thing in itself, and introduce the empiricism of Locke. But this difficulty is removed by reflection, which shows us that the law of causality is of subjective origin, as well as the sensation itself; and besides this, our own body also, inasmuch as it appears in space, already belongs to ideas. But Kant was hindered from confessing this by his fear of the Berkeleian idealism.
“The combination of the manifold of perception” is repeatedly given as the essential operation of the understanding, by means of its twelve categories. Yet this is never adequately explained, nor is it shown what this manifold of perception is before it is combined by the understanding. But time and space, the latter in all its three dimensions, are continua, i. e., all their parts are originally not separate but combined. Thus, then, everything that exhibits itself in them (is given) appears originally as a continuum, i. e., its parts appear already combined and require no adventitious combination of a manifold. If, however, some one should seek to interpret that combining of the manifold of perception by saying that I refer the different sense-impressions of one object to this one only – thus, for example, perceiving a bell, I recognise that what affects my eye as yellow, my hand as smooth and hard, my ear as sounding, is yet only one and the same body, – then I reply that this is rather a consequence of the knowledge a priori of the causal nexus (this actual and only function of the understanding), by virtue of which all those different effects upon my different organs of sense yet lead me only to one common cause of them, the nature of the body standing before me, so that my understanding, in spite of the difference and multiplicity of the effects, still apprehends the unity of the cause as a single object, which just on that account exhibits itself in perception. In the beautiful recapitulation of his doctrine which Kant gives at p. 719-726 or V. 747-754 of the “Critique of Pure Reason,” he explains the categories, perhaps more distinctly than anywhere else, as “the mere rule of the synthesis of that which empirical apprehension has given a posteriori.” It seems as if here he had something in his mind, such as that, in the construction of the triangle, the angles give the rule for the composition of the lines; at least by this image one can best explain to oneself what he says of the function of the categories. The preface to the “Metaphysical First Principles of Natural Science” contains a long note which likewise gives an explanation of the categories, and says that they “differ in no respect from the formal acts of the understanding in judging,” except that in the latter subject and predicate can always change places; then the judgment in general is defined in the same passage as “an act through which given ideas first become knowledge of an object.” According to this, the brutes, since they do not judge, must also have no knowledge of objects. In general, according to Kant, there are only conceptions of objects, no perceptions. I, on the contrary, say: Objects exist primarily only for perception, and conceptions are always abstractions from this perception. Therefore abstract thinking must be conducted exactly according to the world present in perception, for it is only their relation to this that gives content to conceptions; and we must assume for the conceptions no other a priori determined form than the faculty of reflection in general, the nature of which is the construction of conceptions, i. e., of abstract non-perceptible ideas, which constitutes the sole function of the reason, as I have shown in the first book. I therefore require that we should reject eleven of the categories, and only retain that of causality, and yet that we should see clearly that its activity is indeed the condition of empirical perception, which accordingly is not merely sensuous but intellectual, and that the object so perceived, the object of experience, is one with the idea, from which there remains nothing to distinguish except the thing in itself.
After repeated study of the “Critique of Pure Reason” at different periods of my life, a conviction has forced itself upon me with regard to the origin of the Transcendental Logic, which I now impart as very helpful to an understanding of it. Kant's only discovery, which is based upon objective comprehension and the highest human thought, is the apperçu that time and space are known by us a priori. Gratified by this happy hit, he wished to pursue the same vein further, and his love of architectonic symmetry afforded him the clue. As he had found that a pure intuition or perception a priori underlay the empirical perception as its condition, he thought that in the same way certain pure conceptions as presuppositions in our faculty of knowledge must lie at the foundation of the empirically obtained conceptions, and that real empirical thought must be only possible through a pure thought a priori, which, however, would have no objects in itself, but would be obliged to take them from perception. So that as the Transcendental Æsthetic establishes an a priori basis of mathematics, there must, he supposed, also be a similar basis for logic; and thus, then for the sake of symmetry, the former received a pendant in a Transcendental Logic. From this point onwards Kant was no more free, no more in the position of purely, investigating and observing what is present in consciousness; but he was guided by an assumption and pursued a purpose – the purpose of finding what he assumed, in order to add to the Transcendental Æsthetic so happily discovered a Transcendental Logic analogous to it, and thus symmetrically corresponding to it, as a second storey. Now for this purpose he hit upon the table of judgments, out of which he constructed, as well as he could, the table of categories, the doctrine of twelve pure a priori conceptions, which are supposed to be the conditions of our thinking those very things the perception of which is conditioned by the two a priori forms of sensibility: thus a pure understanding now corresponded symmetrically to a pure sensibility. Then another consideration occurred to him, which offered a means of increasing the plausibility of the thing, by the assumption of the schematism of the pure conceptions of the understanding. But just through this the way in which his procedure had, unconsciously indeed, originated betrayed itself most distinctly. For because he aimed at finding something a priori analogous to every empirical function of the faculty of knowledge, he remarked that between our empirical perception and our empirical thinking, conducted in abstract non-perceptible conceptions, a connection very frequently, though not always, takes place, because every now and then we try to go back from abstract thinking to perception; but try to do so merely in order really to convince ourselves that our abstract thought has not strayed far from the safe ground of perception, and perhaps become exaggeration, or, it may be, mere empty talk; much in the same way as, when we are walking in the dark, we stretch out our hand every now and then to the guiding wall. We go back, then, to the perception only tentatively and for the moment, by calling up in imagination a perception corresponding to the conceptions which are occupying us at the time – a perception which can yet never be quite adequate to the conception, but is merely a temporary representative of it. I have already adduced what is needful on this point in my essay on the principle of sufficient reason, § 28. Kant calls a fleeting phantasy of this kind a schema, in opposition to the perfected picture of the imagination. He says it is like a monogram of the imagination, and asserts that just as such a schema stands midway between our abstract thinking of empirically obtained conceptions, and our clear perception which comes to us through the senses, so there are a priori schemata of the pure conceptions of the understanding between the faculty of perception a priori of pure sensibility and the faculty of thinking a priori of the pure understanding (thus the categories). These schemata, as monograms of the pure imagination a priori, he describes one by one, and assigns to each of them its corresponding category, in the wonderful “Chapter on the Schematism of the Pure Conceptions of the Understanding,” which is noted as exceedingly obscure, because no man has ever been able to make anything out of it. Its obscurity, however, vanishes if it is considered from the point of view here indicated, but there also comes out more clearly in it than anywhere else the intentional nature of Kant's procedure, and of the determination formed beforehand of finding what would correspond to the analogy, and could assist the architectonic symmetry; indeed this is here the case to such a degree as to be almost comical. For when he assumes schemata of the pure (empty) a priori conceptions of the understanding (categories) analogous to the empirical schemata (or representatives through the fancy of our actual conceptions), he overlooks the fact that the end of such schemata is here entirely wanting, For the end of the schemata in the case of empirical (real) thinking is entirely connected with the material content of such conceptions. For since these conceptions are drawn from empirical perception, we assist and guide ourselves when engaged in abstract thinking by now and then casting a momentary
