Appearance (Erscheinung) is here defined as the undetermined object of an intuition. By undetermined object is meant, as we have seen, the object in so far as it consists of the given sense contents. When these contents are interpreted through the categories they become phenomena.
“Appearances so far as they are thought as objects according to the unity of the categories are called phenomena.”[365]
But this distinction between appearance and phenomenon is not held to by Kant. He more usually speaks of the categorised objects as appearances. The term phenomenon is of comparatively rare occurrence in the Critique. This has been concealed from English readers, as both Meiklejohn and Max Müller almost invariably translate Erscheinung phenomenon. The statement that appearance is the object of an empirical intuition raises a very fundamental and difficult question, namely, as to the relation in which representation stands to the represented.[366] Frequently Kant’s argument implies this distinction, yet constantly he speaks and argues as if it were non-existent. We have to recognise two tendencies in Kant, subjectivist and phenomenalist.[367] When the former tendency is in the ascendent, he regards all appearances, all phenomena, all empirical objects, as representations, modifications of the sensibility, merely subjective. When, on the other hand, his thinking is dominated by the latter tendency, appearances gain an existence independent of the individual mind. They are known through subjective representations, but must not be directly equated with them. They have a genuine objectivity. To this distinction, and its consequences, we shall have frequent occasion to return.
The phenomenalist standpoint is dominant in these first two paragraphs of the Aesthetic, and it finds still more pronounced expression in the opening of the third paragraph. “That in the appearances which corresponds (correspondirt) to sensation, I call its matter.” This sentence, through the use of the term corresponds, clearly implies a distinction between sensation and the real object apprehended in and through it. That, in turn, involves a threefold distinction, between sensation as subjective content (= appearance in the strict sense), the real enduring object in space (= phenomenon, the categorised object, appearance in its wider and more usual sense), and the thing in itself.[368] Yet in the immediately following sentence Kant says that “the matter of all appearance is given a posteriori.” By “matter of appearance” Kant must there mean sensations, for they alone are given a posteriori.[369] On this view the phenomena or empirical objects reduce to, and consist of, sensations. The intermediate term of the above threefold distinction is eliminated. The matter of appearance does not correspond to, but itself is, sensation. Thus in these successive sentences the two conflicting tendencies of Kant’s teaching find verbal expression. They intervene even in the preliminary definition of his terms. This fundamental conflict cannot, however, be profitably discussed at this stage.
The manifold of appearance (das Mannichfaltige der Erscheinung). The meaning to be assigned to this phrase must depend upon the settlement of the above question.[370] But in this passage it allows only of a subjectivist interpretation, whereby sensations are appearance. The given sensations as such constitute a manifold; as objects in space they are already ordered. Kant’s more usual phrase is “the manifold of intuition.” His adoption of the term “manifold” (the varia of the Dissertation) expresses his conviction that synthesis is indispensable for all knowledge, and also his correlative view that nothing absolutely simple can be apprehended in sense-experience. By the manifold Kant does not mean, however, as some of his commentators would seem to imply, the chaotic or disordered. The emphasis is on manifoldness or plurality, as calling for reduction to unity and system. The unity has to be found in it, not introduced into it forcibly from the outside. The manifold has to be interpreted, even though the principles of interpretation may originate independently of it. Though, for instance, the manifold as given is not in space and time, the specific space and time relations assigned by us are determined for us by the inherent nature of the manifold itself.[371]
The form of appearance is defined—if the definition given in the first edition be translated literally—as “that which causes (dasjenige, welches macht dass) the manifold of appearance to be intuited as ordered in certain relations.” This phrase is employed by Kant in other connections, and, as Vaihinger points out,[372] need not necessarily indicate activity. “Sensation is that in our knowledge which causes it to be called a posteriori knowledge.”[373] In the second edition Kant altered the text from “geordnet angeschaut wird” to “geordnet werden kann.” The reason probably was that the first edition’s wording might seem to imply that the form is (as the Dissertation taught) capable in and by itself of ordering the manifold. Throughout the second edition Kant makes more prominent the part which understanding plays in the apprehension of space.[374]
This distinction between matter and form is central in Kant’s system.[375] As he himself says:
“These are two conceptions which underlie all other reflection, so inseparably are they bound up with all employment of the understanding. The one [matter] signifies the determinable in general, the other [form] its determination.”[376]
On the side of matter falls the manifold, given, empirical, contingent material of sense; on the side of form fall the unifying, a priori, synthetic, relational instruments of sensibility and thought. For Kant these latter are no mere abstractions, capable of being distinguished by the mind; they differ from the matter of experience in nature, in function, and in origin. Upon this dualistic mode of conceiving the two factors depends the strength as well as the weakness of his position. To its perverting influence most of the unsatisfactory features of his doctrine of space and time can be directly traced. But to it is also due his appreciation of the new Critical problems, with their revolutionary consequences, as developed in the Analytic.
Kant proceeds to argue: (a) that the distinction is between two elements of fundamentally different nature and origin. The matter is given a posteriori in sensation; the form, as distinct from all sensation, must lie ready a priori in the mind. (b) Kant also argues that form, because of its separate origin, is capable of being contemplated apart from all sensation. The above statements rest upon the unexpressed assumption that sensations have no spatial attributes of any kind.[377] In themselves they have only intensive, not extensive, magnitude.[378] Kant assumes this without question, and without the least attempt at proof.[379] The assumption appears in Kant’s writings as early as 1768 as a self-evident principle;[380] and throughout the Critique is treated as a premiss for argument, never as a statement calling for proof. The only kind of supporting argument which is even indirectly suggested by Kant is that space cannot by itself act upon the senses.[381] This would seem to be his meaning when he declares[382] that it is no object, but only an ens imaginarium. “Space is no object of the senses.”[383] Such argument, however, presupposes that space can be conceived apart from objects. It is no proof that an extended object may not yield extended sensations. Kant completely ignores the possibility that formal relations may be given in and with the sensations. If our sensibility, in consequence of the action of objects upon it, is able to generate qualitative sensations, why, as Vaihinger very pertinently enquires,[384] should it be denied the power of also producing, in consequence of these same causes, impressions of quantitative formal nature? Sensations, on Kant’s view, are the product of mind much more than of objects. Why, then, may not space itself be sensational?[385] From the point of view of empirical science there is no such radical difference between cause and effect in the latter case as exists in the former. As Herbert Spencer has remarked,[386] Kant makes the enormous assumption