The relation of the law to the self is only a helpful way of thinking about the law, that helps us better understand its validity for us.

Kant's system of duties constitutes a Doctrine of Virtue because the duties also indicate what kinds of attitudes, dispositions and feelings are morally virtuous or vicious.

Descartes recommended that we distrust the senses and rely on the ... use of our intellect.

Kant did think he had a moral route back to rational faith in God, for those who need it, and he thought that at some level, we all do need something like it.

It is actually a nice question how far Descartes himself endorses the monological and metaphysically dualistic theory of mind associated with his name and his legacy in early modern philosophy. But Fichte does reject this tradition, by suggesting that an immaterial thinking substance is an incoherent notion, and a rational being whose rationality was not developed through communication with others is a transcendental impossibility.

It was an important part of Mendelssohn's philosophical and religious view that the traditional rationalist proofs for God's existence should be sound an convincing. Kant thought they were not. So Kant's critique was world-shaking for Mendelssohn.

Those who employ their modest talents as best they can do make a contribution to a better human future.