Camus is not a philosopher, and The Myth of Sisyphus is only philosophical in the loosest sense of that word. Camus does not engage in any sustained argument, and only considers contrary positions in order to point out their differences from his own. The project of the work is colossal: he discusses nothing less than the meaning of life itself. If this were a philosophical discussion, such a colossal project would call for an equally colossal series of arguments.
As Camus states from the outset, however, his goal in this essay is to describe, not explain, and the essay contains no metaphysics. He introduces the absurd not by arguing that there is no order or purpose in the universe, but by observing how we are occasionally struck by the feeling of absurdity. Though he gives a few reasons as to why this feeling might strike us, he never provides any convincing arguments that might convince us that life is, in fact, meaningless. He does not hope to persuade us through argument, but wants us to follow his analysis of a state of mind we have all shared at one time or another.
Camus is not interested in sorting out an intellectual picture of the universe; he is interested in sorting out how we should live. As a result, he may not commit himself to any metaphysics, but he does commit himself to a certain epistemology. His interest in the absurd, he claims, comes from an interest in whether we can live only with certainty, without relying on faith or metaphysical speculations. In defining this interest, however, he is committing himself to a certain picture of what we can know with certainty. According to this picture, we can be certain of only two things: our "nostalgia for unity" and our inability to find an answer in the world.
This epistemology is born in direct reaction to the rationalist tradition that Camus inherited. Rationalism mistrusts knowledge that we can gain from experience, and focuses more on determining what knowledge we can gain from the exercise of pure reason. Camus seems disinterested in experiential knowledge, but he is also skeptical about innate knowledge and concludes that we can only know two things for certain. The first is a psychological observation that seems far from certain, or at the very least stands in dire need of more careful definition, and the second is less an item of knowledge so much as a limitation that Camus places on our knowledge. Essentially, Camus asks if we can live without really knowing anything definite. Can we live when the only certainty is that we cannot be certain?
Camus answers that we can live with this kind of negative certainty, but only if we remain aware that our search for anything more than this certainty is bound to fail. We will continue to live, but we with an ironic detachment born of an awareness that nothing we do has any real significance. Through the examples of the seducer, the actor, the conqueror, and the artist, it becomes clear that the absurd man lives out a kind of show; he lives only "as if" he were fully committed to what he is doing.
If this is true, it would seem the only difference between an absurd man and an ordinary man is that the absurd man is more detached. Camus would argue that the absurd man gets more out of life because his detachment comes from a heightened awareness that makes him more open to experiences. An absurd worldview is one that abandons values, one that rests content with description, and does not seek explanation or justification.