Relativism is weirdly seductive. In our sane moments we know perfectly well that the world doesn’t depend on us. Yet we – some of us anyway – are easily excited by statements like ‘even reality is relative’. 1 Perhaps we get intoxicated by the suggestion that we have the power to construct our own reality. Certainly the ways we think about the world depend on us: on our capacities, interests, values, temperaments, points of view. The world really does strike different people in different ways. We really do think up our own theories. All that is admitted by any sensible realist. But it provides no grounds for relativism.