Character means that the person derives his rules of conduct from himself and from the dignity of humanity. Character is the common ruling principle … - Immanuel Kant

A man shouldn’t claim to know even himself as he really is by knowing himself through inner sensation — i.e. by introspection. For since he doesn’t produce himself (so to speak) or get his concept of himself a priori but only empirically, it is natural that he gets his knowledge of himself through inner sense and consequently only through how his nature appears and how his consciousness is affected. But beyond the character of his own subject, which is made up out of these mere appearances, he necessarily assumes something else underlying it, namely his I as it is in itself. Thus in respect to mere perception and receptivity to sensations he must count himself as belonging to the sensible world; but in respect to whatever pure activity there may be in himself (which reaches his consciousness directly and not by affecting the inner or outer senses) he must count himself as belonging to the intellectual world — though he doesn’t know anything more about it.

...in its practical purpose the footpath of freedom is the only one on which it is possible to make use of reason in our conduct. Hence it is as impossible for the subtlest philosophy as for the commonest reasoning to argue freedom away.

One age cannot bind itself, and thus conspire, to place a succeeding one in a condition whereby it would be impossible for the later age to expand its knowledge (particularly where it is so very important), to rid itself of errors, and generally to increase its enlightenment. That would be a crime against human nature, whose essential destiny lies precisely in such progress; subsequent generations are thus completely justified in dismissing such agreements as unauthorized and criminal. The criterion of everything that can be agreed upon as a law by a people lies in this question: Can a people impose such a law on itself?