It's Jean-Paul Sartre who gave the initial formula for modern existentialism, in which
he uses the phrase being translated, “Existence precedes essence.”
I think that, really, his thinking goes beyond this idea that not only is existence first
in the order of knowing—this would put him simply in the same category as many empiricists
going all the way back to somebody like Heraclitus, who says, “You have becoming rather than
being; you have particulars rather than universals,” and things of that sort.
Really, what Sartre is getting at is that existence—individual, concrete, human existence
precludes essence.
There is no such thing as “mankind.”
There is only men and women.
There are no universals; there are only the particular concrete data of existence.
And because there is no overarching universal truth, that means that there is nothing to
unify our understanding of reality.
Then, in the final analysis, reality itself is absurd and irrational, and nothing really
fits together in any meaningful way.
So, you have another kind or form of nihilism following in the footsteps of Nietzsche in
the thinking of Jean-Paul Sartre.
Now, when he looks at human existence, Sartre says that the defining trait or characteristic
of a human being is subjectivity: We are subjects, not objects.
The chief attribute of a subject is the subject’s will—specifically, his free will.
For without the power of choice, without the ability to makes decisions for oneself, a
person is not truly free.
And if a person is not truly free, then that person is not human.
He is not a subject, as it were.
So, anything for Sartre that threatens the subjectivity of human existence has to go.
Of course, the greatest threat to humanness that Sartre encountered in his thinking was
theism in general and Judeo-Christianity in particular.
Because one of the great tenants of Christian thought, and Judeo-Christian thought, is the
sovereignty of God.
For Sartre, if God is sovereign, truly sovereign, then man in the final analysis cannot be free.
True freedom, according to Sartre, demands autonomy, that we be a law unto ourselves.
The authentic existential person, just as it was with Nietzsche, is a person who rules
himself.
He is subject to the rule of no one and nothing else.
If there is anyone or anything that restricts to any degree the freedom of that individual,
then true freedom has been lost.
So, if man is truly free, according to Sartre, God cannot exist.