The Critique of Pure Reason | Page 9

cognitions, and can thus complete its work, and
leave it for the use of posterity, as a capital which can never receive
fresh accessions. For metaphysics has to deal only with principles and
with the limitations of its own employment as determined by these
principles. To this perfection it is, therefore, bound, as the fundamental
science, to attain, and to it the maxim may justly be applied:
Nil actum reputans, si quid superesset agendum.
But, it will be asked, what kind of a treasure is this that we propose to
bequeath to posterity? What is the real value of this system of
metaphysics, purified by criticism, and thereby reduced to a permanent
condition? A cursory view of the present work will lead to the
supposition that its use is merely negative, that it only serves to warn us
against venturing, with speculative reason, beyond the limits of
experience. This is, in fact, its primary use. But this, at once, assumes a
positive value, when we observe that the principles with which
speculative reason endeavours to transcend its limits lead inevitably,
not to the extension, but to the contraction of the use of reason,
inasmuch as they threaten to extend the limits of sensibility, which is
their proper sphere, over the entire realm of thought and, thus, to
supplant the pure (practical) use of reason. So far, then, as this criticism
is occupied in confining speculative reason within its proper bounds, it
is only negative; but, inasmuch as it thereby, at the same time, removes
an obstacle which impedes and even threatens to destroy the use of
practical reason, it possesses a positive and very important value. In
order to admit this, we have only to be convinced that there is an
absolutely necessary use of pure reason--the moral use--in which it
inevitably transcends the limits of sensibility, without the aid of
speculation, requiring only to be insured against the effects of a

speculation which would involve it in contradiction with itself. To deny
the positive advantage of the service which this criticism renders us
would be as absurd as to maintain that the system of police is
productive of no positive benefit, since its main business is to prevent
the violence which citizen has to apprehend from citizen, that so each
may pursue his vocation in peace and security. That space and time are
only forms of sensible intuition, and hence are only conditions of the
existence of things as phenomena; that, moreover, we have no
conceptions of the understanding, and, consequently, no elements for
the cognition of things, except in so far as a corresponding intuition can
be given to these conceptions; that, accordingly, we can have no
cognition of an object, as a thing in itself, but only as an object of
sensible intuition, that is, as phenomenon--all this is proved in the
analytical part of the Critique; and from this the limitation of all
possible speculative cognition to the mere objects of experience,
follows as a necessary result. At the same time, it must be carefully
borne in mind that, while we surrender the power of cognizing, we still
reserve the power of thinking objects, as things in themselves.* For,
otherwise, we should require to affirm the existence of an appearance,
without something that appears--which would be absurd. Now let us
suppose, for a moment, that we had not undertaken this criticism and,
accordingly, had not drawn the necessary distinction between things as
objects of experience and things as they are in themselves. The
principle of causality, and, by consequence, the mechanism of nature as
determined by causality, would then have absolute validity in relation
to all things as efficient causes. I should then be unable to assert, with
regard to one and the same being, e.g., the human soul, that its will is
free, and yet, at the same time, subject to natural necessity, that is, not
free, without falling into a palpable contradiction, for in both
propositions I should take the soul in the same signification, as a thing
in general, as a thing in itself--as, without previous criticism, I could
not but take it. Suppose now, on the other hand, that we have
undertaken this criticism, and have learnt that an object may be taken in
two senses, first, as a phenomenon, secondly, as a thing in itself; and
that, according to the deduction of the conceptions of the understanding,
the principle of causality has reference only to things in the first sense.
We then see how it does not involve any contradiction to assert, on the

one hand, that the will, in the phenomenal sphere--in visible action--is
necessarily obedient to the law of nature, and, in so far, not free; and,
on the other hand, that, as belonging to a thing in itself, it is