n the
_Metaphysical Deduction_ which nominally connects the list of
categories with the list of forms of judgement.[2] For its real
function is to introduce a new and third account of knowledge, which
forms the keynote of the _Transcendental Deduction_.[3]

[2] B. 102-5, M. 62-3. Cf. pp. 155-6.

[3] The first two accounts are (1) that of judgement given B.
92-4, M. 56-8, and (2) that of judgement implicit in the view
that the forms of judgement distinguished by Formal Logic are
functions of unity. In A. 126, Mah. 215, Kant seems to
imply--though untruly--that this new account coincides with
the other two, which he does not distinguish.

In this passage, the meaning of which it is difficult to state
satisfactorily, Kant's thought appears to be as follows: 'The activity
of thought studied by Formal Logic relates by way of judgement
conceptions previously obtained by an analysis of perceptions. For
instance, it relates the conceptions of body and of divisibility,
obtained by analysis of perceptions of bodies, in the judgement
'Bodies are divisible'. It effects this, however, merely by analysis
of the conception 'body'. Consequently, the resulting knowledge or
judgement, though _a priori_, is only analytic, and the conceptions
involved originate not from thought but from the manifold previously
analysed. But besides the conceptions obtained by analysis of a given
manifold, there are others which belong to thought or the
understanding as such, and in virtue of which thought originates
synthetic _a priori_ knowledge, this activity of thought being that
studied by Transcendental Logic. Two questions therefore arise.
Firstly, how do these conceptions obtain a matter to which they can
apply and without which they would be without content or empty? And,
secondly, how does thought in virtue of these conceptions originate
synthetic _a priori_ knowledge? The first question is easily answered,
for the manifolds of space and time, i. e. individual spaces and
individual times, afford matter of the kind needed to give these
conceptions content. As perceptions (i. e. as objects of perception),
they are that to which a conception can apply, and as pure or _a
priori_ perceptions, they are that to which those conceptions can
apply which are pure or _a priori_, as belonging to the understanding.
The second question can be answered by considering the process by
which this pure manifold of space and time enters