The word perfection is liable to many misconceptions. It is
sometimes understood as a notion belonging to transcendental
philosophy; viz., the notion of the totality of the manifold which
taken together constitutes a thing; sometimes, again, it is understood
as belonging to teleology, so that it signifies the correspondence
of the properties of a thing to an end. Perfection in the former sense
might be called quantitative (material), in the latter qualitative
(formal) perfection. The former can be one only, for the whole of what
belongs to the one thing is one. But of the latter there may be
several in one thing; and it is of the latter property that we here
treat.
When it is said of the perfection that belongs to man generally
(properly speaking, to humanity), that it is in itself a duty to
make this our end, it must be placed in that which may be the effect
of one's deed, not in that which is merely an endowment for which we
have to thank nature; for otherwise it would not be duty.
Consequently, it can be nothing else than the cultivation of one's
power (or natural capacity) and also of one's will (moral disposition)
to satisfy the requirement of duty in general. The supreme element
in the former (the power) is the understanding, it being the faculty
of concepts, and, therefore, also of those concepts which refer to
duty. First it is his duty to labour to raise himself out of the
rudeness of his nature, out of his animal nature more and more to
humanity, by which alone he is capable of setting before him ends to
supply the defects of his ignorance by instruction, and to correct his
errors; he is not merely counselled to do this by reason as
technically practical, with a view to his purposes of other kinds
(as art), but reason, as morally practical, absolutely commands him to
do it, and makes this end his duty, in order that he may be worthy
of the humanity that dwells in him. Secondly, to carry the cultivation
of his will up to the purest virtuous disposition, that, namely, in
which the law is also the spring of his dutiful actions, and to obey
it from duty, for this is internal morally practical perfection.
This is called the moral sense (as it were a special sense, sensus
moralis), because it is a feeling of the effect which the
legislative will within himself exercises on the faculty of acting
accordingly. This is, indeed, often misused fanatically, as though
(like the genius of Socrates) it preceded reason, or even could
dispense with judgement of reason; but still it is a moral perfection,
making every special end, which is also a duty, one's own end.
{INTRODUCTION ^paragraph 50}