A Commentary to Kant's 'Critique of Pure Reason'

by Norman Kemp Smith

But even such reversibility of continuous series does not by itself establish coexistence. For in the imagination[1245] we can represent such series, without thereby acquiring the right to assert that they exist not as series but as simultaneous wholes. And as Kant might also have pointed out, even in sense-perception we can experience reversible continuous series that do not in any way justify the inference to coexistence. We may, for instance, produce on a musical instrument a series of continuously changing sounds, and then in immediate succession produce the same series in reverse order. An additional factor is therefore required, namely, the interpretation of the reversibility of our perceptions as being grounded in objects which, because spatially extended, and spatially continuous with one another, can yield continuous series of perceptions, and which, because of their thoroughgoing reciprocity, make possible the reversing of these series. To summarise the argument in a sentence: as the objectively coexistent, if it is to be known at all, can only be known through sequent representations, the condition of its apprehension is the possibility of interpreting reversible continuous series as due to the reciprocal interaction of spatially ordered substances.

This argument has a twofold bearing. Its most obvious consequence is that all things apprehended as coexistent must be conceived as standing in relations of reciprocal interaction; but by implication this involves the further consequence that the conceptual principle of reciprocity is an integral factor in all apprehension of space. Space, though intuitive in character, has a meaning that demands this concept for its articulation. Just as consciousness of temporal sequence is only possible in terms of causation, so consciousness of spatial coexistence is only possible through application of the category of reciprocity. And since, on Kant’s view, awareness of space conditions awareness of time, these conclusions carry the Critical analysis of our consciousness of time a stage further. In confirmation of the more general argument of the objective deduction, reciprocity is added to the already large sum-total of the indispensable conditions of our time-consciousness; while in regard to time itself it is shown that, owing to its space-reference, coexistence may be counted among its possible modes.

I have made occasional reference to the positions adopted by Stout in his Manual of Psychology, and may here indicate their relation to the present argument. Stout cites four “categories” or ultimate principles of unity which “belong even to rudimentary perceptual consciousness as a condition of its further development,”[1246] namely, spatial unity, temporal unity, causal unity, and the unity of different attributes as belonging to the same thing. The criticism which, from the standpoint of the Analogies, has to be passed upon this list,[1247] is that it ignores the category of reciprocity, i.e. of systematic interconnection, and that it fails to recognise the close relation in which the various principles stand to one another. The temporal unity must not be isolated from causal unity, nor either of them from the spatial unity, with which the category of reciprocity is inseparably bound up. Further, Kant maintains that these principles are demanded, not merely for the development of perceptual consciousness, but for its very existence.

But Kant’s argument suggests many difficulties which we have not yet considered, and we may again employ Schopenhauer’s criticisms to define the issues involved.

“The conception of reciprocity ought to be banished from metaphysics. For I now intend, quite seriously, to prove that there is no reciprocity in the strict sense, and this conception, which people are so fond of using, just on account of the indefiniteness of the thought, is seen, if more closely considered, to be empty, false, and invalid.... It implies that both the states A and B are cause and that both are effect of each other; but this really amounts to saying that each of the two is the earlier and also the later; thus it is an absurdity.”[1248]

This criticism proceeds on the assumption that the category of reciprocity reduces to a dual application of the category of causality. If that were the case, there would, of course, be no separate category of reciprocity,[1249] and further it would, as Schopenhauer maintains, be impossible to regard A and B as being at one and the same time both cause and effect of one another. Causality determines the order of the states of substances in the time series; reciprocity must be distinct from causality if it is to be capable of defining the order of their coexistent states in space. A deduction from the dual application of the conception of causality has, therefore, no bearing upon the question of the possibility of this further category. Kant has laid himself open to this criticism by a passage which occurs in the first proof, and which shows that he was not quite clear in his own mind as to how reciprocity ought to be conceived.

“That alone can determine the position of anything else in time, which is its cause or the cause of its determinations. Every substance (inasmuch as only in its determinations can it be an effect) must therefore contain in itself the causality of certain determinations in the other substance, and at the same time the effects of the causality of that other, i.e. they must stand in dynamical communion (immediately or mediately), if their coexistence is to be known in any possible experience.”[1250]

It should be noted that in the new proof[1251] in the second edition Kant is careful to employ the terms ground and influence in place of the terms cause and causality.

Secondly, Schopenhauer argues that if the two states necessarily belong to each other and exist at one and the same time, they will not be simultaneous, but will constitute only one state.[1252] Schopenhauer is again refusing to recognise the conditions under which alone a special category of reciprocity is called for. We can speak of simultaneity only if a multiplicity be given; and if it be given, its nature as simultaneous plurality cannot be comprehended through a causal law, which, as such, applies only to sequent order.

Lastly, Schopenhauer endeavours to confirm his position by examination of the supposed instances of reciprocity.