their seat and origin completely a priori in the reason, and that,
moreover, in the commonest reason just as truly as in that which is in
the highest degree speculative; that they cannot be obtained by
abstraction from any empirical, and therefore merely contingent,
knowledge; that it is just this purity of their origin that makes them
worthy to serve as our supreme practical principle, and that just in
proportion as we add anything empirical, we detract from their genuine
influence and from the absolute value of actions; that it is not
only of the greatest necessity, in a purely speculative point of view,
but is also of the greatest practical importance, to derive these
notions and laws from pure reason, to present them pure and unmixed,
and even to determine the compass of this practical or pure rational
knowledge, i.e., to determine the whole faculty of pure practical
reason; and, in doing so, we must not make its principles dependent on
the particular nature of human reason, though in speculative
philosophy this may be permitted, or may even at times be necessary;
but since moral laws ought to hold good for every rational creature,
we must derive them from the general concept of a rational being. In
this way, although for its application to man morality has need of
anthropology, yet, in the first instance, we must treat it
independently as pure philosophy, i.e., as metaphysic, complete in
itself (a thing which in such distinct branches of science is easily
done); knowing well that unless we are in possession of this, it would
not only be vain to determine the moral element of duty in right
actions for purposes of speculative criticism, but it would be
impossible to base morals on their genuine principles, even for common
practical purposes, especially of moral instruction, so as to
produce pure moral dispositions, and to engraft them on men's minds to
the promotion of the greatest possible good in the world.