13. By insisting on Locke’s account of the relation between the ideas of sensation and those of reflection we might be brought to a different but not more luminous conclusion. In the passages quoted above, where this relation is most fully spoken of, it appears that the latter are essentially sequent to those of sensation. ‘_In time_ the mind comes to reflect on its own operations, about the ideas got by sensation, and thereby stores itself with a new set of ideas, which I call ideas of reflection.’ Of these only two are primary and original (Book II. c. xxi. sec. 73), viz. motivity or power of moving, with which we are not at present concerned, and perceptivity or power of perception. But according to Locke, as we have seen, there cannot be any, the simplest, idea of sensation without perception. If, then, the _idea_ of perception is only given later and upon reflection, we must suppose perception to take place without any idea of it. But with Locke to have an idea and to perceive are equivalent terms. We must thus conclude that the beginning of knowledge is an unperceived perception, which is against his express statement elsewhere (Book II. c. xxvii. sec. 9), that it is ‘impossible for any one to perceive without perceiving that he does perceive.’ What is the ‘tablet’ impressed? 14. Meanwhile a perpetual equivocation is kept up between a supposed impression on the ‘outward parts,’ and a supposed impression on the ‘tablet of the mind.’ It is not the impression upon, or a motion in, the outward parts, as Locke admits, that constitutes the idea of sensation. It is not an agitation in the tympanum of the ear, or a picture on the retina of the eye, that we are conscious of when we see a sight or hear a sound. [1] The motion or impression, however, has only, as he seems to suppose, to be ‘continued to the brain,’ and it becomes an idea of sensation. Notwithstanding the rough line of distinction between soul and body, which he draws elsewhere, his theory was practically governed by the supposition of a cerebral something, in which, as in a third equivocal tablet, the imaginary mental and bodily tablets are blended. If, however, the idea of sensation, as an object of the understanding when a man thinks, differs absolutely from ‘a motion of the outward parts,’ it does so no less absolutely, however language and metaphor may disguise the difference, from such motion as ‘continued to the brain.’ An instructed man, doubtless, may come to think about a motion in his brain, as about a motion of the earth round the sun, but to speak of such motion as an idea of sensation or an immediate object of intelligent sense, is to confuse between the object of consciousness and a possible physical theory of the conditions of that consciousness. It is only, however, by such an equivocation that any idea, according to Locke’s account of the idea, can be described as an ‘impression’ at all, or that the representation of the mind as