In Living with Difference, a think-tank report on the problems raised by a multi-faith UK, the chair Baroness Butler-Sloss says that the recommendations amount to a ‘new settlement for religion and belief in the UK’ and are aimed at providing space and a role in society for all citizens, ‘regardless of their beliefs or absence of them’. This is what happens when good people decide this messy world needs to be hammered into an intellectually satisfying shape.

Plato’s Republic is a very good example of the genre. It is an extraordinarily interesting document, telling one a very great deal about Plato and the ancient Greeks, deeply influential on intellectuals down the millennia, and complete tosh from start to finish. Composed c. 380 bc, it is a conversation between Socrates and some chums in a house in Athens’ port area Piraeus. This turns on what is meant by ‘justice’, and Socrates, having duly shot down two definitions (‘helping friends and harming enemies’, and ‘the interests of the stronger’), suggests they think not about personal justice but what a just city might look like.

They decide that the city should be run by a select ruling class called ‘guardians’, both male and female, who should be educated in wisdom, courage, justice, self-control, gym (they must not need medical attention), maths and dialectic. The aim is to turn them into philosopher-kings. To ensure a healthy line of potential future philosophers, the state should control their mating and reproduction and the communal care of the children. By the age of 50, those who have come up to philosophical scratch should be ready to rule — something only philosophers, who alone know what is good, can be allowed to do. Everyone else will be assigned tasks suited to them in three areas: the military, farming and trading. There will be no place for luxuries or the arts, especially poetry and the theatre. And so on.

The Living with Difference report suggests sidelining Christianity. So bang go 2,000 years of our history and culture. We must be grateful that think-tanks are not action-tanks.