As Kant says, the contribution of any common laborer would be greater than that of the greatest philosopher unless the philosopher makes some contribution to establishing the rights of humanity.

I do not know how much my own work has achieved, and I must not pretend it has done more than it has.

In the mid-1960s, as hard to believe as it may be now, choosing to go into academic philosophy was not an imprudent career choice. There were lots of academic jobs in philosophy then.

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.

The Russian revolution did not occur until a generation after Marx's death. He was not involved with it, or with what came after it. His works do not describe post-capitalist society, and a fortiori they do not recommend any part of what the Soviet Union did.

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.

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