No More Learning

Now, in nature, as it actually is an object of experience, the free
will is not of itself           to maxims which could of themselves
be the foundation of a natural system of universal laws, or which
could even be adapted to a system so constituted; on the contrary, its
maxims are private inclinations which constitute, indeed, a natural
whole in conformity with pathological (physical) laws, but could not
form part of a system of nature, which would only be possible
through our will acting in accordance with pure practical laws.