What Is Existentialism? - Walter Kaufmann
Excerpted from "Existentialism from Dostoevsky to Sartre", The World Publishing Company, 1956

Existentialism is not a philosophy but a label for several widely different revolts against traditional philosophy. Most of the living "existentialists" have repudiated this label, and a bewildered outsider might well conclude that the only thing they have in common is a marked aversion for each other. To add to the confusion, many writers of the past have frequently been hailed as members of this movement, and it is extremely doubtful whether they would have appreciated the company to which they are consigned. In view of this, it might be argued that the label "existentialism" ought to be abandoned altogether.

Certainly, existentialism is not a school of thought nor reducible to any set of tenets. The Three writers who appear invariably on every list of "existentialists" - Jaspers, Heidegger, and Sartre - are not in agreement on essentials. Such alleged precursors as Pascal and Kierkegaard differed from all three men by being dedicated Christians; and Pascal was a Catholic of sorts while Kierkegaard was a Protestant's Protestant. If, as it is often done, Nietzsche and Dostoevsky are included in the fold, we must make room for an impassioned anti-Christian and a even more fanatical Greek-Orthodox Russian imperialist, By the time we consider adding Rilke, Kafka, and Camus, it becomes plain that one essential feature shared by all these men is their perfervid individualism.