] Synthetical unity of the manifold of perceptions, as given _a
priori_, is therefore the ground of the identity of apperception
itself, which precedes _a priori_ all _my_ determinate thinking. [12.]
But connexion does not lie in the objects, nor can it be borrowed from
them through perception and thereby first taken up into the
understanding, but it is always an operation of the understanding
which itself is nothing more than the faculty of connecting _a
priori_, and of bringing the manifold of given representations under
the unity of apperception, which principle is the highest in all human
knowledge."

[66] I understand this to mean 'This through and through
identical consciousness of myself as the identical subject of
a manifold given in perception involves a synthesis of
representations'.

[67] The drift of the passage as a whole (cf. especially
Sec. 16) seems to show that here 'the synthesis of
representations' means 'their connectedness' and not
'the act of connecting them'.

[13.] "Now this principle of the necessary unity of apperception is
indeed an identical, and therefore an analytical, proposition, but
nevertheless it declares a synthesis of the manifold given in a
perception to be necessary, without which the thorough-going identity
of self-consciousness cannot be thought. [14.] For through the Ego, as
a simple representation, is given no manifold content; in perception,
which is different from it, a manifold can only be given, and through
_connexion_ in one consciousness it can be thought. An understanding,
through whose self-consciousness all the manifold would _eo ipso_ be
given, would _perceive_; our understanding can only _think_ and must
seek its perception in the senses. [15.] I am, therefore, conscious of
the identical self, in relation to the manifold of representations
given to me in a perception, because I call all those representations
_mine_, which constitute _one_. [16.] But this is the same as to say
that I am conscious _a priori_ of a necessary synthesis of them, which
is called the original synthetic unity of apperception, under which
all representations given to me stand, but also under which they must
be brought through a synthesis."[68]

[68] B. 131-5, M. 81-4.

Though this passage involves many difficulties, the main drift of it
is clear. Kant is anxious to establish the fact that the manifold of
sense must be capable of being combined on prin