Which existentialist philosopher believed that existentialism and God could co-exist?

Answer 1

Soren Kierkegaard (1813-1855) was a Danish philosopher, theologian and psychologist. He is considered by some to be the father of existentialism both theistic and atheistic. He wrote that faith is not a decision based upon evidence because the level of evidence required is unavailable. He argued that doubt is an element of faith and it is impossible to find any objective certainty about religious doctrines such as the existence of God. Christian doctrine is inherently doubtful and therefore a Christian must rely on faith to make the commitment to believe. Kierkegaard stressed the importance of self and the self's relation to the world as being grounded in self reflection and introspection. He wrote under pseudonyms that represented his different ways of thinking.

Existentialist Martin Buber also believed this.