[T]he inner sense is affected by ourselves. Every act of attention can pro-vide an example of this. (B 156, note)

According to these passages the understanding determines inner sense as inner intuition. Put otherwise, that which is first given to me in the synthesis is determined by the understanding as an object. Here “self-affection” means [342] concern with oneself, i.e., thinking is concerned with the given. Kant points out (at B 152) that the idea of self-affection necessarily has something paradoxical about it, since being-affected is different from functioning. The senses are affected whereas the understanding functions. The understanding is spontaneity, whereas sensibility is receptivity. But now spontaneity itself is supposed to be receptivity, especially so and exclusively so in this phenomenon of self-affection. The self, in its very being, is supposed to be the condition of the possibility of letting something encounter it.

By interpreting time as the original, universal, pure self-affection, we have led the heretofore disparate features of time back to an essential phenomenon. But with this phenomenon we have also entered an area that we had previously started to explore while analyzing the transcendental apperception—which, as it turned out, was also the condition of possibility of the “existence” [Kant’s word, Dasein] of objects: entities as objectively determinable. And this transcendental apperception was itself also an act of spontaneity. This spontaneity of the I (the self) is thus equiprimordially pure apperception and pure self-affection, pure “I think” and time. So we are back to the context of our basic question. Earlier (p. 255) I said: “It is a matter of the conditions of the possibility of a conjunction of time and the ‘I think’,” and, “Only if we pose the question in this way, i.e., about the conditions of the possibility of the ontological connection between both determinations of the mind (namely, time as pure intuition and the ‘I think’ as an act of the mind’s spontaneity), do we comprehend the question philosophically.” The interpretation of time that we have gained so far clarifies the connection between time and the I, between self-affection and transcendental apperception. Or to put it more prudently: It puts us face to face with the real difficulty. [343]

For Kant there are two self-positings in spontaneity. Kant got to this dimension by pursuing his inquiries, but he never made it primary in

transcendental synthesis. (3) By way of that action (cf. durch die [d.h. die Synthesis] er (der Verstand)), the understanding qua active, is able to determine itself qua passive-receptive inner sense, since the inner sense is in fact a faculty of the understanding. Thus (4) “The understanding, under the title of a transcendental synthesis of the imagination, exercises that action [of synthesis] on the passive subject, which is itself a faculty of the understanding. Thus we can rightly say that inner sense is affected by that action.”]