4. But there is another meaning which may be given to the question “What is good?” “Books are good” would be an answer to it, though an answer obviously false; for some books are very bad indeed. And ethical judgments of this kind do indeed belong to Ethics; though I shall not deal with many of them. Such is the judgment “Pleasure is good”—a judgment, of which Ethics should discuss the truth, although it is not nearly as important as that other judgment, with which we shall be much occupied presently—“Pleasure alone is good.” It is judgments of this sort, which are made in such books on Ethics as contain a list of “virtues”—in Aristotle’s Ethics for example. But it is judgments of precisely the same kind, which form the substance of what is commonly supposed to be a study different from Ethics, and one much less respectable—the study of Casuistry. We may be told that Casuistry differs from Ethics, in that it is much more detailed and particular, Ethics much more general. But it is most important to notice that Casuistry does not deal with anything that is absolutely particular—particular in the only sense in which a perfectly precise line can be drawn between it and what is general. It is not particular in the sense just noticed, the sense in which this book is a particular book, and A’s friend’s advice particular advice. Casuistry may indeed be more particular and Ethics more general; but that means that they differ only in degree and not in kind. And this is universally true of “particular” and “general,” when used in this common, but inaccurate, sense. So far as Ethics allows itself to give lists of virtues or even to name constituents of the Ideal, it is indistinguishable from Casuistry. Both alike deal with what is general, in the sense in which physics and chemistry deal with what is general. Just as chemistry aims at discovering what are the properties of oxygen, wherever it occurs, and not only of this or that particular specimen of oxygen; so Casuistry aims at discovering what actions are good, whenever they occur. In this respect Ethics and Casuistry alike are to be classed with such sciences as physics, chemistry and physiology, in their absolute distinction from those of which history and geography are instances. And it is to be noted that, owing to their detailed nature, casuistical investigations are actually nearer to physics and to chemistry than are the investigations usually assigned to Ethics. For just as physics cannot rest content with the discovery that light is propagated by waves of ether, but must go on to discover the particular nature of the ether-waves corresponding to each several colour; so Casuistry, not content with the general law that charity is a virtue, must attempt to discover the relative merits of every different form of charity. Casuistry forms, therefore, part of the ideal of ethical science: Ethics cannot be complete without it. The defects of Casuistry are not defects of principle; no objection can be taken to its aim and object. It has failed only because it is far too difficult a subject to be treated adequately in our present state of knowledge. The casuist has been unable to distinguish, in the cases which he treats, those elements upon which their value depends. Hence he often thinks two cases to be alike in respect of value, when in reality they are alike only in some other respect. It is to mistakes of this kind that the pernicious influence of such investigations has been due. For Casuistry is the goal of ethical investigation. It cannot be safely attempted at the beginning of our studies, but only at the end.
5. But our question “What is good?” may have still another 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 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 show 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, anyone 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
