It is not surprising that Kant did not permanently hold to this view of the empirical concept. The objections are obvious. Such a view of the function of general concepts renders unintelligible their own first formation. For as they are empirical, they can only be acquired by conscious processes that do not involve them. That is to say, consciousness of objects follows upon a prior consciousness in and through which concepts, such as that of body, are discovered and formed. Yet, as the argument claims, general concepts are the indispensable conditions of unitary consciousness. How through a consciousness that is not yet unified can general concepts be formed? Also it is difficult to see how empirical concepts can be viewed as directly conditioned by, and as immediately due to, anything so general as pure apperception. These objections Kant must have come very quickly to recognise. This was the first part of his teaching to be modified. In the immediately succeeding stage,[778] so far as the stages can be reconstructed from the survivals in the _Critique_, the empirical concepts are displaced once and for all by the _a priori_ categories. The only sentences which can be regarded as possibly conflicting with the above interpretation are those two (in the second last and in the last paragraphs) in which the phrase “rules _a priori_” occurs. Even granting (what is at least questionable as regards the first) that the words are meant to be taken together, it does not follow that Kant is here speaking of categories. For contrary to his usual teaching he speaks of the concept of body as a source of necessity. If so, it may well, with equal looseness, be spoken of as _a priori_. That is indeed done, by implication, in the second and third paragraphs, where he speaks of a rule (referring to “body and triangle”) as making the synthesis of reproduction “_a priori_ necessary.” Such assertions are completely inconsistent with Kant’s Critical teaching, but so is the entire section. The setting in which the passage before us occurs has its own special interest.[779] When Kant, as it would seem, on the very eve of the publication of the _Critique_, developed the doctrine of a threefold synthesis culminating in a “synthesis of recognition in the concept,” he must have bethought himself of this earlier position, and have completed his subjective deduction by incorporation, probably with occasional alterations of phrasing, of the older manuscript. This procedure has bewildered even the most discerning among Kant’s readers; but now, thanks to Vaihinger’s convincing analysis, it may be welcomed as of illuminating interest in the historical study of Kant’s development.