explanation of phenomena, therefore no one would ever have been so
rash as to introduce freedom into science, had not the moral law,
and with it practical reason, come in and forced this notion upon
us. Experience, however, confirms this order of notions. Suppose
some one asserts of his lustful appetite that, when the desired object
and the opportunity are present, it is quite irresistible. [Ask
him]- if a gallows were erected before the house where he finds this
opportunity, in order that he should be hanged thereon immediately
after the gratification of his lust, whether he could not then control
his passion; we need not be long in doubt what he would reply. Ask
him, however- if his sovereign ordered him, on pain of the same
immediate execution, to bear false witness against an honourable
man, whom the prince might wish to destroy under a plausible
pretext, would he consider it possible in that case to overcome his
love of life, however great it may be. He would perhaps not venture to
affirm whether he would do so or not, but he must unhesitatingly admit
that it is possible to do so. He judges, therefore, that he can do a
certain thing because he is conscious that he ought, and he recognizes
that he is free- a fact which but for the moral law he would never
have known.

{BOOK_1|CHAPTER_1 ^paragraph 65}



VII. FUNDAMENTAL LAW OF THE PURE PRACTICAL REASON.



Act so that the maxim of thy will can always at the same time hold