"[1.] It must be possible that the 'I think' should accompany all my representations; for otherwise something would be represented in me which could not be thought; in other words, the representation would be either impossible or at least for me nothing. [2.] That representation which can be given before all thought is called _perception_. All the manifold of perception has therefore a necessary relation to the 'I think' in the same subject in which this manifold is found. [3.] But this representation[64] [i. e. the 'I think'] is an act of _spontaneity_, i. e. it cannot be regarded as belonging to sensibility. I call it _pure apperception_, to distinguish it from _empirical apperception_, or _original apperception_ also, because it is that self-consciousness which, while it gives birth to the representation 'I think', which must be capable of accompanying all others and is one and the same in all consciousness, cannot itself be accompanied by any other.[65] [4.] I also call the unity of it the _transcendental_ unity of self-consciousness, in order to indicate the possibility of _a priori_ knowledge arising from it. For the manifold representations which are given in a perception would not all of them be _my_ representations, if they did not all belong to one self-consciousness, that is, as my representations (even though I am not conscious of them as such), they must necessarily conform to the condition under which alone they _can_ stand together in a universal self-consciousness, because otherwise they would not all belong to me. From this original connexion much can be concluded." [64] This is an indisputable case of the use of representation in the sense of something represented or presented. [65] I. e. consciousness of our identity is final; we cannot, for instance, go further back to a consciousness of the consciousness of our identity.