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.