This argument recurs in B 422.

“The subject of the categories cannot by thinking the categories acquire a conception of itself as an object of the categories. For, in order to think them, its pure self-consciousness, which is what was to be accounted for, must itself be presupposed.”

It is extremely difficult to estimate the value and cogency of this argument.[1085] Many objections or rather qualifications must be made before it can be either accepted or rejected. If it be taken only as asserting that the unity of self-consciousness is not adequately expressible through any of the categories, it is undoubtedly valid. If, further, the categories be identified with the schemata, it is also true that they are not applicable in any degree or manner. The schemata are applicable only to natural existences in space and time. Self-consciousness can never be reduced to a natural existence of that type. On the other hand, if it is not self-consciousness as such, but the self-conscious subject, which on Kant’s view is always noumenal—“this I or he or it (the thing) which thinks”[1086]—that is referred to, and if we distinguish between the categories strictly so called, that is, the pure forms of understanding, and the schemata, it is not at all evident that the self-conscious subject may not be described as being an existence that is always a subject and never a predicate, and as being related to experience as a ground or condition. These indefinite assertions leave open alternative possibilities. They do not even decide whether the self is “I or he or it.”[1087] In so far as they advance beyond the mere assertion that the self rests upon noumenal conditions they are, indeed, incapable of proof, but by no Critical principle can they be shown to be inapplicable. When, therefore, Kant may seem to extract a more definite conclusion from the above argument,[1088] he advances beyond what it can be made to support.

Kant is here influenced by the results of the ethical enquiries with which in the period subsequent to 1781 he was chiefly preoccupied. He believed himself to have proved that the self, as a self-conscious being, is a genuinely noumenal existence. That being so, he was bound to hold that the categories, even as pure logical forms, are inadequate to express its real determinate nature. But he confounds this position with the assertion that they are not only inadequate, but in and by themselves are likewise inapplicable. That is not a legitimate conclusion, for even if the self is more than mere subject or mere ground, it will at least be so much. When ethical considerations are left out of account, the only proper conclusion is that the applicability of the categories to the self-conscious subject is capable neither of proof nor of disproof, but that when the distinction between appearance and reality (which as we shall find is ultimately based upon the Ideas of Reason) has been drawn, the categories can be employed to define the possible difference between self-conscious experience and its unknown noumenal conditions. Any other conclusion conflicts with the teaching of the section on the Paralogisms.

It is important to observe—a point ignored by such critics as Caird and Watson—that in the sections under consideration[1089] Kant most explicitly declares self-consciousness to be merely “the representation of that which is the condition of all unity.” He maintains that this representation, as standing for “the determining self (the thinking), is to be distinguished from the self which we are seeking to determine (the subject which thinks) as knowledge from its object,”[1090] or in other words, that, without special proof, unattainable on theoretical grounds, “the unity of thought” may not be taken as equivalent to the unity of the thinking subject.[1091] They may be as diverse as unity of representation and unity of object represented are frequently found to be. We may never argue from simplicity in a representation to simplicity in its object.

But to return to the main thesis, it may be observed that these arguments, with the exception of that which we have just been considering from the nature of self-consciousness, lead to the conclusion that the categories are as little applicable to the thing in itself as to the transcendental subject. Even the argument from the necessary and invariable presence of self-consciousness in each and every act of judgment is itself valid only from a point of view which regards self-consciousness in the manner of Kant’s early semi-Critical view of the transcendental subject[1092] as an ultimate. But if, as is maintained in the section in which this argument occurs, viz. that on the Paralogisms, self-consciousness may be complexly conditioned, and may indeed have conditions similar in nature to those which underlie outer experience, the categories may be just as applicable, or as inapplicable, to its noumenal nature as to the nature of the thing in itself. It is noticeable that in the second edition, doubtless under the influence of preoccupation with ethical problems, some of Kant’s utterances betray a tendency to relax the rigour of his thinking, and to bring his theoretical teaching into closer agreement with his ethical results than the theoretical analysis in and by itself at all justifies. This tendency was, of course, reinforced by the persisting influence of that view of the transcendental subject which he had held in the middle ’seventies, and from which he never completely emancipated either his language or his thinking.[1093] Indeed in several of the passages added in the second edition[1094] Kant even goes so far as to adopt language which if taken quite literally would mean that the ‘I think’ is an immediate consciousness of the mind’s purely intellectual activity—a view which, as we have seen,[1095] is altogether alien to the Critical position. It would, as he argues so forcibly elsewhere, involve a kind of experience which does not conform to Critical requirements, and which would lie open to the attacks of sceptics such as Hume.

In B 157-8 the difficulties of Kant’s position are again manifest. Speaking of the representation of the self, he declares that “I am conscious of myself ..., not as I appear to myself, nor as I am in myself, but only that I am.” This may seem to imply that existence is predicable of the transcendental self. He adds that though the determination, i.e. specification in empirical form, of my existence (mein eigenes Dasein) is possible only in inner sensuous intuition, it is “not appearance and still less mere illusion.” But in the appended note it is urged that my existence (Dasein) as self-active being is represented in purely indeterminate fashion. Only my existence as sensuous, and therefore as appearance, can be known, i.e. can be made determinate.

The problem is more directly and candidly faced in the note to B 422. That note is interesting for quite a number of reasons. It reveals Kant in the very act of recasting his position, and in the process of searching around for a mode of formulation which will enable him to hold to a transcendental consciousness of the self’s existence and at the same time not to violate the definition of existence given in the Postulates, i.e. both to posit the transcendental self as actual and yet to deny the applicability to it of any of the categories. After stating that the ‘I think’ is an empirical proposition in which my existence is immediately involved, he proceeds further to describe it as expressing “an undetermined empirical intuition, i.e. perception,” and so as showing that sensation underlies its assertion of existence. Kant does not, however, mean by these words that the existence asserted is merely that of the empirical self; for he proceeds:

“...existence is here not a category, which as such does not apply to an indeterminately-given object.... An indeterminate perception here signifies only something real that is given, given indeed to thought in general, and so not as appearance, nor as thing in itself (Noumenon), but as something which actually [in der That] exists, and which in the proposition, I think, is denoted [bezeichnet] as such.”

The phrases here employed are open to criticism on every side. Kant completely departs from his usual terminology when he asserts that through an “indeterminate perception” the self is given, and “given to thought in general” as “something real.” The contention, that the existence asserted is not a category, is also difficult to accept.[1096] It is equally surprising to read that its reality is given “neither as appearance nor as thing [Sache] in itself (Noumenon)”; for hitherto no such alternative form of real existence has been recognised.