All of us are, more or less, in trouble today about trying to understand cultures strange to us. We hear constantly of alien customs. We see changes in our lifetime which would have astonished our parents. I want to discuss here one very short way of dealing with this diﬃculty, a drastic way which many people now theoretically favour. It consists in simply denying that we can ever understand any culture except our own well enough to make judgements about it. Those who recommend this hold that the world is sharply divided into separate societies, sealed units, each with its own system of thought. They feel that the respect and tolerance due from one system to another forbids us ever to take up a critical position to any other culture. Moral judgement, they suggest, is a kind of coinage valid only in its country of origin.