that much disputed mystery, the nature of Force. We see that while extended things form the visible factor in every process of natural causation, force is the unseen, the imperceptible factor. Nor is our knowledge limited to this negative and yet very suggestive mark of imperceptibility. The marks mentioned by Schopenhauer-its ubiquity and inexhaustibleness-also really belong to it. And above all else one feature that he did not mention, its uniformity. That is what science means by her doctrine of the conservation of energy-the conviction that force works by methods absolutely uniform and invariable. Thus, strange to say, our knowledge of the invisible factor is the very means by which we come to an ever-deepening, widening knowledge of the visible. The cause, then, is neither mere substance, nor phenomenon, nor a kind of force. On the contrary, it is a complex of all these combined in a unitary and uniform causal process. Let us see now what bearing this view has upon the objection that the substance or thing is but a name for the Unknowable Cause of its qualities. First, I repeat the comprehensive answer already given, that if the thing is unknowable apart from its qualities, so are the qualities apart from the thing. Second, the thing is known as that which determines the specific character of a quality; the other factors are general conditions giving only general results. Third, the thing is known as the one, persistent factor in each and all the many causal processes whereby its qualities are produced. Thus its known relationship with other things and agencies widens out immensely, and our knowledge of it is correspondingly enlarged. We know the object perceived not merely through its casual, superficial relations to the perceiving subject, but through its deep-lying, wide-spreading, essential relations to that illimitable host of other factors which co-operate with it in the production of its attributes. It is the climax of silliness to talk of a thing thus widely and luminously known as an Unknowable Cause. Fourth and above all else, the thing is always a perceptible factor, while the other factors have to be demonstrated as indispensable by the strict experimental methods of inductive science. A causal process, as a whole, then, is not seen or given by sensible experience. Hume was right there; and his famous problem would forever remain insoluble were it not for my demonstration that the cancelling of causality means the extinction of thought. The sole essential function of thought being thus proved to be the disclosure of causality, it follows that thought is fundamentally a revelation of the unseen. Thus the new realism is lifted far above that mire of materialism into which previous forms of realism have sunk. It accomplishes what both subjective and absolute idealism have failed to accomplish by their assumption that the visible universe was an illusion. Without appealing to any such nonsense, the new realism demonstrates the existence of the invisible. What seemed then a weighty objection has been overcome and converted into a crowning proof of realism. But there are certain perplexities concerning space and time which have heretofore defied solution; these I hope to disentangle in the next two chapters, and then our proof will be complete. CHAPTER V SPACE Section II. Perceptual and Conceptual Space ALL the perplexities and supposed self-contradictions that from time immemorial have clustered around the thought of space seem of late to be focalizing themselves upon the contrast between space as perceived and as conceived. On the one hand, conceptual space is regarded as one, homogeneous, continuous infinitely extended and also infinitely divisible. On the other hand, perceptual space seems somehow to be devoid of all positive characteristics; it exhausts itself in negating, pointblank, all the characteristics of conceptual space. Thus per ceptive and reflective thought are made to appear in hopeless, irreconcilable conflict with each other. At first Kant seemed little mindful of this antagonism. Indeed in the Analytic the very pith of his argument for the ideality of space is that it is neither a percept nor a concept. But later on in discussing the Antinomies the tangles involved in the thought of space as infinitely divisible begin to trouble him: he will not say that space is a whole really compounded of an infinite number of parts, but at any rate it is ideally so compounded. And in the "Critique of Judgment" he tentatively suggests this opposition of space perceived and conceived. At present the entire space-problem seems to hinge upon this alleged discrepancy. But for two good reasons it seems to me all a' delusion. First, my perfect faith in the unity of thought forbids my believing in any such antithesis between perception and conception. Secondly, all this apparent antagonism vanishes instantly in the light of our fundamental law that the essence of all thinking is a discriminating between cause and effect. What has been erroneously regarded as a distinction between conceptual and perceptual space is really a distinction between space and the spatial relations of things. And the two, so far from being in any antagonism with each other, are really related as cause and effect. For consider first the spatial relations-distances, directions, length, breadth, etc.—which are certainly perceptible. Mark that it is not said here that space is the sole or entire cause of these spatial relations. We have got beyond that great error which has wrought so much confusion and darkness in philosophy-to wit, the failure to see that an effect is not the product of a single cause, but of a causal process interweaving many factors. Particular things are also indispensable factors in the production of spatial relations, which otherwise would not be perceptible. But so also is unchanging space. Do you object that space is inactive, does nothing, neither produces nor resists motion, and therefore cannot be a factor in causal processes? Lotze especially makes this inactivity of space one of his main |