252. Disguise it as he might, however, the admission that there was in some sense an abstract idea of space, which the existence of geometry required of him, really carried with it the admission either of a distinct impression of the same, or of some transmuting process by which the idea may become what the impression is not. His way of evading this consequence has been already noticed in our examination of his doctrine of ‘abstract ideas’ generally, though without special reference to extension. [1] It consists in asserting figure and colour to be ‘really,’ or as an impression, ‘the same and indistinguishable,’ but different as ‘relations and resemblances’ of the impression; in other words, different according to the ‘light in which the impression is considered’ or ‘the aspect in which it is viewed.’ Of these ‘separate resemblances and relations,’ however, are there ideas or are there not? If there are not, they are according to Hume nothing of which we are conscious at all; if there are, there must be distinguishable, and therefore separable, impressions corresponding. To say then that figure and colour form one and the same indistinguishable impression, and yet that they constitute ‘different resemblances and relations,’ without such explanation as Hume cannot consistently give, is in fact a contradiction in terms. The true explanation is that the ‘impression’ has a different meaning, when figure and colour are said to be inseparable in the impression, from that which it has when spoken of as a subject of different resemblances and relations. In the former sense it is the feeling pure and simple--_one_ as presented singly in time, after another and before a third. In this sense it is doubtless insusceptible of distinction into qualities of figure and colour, because (for reasons already stated) it can have no qualities at all. But the ‘simplicity in which many different resemblances and relations may be contained’ is quite other than this singleness. It is the unity of an object thought of under manifold relations--a unity of which Hume, reducing all consciousness to ‘impression’ and impression to feeling, has no consistent account to give. Failing such an account, the unity of the intelligible object, and the singleness of the feeling in time, are simply confused with each other. It is only an object as thought of, not a feeling as felt, that can properly be said to have qualities at all; while it is only because it is still regarded as a feeling that qualities of it, which cannot be referred to separate impressions, are pronounced the same and indistinguishable. If the idea of space is other than a feeling grown fainter, the sole reason for regarding it as originally an impression of colour disappears; if it _is_ such a feeling, it cannot contain such ‘different resemblances and relations’ as render it representative of objects not only coloured in every possible way, but not coloured at all. [1] Above, paragraph 218.