reason, must make the mind waver between motives which cannot be
brought under any principle, which lead to good only by mere
accident and very often also to evil.

  *I have a letter from the late excellent Sulzer, in which he asks me
what can be the reason that moral instruction, although containing
much that is convincing for the reason, yet accomplishes so little? My
answer was postponed in order that I might make it complete. But it is
simply this: that the teachers themselves have not got their own
notions clear, and when they endeavour to make up for this by raking
up motives of moral goodness from every quarter, trying to make
their physic right strong, they spoil it. For the commonest
understanding shows that if we imagine, on the one hand, an act of
honesty done with steadfast mind, apart from every view to advantage
of any kind in this world or another, and even under the greatest
temptations of necessity or allurement, and, on the other hand, a
similar act which was affected, in however low a degree, by a
foreign motive, the former leaves far behind and eclipses the
second; it elevates the soul and inspires the wish to be able to act
in like manner oneself. Even moderately young children feel this
impression, ana one should never represent duties to them in any other
light.

  From what has been said, it is clear that all moral conceptions have
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.

  But in order that in this study we may not merely advance by the
natural steps from the common moral judgement (in this case very
worthy of respect) to the philosophical, as has been already done, but
also from a popular philosophy, which goes no further than it can
reach by groping with the help of examples, to metaphysic (which
does allow itself to be checked by anything empirical and, as it
must measure the whole extent of this kind of rational knowledge, goes
as far as ideal conceptions, where even examples fail us), we must
follow and clearly describe the practical faculty of reason, from
the general rules of its determination to the point where the notion
of duty springs from it.

  Everything in nature works according to laws. Rational beings
alone have the faculty of acting according to the conception of
laws, that is according to principles, i.e., have a will. Since the
deduction of actions from principles requires reason, the will is
nothing but practical reason. If reason infallibly determines the
will, then the actions of such a being which are recognised as
objectively necessary are subjectively necessary also, i.e., the
will is a faculty to choose that only which reason independent of
inclination recognises as practically necessary, i.e., as good. But if
reason of itself does not sufficiently determine the will, if the
latter is subject also to subjective conditions (particular
impulses) which do not always coincide with the objective
conditions; in a word, if the will does not in itself completely
accord with reason (which is actually the case with men), then the
actions which objectively are recognised as necessary are subjectively
contingent, and the determination of such a will according to
objective laws is obligation, that is to say, the relation of the
objective laws to a will that is not thoroughly good is conceived as
the determination of the will of a rational being by principles of
reason, but which the will from its nature does not of necessity
follow.

  The conception of an objective principle, in so far as it is
obligatory for a will, is called a command (of reason), and the
formula of the command is called an imperative.

  All imperatives are expressed by the word ought [or shall], and
thereby indicate the relation of an objective law of reason to a will,
which from its subjective constitution is not necessarily determined
by it (an obligation). They say that something would be good to do
or to forbear, but they say it to a will which does not always do a
thing because it is conceived to be good to do it. That is practically
good, however, which determines the will by means of the conceptions
of reason, and consequently not from subjective causes, but