129. This attempt to present Locke’s doctrine of the relation between the mind and the world, as it would be without phraseological disguises, must not be ascribed to any polemical interest in making a great writer seem to talk nonsense, The greatest writer must fall into confusions when he brings under the conceptions of cause and substance the self-conscious thought which is their source; and nothing else than this is involved in Locke’s avowed enterprise of knowing that which renders knowledge possible as he might know any other object. The enterprise naturally falls into two parts, corresponding to that distinction of subject and object which self-consciousness involves. Hitherto we have been dealing with it on the objective side--with the attempt to know knowledge as a result of experience received through the senses--and have found the supposed source of thought already charged with its creations; with the relations of inner and outer, of substance and attribute, of cause and effect, of appearance and reality. The supposed ‘outward’ turns out to have its outwardness constituted by thought, and thus to be inward. The ‘outer sense’ is only an outer sense at all so far as feelings, by themselves neither outward nor inward, are by the mind referred to a thing or cause which ‘the mind supposes;’ and only thus have its reports a prerogative of reality over the ‘fantasies,’ supposed merely of the mind. Meanwhile, unable to ignore the subjective side of self-consciousness, Locke has to put an inward experience as a separate, but co-ordinate, source of knowledge alongside of the outer. But this inward experience, simply as a succession of feelings, does not differ from the outer: it only so differs as referred to that very ‘thinking thing,’ called the mind, which by its supposition of causal substance has converted feeling into an experience of an outer thing. ‘Mind’ thus, by the relations which it ‘invents,’ constitutes both the inner and outer, and yet is treated as itself the inner ‘substratum which it accustoms itself to suppose.’ It thus becomes the creature of its own suppositions. Nor is this all. This, indeed, is no more than the fate which it must suffer at the hands of every philosopher who, in Kantian language, brings the source of the Categories under the Categories. But with Locke the constitution of the outer world by mental supposition, however uniformly implied, is always ignored; and thus mind, as the inward substance, is not only the creature of its own suppositions, but stands over against a real existence, of which the reality is held to consist just in its being the opposite of all such suppositions: while, after all, the effect of these mutually exclusive causes is one and the same experience, one and the same system of sequent and co-existent ideas. To get rid of the inner source of ideas in favour of the outer would be false to Locke.