EXISTENTIALISM is a type of philosophy difficult to define because it does not have any agreed body of doctrine; it is rather a way of doing philosophy in which life and thought are closely related to each other. Thus, while some existentialists have been theists and others atheists, they have arrived at their different results by rather similar processes of thought. The existentialist who believes in God does so not as a result of intellectual demonstration—he or she is more likely to say that the attempts to prove God's existence are a waste of time, or even harmful—but on the grounds of passionate inward conviction; likewise the atheistic existentialist rejects God not because of being persuaded by argument but because the very idea of God poses a threat to the freedom and autonomy of the human being, and so to the integrity of humanity. But if...