No philosophical relation admissible with Hume that is not derived from a natural one. 316. It may be said, however, that wherever Hume admits a definition purporting to be of a ‘philosophical relation,’ he does so only as an accommodation, and under warning that every such relation is ‘fictitious’ except so far as it is equivalent to a natural one; that according to his express statement ‘it is only so far as causation is a _natural_ relation, and produces an union among our ideas, that we are able to reason upon it or draw any inference from it’; [1] and that therefore it is only by his definition of it as a ‘natural relation’ that he is to be judged. Such a vindication of Hume would be more true than effective. That with him the ‘philosophical’ relation of cause and effect is ‘fictitious,’ with all the fictitiousness of a ‘continued existence distinct from perceptions,’ is what it has been the object of the preceding paragraphs to show. But the fictitiousness of a relation can with him mean nothing else than that, instead of having an idea of it, we have only a ‘tendency to suppose’ that we have such an idea. Thus the designation of the philosophical relation of cause and effect carries with it two conditions, one negative, the other positive, on the observance of which the logical value of the designation depends. The ‘tendency to suppose’ must _not_ after all be itself translated into the idea which it is to replace; and it _must_ be accounted for as derived from a ‘natural relation’ which is not fictitious. That the negative condition is violated by Hume, we have sufficiently seen. He treats the ‘philosophical relation’ of cause and effect, in spite of the ‘fictions’ which it involves, not as a name for a tendency to suppose that we have an idea which we have not, but as itself a definite idea on which he founds various ‘rules for judging what objects are really so related and what are not’. [2] That the positive condition is violated also--that the ‘natural relation’ of cause and effect, according to the sense in which his definition of it is meant to be understood, already itself involves ‘fictions,’ and only for that reason is a possible source of the ‘philosophical’--is what we have next to show. [1] P. 394. [Book I, part III., sec. VII.] [2] Part III. § 15. Examination of his account of cause and effect as ‘natural relation’.