Only in regard to identity and causation that he sees any difficulty. These he treats as fictions resulting from ‘natural relations’ of ideas: i.e. from resemblance and contiguity.
210. Respect for Hume’s thoroughness as a philosopher must be qualified by the observation that he does not attempt to meet this difficulty in its generality, but only as it affects the relations of identity and causation. The truth seems to be that he wrote with Berkeley steadily before his mind; and it was Berkeley’s treatment of these two relations in particular as not sensible but intelligible, and his assertion of a philosophic Theism on the strength of their mere intelligibility, that determined Hume, since it would have been an anachronism any longer to treat them as sensible, to dispose of them altogether. The condition of his doing so with success was that, however unwarrantably, he should treat the other relations as sensible. The language, which seems to express ideas of the two questionable relations, he has to account for as the result of certain impressions of reflection, called ‘propensities to feign,’ which in their turn have to be accounted for as resulting from the natural relations of ideas according to the definition of these quoted above, [1] as ‘the qualities by which one idea habitually introduces another.’ Among these, as we saw, he included not only resemblance and contiguity in time or place, but ‘cause and effect.’ ‘There is no relation,’ he says, ‘which produces a stronger connection in the fancy than this.’ But in this, as in much of the language which gives the first two Parts their plausibility, he is taking advantage of received notions on the part of the reader, which it is the work of the rest of the book to set aside. In any sense, according to him, in which it differs from usual contiguity, the relation of cause and effect is itself reducible to a ‘propensity to feign’ arising from the other natural relations; but when the reader is told of its producing ‘a strong connection in the fancy,’ he is not apt to think of it as itself nothing more than the product of such a connection. For the present, however, we have only to point out that Hume, when he co-ordinates it with the other natural relations, must be understood to do so provisionally. According to him it is derived, while they are primary. Upon them, then, rested the possibility of filling the gap between the occurrence of single impressions, none ‘determined by reference to anything other than itself,’ and what we are pleased to call our knowledge, with its fictions of mind and thing, of real and apparent, of necessary as distinct from usual connection.
[1] See above, paragraph 206.
211. We will begin with Resemblance. As to this, it will be said, it is an affectation of subtlety to question whether there can be an impression of it or no. The difficulty only arises from our regarding the perception of resemblance as different from, and subsequent to, the resembling sensations; whereas, in fact, the occurrence of two impressions of sense, such as (let us say) yellow and red, is itself the impression of their likeness and unlikeness. Hume himself, it may be further urged, at any rate in regard to resemblance, anticipates this solution of an imaginary difficulty by his important division of philosophical relations into two classes [1]—‘such as depend entirely on the ideas which we compare together, and such as may be changed without any change in the ideas’—and by his inclusion of resemblance in the former class.
[1] p. 372 [Book I, part III., sec. I.]
Is resemblance then an impression?
212. Now we gladly admit the mistake of supposing that sensations undetermined by relation first occur, and that afterwards we become conscious of their relation in the way of likeness or unlikeness. Apart from such relation, it is true, the sensations would be nothing. But this admission involves an important qualification of the doctrine that impressions are single, and that the mind (according to Hume’s awkward figure) is a ‘bundle or collection of these,’ succeeding each other ‘in a perpetual flux or movement.’ It implies that the single impression in its singleness is what it is through relation to another, which must therefore be present along with it; and that thus, though they may occur in a perpetual flux of succession—every turn of the eyes in their sockets, as Hume truly says, giving a new one—yet, just so far as they are qualified by likeness or unlikeness to each other, they must be taken out of that succession by something which is not itself in it, but is indivisibly present to every moment of it. This we may call soul, or mind, or what we will; but we must not identify it with the brain [1] either directly or by implication (as we do when we ‘refer to the anatomist’ for an account of it), since by the brain is meant something material, i.e. divisible, which the unifying subject spoken of, as feeling no less than as thinking, cannot be. In short, any such modification of Hume’s doctrine of the singleness and successiveness of impressions as will entitle us to speak of their carrying with them, though single and successive, the consciousness of their resemblance to each other, will also entitle us to speak of their carrying with them a reference to that which is not itself any single impression, but is permanent throughout the impressions; and the whole ground of Hume’s polemic against the idea of self or spirit is removed. [2]
[1] It is, of course, quite a different thing to say that the brain (or, more properly, the whole body) is organic to it.
[2] See above, paragraph 205.
Distinction between resembling feelings and idea of resemblance.