CHAPTER II. System of all Principles of the Pure Understanding.
In the foregoing chapter we have merely considered the general
conditions under which alone the transcendental faculty of judgement
is justified in using the pure conceptions of the understanding for
synthetical judgements. Our duty at present is to exhibit in
systematic connection those judgements which the understanding
really produces a priori. For this purpose, our table of the
categories will certainly afford us the natural and safe guidance. For
it is precisely the categories whose application to possible
experience must constitute all pure a priori cognition of the
understanding; and the relation of which to sensibility will, on
that very account, present us with a complete and systematic catalogue
of all the transcendental principles of the use of the understanding.
Principles a priori are so called, not merely because they contain
in themselves the grounds of other judgements, but also because they
themselves are not grounded in higher and more general cognitions.
This peculiarity, however, does not raise them altogether above the
need of a proof. For although there could be found no higher
cognition, and therefore no objective proof, and although such a
principle rather serves as the foundation for all cognition of the
object, this by no means hinders us from drawing a proof from the
subjective sources of the possibility of the cognition of an object.
Such a proof is necessary, moreover, because without it the
principle might be liable to the imputation of being a mere gratuitous
assertion.
In the second place, we shall limit our investigations to those
principles which relate to the categories. For as to the principles of
transcendental aesthetic, according to which space and time are the
conditions of the possibility of things as phenomena, as also the
restriction of these principles, namely, that they cannot be applied
to objects as things in themselves- these, of course, do not fall
within the scope of our present inquiry. In like manner, the
principles of mathematical science form no part of this system,
because they are all drawn from intuition, and not from the pure
conception of the understanding. The possibility of these
principles, however, will necessarily be considered here, inasmuch
as they are synthetical judgements a priori, not indeed for the
purpose of proving their accuracy and apodeictic certainty, which is
unnecessary, but merely to render conceivable and deduce the
possibility of such evident a priori cognitions.
But we shall have also to speak of the principle of analytical
judgements, in opposition to synthetical judgements, which is the
proper subject of our inquiries, because this very opposition will
free the theory of the latter from all ambiguity, and place it clearly
before our eyes in its true nature.
