Socrates was sentenced to death for corrupting the youth of Athens. Why? He had publicly questioned the authority of the city's gods to legislate how we should live. His more or less explicit prioritisation of ethics over state religion was subversive. If social moral standards are not dependent on the whims of the gods – if the gods don’t determine the standards we should live by – then individuals appear to be licensed to think for themselves.

Plato, who agreed with his teacher that gods can’t underwrite social morality, postulated a realm of transcendent value in the place of gods. Where a god might command and punish, Plato’s transcendent value was supposed to inspire and be loved by all who glimpsed it. Nietzsche went further, proclaiming the death of God and of transcendent value too. On his proposal, conventional social morality is only an ideological social construct developed by the physically weak to subjugate the physically strong. An all-powerful ethically authoritative god is a rhetorical conceit to sustain an illusion of transcendent value – an illusion that we would do better without.

If we cease to believe in the existence of gods or transcendent value, is there yet any reason to act as social morality requires? Can our practices survive even if their imagined foundations are exposed as sham – just as Christmas celebrations might survive without belief in Jesus or Santa Claus? If we give up belief in gods or transcendent value but continue to hold everyone to conventional moral standards, is it, as Elizabeth Anscombe writes in 1957, “as if the notion ‘criminal’ were to remain when criminal law and criminal courts had been abolished”?