How is a Categorical Imperative Possible?



Every rational being reckons himself qua intelligence as belonging
to the world of understanding, and it is simply as an efficient
cause belonging to that world that he calls his causality a will. On
the other side he is also conscious of himself as a part of the
world of sense in which his actions, which are mere appearances
[phenomena] of that causality, are displayed; we cannot, however,
discern how they are possible from this causality which we do not
know; but instead of that, these actions as belonging to the
sensible world must be viewed as determined by other phenomena,
namely, desires and inclinations. If therefore I were only a member of
the world of understanding, then all my actions would perfectly
conform to the principle of autonomy of the pure will; if I were
only a part of the world of sense, they would necessarily be assumed
to conform wholly to the natural law of desires and inclinations, in
other words, to the heteronomy of nature. (The former would rest on
morality as the supreme principle, the latter on happiness.) Since,
however, the world of understanding contains the foundation of the
world of sense, and consequently of its laws also, and accordingly
gives the law to my will (which belongs wholly to the world of
understanding) directly, and must be conceived as doing so, it follows
that, although on the one side I must regard myself as a being
belonging to the world of sense, yet on the other side I must
recognize myself as subject as an intelligence to the law of the world
of understanding, i.e., to reason, which contains this law in the idea