be practical reasons. Pure reason, however, cannot command any ends
a priori, except so far as it declares the same to be also a duty,
which duty is then cared a duty of virtue.





X. The Supreme Principle of Jurisprudence was Analytical; that of

Ethics is Synthetical

{INTRODUCTION ^paragraph 95}



That external constraint, so far as it withstands that which hinders
the external freedom that agrees with general laws (as an obstacle
of the obstacle thereto), can be consistent with ends generally, is
clear on the principle of contradiction, and I need not go beyond
the notion of freedom in order to see it, let the end which each may
be what he will. Accordingly, the supreme principle of jurisprudence
is an analytical principle. On the contrary the principle of ethics
goes beyond the notion of external freedom and, by general laws,
connects further with it an end which it makes a duty. This principle,
therefore, is synthetic. The possibility of it is contained in the
deduction (SS ix).

This enlargement of the notion of duty beyond that of external
freedom and of its limitation by the merely formal condition of its