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 still have 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 live 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
