If debating the Enlightenment has become tedious, one reason is that it has produced so many exercises in what old-fashioned religious believers still describe as apologetics – the defence of a pre-existing system of belief. Some of the many recent defences of the Enlightenment are better argued than others. What all of them have in common is that they aim to silence any doubt as to the truth of the creed. Mixing large doses of soothing moral uplift with hectoring attacks on those who wilfully turn their backs on the light, these secular sermons lack the flashes of humour and scepticism that redeem more traditional types of preaching.

Adamant certainty is the unvarying tone. Yet beneath the insistent didacticism of these apologists there is more than a hint of panic that the world has not yet accepted the rationalist verities that have been so often preached before. If the Enlightenment really does embody humanity’s most essential hopes, why do so many human beings persistently refuse to sign up to it?

— John Gray