Existentialism

Humanity, the universal, is more real than any individual man. ~Irrational Man

This is a much abbreviated account of the Platonic Ideal. Existentialism rebels from just this type of abstraction.

An interesting parallel to Utilitarianism, which holds that the value of a man is determined by his contribution to the collective good, is Platonism which subjugates the value of the individual to the collective (the universal - the abstract), a move thought to be justified by pure reason (or rationality?). Existentialism questions the justification.

Kant's Categorical Imperative, too. It is precisely because of our reasoning capacities that we are moral agents. For Kant, our moral agency is rooted in our reason. But what is this necessary connection between morality and reason? Why is reason so privileged?

For man to enter history as the rational animal, it was necessary for him to be convinced that the objects of his reasoning, the Ideas, were more real than his own individual person or the particular objects that made up his world. ~Irrational Man

But what if things are the other way around.

I gave a talk on Existentialism 36 hours ago. I feel like I could give another talk.