We can conceive the relation of end to duty in two ways; either
starting from the end to find the maxim of the dutiful actions; or
conversely, setting out from this to find the end which is also
duty. Jurisprudence proceeds in the former way. It is left to
everyone's free elective will what end he will choose for his
action. But its maxim is determined a priori; namely, that the freedom
of the agent must be consistent with the freedom of every other
according to a universal law.
{INTRODUCTION ^paragraph 20}
Ethics, however, proceeds in the opposite way. It cannot start
from the ends which the man may propose to himself, and hence give
directions as to the maxims he should adopt, that is, as to his
duty; for that would be to take empirical principles of maxims, and
these could not give any notion of duty; since this, the categorical
ought, has its root in pure reason alone. Indeed, if the maxims were
to be adopted in accordance with those ends (which are all selfish),
we could not properly speak of the notion of duty at all. Hence in
ethics the notion of duty must lead to ends, and must on moral
principles give the foundation of maxims with respect to the ends
which we ought to propose to ourselves.
Setting aside the question what sort of end that is which is in
itself a duty, and how such an end is possible, it is here only
necessary to show that a duty of this kind is called a duty of virtue,
and why it is so called.
To every duty corresponds a right of action (facultas moralis
generatim), but all duties do not imply a corresponding right
(facultas juridica) of another to compel anyone, but only the
duties called legal duties. Similarly to all ethical obligation
corresponds the notion of virtue, but it does not follow that all
ethical duties are duties of virtue. Those, in fact, are not so
which do not concern so much a certain end (matter, object of the
elective will), but merely that which is formal in the moral
determination of the will (e.g., that the dutiful action must also
be done from duty). It is only an end which is also duty that can be
called a duty of virtue. Hence there are several of the latter kind
(and thus there are distinct virtues); on the contrary, there is
only one duty of the former kind, but it is one which is valid for all
actions (only one virtuous disposition).
The duty of virtue is essentially distinguished from the duty of
justice in this respect; that it is morally possible to be
externally compelled to the latter, whereas the former rests on free
self-constraint only. For finite holy beings (which cannot even be
tempted to the violation of duty) there is no doctrine of virtue,
but only moral philosophy, the latter being an autonomy of practical
reason, whereas the former is also an autocracy of it. That is, it
includes a consciousness- not indeed immediately perceived, but
rightly concluded, from the moral categorical imperative- of the power
to become master of one's inclinations which resist the law; so that
human morality in its highest stage can yet be nothing more than
virtue; even if it were quite pure (perfectly free from the
influence of a spring foreign to duty), a state which is poetically
personified under the name of the wise man (as an ideal to which one
should continually approximate).
Virtue, however, is not to be defined and esteemed merely as
habit, and (as it is expressed in the prize essay of Cochius) as a
long custom acquired by practice of morally good actions. For, if this
is not an effect of well-resolved and firm principles ever more and
more purified, then, like any other mechanical arrangement brought
about by technical practical reason, it is neither armed for all
circumstances nor adequately secured against the change that may be
wrought by new allurements.
{INTRODUCTION ^paragraph 25}