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.

Being aware of truths about what is good or right or about what we ought to do is not the same as deciding what to do. Nor can the former truths be derived from decisions about what to do, or about procedures for making such decisions, unless these procedures themselves rest in some way on the apprehension of truths about what we ought to do.

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.

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

Kant takes a free will to be a being or substance with the power to cause a state of the world (or a whole series of such states) spontaneously or from itself.

That Hegel's theory is derivative from Fichte's does not prevent it from being strikingly original and of independent value.

Marx is thought of as an implacable foe of capitalism. But go back and read the first section of the Communist Manifesto. Notice how it contains a paean of praise for the way capitalism and the bourgeoisie have both enriched the human powers of production and also enabled us to see with clear vision the nature of human society and human history.