No theory about our bodies as mere objects of observation and calculation (as distinct from partners in communicative interaction, assumed to be free) can comprehend human nature.

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.

The problem I see with utilitarianism, or any form of consequentialism, is not that it gets the wrong answers to moral questions. I think just about any moral theory, worked out intelligently, and applied with good judgment, would get just about the same results as any other.

Those who employ their modest talents as best they can do make a contribution to a better human future.

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.

It was an important part of Mendelssohn's philosophical and religious view that the traditional rationalist proofs for God's existence should be sound an convincing. Kant thought they were not. So Kant's critique was world-shaking for Mendelssohn.

Fichte would identify all states of our minds with states of our body - perhaps not merely of our brain, but the whole body as an acting organism.