If the problem of free will is to see how freedom fits into the order of nature, then Kant's basic view about the free will problem is that it is insoluble.

We can establish empirical criteria for free actions, and investigate human actions on the presupposition we are free.

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.

When Marx, in the Theses on Feuerbach, says that only idealism up to now has understood the active side of material Praxis, what he says is more true of Fichte than of any other philosopher in the classical German tradition.

It is often difficult to know about one's own era which philosophers in it will be remembered as the most important ones, but I think it is already clear that John Rawls is the greatest moral philosopher of the twentieth century.

We totally misunderstand both his aims and his contribution if we try to read into Marx some anticipation of either the modest successes or the disastrous failures of those who later thought they were acting in his name.

Kant's description of most ethical duties reads more like a description of moral virtues and vices. Once we see this, we see that Kantian ethics is indeed a kind of virtue ethics, and that it does not "divide the heart from the head" (to anticipate one of your later questions) but instead recognizes the deep truth that reason and emotion are not opposites.