Now, if the distinction, thus drawn, between the form and matter of the world of experience were necessary or even admissible, the effect of tracing those relations between phenomena, which form the laws of nature as we know it, to the action of a spiritual principle, would simply have been to bring us to a dead-lock. The distinction implies that phenomena have a real nature as effects of things-in-themselves other than that which they have as related to each other in the universe of our experience: and not only so, it puts the two natures in a position towards each other of mere negation and separation, of such a kind that any correspondence between them, any dependence of one upon the other, is impossible. As effects of things-in-themselves, phenomena are supposed to have a nature of their own, but they cannot, according to Kant's doctrine, be supposed to carry any of that nature with them into experience. All the nature which they have in experience belongs to them in virtue of relations to each other which the action of the intellectual principle, expressly opposed to the action of things-in-themselves, brings about. The nature which a sensation is supposed to possess materialiter spectata, as the appearance of a thing-in-itself, must not be confused with its nature as conditioned by a particular mode of matter and motion--the nature which the man of science investigates. It is probably from this confusion that Kant's doctrine of the relation between phenomena and things-in-themselves derives any plausibility which it may have for most of his readers: but, after what has been said above, a moment's consideration will show how unwarrantable according to his principles it is. The nature of a sensation, as dependent upon any motion or configuration of molecules, is still a nature determined by its relation to other data of experience--a relation which (like every other relation within, or capable of coming within, experience) the single self-distinguishing principle, which Kant calls understanding, is needed to constitute. It is not such a nature, but one to which no experience or interrogation of experience brings us any the nearer, that we must suppose to belong to the phenomenon as an appearance of a thing-in-itself, if Kant's antithesis is to be maintained. (§ 39 ¶ 1)

And if phenomena, as materialiter spectata, have such another nature, it will follow--not indeed that all our knowledge is an illusion in the ordinary sense of the term, for that implies a possibility of correction by true knowledge--but that there is no ground for that conviction of there being some unity and totality in things, from which the quest for knowledge proceeds. The cosmos of our experience, and the order of things-in-themselves, will be two wholly unrelated worlds, of which, however, each determines the same sensations. All that determination of a sensible occurrence which can be the object of possible experience or inferred as an explanation of experience--its simple position of antecedence or sequence in time to other occurrences, as well as its relation to conditions which regulate that position and determine its sensible nature--will belong to one world of which a unifying self-consciousness is the organising principle: while the very same occurrence, as an effect of things-in-themselves, will belong to another world, will be subject to a wholly different order of determinations, which may have--and indeed, in being so described, is assumed to have--some principle of unity of its own, but of which, because it is a world of things-in-themselves, the principle must be taken to be the pure negation of that which determines the world of experience. If this be so, the conception of a universe is a delusive one. Man weaves a web of his own and calls it a universe; but if the principle of this universe is neither one with, nor dependent on, that of things-in-themselves, there is in truth no universe at all, nor does there seem to be any reason why there should not be any number of such independent creations. We have asserted the unity of the world of our experience only to transfer that world to a larger chaos. (§ 39 ¶ 2)