Moore states that defining the "province of Ethics" requires identifying "the whole truth about that which is at the same time common to all such judgments and peculiar to them." Explain why this specific formulation makes the task of defining ethics significantly more challenging than simply listing examples, and what the philosophical implications are if this "common and peculiar" aspect remains elusive.

From the book

sing a point of Ethics. So much as this is not disputed; but it falls very far short of defining the province of Ethics. That province may indeed be defined as the whole truth about that which is at the same time common to all such judgments and peculiar to them. But we have still to ask the question: What is it that is thus common and peculiar? And this is a question to which very different answers have been given by ethical philosophers of acknowledged reputation, and none of them, perhaps, completely satisfactory. 2 . If we take such examples as those given above, we shall not be far wrong…

end our ethical principles in any way whatever, we shall also be much less apt to defend them well, even if illogically. For we shall start with the conviction that good ​ must mean so and so, and shall therefore be inclined either to misunderstand our opponent’s arguments or to cut them short with the reply, ‘This is not an open question: the very meaning of the word decides it; no one can think otherwise except through confusion.’ 15 . Our first conclusion as to the subject-matter of Ethics is, then, that there is a simple, indefinable, unanalysable object of thought by reference to which…

er meaning. We may, in the third place, mean to ask, not what thing or things are good, but how ‘good’ is to be defined. This is an enquiry which belongs only to Ethics, not to Casuistry; and this is the enquiry which will occupy us first. It is an enquiry to which most special attention should be directed; since this question, how ‘good’ is to be defined, is the most fundamental question in all Ethics. That which is meant by ‘good’ is, in fact, except its converse ‘bad,’ the only simple object of thought which is peculiar to Ethics. Its definition is, therefore, the most essential point in…

sure. He might just as well try to prove that an orange is yellow by shewing that it is always wrapped up in paper. 13 . In fact, if it is not the case that ‘good’ denotes something simple and indefinable, only two alternatives are possible: either it is a complex, a given whole, about the correct analysis of which there could be disagreement; or else it means nothing at all, and there is no such subject as Ethics. In general, however, ethical philosophers have attempted to define good, without recognising what such an attempt must mean. They actually use arguments which involve one or both…

culiarity of the whole which we are defining: for every whole contains some parts which are common to other wholes also. There is, therefore, no intrinsic difficulty in the contention that ‘good’ denotes a simple and indefinable quality. There are many other instances of such qualities. Consider yellow, for example. We may try to define it, by describing its physical equivalent; we may state what kind of light-vibrations must stimulate the normal eye, in order that we may perceive it. But a moment’s reflection is sufficient to shew that those light-vibrations are not themselves what we mean…