Fundamental Principals of the Metaphysic of Morals | Page 3

moral philosophy, namely, his
so-called general practical philosophy, and that, therefore, we have not to strike into an
entirely new field. just because it was to be a general practical philosophy, it has not
taken into consideration a will of any particular kind- say one which should be
determined solely from a priori principles without any empirical motives, and which we
might call a pure will, but volition in general, with all the actions and conditions which
belong to it in this general signification. By this it is distinguished from a metaphysic of
morals, just as general logic, which treats of the acts and canons of thought in general, is
distinguished from transcendental philosophy, which treats of the particular acts and
canons of pure thought, i.e., that whose cognitions are altogether a priori. For the
metaphysic of morals has to examine the idea and the principles of a possible pure will,
and not the acts and conditions of human volition generally, which for the most part are
drawn from psychology. It is true that moral laws and duty are spoken of in the general
moral philosophy (contrary indeed to all fitness). But this is no objection, for in this
respect also the authors of that science remain true to their idea of it; they do not
distinguish the motives which are prescribed as such by reason alone altogether a priori,
and which are properly moral, from the empirical motives which the understanding raises
to general conceptions merely by comparison of experiences; but, without noticing the
difference of their sources, and looking on them all as homogeneous, they consider only
their greater or less amount. It is in this way they frame their notion of obligation, which,
though anything but moral, is all that can be attained in a philosophy which passes no
judgement at all on the origin of all possible practical concepts, whether they are a priori,
or only a posteriori.
Intending to publish hereafter a metaphysic of morals, I issue in the first instance these
fundamental principles. Indeed there is properly no other foundation for it than the
critical examination of a pure practical Reason; just as that of metaphysics is the critical
examination of the pure speculative reason, already published. But in the first place the
former is not so absolutely necessary as the latter, because in moral concerns human
reason can easily be brought to a high degree of correctness and completeness, even in
the commonest understanding, while on the contrary in its theoretic but pure use it is
wholly dialectical; and in the second place if the critique of a pure practical reason is to
be complete, it must be possible at the same time to show its identity with the speculative
reason in a common principle, for it can ultimately be only one and the same reason
which has to be distinguished merely in its application. I could not, however, bring it to
such completeness here, without introducing considerations of a wholly different kind,
which would be perplexing to the reader. On this account I have adopted the title of
Fundamental Principles of the Metaphysic of Morals instead of that of a Critical
Examination of the pure practical reason.
But in the third place, since a metaphysic of morals, in spite of the discouraging title, is
yet capable of being presented in popular form, and one adapted to the common
understanding, I find it useful to separate from it this preliminary treatise on its
fundamental principles, in order that I may not hereafter have need to introduce these

necessarily subtle discussions into a book of a more simple character.
The present treatise is, however, nothing more than the investigation and establishment of
the supreme principle of morality, and this alone constitutes a study complete in itself and
one which ought to be kept apart from every other moral investigation. No doubt my
conclusions on this weighty question, which has hitherto been very unsatisfactorily
examined, would receive much light from the application of the same principle to the
whole system, and would be greatly confirmed by the adequacy which it exhibits
throughout; but I must forego this advantage, which indeed would be after all more
gratifying than useful, since the easy applicability of a principle and its apparent
adequacy give no very certain proof of its soundness, but rather inspire a certain partiality,
which prevents us from examining and estimating it strictly in itself and without regard to
consequences.
I have adopted in this work the method which I think most suitable, proceeding
analytically from common knowledge to the determination of its ultimate principle, and
again descending synthetically from the examination of this principle and its sources to
the common knowledge in which we find it employed. The division will, therefore, be as
follows:

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