Existentialism is a term that incorporates both a specific philosophical history and its subsequent literary reception and popular use. Philosophically, "existentialism" loosely describes a reaction against abstract rationalist philosophical thought, and is mainly found in the work of SØren Kierkegaard, Friedrich Nietzsche, Martin Heidegger, Karl Jaspers, Jean-Paul Sartre, and Gabrielle Marcel (who in fact coined the term). Each of these thinkers argued in various ways for the irreducibility of the subjective, personal dimension of human life against the objective or formal considerations of "being" or "existence" found in other philosophical traditions. Existentialism generally holds that "Man" is a conscious subject, rather than a thing to be predicted or manipulated; he exists as a conscious being, and not in accordance with any pre-determined characteristics.

Given this, existentialist thought is largely concerned with the realms of ethics, politics, personal freedom, and will. Always central is the role of the...