died on 27 June 1989. From 1980 to 1989 he lived at 51 York Street, Marylebone, where a memorial plaque was unveiled on 19 November 1995. Philosophical ideas In Language, Truth and Logic (1936), Ayer presents the verification principle as the only valid basis for philosophy. Unless logical or empirical verification is possible, statements like "God exists" or "charity is good" are not true or untrue but meaningless, and may thus be excluded or ignored. Religious language in particular is unverifiable and as such literally nonsense. He also criticises C. A. Mace's opinion that metaphysics is a form of intellectual poetry. The stance that a belief in God denotes no verifiable hypothesis is sometimes referred to as igtheism (for example, by Paul Kurtz). In later years, Ayer reiterated that he did not believe in God and began to call himself an atheist. He followed in the footsteps of Bertrand Russell by debating religion with the Jesuit scholar Frederick Copleston. Ayer's version of emotivism divides "the ordinary system of ethics" into four classes: "Propositions that express definitions of ethical terms, or judgements about the legitimacy or possibility of certain definitions" "Propositions describing the phenomena of moral experience, and their causes" "Exhortations to moral virtue" "Actual ethical judgments" He focuses on propositions of the first class—moral judgments—saying that those of the second class belong to science, those of the third are mere commands, and those of the fourth (which are considered normative ethics as opposed to meta-ethics) are too concrete for ethical philosophy. Ayer argues that moral judgments cannot be translated into non-ethical, empirical terms and thus cannot be verified; in this he agrees with ethical intuitionists. But he differs from intuitionists by discarding appeals to intuition of non-empirical moral truths as "worthless" since the intuition of one person often contradicts that of another. Instead, Ayer concludes that ethical concepts are "mere pseudo-concepts": Between 1945 and 1947, together with Russell and George Orwell, Ayer contributed a series of articles to Polemic, a short-lived British "Magazine of Philosophy, Psychology, and Aesthetics" edited by the ex-Communist Humphrey Slater. Ayer was closely associated with the British humanist movement. He was an Honorary Associate of the Rationalist Press Association from 1947 until his death. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1963. In 1965, he became the first president of the Agnostics' Adoption Society and in the