our moral judgement, whereas it must rather be viewed as the
subjective effect that the law exercises on the will, the objective
principle of which is furnished by reason alone.



* Interest is that by which reason becomes practical, i.e., a cause
determining the will. Hence we say of rational beings only that they
take an interest in a thing; irrational beings only feel sensual
appetites. Reason takes a direct interest in action then only when the
universal validity of its maxims is alone sufficient to determine
the will. Such an interest alone is pure. But if it can determine
the will only by means of another object of desire or on the
suggestion of a particular feeling of the subject, then reason takes
only an indirect interest in the action, and, as reason by itself
without experience cannot discover either objects of the will or a
special feeling actuating it, this latter interest would only be
empirical and not a pure rational interest. The logical interest of
reason (namely, to extend its insight) is never direct, but
presupposes purposes for which reason is employed.



In order indeed that a rational being who is also affected through
the senses should will what reason alone directs such beings that they
ought to will, it is no doubt requisite that reason should have a
power to infuse a feeling of pleasure or satisfaction in the
fulfilment of duty, that is to say, that it should have a causality by
which it determines the sensibility according to its own principles.
But it is quite impossible to discern, i.e., to make it intelligible a