The Critique of Practical Reason | Page 2

is a
subjective necessity (a need of pure reason) to assume them.
Nevertheless the theoretical knowledge of reason is not hereby enlarged,
but only the possibility is given, which heretofore was merely a
problem and now becomes assertion, and thus the practical use of
reason is connected with the elements of theoretical reason. And this
need is not a merely hypothetical one for the arbitrary purposes of
speculation, that we must assume something if we wish in speculation
to carry reason to its utmost limits, but it is a need which has the force
of law to assume something without which that cannot be which we
must inevitably set before us as the aim of our action.

{PREFACE ^paragraph 5}
* Lest any one should imagine that he finds an inconsistency here when
I call freedom the condition of the moral law, and hereafter maintain in
the treatise itself that the moral law is the condition under which we
can first become conscious of freedom, I will merely remark that
freedom is the ratio essendi of the moral law, while the moral law is the
ratio cognoscendi of freedom. For Pad not the moral law been
previously distinctly thought in our reason, we should never consider
ourselves justified in assuming such a thing as freedom, although it be
not contradictory. But were there no freedom it would be impossible to
trace the moral law in ourselves at all.

It would certainly be more satisfactory to our speculative reason if it
could solve these problems for itself without this circuit and preserve
the solution for practical use as a thing to be referred to, but in fact our
faculty of speculation is not so well provided. Those who boast of such
high knowledge ought not to keep it back, but to exhibit it publicly that
it may be tested and appreciated. They want to prove: very good, let
them prove; and the critical philosophy lays its arms at their feet as the
victors. Quid statis? Nolint. Atqui licet esse beatis. As they then do not
in fact choose to do so, probably because they cannot, we must take up
these arms again in order to seek in the mortal use of reason, and to

base on this, the notions of God, freedom, and immortality, the
possibility of which speculation cannot adequately prove.
Here first is explained the enigma of the critical philosophy, viz.: how
we deny objective reality to the supersensible use of the categories in
speculation and yet admit this reality with respect to the objects of pure
practical reason. This must at first seem inconsistent as long as this
practical use is only nominally known. But when, by a thorough
analysis of it, one becomes aware that the reality spoken of does not
imply any theoretical determination of the categories and extension of
our knowledge to the supersensible; but that what is meant is that in
this respect an object belongs to them, because either they are
contained in the necessary determination of the will a priori, or are
inseparably connected with its object; then this inconsistency
disappears, because the use we make of these concepts is different from
what speculative reason requires. On the other hand, there now appears
an unexpected and very satisfactory proof of the consistency of the
speculative critical philosophy. For whereas it insisted that the objects
of experience as such, including our own subject, have only the value
of phenomena, while at the same time things in themselves must be
supposed as their basis, so that not everything supersensible was to be
regarded as a fiction and its concept as empty; so now practical reason
itself, without any concert with the speculative, assures reality to a
supersensible object of the category of causality, viz., freedom,
although (as becomes a practical concept) only for practical use; and
this establishes on the evidence of a fact that which in the former case
could only be conceived. By this the strange but certain doctrine of the
speculative critical philosophy, that the thinking subject is to itself in
internal intuition only a phenomenon, obtains in the critical
examination of the practical reason its full confirmation, and that so
thoroughly that we should be compelled to adopt this doctrine, even if
the former had never proved it at all. *

{PREFACE ^paragraph 10}
* The union of causality as freedom with causality as rational

mechanism, the former established by the moral law, the latter by the
law of nature in the same subject, namely, man, is impossible, unless
we conceive him with reference to the former as a being in himself, and
with reference to the latter as a phenomenon- the former in pure
consciousness, the latter in empirical consciousness. Otherwise reason
inevitably contradicts itself.

By this