THE use of the word ‘good’ has provided a focus for many discussions of basic issues in moral philosophy; while it would be a mistake to think that this word, or its approximate equivalents in other languages, could possibly bear by itself the weight of the issues, nevertheless the consideration of it provides a useful lever for lifting up some of them. We shall start with some logical considerations: these will lead us to things of greater moral substance.

As Aristotle observed, ‘good’ is used of many different sorts of things, of things indeed in different categories. While in one way we do not mean the same when we apply it to these different sorts of things – in this sense, that what makes a general a good general is different from what makes a doctor a good doctor – nevertheless the word is not just ambiguous: we could not tidy language up and say just what we want to say now by replacing ‘good’ with a different expression in each of these occurrences.

More than one theory in recent times has tried to provide a model to show that ‘good’ is genuinely unambiguous. One such attempt was that of G. E. Moore, who claimed that goodness was a simple indefinable property like yellowness, but that, unlike yellowness, it was nonnatural – that is to say (roughly), it was not the sort of property whose presence or absence could be established by empirical investigation, although (in a way left very obscure by his theory) observation of a thing's empirical characteristics was doubtless relevant to the apprehension of goodness.