Alfred Jules Ayer was born in London on 29 October 1910. His mother, Reine, was Jewish, and his father, Jules, came from a Swiss Calvinist background. It is clear that from a very early age Ayer was disinclined to believe in any religion. It is reported that, on winning a scholarship to Eton when he was thirteen, he made himself unpopular with his fellow students due to his evangelical atheism (he reports to being “a very militant atheist from the age of about sixteen onwards”; Honderich 1991: 212). The first philosophical book Ayer read was Bertrand Russell's Sceptical Essays, and he was much impressed by Russell's advice never to believe a proposition if there was no reason for thinking it true (Rogers 1999: 45). This, he said, remained a motto for him throughout his philosophical career. It appears that he never found a reason for believing any religious doctrine to be true.

Ayer's atheism became, in fact, more radical and a bit more complicated, as he was to form the belief that typical religious statements, such as those about a transcendent deity, were not so much false as meaningless or nonsensical. This view was formed under the influence of an empiricist theory of meaning incorporating a criterion of meaning, the verification principle. The core of the verification principle was that for a statement to be cognitively (or empirically) meaningful, that statement had to be capable of being directly or indirectly ‘verified’. That is, the statement had to be capable of being supported by sensory experience.