302. The problem of identity necessarily arises from the fusion of reality and feeling. We must once again recall the propositions in which Hume represents this fusion--that ‘everything which enters the mind is both in reality and appearance as the perception;’ that ‘so far as the senses are judges, all perceptions are the same in the manner of their existence;’ that ‘perceptions’ are either impressions, or ideas which are ‘fainter impressions;’ and ‘impressions are internal and perishing existences, and appear as such.’ If these propositions are true--and the ‘new way of ideas’ inevitably leads to them--how is it that we _believe_ in ‘a _continued_ existence of objects even when they are not present to the senses,’ and an existence ‘distinct from the mind and perception’? They are the same questions from which Berkeley derived his demonstration of an eternal mind--a demonstration premature because, till the doctrine of ‘ideas,’ and of mind as their subject, had been definitely altered in a way that Berkeley did not attempt, it was explaining a belief difficult to account for by one wholly unaccountable. Before Theism could be exhibited with the necessity which Locke claimed for it, it was requisite to try what could be done with association of ideas and ‘propensities to feign’ in the way of accounting for the world of knowledge, in order that upon their failure another point of departure than Locke’s might be found necessary. The experiment was made by Hume. He has the merit, to begin with, of stating the nature of identity with a precision which we found wanting in Locke. ‘In that proposition, _an object is the same with itself_, if the idea expressed by the word _object_ were no ways distinguished from that meant by _itself_, we really should mean nothing.’ ‘On the other hand, a multiplicity of objects can never convey the idea of identity, however resembling they may be supposed. ... Since then both number and unity are incompatible with the relation of identity, it must lie in something that is neither of them. But at first sight this seems impossible.’ The explanation is that when ‘we say that an object is the same with itself, we mean that the object existent at one time is the same with itself existent at another. By this means we make a difference betwixt the idea meant by the word _object_ and that meant by _itself_ without going the length of number, and at the same time without restraining ourselves to a strict and absolute unity.’ In other words, identity means the unity of a thing through a multiplicity of times; or, as Hume puts it, ‘the invariableness and uninterruptedness of any object through a supposed variation of time’. [1] [1] Pp. 489, 490. [Book I, part IV., sec. II.] Properly with him it is a fiction, in the sense that we have no such idea. Yet he implies that we have such idea, in saying that we mistake something else for it.