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’.
317. That definition, it will be remembered, runs as follows: ‘A cause is an object precedent and contiguous to another, and so united with it in the imagination that the idea of the one determines the mind to form the idea of the other, and the impression of the one to form a more lively idea of the other.’ Now, as has been sufficiently shown, the object of an idea with Hume can properly mean nothing but the impression from which the idea is derived, which again is only the livelier idea, even as the idea is the fainter impression. The idea and the object of it, then, only differ as different stages in the vivacity of a feeling. [1] It must be remembered, further, in regard to the ‘determination of the mind’ spoken of in the definition, that the ‘mind’ according to Hume is merely a succession of impressions and ideas, and that its ‘determination’ means no more than a certain habitualness in this succession. Deprived of the benefit of ambiguous phraseology, then, the definition would run thus: ‘A cause is a lively feeling immediately precedent to another, [2] and so united with it that when either of the two more faintly recurs, the other follows with like faintness, and when either occurs with the maximum of liveliness the other follows with less, but still great, liveliness.’ Thus stated, the definition would correspond well enough to the process by which Hume arrives at it, of which the whole drift, as we have seen, is to merge the so-called objective relation of cause and effect, with the so-called inference from it, in the mere habitual transition from one feeling to another. But it is only because not thus stated, and because the actual statement is understood to carry a meaning of which Hume’s doctrine does not consistently admit, that it has a chance of finding acceptance. Its plausibility depends on ‘object’ and ‘mind’ and ‘determination’ being understood precisely in the sense in which, according to Hume, they ought not to be understood, so that it shall express not a sequence of feeling upon feeling, as this might be for a merely feeling subject, but that permanent relation or law of nature which to a subject that thinks upon its feelings, and only to such a subject, their sequence constitutes or on which it depends.
[1] See above, paragraphs 195 and 208. Cf. also, among other passages, one in the chapter now under consideration (p. 451) [Book I, part III., sec. XIV.]—‘Ideas always represent their objects or impressions.’
[2] The phrase ‘immediately precedent’ would seem to convey Hume’s meaning better than his own phrase ‘precedent and contiguous.’ Contiguity in space (which is what we naturally understand by ‘contiguity,’ when used absolutely) he could not have deliberately taken to be necessary to constitute the relation of cause and effect, since the impressions so related, as he elsewhere shows, may often not be in space at all.
Double meaning of natural relation. How Hume turns it to account.
318. It is this essential distinction between the sequence of feeling upon feeling for a sentient subject and the relation which to a thinking subject this sequence constitutes—a distinction not less essential than that between the conditions, through which a man passes in sleep, as they are for the sleeping subject himself, and as they are for another thinking upon them—which it is the characteristic of Hume’s doctrine of natural relation in all its forms to disguise. Only in virtue of the presence to feelings of a subject, which distinguishes itself from them, do they become related objects. Thus, with Hume’s exclusion of such a subject, with his reduction of mind and world alike to the succession of feelings, relations and ideas of relation logically disappear. But by help of the phrase ‘natural relation,’ covering, as it does, two wholly different things—the involuntary sequence of one feeling upon another, and that determination of each by the other which can only take place for a synthetic self-consciousness—he is able on the one hand to deny that the relations which form the framework of knowledge are more than sequences of feeling, and on the other to clothe them with so much of the real character of relations as qualifies them for ‘principles of union among ideas.’ Thus the mere occurrence of similar feelings is with him already that relation in the way of resemblance, which in truth only exists for a subject that can contemplate them as permanent objects. In like manner the succession of feelings, which can only constitute time for a subject that contrasts the succession with its own unity, and which, if ideas were feelings, would exclude the possibility of an idea of time, is yet with him indifferently time and the idea of time, though ideas are feelings and there is no ‘mind’ but their succession.
If an effect is merely a constantly observed sequence, how can an event be an effect the first time it is observed? Hume evades this question;