Sir Alfred Jules (“Freddie”) Ayer (1910–1989) was the British logical positivist who became famous for his Language, Truth and Logic (1936), which was followed by The Problem of Knowledge (1956). Ayer’s main contribution was to relate logical positivism to traditional philosophy, which in no uncertain terms resulted in a devastating attack on metaphysics, ethics, and religion. The attack was on the meaning of terms used in these fields and resulted in the claim that they were meaningless.

Ayer was the Grote Professor of the Philosophy of Mind and Logic at the University College London from 1946 until 1959, and after that the Wykeham Professor of Logic at the University of Oxford. From 1951 to 1952 he was president of the prestigious Aristotelian Society. In 1973 he became a Knight in the Legion of Honor.

Ayer’s publications include Philosophical Essays (1954), The Concept of a Person and Other Essays (1956), The Origins of Pragmatism (1958), Metaphysics and Common Sense (1969), Russell and Moore: The Analytical Heritage (1971), Probability and Evidence (1972), Bertrand Russell (1972), The Central Questions of Philosophy (1973), Hume (1980), Philosophy in the Twentieth Century (1982), Freedom and Morality and Other Essays (1984), Ludwig Wittgenstein (1986), Part of My Life (1977), and More of My Life (1984), as well as numerous articles on related topics.