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