[2] Ibid.
[3] ‘A false idea,’ that is, according to the doctrine that extension is a primary quality, while colour is only an idea of a secondary quality, not resembling the quality as it is in the thing.
Locke’s shuffle of ‘body,’ ‘solidity,’ and ‘touch,’ fairly exposed.
230. Our examination of Locke has shown us how it is that his interpretation of ideas by reference to body is fairly open to this attack. It is so because, in thus interpreting them, he did not know what he was really about. He thought he was explaining ideas of sense according to the only method of explanation which he recognises—the method of resolving complex into simple ideas, and of ‘sending a man to his senses’ for a knowledge of the simple. In fact, however, when he explained ideas of sense as derived from the qualities of body, he was explaining simple ideas by reference to that which, according to his own showing, is a complex idea. To say that, as Locke understood the derivation in question, the primary qualities are an ἄιτιον γενέσεως to the ideas of secondary qualities, but not an ἄιτιον γνώσεως [1]—that without our having ideas of them they cause those ideas of sense from which afterwards our ideas of the primary qualities are formed—is to suppose an order of reality other than the order of our sensitive experience, and thus to contradict Locke’s fundamental doctrine that the genesis of ideas is to be found by observing their succession in ‘our own breasts.’ It is not thus that Locke himself escapes the difficulty. As we have seen, he supposes our ideas of sense to be from the beginning ideas of the qualities of bodies, and virtually justifies the supposition by sending the reader to his sense of touch for that idea of solidity in which, as he defines it, all the primary qualities are involved. That the sense in question does not really yield the idea is what Hume points out when he says that, ‘though bodies are felt by means of their solidity, yet the feeling is quite a different thing from the solidity, nor have they the least resemblance to each other.’ In other words, having come to suppose that there are solid bodies, we explain our feeling as due to their solidity; but we may not at once interpret feeling as the result of solidity, and treat solidity as itself a feeling. It was by allowing himself so to treat it that Locke disguised from himself the objection to his interpretation of feeling. Hume tears off the disguise, and in effect gives him the choice of being convicted either of reasoning in a circle or of explaining the simple idea by reference to the complex. The solidity, which is to explain feeling, can itself only be explained by reference to body. If body is only a complex of ideas of sense, in referring tactual feeling to it we are explaining a simple idea by reference to a compound one. If it is not, how is it to be defined except in the ‘circular’ way, which Locke in fact adopts when he makes body a ‘texture of solid parts’ and solidity a relation of bodies? [2]
[1] [Greek ἄιτιον γενέσεως (aition geneseos) = cause of coming-to-be, ἄιτιον γνώσεως (aition gnoseos) = cause of being known. Tr.]
[2] See above, paragraph 101.
True rationale of Locke’s doctrine.
231. This ‘vicious circle’ was nothing of which Locke need have been ashamed, if only he had understood and avowed its necessity. Body is to solidity and to the primary qualities in general simply as a substance to the relations that determine it; and the ‘circle’ in question merely represents the logical impossibility of defining a substance except by relations, and of defining these relations without presupposing a substance. It was only Locke’s confusion of the order of logical correlation with the sequence of feelings in time, that laid him open to the charge of making body and the ideas of primary qualities, and again the latter ideas and those of secondary qualities, at once precede and follow each other. To avoid this confusion by recognising the logical order—the order of intellectual ‘fictions’—as that apart from which the sequence of feelings would be no order of knowable reality at all, would be of course impossible for one who took Locke’s antithesis of thought and fact for granted. The time for that was not yet. A way of escape had first to be sought in a more strict adherence to Locke’s identification of the sequence of feelings with the order of reality. Hence Hume’s attempt, reversing Locke’s derivation of ideas of sense from primary qualities of body, to derive what with Locke had been primary qualities, as compound impressions of sense, from simple impressions and to reduce body itself to a name not for any ‘just and consistent idea,’ but for a ‘propensity to feign,’ the gradual product of custom and imagination. The question by which the value of such derivation and reduction is to be tried is our old one, whether it is not a tacit conversion of the supposed original impressions into qualities of body that alone makes them seem to yield the result required of them. If the Fourth Book of the ‘Treatise on Human Nature,’ with its elimination of the idea of body, had come before the second, would not the plausibility of the account of mathematical ideas contained in the latter have disappeared? And conversely, if these ideas had been reduced to that which upon elimination of the idea of body they properly become, would not that ‘propensity to feign,’ which is to take the place of the excluded idea, be itself unaccountable?
With Hume ‘body’ logically disappears. What then?
232. ‘After exclusion of colours, sounds, heat and cold, from the rank of external existences, there remains nothing which can afford us a just and consistent idea of body.’ Now, no one can ‘exclude them from the rank of external existences’ more decisively than Hume. They are impressions, and ‘all impressions are internal and perishing existences, and appear as such.’ Nor does he shirk the consequence, that we have no ‘just and consistent idea of body.’ It is true that we cannot avoid a ‘belief in its existence’—a belief which according to Hume consists in the supposition of ‘a continued existence of objects when they no longer appear to the senses, and of their existence as distinct from the mind and perceptions;’ in other words, as ‘external to and independent of us.’ This belief, however, as he shows, is not given by the senses. That we should feel the existence of an object to be continued when we no longer feel it, is a contradiction in terms; nor is it less so, that we should feel it to be distinct from the feeling. We cannot, then, have an impression of body; and, since we cannot have an idea which does not correspond to an impression or collection of impressions, it follows that we can have no idea of it. How the ‘belief in its existence’ is accounted for by Hume in the absence of any idea of it, is a question to be considered later. [1] Our present concern is to know whether the idea of extension can hold its ground when the idea of body is excluded.