This may well be the crux of the matter. But we need to explore it in greater depth. For a theist, God is the absolute. But Sartre famously denies God on the ground that a for-itself-in-itself is impossible: see Being and Nothingness. For Sartre the God-denier, man is the absolute. But there is no Man, only men. Man is an abstraction. So the absolute fractures into finite individual subjectivities, each of which exists contingently. Here is a crucial passage:
What is at the very heart and center of existentialism, is the absolute character of the free commitment, by which every man realises himself in realising a type of humanity . . . . In this sense you may say, if you like, that every one of us makes the absolute by breathing, by eating, by sleeping or by behaving in any fashion whatsoever. There is no difference between free being – being as self-committal, as existence choosing its essence – and absolute being. And there is no difference whatever between being as an absolute, temporarily localised that is, localised in history – and universally intelligible being. ("Existentialism is a Humanism, Kaufmann anthology, p. 363, emphasis added)
The bolded portion is striking but puzzling. What does it mean? We can compress it into two main claims:
1. Free being is absolute being
and
2. Absolute being is universally intelligible being.
Every philosopher has his absolute, and Sartre's absolute is the individual subject whose mode of being is l’être pour-soi, being for-itself as opposed to l’être en-soi, being in-itself. As a subject for whom there is a world of objects, I am a case of being-for-itself and as such am entirely free. The freedom resides in the consciousness-of objects, objects that I am not. But I am also an object in the world. As such, I partake of the en-soi, the in-itself. Borrowing some terminology from Being and Nothingness, we can say that an individual human being is a compound of transcendence and facticity.
As a case of the pour-soi, I am ever beyond myself, ever transcending myself. As subject, I am not myself as object. For example, my body with all its current properties is part of my facticity. But I am not my body precisely insofar as I am aware of it. It is one of my objects. I 'surpass' it toward certain possibilities that lie in the future, e.g. the possibility of weighing less or having stronger abdominal muscles.
In a famous paradoxical formulation from Being and Nothingness, "The for-itself is what it is not and is not what it is." For example, I am my body but I am not my body insofar as I am aware of my body, insofar as my body is an object for me as subject. Or I lose myself in a certain project, seemingly becoming one with it, though I know I am not that project inasmuch as I freely chose it.
Man realizes himself by his choices. He freely commits himself to this or that project and in so doing freely makes his life. He is bound by no objective constraint, not by a pre-given human nature or an Aristotelean proper function (ergon), not by objective values, and not by divine commands. Not determined by any exogenic factor, he is self-determining. That he exists at all is a contingent fact; but what he makes of himself is entirely up to him. His free being-for-self is absolute being. And this free absolute being is "universally intelligible being." Perhaps this can be glossed by saying that, for Sartre, all intelligibility has its source in man, and man alone is intrinsically intelligible. Nothing apart from man in intrinsically intelligible. A rock or a tree is intelligible only derivatively, only as material for the for-itself's projects.
Each man, then, is a sort of contingent god. Although there is no "universal essence that can be called human nature, there is nevertheless a human universality of condition." (362) Each is on the condition f being a 'thrown project,' ein geworfenes Entwurf in Heideggerian jargon. Our choices are free, but we must choose. Not to choose is to choose, and we cannot not choose. We are "condemned to be free."
Critique. For Sartre, man makes himself. His dignity resides in his free subjectivity, and there is nothing that can guide or objectively constrain his free choices. If he attempts to rely on anything ab extra that is objectively constraining, he falls into bad faith: he enters into a form of self-deception that consists in not facing up to his radical freedom. His existence cannot have any objective meaning or purpose. An objective purpose is inconsistent with radical freedom. Neither God nor nature can 'assign' him a purpose for he is not an artifact of God, nor is he as free subjectivity a product of nature. Man as subject, as 'upsurge' of the for-itself, is uncreated and undetermined. Refusing to own up to this involves one in bad faith. If man is to have a purpose he must assign it to himself.
A. One problem, though, is that one cannot give the very fact that one exists in the first place a purpose. A healthy, well-situated adult can assign purpose to his waking life, but that he exists at all is not within the scope of his 'purposing.' I can no more 'purpose' my existence as a whole than I can cause my existence as a whole. I can do various things to maintain my existence. But I couldn't do these things if I didn't already (both logically and temporally) exist. The same goes for 'purposing': I cannot give my existence as a whole a purpose. I remain on Sartre's scheme a fundamentally purposeless purpose-positer. I cannot 'retroactively' give my life as a whole a purpose. At best I can give my lucid hours a purpose, albeit a merely subjective one. I cannot 'recuperate' my entire existence from purposelessness by assigning myself tasks in the present. For example, if I just now 'wake up' in authenticity to my radical freedom and assume the burden of making myself, this does nothing to rescue my past, all the way back to infancy, from purposelessness.
Thus my Sartrean making of myself presupposes a substratum of facticity that is beyond the scope of my making. And if there is no God, then it is beyond the scope of any divine making as well. Thus the substratum and presupposition of my meaning-giving activities is itself meaningless, purposeless, absurd. Sartre might say that this is just the way things are. But it does not seem quite satisfying, does it? What good is it to say that we give our lives meaning if we cannot give the substratum of our meaning-giving activities meaning? At most, we give our lucid hourse meaning. But the vast backdrop of our lucidity is darkness and absurdity.
B. A second problem concerns whether the central organizing purpose I choose is worthwhile. Whatever one chooses is open to doubt, and will be doubted by many. The choices I make are merely my choices and there is nothing to validate them objectively. We invent values and in so doing we invent the sense of our lives. We are creative like artists. (364) Aware of this, I must admit in all honesty that none of my choices can lay claim to being objectively worthwhile. Uncomfortable with this upshot, Sartre says repeatedly (e.g. 350) that when one chooses for oneself one chooses for all men. But he never, as far as I can see, gives any justification for the leap from oneself to all. He remains stuck in value subjectivism.
Near the end of my last Sartre installment I wrote,