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 the definition of Ethics; and moreover a mistake with regard to it entails a far larger number of erroneous ethical judgments than any other. Unless this first question be fully understood, and its true answer clearly recognised, the rest of Ethics is as good as useless from the point of view of systematic knowledge. True ethical judgments, of the two kinds last dealt with, may indeed be made by those who do not know the answer to this question as well as by those who do; and it goes without saying that the two classes of people may lead equally good lives. But it is extremely unlikely that the _most general_ ethical judgments will be equally valid, in the absence of a true answer to this question: I shall presently try to shew that the gravest errors have been largely due to beliefs in a false answer. And, in any case, it is impossible that, till the answer to this question be known, any one should know _what is the evidence_ for any ethical judgment whatsoever. But the main object of Ethics, as a systematic science, is to give correct _reasons_ for thinking that this or that is good; and, unless this question be answered, such reasons cannot be given. Even, therefore, apart from the fact that a false answer leads to false conclusions, the present enquiry is a most necessary and important part of the science of Ethics. =6.= What, then, is good? How is good to be defined? Now, it may be thought that this is a verbal question. A definition does indeed often mean the expressing of one word’s meaning in other words. But this is not the sort of definition I am asking for. Such a definition can never be of ultimate importance in any study except lexicography. If I wanted that kind of definition I should have to consider in the first place how people generally used the word ‘good’; but my business is not with its proper usage, as established by custom. I should, indeed, be foolish, if I tried to use it for something which it did not usually denote: if, for instance, I were to announce that, whenever I used the word ‘good,’ I must be understood to be thinking of that object which is usually denoted by the word ‘table.’ I shall, therefore, use the word in the sense in which I think it is ordinarily used; but at the same time I am not anxious to discuss whether I am right in thinking that it is so used. My business is solely with that object or idea, which I hold, rightly or wrongly, that the word is generally used to stand for. What I want to discover is the nature of that object or idea, and about this I am extremely anxious to arrive at an agreement.