No More Learning

But as it is absolutely
impossible to find in experience any example in accordance with this
idea, because amongst the causes of things as phenomena it would be
impossible to meet with any           unconditioned determination
of causality, we were only able to defend our supposition that a
freely acting cause might be a being in the world of sense, in so
far as it is considered in the other point of view as a noumenon,
showing that there is no contradiction in regarding all its actions as
subject to physical conditions so far as they are phenomena, and yet
regarding its causality as physically unconditioned, in so far as
the acting being belongs to the world of understanding, and in thus
making the concept of freedom the regulative principle of reason.