Simone de Beauvoir, Ethics of Ambiguity.

At the very moment he can grasp the non-temporal truth of his existence. But between the past that no longer is and the future that is not yet, this moment when he exists is nothing. This privilege, which he alone possesses, of being a sovereign and unique subject in a universe of objects, is what he shares with all his fellow-men.
Simone de Beauvoir, Ethics of Ambiguity.