Inevitability really doesn’t play much of a role in existentialism as found in those philosophers and their writings usually called “existentialist.” It has been said that the “hard core” of existentialism is constituted by Sartre, Heidegger, and Jaspers. This is pretty accurate, but Marcel represents an important pole of Christian/Catholic existentialism, and if we include pre-existentialist thinkers like Kierkegaard and Nietzsche there are other important points of view that supplement the “technical” views of Sartre, Heidegger, and Jaspers.
