e or knowledge. Now it is so
presupposed. For, as we have already shown, the relation of
representations to an object presupposes one consciousness which
combines and unifies them, and is at the same time conscious of the
identity of its own action in unifying them. This consciousness is the
ground of the unity of consciousness in the synthesis of the manifold.
It may fairly be called transcendental, because even a conception
which relates to space or time, and therefore is the most remote from
sensation, presupposes one consciousness which combines and unifies
the manifold of space and time through the conception, and is
conscious of the identity of its own action in so doing. It may,
therefore, be regarded as the presupposition of _all_ conceiving or
bringing a manifold under a conception, and therefore of all
knowledge. Consequently, since knowledge is possible, i. e. since the
manifold of representations can be related to an object, there must be
one self capable of being aware of its own identity throughout its
representations.'

At this point of Kant's argument, however, there seems to occur an
inversion of the thought. Hitherto, Kant has been arguing from the
possibility of knowledge to the possibility of the consciousness of
our own identity. But in the next paragraph he appears to reverse this
procedure and to argue from the possibility of self-consciousness to
the possibility of knowledge.

"But it is just this transcendental unity of apperception[55] which
forms, from all possible phenomena which can be together in one
experience, a connexion of them according to laws. For this unity of
consciousness would be impossible, if the mind in the knowledge of the
manifold could not become conscious of the identity of the function
whereby it unites the manifold synthetically in one knowledge.
Consequently, the original and necessary consciousness of the identity
of oneself is at the same time a consciousness of an equally necessary
unity of the synthesis of all phenomena according to conceptions,
i. e. according to rules which not only make them necessarily
reproducible, but thereby determine an object for their perception,
i. e. determine the conception of something in which they are
necessarily connected. For the mind could not possibly think the
identity of itself in the manifold of its representations, and this
indeed _a priori_, if it had not before its eyes the identity of its
action which subjects all synth