* Propositions which in mathematics or physics are called practical
ought properly to be called technical. For they have nothing to do
with the determination of the will; they only point out how a certain
effect is to be produced and are, therefore, just as theoretical as
any propositions which express the connection of a cause with an
effect. Now whoever chooses the effect must also choose the cause.



{BOOK_1|CHAPTER_1 ^paragraph 40}

Even supposing, however, that all finite rational beings were
thoroughly agreed as to what were the objects of their feelings of
pleasure and pain, and also as to the means which they must employ
to attain the one and avoid the other; still, they could by no means
set up the principle of self-love as a practical law, for this
unanimity itself would be only contingent. The principle of
determination would still be only subjectively valid and merely
empirical, and would not possess the necessity which is conceived in
every law, namely, an objective necessity arising from a priori
grounds; unless, indeed, we hold this necessity to be not at all
practical, but merely physical, viz., that our action is as inevitably
determined by our inclination, as yawning when we see others yawn.
It would be better to maintain that there are no practical laws at
all, but only counsels for the service of our desires, than to raise
merely subjective principles to the rank of practical laws, which have
objective necessity, and not merely subjective, and which must be
known by reason a priori, not by experience (however empirically