other hand, it remains permissible for
us to postulate another kind of causality for the realm of things in
themselves, although we can have no idea of its _how_, and to ascribe to
ourselves a free intelligible character.

While the Idea of freedom can be derived directly from the moral law as
a postulate thereof, the proof of the reality of the two other Ideas is
effected indirectly by means of the concept of the "highest good," in which
reason conceives a union of perfect virtue and perfect happiness. The
moral law requires absolute correspondence between the disposition and the
commands of reason, or holiness of will. But besides this supreme good
(_bonum supremum_) of completed morality, the highest good (_bonum
consummatum_) further contains a degree of happiness corresponding to the
degree of virtue. Everyone agrees in the judgment that, by rights, things
should go well with the virtuous and ill with the wicked, though this must
not imply any deduction from the principle previously announced that the
least impulse of self-interest causes the maxim to forfeit its worth: the
motive of the will must never be happiness, but always the being worthy of
happiness. The first element in the highest good yields the argument for
_immortality_, and the second the argument for the _existence of God_. (1)
Perfect correspondence between the will and the law never occurs in this
life, because the sensibility never allows us to attain a permanently good
disposition, armed against every temptation; our will can never be
holy, but at best virtuous, and our lawful disposition never escape the
consciousness of a constant tendency to transgression, or at least of
impurity. Since, nevertheless, the demands of the (Christian) moral law
continue in their unrelenting stringency to be the standard, we are
justified in the hope of an unlimited continuation of our existence,
in order that by constant progress in goodness we may draw nearer _in
infinitum_ to the ideal of holiness. (2) The establishment of a rational
proportion between happiness and virtue is also not to be expected until
the future life, for too often on earth it is the evil man who prospers,
while the good man suffers. A justly proportioned distribution of rewards
and punishment can only be expected from an infinite power, wisdom, and
goodness, which rules the moral world even as it has created the natural
world. Deity alone is able to bring the physical and moral realms into