British philosopher Alfred Jules Ayer, born in London on 29 October 1910, was at the same time a proponent of logical positivism and an original thinker with respect to some of its central themes.
Ayer graduated in Oxford (B.A. 1932; M.A. 1936), where while in contact with the empiricist Henry H. Prince he became interested to the philosophical problem of perception. In 1932, during a stay in Vienna, he was exposed to logical positivism. He began teaching at the University of Oxford in 1932. He was elected a fellow of Wadham College in 1944 and named dean in 1945. From 1946 to 1959 Ayer was a professor and Dean of the Arts Faculty at University College, London. In 1959 he returned to Oxford, where he was Wykeham Professor of Logic and Fellow of New College until 1978, and Fellow of Wolfson College in 1978–1983. At several periods he taught or lectured in the United States. In 1952 Ayer was named a Fellow of the British Academy (FBA), and he was knighted in 1970. He died 27 June 1989.
Ayer gained international notice with his first book, Language, Truth and Logic, published in 1936, where both his endorsement and development of the ideas of logical positivism, which the book helped to popularise in English-speaking countries, are first presented. Here Ayer adopts the distinction introduced by Hume between assertions expressing relations among ideas and assertions expressing factual judgments, and adopts the neo-empiricist principle of verification, according to which a synthetic assertion is only meaningful if it is possible to assert its truth or falsity on the basis of observation. Reference to Hume is also essential in accounting for the main differences between Ayer’s philosophy and that of the Vienna circle, in that these may be spelt out in terms of his acceptance of Hume’s theory of causality (and rejection of necessary connections), as well as in Ayer’s idea that a synthetic statement can never be conclusively proven or disproven.
Ayer believed that large parts of what was traditionally called ‘philosophy’—including metaphysics, theology and aesthetics—were not matters that could be judged as being true or false and that it was thus meaningless to discuss them. His main interests lay in the theory of knowledge and in the philosophy of language; in the fifties and sixties he developed some sympathy for the philosophy of ordinary language, although he always opposed the views of Wittgenstein and his followers.
His publications include: Language, Truth and Logic (1936; rev. ed., 1946); The Foundations of Empirical Knowledge (1940); The Problem of Knowledge (1956); The Origins of Pragmatism (1968); Russell and Moore: The Analytical Heritage (1971); The Central Questions of Philosophy (1973); and Wittgenstein (1985). His autobiography was published in two volumes: Part of My Life (1977) and More of My Life (1984).