A. J. Ayer

A. J. Ayer (1910-1989), British philosopher who influenced the development of contemporary analytic philosophy. Ayer was born in London and educated at Eton College and the University of Oxford. He went on to teach at the universities of Oxford and London and became Wykeham Professor of Logic at Oxford in 1959.

Ayer's first book, Language, Truth, and Logic (1936), remains his best-known work. It was an enthusiastic and influential expression of logical positivism. Although he would later modify his views, at this time Ayer enthusiastically promoted the verification principle, according to which a statement is meaningful if and only if we know which sensory experiences would count towards its truth or falsity. Using this criterion, Ayer attempted to show that many of the traditional claims of philosophy, as well as all statements about God (see below), were meaningless.

The verification principle was construed very strictly by Ayer, as implying that the entire meaning of any statement must ultimately be expressible on a purely sensory level (that is, in terms of “sense-contents”). Thus he embraced phenomenalism: all talk of physical objects must in principle be able to be replaced by a (very complex) set of sentences referring only to sense-contents. Similarly, all statements ostensibly about unobservables (for example, all talk of electrons) Ayer held to be meaningful only on the basis that they could be regarded as a shorthand way of referring to observable phenomena—and hence, ultimately, to sense-contents. By the same token, he rejected as meaningless all talk about God; for God was the supposedly unobservable cause of observed effects, such as the beauty of nature.

Truths of logic and pure mathematics posed a problem for Ayer, since on the face of it they are independent of the test of sensory experience. Ayer regarded such statements as illustrating conventions of language rather than as giving genuine information. Moral and aesthetic value judgements were held by Ayer to have only emotive meaning. They express approval or disapproval, but the addition of, for example, “ ... is good” or “ ... is ugly” to a phrase adds no new information. On this view (known as emotivism) moral and aesthetic expressions are ultimately expressions of attitude, and cannot be said to be either true or false.

The verification principle attracted much discussion and criticism, and Ayer himself came to see it as having a number of problems. One is that verifiability is not a precise enough notion to serve as a criterion of meaning. Thus, initially, Ayer assumed that verification must be possible in principle for an observer here and now; but later he postulated an ideal observer, able to range in space and time. The latter interpretation would clearly make the test of verification easier to pass, and would lead to more sentences being counted as meaningful.

Subsequently, Ayer modified his position on many of the positions taken in Language, Truth, and Logic. He came to think that it was not necessary that the meaning of any statement be wholly expressible in terms of sense-contents: it was enough for it to have some consequences for sense-experience. In addition, Ayer came to doubt whether it was even possible to translate talk about physical objects fully into talk of sense-contents. However, he continued to maintain a strongly empiricist stance, taking sensory experience as his starting-point.

With regard to other philosophers working in the field around the same time, Ayer retained a greater admiration for the work of Bertrand Russell than that of Ludwig Wittgenstein, and his approach to philosophical problems was often somewhat out of step with that prevailing in Britain in the latter half of the 20th century. Nevertheless, Ayer always defended a position well and lucidly, both in print and in discussion, and his views continue to be respected.

To the end, Ayer remained sceptical of the existence of a deity, despite undergoing a strange experience, as if of an afterlife, when, during an illness, his heart stopped beating for several minutes. Ayer's account of this is contained in The Philosophy of A. J. Ayer (1992), by L. Hahn.

Other of Ayer's works include The Problem of Knowledge (1956), the Gifford Lectures of 1972-1973 published as The Central Questions of Philosophy (1973), and Part of My Life: The Memoirs of a Philosopher (1977). He also produced works on other philosophers, including Russell and Moore (1971).