IV. DISCUSSION. SEPARATION OF QUESTIONS IN PHILOSOPHY. By EEV. W. L. DAVIDSON. The keeping separate of distinct but allied questions in philo- sophy is a point of the utmost importance, both for the expositor and for the critic. It means clearness and the absence of con- fusion, in the one ; it is the greatest safeguard against the worst of logical fallacies, ignoratio elenchi, in the other. The process is essentially Definition. It is the discriminating of things that tend to run together ; the drawing of boundary lines, with a firm and steady hand, in this direction and in that. Yet there is nothing commoner than to find woful laxity in this respect, and, consequently, interminable misunderstanding and dispute. Prof. Sidgwick, in his Methods of Ethics, and Mr. Balfour, in his Defence of Philosophic Doubt, have both shown us somewhat of the magnitude of the evil; and those who have criticised the critics have not been slow with their Tu quoque in return. Nor is there any department of philosophy where the evil does not reign. Logic, psychology, ethics all come under its influence, and we need hardly mention metaphysics and ontology. It may not be amiss, then, if we here follow out the subject a little ; and, as our chief object is to exhibit the working of Logical Method, we shall best perhaps put the matter in the form of a few leading examples. A commencement may fitly enough be made with questions that range themselves around a single conception in one distinct province of philosophy : and, as Metaphysics offers a tempting field, let us begin with the notion of Cause. The first question to be asked and to be settled in connexion with Cause is, What is the import of the notion ? where shall we find its differentia ? Much depends upon our determi- nation here, and upon the persistence with which we abide by it. For Cause may stand for at least three different things. It may stand for priority or antecedence ; it may be taken in the old Stoical sense (familiarised to the West by Cicero) of efficiency or power ; it may be regarded as the sum total of conditions the aggregate of concauses, positive and negative (the presence of such and such things plus the absence of such and such hindrances or impediments) emphasised by Mill. And, according as we strictly adhere to any one of these conceptions or pass indifferently
