536 J. HUTCHISON STIRLING : stratum (ii., 23, 1, and note). (24) Custom a greater power than nature (i., 3, 35). (25) Cause and effect ; such correlative terms seem so nearly to belong one to another, and through custom do so readily chime and answer one another in people's memories that upon the naming of either of them, the thoughts are presently carried beyond the thing so named (ii., 25, 2). (26) When a countryman says the cold freezes water, though the word freezing seems to import some action, yet truly it signifies nothing but the effect, viz., that water that was before fluid is become hard and consistent without containing any idea of the action whereby it is done (ii., 22, 11). Few, it appears to me, will be able to read these extracts (the Treatise and the Enquiry being open before them) with- out having it forcibly borne in upon them, at all events for the moment, that Hume on the whole must have simply reproduced and repeated, in regard to causality, that whole course of considerations and that general attitude of thought which Locke, already in advance, had exhibited in regard to substantiality. In both what we may call the fulcra are precisely identical ; and these are : (1) That the idea con- cerned can show for itself no correspondent voucher of sense; and (2) That its origin can only be referred to custom. But it will be well to point out the parallel a little more in de- tail. Locke, in the first quotation, terms causality the most comprehensive of all relations, while, whether as a principle of association or as a principle of inference, it is to Hume "the strongest of all others". In fact, it was precisely Hume's affair, his object being seen, to make causality no less. In the whole of the theoretical part of the Treatise in the first place, and of the Enquiry in the second, he has no purpose whatever, no thought, no idea in his mind but what centres in causality. Chapter after chapter, paragraph after para- graph only lead up to it. So much is this the case, indeed, that it is impossible to conceive of a clumsier stroke to one's own self than that which was aimed at Hume for his as- sumed inconsistency in usage of the principle as a law of suggestion. That causality should be considered, as in the Essay, " the most comprehensive relation, wherein all things that do or can exist, are concerned," and, as in the Treatise, the relation than which none "produces a stronger con- nexion," of the three principles of association " the most extensive," " not only a true species of reasoning, but the strongest of all others, and more convincing than when we interpose another idea to connect the two extremes " (syllo- gism, to wit) that was accurately and precisely Hume's single desire. ' It was " by means of that relation alone that we could go beyond the evidence of our memory and senses " ;
