played by a faculty different from the understanding; _or_ the imagination is the understanding working unreflectively, and the subsequent process of bringing the synthesis to a conception is merely a process by which the understanding becomes conscious of its own procedure. Moreover, it is the latter alternative which we must accept as more in accordance with the general tenor of Kant's thought. For the synthesis of the imagination is essentially the outcome of activity or spontaneity, and, as such, it belongs to the understanding rather than to the sensibility; in fact we find Kant in one place actually saying that 'it is one and the same spontaneity which at one time under the name of imagination, at another time under that of understanding, introduces connexion into the manifold of perception'.[15] Further, it should be noted that since the imagination must be the understanding working unreflectively, and since it must be that which introduces unity into the manifold, there is some justification for his use of language which implies that the understanding is the source of the unity, though it will not be so in the sense in which the passage under discussion might at first sight lead us to suppose. [12] The italics are mine. [13] The italics are mine. [14] Cf. the description of the imagination as 'blind'. [15] B. 162 note, M. 99 note. Cf. B. 152, M. 93. Similarly at one point in the passage under discussion (B. 102 fin., M. 62 med.) the synthesis is expressly attributed to the spontaneity of thought. We can now turn to the argument of the _Transcendental Deduction_ itself. Kant introduces it in effect by raising the question, 'How is it that, beginning with the isolated data of sense, we come to acquire knowledge?' His aim is to show (1) that knowledge requires the performance of certain operations by the mind upon the manifold of sense; (2) that this process is a condition not merely of knowledge, but also of self-consciousness; and (3) that, since the manifold is capable of entering into knowledge, and since we are capable of being self-conscious, the categories, whose validity is implied by this process, are valid. Kant begins by pointing out[16] that all knowledge, _a priori_ as well as empirical, requires the manifold, produced successively in the mind, to be subjected to three operations. [16] A. 95-104, Mah. 194-8.