Sartre's Atheist Existentialism & After
The primary Christian objection to Sartre's existentialism is based on his views of God and morality. Sartre defines his existentialism as "nothing else but an attempt to draw the full conclusions from a consistently atheistic position." Sartre positions man as existing first before he obtains an essence. Essence is basically the form a man should take both spiritually and physically after being created by God. Sartre summarizes the theistic Christian view: "When we think of God as the creator, we are thinking of him, most of the time, as a supernal artisan... each individual man is the realization of a certain conception which dwells in the divine understanding... each man is a particular example of a universal conception, the conception of Man." The idea of "man" was already in the mind of God before he created man, and so there's already a pattern that man should follow. Some of man's essence is biological, humans grow from kids to adults, but there's also an eternal universal moral pattern that man is meant to live by. If mankind was created with a common essence that dwells eternally in the mind God, that means all mankind shares an identity that owes its origin and obligations to something outside itself (God).
Sartre rejects all this. For him, God does not exist. Unlike angry internet atheists, however, he does not regard God's non-existence as a pure good. Sartre explains: "The existentialist, on the contrary, finds it extremely embarrassing that God does not exist, for there disappears with Him all possibility of finding values in an intelligible heaven. There can no longer be any good a priori, since there is no infinite and perfect consciousness to think it." The "death of God" is a social disaster because if the only truth is Descartes individualistic cogito, "I think," and there's no God from which the whole of mankind's essence and morality can be discerned, then there's no possibility that society can ever have any communal moral laws, or at least none that actually possess transcendent reality. If you extend the atheist logic further, and Sartre did not here do that, then without God it's impossible to believe that other people exist, because everything could be a figment of your imagination. If man has no universal essence, there's no reason to assume that the category of "mankind" even exists. "Mankind" exists as a universal category because God said that "man" was a category when he created us. God literally spoke "man" into existence. This has all kinds of implications for our current culture wars surrounding the nature of gender and sexual identity, but that's not directly related to Sartre's atheism. However, it's important to note that this is the philosophical grounding for human rights. Without a God holding mankind into a single category, there's no reason to assume everyone deserves similar treatment. For example, if black people are men then they deserve rights, but if they're something else, or we don't even believe that "men" exist as a category, then black people might just be "animals" who don't have rights.
I don't remember how Sartre escapes his deep individualism in 'Existentialism is a Humanism,' but I remember not really understanding how he did it, or if he ever did. But, when he finally manages to reassert the existence of "man" as a category, he tries to reconstruct morality from an atheistic perspective. Sartre claims that man must create himself because he was not created beforehand. This seems like a weird thing to say because we all know that we didn't bring ourselves into existence, but this is the exact reversal of thought that Sartre is trying to inspire: humans came into existence before being created. "Existence precedes essence." Man creates himself after finding himself thrown into the world. A Christian might object: if man created himself, then how can anything man does ever be considered wrong or immoral? Sartre's response is that it's possible to be wrong because there are certain actions that result in deceiving oneself. For example, Christians are lying to themselves by claiming that God created mankind's essence. A Christian might respond that if man wants to deceive himself about God's existence then why is this deception wrong? Sartre admits he can't give much of an answer: "If anyone says to me, 'And what if I wish to deceive myself?' I answer, 'There is no reason why you should not, but I declare that you are doing so, and that the attitude of strict consistency alone is that of good faith.'"
Sartre eventually offers his own prescription for a universal morality without God or any a priori essence. He believes that, because mankind creates itself, every individual has the obligation to live in such a way that his actions are creating the kind of mankind that he wishes mankind would be. The idea is that when I choose to drink coffee in the morning I'm asserting that man's essence is that of a being who drinks coffee in the morning. Or, at least, that "man" is the kind of being who's able and willing to drink coffee in the morning. Because I am a man, and I'm creating myself, I'm also therefore creating a part of what mankind as a whole can be defined by. If most men become fascists tomorrow, then they will have decided that mankind is the kind of thing that loves fascism. There's no way that mankind should be, because God does not exist, so it's up to all of us to decide how mankind should be. All the responsibility is on us, we can't import our essence from God's mind.
Existentialism was the last major philosophical movement. Since the mid-1960s, society and philosophy have been caught up in the convoluted vortex of "postmodernism" (whatever that term now means), and it's easy to see how Sartre's atheist existentialism has effected our contemporary thinking. Ironically, however, Sartre had a massive change of heart at the end of his life. He suddenly became a convicted theist, to the consternation of his closest followers. He said: "I do not feel that I am the product of chance, a speck of dust in the
universe, but someone who was expected, prepared, prefigured. In short, a
being whom only a Creator could put here; and this idea of a creating
hand refers to god." According to at least one of his closest acquaintances, Sartre even began having faith in Jesus Christ as the messiah. I suspect the history of the modern world will follow much the same trajectory. This whole secular cycle of rebellion will end, and mankind will return to its God and Savior.