How this contradiction is disguised.
17. It is not difficult to show that to have a simple idea, according to Locke’s account of it, means to have already the conception of substance and relation, which are yet according to him ‘complex and derived ideas,’ ‘the workmanship of the mind’ in opposition to its original material, the result of its action in opposition to what is given it as passive. The equivocation in terms under which this contradiction is generally covered is that between ‘idea’ and ‘quality.’ ‘Whatever the mind perceives in itself, or is the immediate object of perception, thought, or understanding, that I call idea; and the power to produce that idea I call quality of the subject wherein that power is. Thus a snowball having power to produce in us the ideas of white, cold, and round, the powers to produce these ideas in us, as they are in the snowball, I call qualities; and as they are sensations or perceptions in our understandings, I call them ideas; which ideas, if I speak of sometimes as in the things themselves, I would be understood to mean those qualities in the object which produce them in us.’ (Book II. chap. viii. sec. 8.)
Locke’s way of interchanging ‘idea’ and ‘quality’ and its effects.
18. An equivocation is not the less so because it is announced. It is just because Locke allows himself at his convenience to interchange the terms ‘idea’ and ‘quality’ that his doctrine is at once so plausible and so hollow. The essential question is whether the ‘simple idea,’ as the original of knowledge, is on the one hand a mere feeling, or on the other a thing or quality of a thing. This question is the crux of empirical psychology. Adopting the one alternative, we have to face the difficulty of the genesis of knowledge, as an apprehension of the real, out of mere feeling; adopting the other, we virtually endow the nascent intelligence with the conception of substance. By playing fast and loose with ‘idea’ and ‘quality,’ Locke disguised the dilemma from himself. Here again the metaphor of Impression did him yeoman’s service. The idea, or ‘immediate object of thought,’ being confused with the affection of the sensitive organs, and this again being accounted for as the result of actual impact, it was easy to represent the idea itself as caused by the action of an outward body on the ‘mental tablet.’ Thus Locke speaks of the ‘objects of our senses obtruding their particular ideas on our minds, whether we will or no.’ (Book II. chap. i. sec. 25.) This sentence holds in solution an assumption and two fallacies. The assumption (with which we have no further concern here) is the physical theory that matter affects the sensitive organs in the way of actual impact. Of the fallacies, one is the confusion between this affection and the idea of which it is the occasion to the individual; the other is the implication that this idea, as such, in its prime simplicity, recognises itself as the result of, and refers itself as a quality to, the matter supposed to cause it. This recognition and reference, it is clearly implied, are involved in the idea itself, not merely made by the philosopher theorising it. Otherwise the ‘obtrusion’ would be described as of a property or effect, not of an idea, which means, it must be remembered, the object of consciousness just as the object of consciousness. Of the same purport is the statement that ‘the mind is furnished with simple ideas as they are found in exterior things.’ (Book II. chap, xxiii. sec. 1.) It only requires a moment’s consideration, indeed, to see that the beginning of consciousness cannot be a physical theory, which, however true it may be and however natural it may have become to us, involves not only the complex conception of material impact, but the application of this to a case having no palpable likeness to it. But the ‘interrogator of consciousness’ finds in its primitive state just what he puts there, and thus Locke, with all his pains ‘to set his mind at a distance from itself,’ involuntarily supposes it, in the first element of intelligence, to ‘report’ that action of matter upon itself, which, as the result of a familiar theory—involving not merely the conceptions of substance, power, and relation, but special qualifications of these—it reports to the educated man.
Primary and secondary qualities of bodies.
19. This will appear more clearly upon an examination of his doctrine of ‘the ideas of primary and secondary qualities of bodies.’ The distinction between them he states as follows. The primary qualities of bodies are ‘the bulk, figure, number, situation, motion, and rest of their solid parts; these are in them, whether we perceive them or no; and when they are of that size that we can discover them, we have by these an idea of the thing as it is in itself.’ … Thus ‘the ideas of primary qualities are resemblances of them, and their patterns do really exist in the bodies themselves. But the ideas produced in us by the secondary qualities have no resemblance of them at all. There is nothing like them existing in the bodies themselves. They are in the bodies, we denominate from them, only a power to produce these sensations in us; and what is sweet, blue, or warm in idea is but the certain bulk, figure, and motion of the insensible parts in the bodies themselves which we call so.’ This power is then explained to be of two sorts: (a) ‘The power that is in any body, by reason of its insensible primary qualities, to operate after a peculiar manner on any of our senses, and thereby produce in us the different ideas of several colours, sounds, smells, tastes, &c. These are usually called sensible qualities, (b) The power that is in any body, by reason of the particular constitution of its primary qualities, to make such a change in the bulk, figure, texture, and motion of another body, as to make it operate differently on our senses from what it did before. Thus the sun has a power to make wax white, and fire to make lead fluid. These are usually called powers.’ (Book II. chap. viii. sec. 15, 23.)
‘Simple idea’ represented as involving a theory of its own cause.
20. What we have here is a theory of the causes of simple ideas; but we shall find Locke constantly representing this theory as a simple idea itself, or the simple idea as involving this theory. By this unconscious device he is enabled readily to exhibit the genesis of knowledge out of ‘simple ideas,’ but it is at the cost of converting these into ‘creations of the mind,’ which with him are the antitheses of ‘facts’ or ‘reality.’ The process of conversion takes a different form as applied respectively to the ideas of primary and to those of secondary qualities. We propose to follow it in the latter application first.
Phrases in which this is implied.
21. The simple idea caused by a quality he calls the idea of that quality. Under cover of this phrase, he not only identifies the idea of a primary quality with the quality itself of which he supposes it to be a copy, but he also habitually regards the idea of a secondary quality as the consciousness of a quality of a thing, though under warning that the quality as it is to consciousness is not as it is in the thing. This reservation rather adds to the confusion. There are in fact, according to Locke, as appears from his distinction between the ‘nominal’ and ‘real essence,’ two different things denoted by every common noun; the thing as it is in itself or in nature, and the thing as it is for consciousness. The former is the thing as constituted by a certain configuration of particles, which is only an object for the physical philosopher, and never fully cognisable even by him; [1] the latter is the thing as we see and hear and smell it. Now to a thing in this latter sense, according to Locke, such a simple idea as to the philosopher is one of a secondary quality (i.e. not a copy, but an effect, of something in a body), is already in the origin of knowledge referred as a quality, though without distinction of primary and secondary. He does not indeed state this in so many words. To have done so might have forced him to reconsider his doctrine of the mere passivity of the mind in respect of simple ideas. But it is implied in his constant use of such phrases as ‘reports of the senses,’ ‘inlet through the senses’—which have no meaning unless something is reported, something let in—and in the familiar comparison of the understanding to a ‘closet, wholly shut from light, with only some little opening left, to let in external visible resemblances, or ideas, of things without.’ (Book II. chap. xi. sec. 17.)