Kantian ethical theory distinguishes three levels: First, that of a fundamental principle (the categorical imperative, formulated in three main ways in Kant's Groundwork); second, a set of duties, not deduced from but derived from this principle, by way of its interpretation or specification, its application to the general conditions of human life - which Kant does in the Doctrine of virtue, the second main part of the Metaphysics of Morals; and then finally an act of judgment, through which these duties are applied to particular cases.

We can't coherently deny, or even decline to affirm, that we are free.

Kant's aim was to develop a religion within the boundaries of mere reason (that is, reason unaided by special empirical revelation) and then to ask about existing ecclesiastical faith (especially about Christianity, and the Lutheran Christianity of his time and place) how this revealed faith must be interpreted if it is to be reconciled with reason, and even seen as a wider (though morally optional) extension of a religion of reason.

Reason necessarily expresses itself through emotions and emotions are healthy only insofar as they are expressions of reason.

There is a very common, though also very silly, picture of Kant according to which as empirical beings we are not free at all, and we are free only as noumenal jellyfish floating about in an intelligible sea above the heavens, outside any context in which our supposedly "free" choices could have any conceivable human meaning or significance. Part of the problem here is that Kant faces up honestly to the fact that how freedom is possible is a deep philosophical problem to which there is no solution we can rationally comprehend.

The picture of Kant as the 'theological Robespierre' or the "world-crusher" was first suggested by someone with whom Kant stood in a relation of philosophical disagreement but also great mutual respect: namely, Moses Mendelssohn.

I am a one-trick pony. But I have worked hard at something I would have liked to do even if I weren't paid a penny for it, and made a good living at it. You can't be luckier than that in this life, no matter who you are or what you do.