The Critique of Practical Reason | Page 8

as valid only for his own will, but are objective, or practical
laws, when the condition is recognized as objective, that is, valid for
the will of every rational being.

{BOOK1|CHAPTER1 ^paragraph 10}
REMARK.

Supposing that pure reason contains in itself a practical motive, that is,
one adequate to determine the will, then there are practical laws;
otherwise all practical principles will be mere maxims. In case the will
of a rational being is pathologically affected, there may occur a conflict
of the maxims with the practical laws recognized by itself. For example,
one may make it his maxim to let no injury pass unrevenged, and yet he
may see that this is not a practical law, but only his own maxim; that,
on the contrary, regarded as being in one and the same maxim a rule for
the will of every rational being, it must contradict itself. In natural
philosophy the principles of what happens, e.g., the principle of
equality of action and reaction in the communication of motion) are at
the same time laws of nature; for the use of reason there is theoretical
and determined by the nature of the object. In practical philosophy, i.e.,
that which has to do only with the grounds of determination of the will,
the principles which a man makes for himself are not laws by which
one is inevitably bound; because reason in practical matters has to do
with the subject, namely, with the faculty of desire, the special
character of which may occasion variety in the rule. The practical rule
is always a product of reason, because it prescribes action as a means to
the effect. But in the case of a being with whom reason does not of
itself determine the will, this rule is an imperative, i.e., a rule
characterized by "shall," which expresses the objective necessitation of
the action and signifies that, if reason completely determined the will,
the action would inevitably take place according to this rule.
Imperatives, therefore, are objectively valid, and are quite distinct from
maxims, which are subjective principles. The former either determine

the conditions of the causality of the rational being as an efficient cause,
i.e., merely in reference to the effect and the means of attaining it; or
they determine the will only, whether it is adequate to the effect or not.
The former would be hypothetical imperatives, and contain mere
precepts of skill; the latter, on the contrary, would be categorical, and
would alone be practical laws. Thus maxims are principles, but not
imperatives. Imperatives themselves, however, when they are
conditional (i.e., do not determine the will simply as will, but only in
respect to a desired effect, that is, when they are hypothetical
imperatives), are practical precepts but not laws. Laws must be
sufficient to determine the will as will, even before I ask whether I have
power sufficient for a desired effect, or the means necessary to produce
it; hence they are categorical: otherwise they are not laws at all,
because the necessity is wanting, which, if it is to be practical, must be
independent of conditions which are pathological and are therefore only
contingently connected with the will. Tell a man, for example, that he
must be industrious and thrifty in youth, in order that he may not want
in old age; this is a correct and important practical precept of the will.
But it is easy to see that in this case the will is directed to something
else which it is presupposed that it desires; and as to this desire, we
must leave it to the actor himself whether he looks forward to other
resources than those of his own acquisition, or does not expect to be old,
or thinks that in case of future necessity he will be able to make shift
with little. Reason, from which alone can spring a rule involving
necessity, does, indeed, give necessity to this precept (else it would not
be an imperative), but this is a necessity dependent on subjective
conditions, and cannot be supposed in the same degree in all subjects.
But that reason may give laws it is necessary that it should only need to
presuppose itself, because rules are objectively and universally valid
only when they hold without any contingent subjective conditions,
which distinguish one rational being from another. Now tell a man that
he should never make a deceitful promise, this is a rule which only
concerns his will, whether the purposes he may have can be attained
thereby or not; it is the volition only which is to be determined a priori
by that rule. If now it is found that this rule is practically right, then it is
a law, because it is a categorical imperative. Thus, practical laws refer
to