By this also I can understand why the most considerable objections
which I have as yet met with against the Critique turn about these two
points, namely, on the one side, the objective reality of the
categories as applied to noumena, which is in the theoretical
department of knowledge denied, in the practical affirmed; and on
the other side, the paradoxical demand to regard oneself qua subject
of freedom as a noumenon, and at the same time from the point of
view of physical nature as a phenomenon in one's own empirical
consciousness; for as long as one has formed no definite notions of
morality and freedom, one could not conjecture on the one side what
was intended to be the noumenon, the basis of the alleged
phenomenon, and on the other side it seemed doubtful whether it was at
all possible to form any notion of it, seeing that we had previously
assigned all the notions of the pure understanding in its
theoretical use exclusively to phenomena. Nothing but a detailed
criticism of the practical reason can remove all this
misapprehension and set in a clear light the consistency which
constitutes its greatest merit.

So much by way of justification of the proceeding by which, in
this work, the notions and principles of pure speculative reason which
have already undergone their special critical examination are, now and
then, again subjected to examination. This would not in other cases be
in accordance with the systematic process by which a science is
established, since matters which have been decided ought only to be
cited and not again discussed. In this case, however, it was not
only allowable but necessary, because reason is here considered in
transition to a different use of these concepts from what it had