Fifth Paragraph. Criticism of Locke’s View of Appearance.—This paragraph discusses Locke’s doctrine[573] that the secondary qualities are subjective, and that in the primary qualities we possess true knowledge of things in themselves. The distinction is drawn upon empirical grounds, namely, that while certain qualities are uniform for more than one sense, and belong to objects under all conditions, others are peculiar to the different senses, and arise only through the accidental relation of objects to the special senses.[574] This distinction is, Kant says, entirely justified from the physical standpoint.[575] A rainbow is an appearance of which the raindrops constitute the true empirical reality. But Locke and his followers interpret this distinction wrongly. They ignore the more fundamental transcendental (i.e. metaphysical) distinction between empirical reality and the thing in itself. From the transcendental standpoint the raindrops are themselves merely appearance. Even their round shape, and the very space in which they fall; are only modifications of our sensuous intuition. The ‘transcendental object’[576] remains unknown to us.
When Kant thus declares that the distinction between primary and secondary qualities is justified (richtig) from the physical standpoint, he is again[577] speaking from a phenomenalist point of view. And it may be noted that in developing his transcendental distinction he does not describe the raindrops as mere representations. His phrase is much more indefinite. They are “modifications or fundamental forms (Grundlagen) of our sensuous intuition.”
Kant does not here criticise the view of sensibility which underlies Locke’s view of appearance. But he does so in A 271 = B 327, completing the parallel and contrast between Leibniz and Locke.
“Leibniz intellectualised appearances, just as Locke, according to his system of noogony (if I may be allowed these expressions), sensualised all concepts of the understanding, i.e. interpreted them as simply empirical or abstracted concepts of reflection. Instead of interpreting understanding and sensibility as two quite different sources of representations, which yet can supply objectively valid judgments of things only in conjunction with each other, each of these great men holds only to one of the two, viewing it as in immediate relation to things in themselves. The other faculty is regarded as serving only to confuse or to order the representations which this selected faculty yields.”[578]
Proof that the above View of Space and Time is not a mere Hypothesis, but completely certain.[579]—The proof, which as here recapitulated and developed follows the analytic method, has already been considered in connection with A 39 = B 56. It proceeds upon the assumption that space cannot be both an a priori form of intuition and also independently real. The argument as a whole lacks clearness owing to Kant’s failure to distinguish between the problems of pure and applied geometry, between pure intuition and form of intuition. This is especially obvious in the very unfortunate and misleading second application of the triangle illustration.[580] Kant’s tendency to conceive mathematical science almost exclusively in terms of geometry is likewise illustrated.
“There is in regard to both [space and time] a large number of a priori apodictic and synthetic propositions. This is especially true of space, which for this reason will be our chief illustration in this enquiry.”[581]
II. Paragraphs added in the Second Edition.[582]—Kant proceeds to offer further proof of the ideality of the appearances (a) of outer and (b) of inner sense. Such proof he finds in the fact that these appearances consist solely of relations. (a) Outer appearances reduce without remainder to relations of position in intuition (i.e. of extension), of change of position (motion), and to the laws which express in merely relational terms the motive forces by which such change is determined. What it is that is thus present in space, or what the dynamic agencies may be to which the motion is due, is never revealed. But a real existent (Sache an sich) can never be known through mere relations. Outer sense consequently reveals through its representations only the relation of an object to the subject, not the intrinsic inner nature of the object in itself (Object an sich). Kant’s avoidance of the term Ding an sich may be noted.[583]
(b) The same holds true of inner sense, not only because the representations of outer sense constitute its proper (eigentlichen) material, but also because time, in which these are set, contains only relations of succession, coexistence, and duration. This time (which as consisting only of relations can be nothing but a form[584]) is itself, in turn, a mere relation. It is only the manner in which through its own activity the mind is affected by itself. But in order to be affected by itself it must have receptivity, in other words, sensibility. Time, consequently, must be regarded as the form of this inner sense.
That everything represented in time, like that which is represented in space, consists solely of relations, Kant does not, however, attempt to prove. He is satisfied with repeating the conclusion reached in the first edition of the Aesthetic, that, as time is the object of a sense, it must of necessity be appearance. This, like everything which Kant wrote upon inner sense, is profoundly unsatisfactory. The obscurities of his argument are not to be excused on the ground that “the difficulty, how a subject can have an internal intuition of itself, is common to every theory.” For no great thinker,[585] except Locke, has attempted to interpret inner consciousness on the analogy of the senses. Discussion of the doctrine must meantime be deferred.[586]