"Sir Alfred Jules" ""Freddie"" "Ayer" was a British philosopher known for his promotion of logical positivism, particularly in his books Language, Truth, and Logic (1936) and The Problem of Knowledge (1956).
Ayer was a Special Operations Executive and MI6 agent during the Second World War. He was the Grote Chair of the Philosophy of Mind and Logic/Grote Professor of the Philosophy of Mind and Logic at University College London from 1946 until 1959, when he became Wykeham Professor of Logic at the University of Oxford. He was president of the Aristotelian Society from 1951 to 1952. He was knighted in 1970.More A. J. Ayer on Wikipedia.