4.) Now, as Hume afterwards pointed out, identity is not simple unity. It cannot be predicated of the ‘idea’ as merely single, but only as a manifold in singleness. To speak of an idea as the ‘same with itself’ is unmeaning unless it mean ‘same with itself _in its manifold appearances_’ _i.e._ unless the idea is distinguished, as an object existing continuously, from its present appearance. Thus ‘the infallible knowledge,’ which Locke describes in the above passage, consists in this, that on the occurrence of a certain ‘idea’ the man _recognises_ it as one, which at other times of its occurrence he has called ‘_white_.’ Such a ‘synthesis of recognition,’ however, expressed by the application of a common term, implies the reference of a present sensation to a permanent object of thought, in this case the object thought under the term ‘white,’ so that the sensation becomes an idea of that object. Were there no such objects, there would be no significant names, but only noises; and were the present sensation not so referred, it would not be named. It may be said indeed that the ‘permanent object of thought’ is merely the instinctive result of a series of past resembling sensations, and that the common name is merely the register of this result. But the question is thus merely thrown further back. Unless the single fleeting sensation was, to begin with, fixed and defined by relation to and distinction from something permanent--in other words, unless it ceased to be a mere sensation--how did it happen that other sensations were referred to it, as different cases of an identical phenomenon, to which the noise suggested by it might be applied as a sign? The same implied in calling it an idea of an object. 26. This primary distinction and relation of the simple idea Locke implicitly acknowledges when he substitutes for the simple idea, as in the passage last quoted, the man’s knowledge that he has the idea; for such knowledge implies the distinction of the idea from its permanent conscious subject, and its determination by that negative relation. [1] Thus determined, it becomes itself a permanent object, or (which comes to the same) an idea _of an object_; a phrase which Locke at his convenience substitutes for the mere idea, whenever it is wanted for making his theory of knowledge square with knowledge itself. Once become such an object, it is a basis to which other sensations, like and unlike, may be referred as differentiating attributes. Its identity becomes a definite identity. [1] Cf. the passage in Book II. chap. vii. sec. 7. ‘When ideas are in our minds, we consider them as being actually there.’ The mere ‘idea’ is in fact essentially different from the ‘consideration of it as actually there,’ as sensation is different from thought. The ‘consideration, &c.,’ really means the thought of the ‘idea’ (sensation) as determined by relation to the conscious subject. Made _for_, not _by_, us, and therefore according to Locke really existent.