reluctantly, take a step into metaphysic, although into a domain of it
which is distinct from speculative philosophy, namely, the
metaphysic of morals. In a practical philosophy, where it is not the
reasons of what happens that we have to ascertain, but the laws of
what ought to happen, even although it never does, i.e., objective
practical laws, there it is not necessary to inquire into the
reasons why anything pleases or displeases, how the pleasure of mere
sensation differs from taste, and whether the latter is distinct
from a general satisfaction of reason; on what the feeling of pleasure
or pain rests, and how from it desires and inclinations arise, and
from these again maxims by the co-operation of reason: for all this
belongs to an empirical psychology, which would constitute the
second part of physics, if we regard physics as the philosophy of
nature, so far as it is based on empirical laws. But here we are
concerned with objective practical laws and, consequently, with the
relation of the will to itself so far as it is determined by reason
alone, in which case whatever has reference to anything empirical is
necessarily excluded; since if reason of itself alone determines the
conduct (and it is the possibility of this that we are now
investigating), it must necessarily do so a priori.

The will is conceived as a faculty of determining oneself to
action in accordance with the conception of certain laws. And such a
faculty can be found only in rational beings. Now that which serves
the will as the objective ground of its self-determination is the end,
and, if this is assigned by reason alone, it must hold for all
rational beings. On the other hand, that which merely contains the
ground of possibility of the action of which the effect is the end,
this is called the means. The subjective ground of the desire is the
spring, the objective ground of the volition is the motive; hence