315. The supposed difference then between immediate and mediate cognition is no absolute difference. It is not a difference between experience and a process that goes beyond experience, or between an experience unregulated by a conception of a permanent system and one that is so regulated. It lies merely in the degree of fullness and articulation which that conception has attained. If this had been what Hume meant to convey in his assimilation of inference to perception, he would have gone far to anticipate the result of the enquiry which Kant started. And this is what he might have come to mean if, instead of playing fast and loose with ‘impression’ and ‘object,’ using each as plausibility required on the principle of accommodation to the ‘vulgar,’ he had faced the consequence of his own implicit admission, that every perception of an object as identical is a ‘fiction’ in which we go beyond present feeling. As it is, his ‘scepticism with regard to the senses’ goes far enough to empty their ‘reports’ of the content which the ‘vulgar’ ascribe to them, and thus to put a breach between sense and the processes of knowledge, but not far enough to replace the ‘sensible thing’ by a function of reason. In default of such replacement, there was no way of filling the breach but to bring back the vulgar theory under the cover of habits and ‘tendencies to feign,’ which all suppose a ready-made knowledge of the sensible thing as their starting-point. Hence the constant contradiction, which it is our thankless task to trace, between his solution of the real world into a succession of feelings and the devices by which he sought to make room in his system for the actual procedure of the physical sciences. Conspicuous among these is his allowance of that view of relation in the way of cause and effect as an objective reality, which is represented by his definition of it as a ‘philosophical relation.’ It is in the sense represented by that definition that his doctrine has been understood and retained by subsequent formulators of inductive logic; but on examining it in the light of his own statements we have found that the relation, as thus defined, is not that which his theory required, and as which to represent it is the whole motive of his disquisition on the subject. It is not a sequence of impression upon impression, distinguished merely by its constancy; nor a sequence of idea upon impression, distinguished merely by that transfer of liveliness to the idea which arises from the constancy of its sequence upon the impression. It is a relation between ‘objects’ of which each is what it is only as ‘an instance of a species’ that exists continuously, and therefore in distinction from our ‘perishing impressions,’ according to a regular order of ‘contiguity and succession.’ As such existence and order are by Hume’s own showing no possible impressions, and by consequence no possible ideas, so neither are the ‘objects’ which derive their whole character from them.