. The philosopher does not deal with the properties of things in the world, but only with the way we speak of them. The propositions of philosophy are not factual, but linguistic in character: " (Propositions) … do not describe the behavior of physical, or even mental, objects; they express definitions, or the factual consequences of definitions."

In the second edition of Language, Truth and Logic, Ayer provided an extended reworking of his notion of the verification principle. It was this principle which was chiefly criticized by the philosophical commentators. It would seem that the verification principle, as formulated by Ayer, is a kind of meaningless metaphysical statement that the verification principle itself was supposed to prohibit.

In his later works, Ayer proceeded boldly, and with wisdom and clarity, to deal with the major problems that have confronted and confounded other 20th century philosophers: such problems as perception, induction, knowledge, meaning, truth, value theory, other minds, the mind-body dichotomy, personal identity, and intention. Ayer was always an original and bold thinker who, in later life, espoused a more selective assessment of metaphysics due to the works of his trusted colleagues. His views on death, dying and the afterlife were slightly altered after briefly dying for four minutes and subsequently being revived. His death on June 27, 1989 marked the end of the second golden age of British philosophy.

Further Reading

Ayer provided an autobiographical volume which is filled with trenchant philosophical insights about the role of the philosopher in the 20th century; A. J. Ayer, Part of My Life: The Memoirs of a Philosopher (1977). Ayer was a popular broadcaster for the British Broadcasting Company (BBC). One of the most exciting broadcasts was in the form of a debate with a Jesuit Christian philosopher; see "Logical Positivism—A Debate" delivered on the BBC June 13, 1949, with A. J. Ayer and F. C. Copleston, published in P. Edwards and A. Pap (editors), A Modern Introduction to Philosophy (1957). Among the many commentators of A. J. Ayer's philosophical perspective, the following are helpful: Carl G. Hempel, Aspects of Scientific Explanation (1965); Viktor Kraft, The Vienna Circle: The Origin of Neo-Positivism (1969); John Wisdom, "Note on the New Edition of Professor Ayer's Language, Truth and Logic," reprinted in Wisdom's Philosophy and Pyscho-analysis (Oxford, 1953); H. H. Price, "Critical Notice of A. J. Ayer's The Foundation of Empirical Knowledge," in Mind (1941); H. H. Price, "Discussion: Professor Ayer's Essays," in Philosophical Quarterly (1955); D. J. O'Connor, "Some Consequences of Professor A. J. Ayer's Verification Principle," in Analysis (1949-1950); W. V. O. Quine, "Two Dogmas of Empiricism," in From a Logical Point of View (1953).

Reflections on Ayer's legacy can be found in "The Logical End of an Empire, " Economist (July 8, 1989) and "Logic in High Gear, " Spectator (July 8, 1989). □

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Ayer, Alfred Jules (1910–1989)


Alfred Jules Ayer, the British philosopher, received his education at Eton, where he was a king's scholar, and at Christ Church, Oxford. After graduating in 1932, he spent some time at the University of Vienna familiarizing himself with the logical positivist movement, then little known among English-speaking philosophers. He returned to Oxford in 1933 as a lecturer in philosophy at Christ Church and in 1935 became a research fellow of the college. Army service in World War II kept him from philosophy until 1945, when he went back to university teaching as fellow and dean of Wadham College, Oxford. In the following year he became Grote professor of the philosophy of mind and logic at University College, London, where he remained until his return to Oxford as Wykeham professor of logic in 1959.

Ayer's first book, Language, Truth and Logic, was published in 1936. Its combination of lucidity, elegance, and vigor with an uncompromisingly revolutionary position has made it one of the most influential philosophical books of the century. As Ayer explains in the preface, the views he advocates derive from Bertrand Russell and Ludwig Wittgenstein among modern philosophers and from the earlier empiricism of George Berkeley and David Hume and have much in common with the logical positivism of the Vienna circle. But he accepts none of these influences uncritically and clearly puts his own stamp on the position he outlines. He adopts Hume's division of genuine statements into logical and empirical, together with a principle of verification that requires that an empirical statement shall not be counted as meaningful unless some observation is relevant to its truth or falsity. This starting point has drastic and far-reaching results. Metaphysical statements, since they purport to express neither logical truths nor empirical hypotheses, must accordingly be reckoned to be without meaning. Theology is a special case of metaphysics; affirmations of divine existence are not even false, they are without sense. For the same reason, value statements in ethics or aesthetics fail to attain the status of genuine statements and are exposed as expressions of emotion with imperative overtones. The a priori statements of logic and mathematics are empty of factual content and are true in virtue of the conventions that govern the use of the words that compose them. The tasks left for philosophy after this withdrawal from its traditional boundaries are those of solving by clarification the problems left untouched by the advance of the sciences. Philosophy is an activity of analysis and is seen, in the end, to be identical with the logic of science.

The second edition of the book (1946) contains an introduction that modifies, though it does not retract, the main theses of the first edition. Ayer's attention here is directed chiefly to giving a precise formulation of the principle of verification. His original version is replaced by a much more elaborate and carefully worded formula. Both versions have, however, been shown to be faulty in admitting as meaningful metaphysical statements of precisely the kind that the principle is designed to outlaw. Indeed, there seems to be a weakness of the principle in that, it appears plausible only when its expression is left uncomfortably vague.

The Foundations of Empirical Knowledge (1940) is concerned with two groups of problems, those of perception and those of "the ego-centric predicament" (privacy and publicity in language and in sense experience and the problem of other minds). The most interesting and original feature of the book is Ayer's treatment of the terminology of sense data as a language in which the problems of perception can be most appropriately dealt with rather than as a thesis embodying a discovery about the facts of sense experience. Thinking and Meaning (1947) was Ayer's inaugural lecture in the University of London. It is a trenchant application of Ockham's razor to the problems of intentionality and the relations between minds, thinking objects, words, and meaning. This short, powerful essay has so far received less than its due of critical attention. Philosophical Essays (1954) is a collection of papers ranging over philosophical logic, the theory of knowledge, and moral philosophy. Half the papers are carefully argued treatments of problems raised in Ayer's first two books; in particular, "The Analysis of Moral Judgements" is a moderate and persuasive restatement of the hints on ethics thrown out in Language, Truth and Logic.

In 1956 Ayer published The Problem of Knowledge, his most important book since his first was published in 1936. It is a sympathetic and constructive treatment of the various problems of philosophical skepticism. After a short discussion of philosophical method and the nature of knowledge, he discusses at length the pattern of skeptical arguments. He then examines three problems familiar from his earlier workperception, memory, and other mindsas instances of skepticism at work. It may be that no statement is immune from doubt, but this does not entail that no statement can be known to be true. Where statements cannot, even in principle, be justified, we may conclude not that they are to be rejected but rather that no justification is called for.

The Concept of a Person (1963) is a collection of essays. The most striking, the one that gives the book its title, is a notable survey of some aspects of the problems of body, mind, and personal identity. The outcome can be roughly summarized as follows: To say that I own a mental state M is to say that there is a physical body B by which I am identified and that a state of B causes M.

Ayer's Shearman Lectures at the University of London in 1964 were on induction and probability. This was a new field of interest for Ayer, although it was foreshadowed in two papers in The Concept of a Person.

Ayer's work is very much of a piece, both in style and attitude. He became more catholic in interest and more cautious and temperate in expression than in his earlier writings. But his arguments were informed by the same principles and set out with the same grace and clarity. He leaned perhaps too heavily on Hume's dichotomy of statements into logical and factual, and he has not so far set himself seriously to meet contemporary criticisms (particularly those of W. V. O. Quine) that have been made of this famous distinction. This is at once a weakness of his present position and, perhaps, a presage of its future development.

Ayer died on June 29, 1989. He was professionally active virtually until the time of his death. In recognition of his accomplishments and public service, Ayer was Knighted in 1968. The following year he published both Metaphysics and Common Sense, a set of essays on diverse topics, and also The Origins of Pragmatism, an account of the philosophies of William James and Charles Sanders Peirce. In 1970 Ayer presented the William James lectures at Harvard in which he discussed the thought of G. E. Moore and Bertrand Russell. In that same year he gave the John Dewey lectures at Columbia University in which he revisited induction and probability, the topic of his 1964 Shearman lectures at the University of London. Ayer's The Central Questions of Philosophy (1974) is regarded by some as a new and refined version of his classic work Language, Truth and Logic. After serving for almost twenty years as Wykeham professor of logic at Oxford, Ayer retired from the position in 1978. Shortly thereafter a festschrift Perception and Identity was published in his honor, which contained essays by prominent thinkers and Ayer's replies to them. In 1982 Ayer offered his Philosophy in the Twentieth Century as a possible sequel to Bertrand Russell's History of Western Philosophy. He published interpretations of Ludwig Wittgenstein in 1985, Voltaire in 1986, and Thomas Paine in 1988. He also wrote two autobiographical volumes: Part of My Life (1977) and More of My Life (1984). His rather lengthy obituary in The Times of London concludes with these words: "Ayer was not a major philosopher like Russell or Wittgenstein, or even, perhaps like Popper and Ryle. But he was a very able philosopher indeed, endowed with particularly sparkling intellectual gifts, an admirable if slightly chilly prose style and unflagging energy. As a philosophical teacher and influence there is no one to compare with him since Russell and Moore."

See also Analytic and Synthetic Statements; Basic Statements; Berkeley, George; Ethics, History of; Hume, David; Logical Positivism; Other Minds; Personal Identity; Private Language Problem; Quine, Willard Van Orman; Russell, Bertrand Arthur William; Skepticism, History of; Verifiability Principle; William of Ockham; Wittgenstein, Ludwig Josef Johann.


works by ayer


Language, Truth and Logic. London: Gollancz, 1936; 2nd ed., 1946.

The Foundations of Empirical Knowledge. London: Macmillan, 1940.

Thinking and Meaning. London: Athlone Press, 1947.

Philosophical Essays. London: Macmillan, 1954.

The Problem of Knowledge. London: Macmillan, 1956.

The Concept of a Person. London: Macmillan, 1963.

The Origins of Pragmatism. London: Macmillan, 1968.

Metaphysics and Common Sense. London: Macmillan, 1969.

Russell and Moore: The Analytical Heritage. London: Macmillan, 1971.

Probability and Evidence. London: Macmillan, 1972.

Bertrand Russell. London: Fontana, 1972.

The Central Questions of Philosophy. London: Weidenfeld, 1973.

Part of My Life. London: Collins, 1977.

Hume. Oxford: Oxford University Press, 1980.

Philosophy in the Twentieth Century. London: Weidenfeld, 1982.

Freedom and Morality and Other Essays. Oxford: Clarendon Press, 1984.

More of My Life. London: Collins, 1984.

Ludwig Wittgenstein. London: Penguin, 1986.

Articles and Symposium Pieces

"Jean-Paul Sartre." Horizon (1945).

"Albert Camus." Horizon (1945).

"Some Aspects of Existentialism." Rationalist Annual (1948).

"Logical PositivismA Debate." Delivered on the BBC June 13, 1949. The participants were Ayer and F. C. Copleston. Published in A Modern Introduction to Philosophy, edited by P. Edwards and A. Pap (Glencoe, IL: Free Press, 1957).

"Professor Malcolm on Dreaming." Journal of Philosophy (1960): 517535. Malcolm's reply, with Ayer's rejoinder, Journal of Philosophy (1961), 294299.

works on ayer

For critical discussion of Ayer, see John Wisdom, "Note on the New Edition of Professor Ayer's Language, Truth and Logic," Mind 57 (228) (1948): 401419, reprinted in Wisdom's Philosophy and Psycho-analysis (Oxford: Blackwell, 1953); H. H. Price, "Critical Notice of A. J. Ayer's The Foundations of Empirical Knowledge," Mind 50 (199) (1941): 280293; H. H. Price, "Discussion: Professor Ayer's Essays," Philosophical Quarterly (1955); D. J. O'Connor, "Some Consequences of Professor A. J. Ayer's Verification Principle," Analysis (19491950); W. V. O. Quine, "Two Dogmas of Empiricism," in From a Logical Point of View (Cambridge, MA: Harvard University Press, 1953); M. Lazerowitz, "Strong and Weak Verification I," Mind (1939) and "Strong and Weak Verification II," Mind (1950), reprinted in Lazerowitz's The Structure of Metaphysics (London: Routledge and Paul, 1955).

Austin, J. L. Sense and Sensibilia. Oxford: Clarendon Press, 1962.

Church, A. "Review of Language, Truth, and Logic. " Journal of Symbolic Logic (1949): 14:5253.

Foster, J. A. J. Ayer. London: Routledge & Kegan Paul, 1985.

Griffiths, A. P. A. J. Ayer Memorial Essays. Cambridge, U.K.: Cambridge University Press, 1991.

Hahn, L. E. The Philosophy of A. J. Ayer. La Salle, IL: Open Court, 1992.

Hanfling, O. Ayer. London: Routledge, 1999.

Honderich, T. Essays on A. J. Ayer. Cambridge, U.K.: Cambridge University Press, 1991.

Macdonald, G., ed. Perception and Identity. London: Macmillan, 1979.

Macdonald, Graham, and C. Wright, eds. Fact, Science, and Morality. Oxford: Blackwell, 1986.

Martin, R. On Ayer. Belmont, CA: Wadsworth, 2000.

Rogers, Ben. A. J. Ayer: A Life. London: Grove Press, 2002.

D. J. O'Connor (1967)

Donald M. Borchert (2005)

Bibliography updated by Michael J. Farmer (2005)

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"Ayer, Alfred Jules (1910–1989)." Encyclopedia of Philosophy. . 22 Apr. 2017 <>.

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