For Albert Camus, the world is absurd. But the world could not be absurd unless man judged it to be so. So, this sense of the absurdity of life, this awareness that life is without meaning, this, for the existentialists, is the starting point of all philosophy. Nor do we exist because of Reason. It's the other way around.
Man is a conscious subject, rather than a thing to be predicted or manipulated.
He exists as a conscious being not in accordance with any essence, definition or system. Man exists and his will leads him to invent rational systems which are products of his drives, instincts, fears and hopes. Man alone can only be understood by man alone. The human personality ought to be free and unique, not directed by outside forces or objects. This last statement deserves further comment because what we are really talking about is liberation.