It is just the same with the foregoing antinomy of pure practical
reason. The first of the two propositions, "That the endeavour after
happiness produces a virtuous mind," is absolutely false; but the
second, "That a virtuous mind necessarily produces happiness," is
not absolutely false, but only in so far as virtue is considered as
a form of causality in the sensible world, and consequently only if
I suppose existence in it to be the only sort of existence of a
rational being; it is then only conditionally false. But as I am not
only justified in thinking that I exist also as a noumenon in a
world of the understanding, but even have in the moral law a purely
intellectual determining principle of my causality (in the sensible
world), it is not impossible that morality of mind should have a
connection as cause with happiness (as an effect in the sensible
world) if not immediate yet mediate (viz., through an intelligent
author of nature), and moreover necessary; while in a system of nature
which is merely an object of the senses, this combination could
never occur except contingently and, therefore, could not suffice
for the summum bonum.
Thus, notwithstanding this seeming conflict of practical reason with
itself, the summum bonum, which is the necessary supreme end of a will
morally determined, is a true object thereof; for it is practically
possible, and the maxims of the will which as regards their matter
refer to it have objective reality, which at first was threatened by
the antinomy that appeared in the connection of morality with
happiness by a general law; but this was merely from a
misconception, because the relation between appearances was taken
for a relation of the things in themselves to these appearances.