Kant's Theory of Knowledge

by H. A. Prichard

In view of the preceding, it is possible to make clear the nature of certain mistakes on Kant's part. In the first place, space, and time also, so far as we are thinking of the world, and not of our apprehension of it, as undergoing a temporal process, are essentially characteristics not of perception but of the reality perceived, and Kant, in treating space, and time, so regarded, as forms of perception, is really transferring to the perceiving subject that which in the whole fact 'perception of an object' or 'object perceived' belongs to the object.

Again, if we go on to ask how Kant manages to avoid drawing the conclusion proper to this transference, viz. that space and time are not characteristics of any realities at all, but belong solely to the process by which we come to apprehend them, we see that he does so because, in effect, he contravenes both the characteristics of perception referred to. For, in the first place, although in conformity with his theory he almost always speaks of space and time in terms of perception,[9] he consistently treats them as features of the reality perceived, i. e. of phenomena. Thus in arguing that space and time belong not to the understanding but to the sensibility, although he uniformly speaks of them as perceptions, his argument implies that they are objects of perception; for its aim, properly stated, is to show that space and time are not objects of thought but objects of perception. Consequently, in his treatment of space and time, he refers to what are both to him and in fact objects of perception in terms of perception, and thereby contravenes the second implication of perception to which attention has been drawn. Again, in the second place, if we go on to ask how Kant is misled into doing this, we see that it is because he contravenes the first implication of perception. In virtue of his theory of perception[10] he interposes a tertium quid between the reality perceived and the percipient, in the shape of an 'appearance'. This tertium quid gives him something which can plausibly be regarded as at once a perception and something perceived. For, though from the point of view of the thing in itself an appearance is an appearance or a perception of it, yet, regarded from the point of view of what it is in itself, an appearance is a reality perceived of the kind called mental. Hence space and time, being characteristics of an appearance, can be regarded as at once characteristics of our perception of a reality, viz. of a thing in itself, and characteristics of a reality perceived, viz. an appearance. Moreover, there is another point of view from which the treatment of bodies in space as appearances or phenomena gives plausibility to the view that space, though a form of perception, is a characteristic of a reality. When Kant speaks of space as the form of phenomena the fact to which he refers is that all bodies are spatial.[11] He means, not that space is a way in which we perceive something, but that it is a characteristic of things perceived, which he calls phenomena, and which are bodies. But, since in his statement of this fact he substitutes for bodies phenomena, which to him are perceptions, his statement can be put in the form 'space is the form of perceptions'; and the statement in this form is verbally almost identical with the statement that space is a form of perception. Consequently, the latter statement, which should mean that space is a way in which we perceive things, is easily identified with a statement of which the meaning is that space is a characteristic of something perceived.[12]

Again, Kant's account of time will be found to treat something represented or perceived as also a perception. We find two consecutive paragraphs[13] of which the aim is apparently to establish the contrary conclusions: (1) that time is only the form of our internal state and not of external phenomena, and (2) that time is the formal condition of all phenomena, external and internal.

To establish the first conclusion, Kant argues that time has nothing to do with shape or position, but, on the contrary, determines the relation of representations in our internal state. His meaning is that we have a succession of perceptions or representations of bodies in space,[14] and that while the bodies perceived are not related temporally, our perceptions or representations of them are so related. Here 'representations' refers to our apprehension, and is distinguished from what is represented, viz. bodies in space.

How, then, does Kant reach the second result? He remembers that bodies in space are 'phenomena', i. e. representations. He is, therefore, able to point out that all representations belong, as determinations of the mind, to our internal state, whether they have external things, i. e. bodies in space, for their objects or not, and that, consequently, they are subject to time. Hence time is concluded to be the form of all phenomena. In this second argument, however, it is clear that Kant has passed from his previous treatment of bodies in space as something represented or perceived to the treatment of them as themselves representations or perceptions.[15]

In conclusion, we may point out an insoluble difficulty in Kant's account of time. His treatment of space and time as the forms of outer and inner sense respectively implies that, while spatial relations apply to the realities which we perceive, temporal relations apply solely to our perceptions of them. Unfortunately, however, as Kant in certain contexts is clearly aware, time also belongs to the realities perceived. The moon, for instance, moves round the earth. Thus there are what may be called real successions as well as successions in our perception. Further, not only are we aware of this distinction in general, but in particular cases we succeed in distinguishing a succession of the one kind from a succession of the other. Yet from Kant's standpoint it would be impossible to distinguish them in particular cases, and even to be aware of the distinction in general. For the distinction is possible only so long as a distinction is allowed between our perceptions and the realities perceived. But for Kant this distinction has disappeared, for in the end the realities perceived are merely our perceptions; and time, if it be a characteristic of anything, must be a characteristic only of our perceptions.

FOOTNOTES

[1] Cf. pp. 235-6.

[2] Cf. p. 119.

[3] Though not apart from relation to the mind of some other kind.