Virtues consist not only of acting in certain ways, but in ways of caring and feeling.

As I understand it, Kantian constructivism is partly a position in normative ethics and partly a position in metaethics. In metaethics, it is the position that ethical claims have truth values, but their truth conditions consist not in a set of objective facts to which they correspond, but instead in the outcome of some procedure of deliberation resulting in decisions about what to do.

I think the term "Kantian constructivism" as an oxymoron. Kant was a constructivist about mathematics, but not about ethics.

Marx's own illusion was to think that the working class movement, which he devoted his life to creating and strengthening, would both be socially and politically successful in the industrial nations of Western Europe, and that it would develop an entirely new way of human social life that would retain and even enhance the productive benefits of capitalism while overcoming the inhumanity and exploitation of capitalist social relations. Marx himself had no solutions to these problems. His object of study was capitalism itself.

Kant does not regard freedom as an item of faith because it is too basic to our agency to be related to any end.

We cannot predict the effects of our actions, especially our collective actions over generations or centuries, to use instrumental reasoning toward these big final ends to tell us what we ought to do.

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.