Ayer was Wykeham professor of logic at Oxford, where he completed his education in 1932. Through his early association with the Austrian group of philosophers known as the Vienna Circle, he became a logical positivist. In 1936, he published his best-known book Language, Truth and Logic, one of the most influential philosophical essays of the twentieth century. In it, Ayer defended the logical positivist doctrine known as the verification principle, which states that the meaning of any statement is its method of verification. According to this view, which was adopted in order to eliminate all metaphysics, a statement is meaningful if and only if it is either analytic or verifiable by empirical means. Thus, many utterances are pseudo-statements, since they do not express any matter of fact even though they have the grammatical appearance of doing so. Such utterances are therefore neither true nor false. Moral utterances conform to this analysis. So-called “judgments of value” of the form “x is good” are not factual judgments at all; instead, they are emotional judgments (reports) meaning “x is pleasant” or “x is desired.” This view of the nature of moral judgments came to be called “emotivism.” For Ayer, who was an atheist, moral philosophy is reducible to the metaethical analysis of the meaning of ethical terms.