A number of years ago I heard a preacher say that existentialism was one of the destructive and ungodly philosophies of modern times. I did not have an opportunity to visit with him about this, but I wonder what existentialists he was talking about.
Existentialism covers a wide range of thinkers and it indeed has a group of atheist adherents.
I believe that if we are to understand the modern Christian existentialists we need to have some understanding of their spiritual father, Soren Kierkegaard. I am not sure that we should judge him on whether he was pessimistic or optimistic, but rather on whether he was right and spoke the truth. Sin is worse than suffering. Human beings are egotists and must experience despair. God is beyond reason and humanity.