Alfred Jules Ayer was born at 8 Neville Court, Abbey Road, in St John’s Wood in 1910 to a wealthy family from continental Europe. His mother was from the Dutch-Jewish family who founded the Citroen car company in France, while his father was a Swiss Calvinist financier who worked for the Rothschild family.
After graduation from Oxford University in 1936 he published his first book on the subject of logical positivism. In World War 11 he served as an officer , chiefly in Intelligence and MI6, and after the war he was Professor of the Philosophy of Mind and Logic at University College London for 13 years, after which he returned to Oxford to become Professor of Logic at New College. He was a Fellow of the British Academy and he was knighted in 1970.
He was married four times to three women. First was to Renee, the second was to Dee Wells with whom he had one son, the third was to Vanessa Salmon, former wife of Nigel Lawson, the politician. She died two years later and four years later he remarried Dee Wells. He died in London in 1989, aged 78. From 1980 to 1989 Ayer lived at 51 York Street, Marylebone where a memorial plaque was unveiled in 1995.