existentialism (ĕgzĭstĕnˈshəlĭzəm, ĕksĭ–) [key], any of several philosophic systems, all centered on the individual and his relationship to the universe or to God. Important existentialists of varying and conflicting thought are Søren Kierkegaard, Karl Jaspers, Martin Heidegger, Gabriel Marcel, and Jean-Paul Sartre. All revolt against the traditional metaphysical approaches to man and his place in the universe. Thinkers such as St. Thomas Aquinas, Blaise Pascal, and Friedrich Nietzsche have been called existentialists, but it is more accurate to place the beginnings of the movement with Kierkegaard. In his concern with the problem of the individual's relationship to God, Kierkegaard bitterly attacked the abstract metaphysics of the Hegelians and the worldly complacency of the Danish church. Kierkegaard's fundamental insight was the recognition of the concrete ethical and religious demands confronting the individual. He saw that these demands could not be met by a merely intellectual decision but required the subjective commitment of the individual. The necessity and seriousness of these ethical decisions facing man was for Kierkegaard the source of his dread and despair. Kierkegaard's analysis of the human situation provides the central theme of contemporary existentialism. Following him, Heidegger and Sartre were the major thinkers connected with this movement. Both were influenced by the work of Edmund Husserl and developed a phenomenological method that they used in developing their own existential analyses. Heidegger rejected the label of "existentialist" and described his own philosophy as an investigation of the nature of being in which the analysis of human existence is only the first step. Sartre was the only self-declared existentialist among the major thinkers. For him the central idea of all existential thought is that existence precedes essence. For Sartre there is no God and therefore no fixed human nature that forces one to act. Man is totally free and entirely responsible for what he makes of himself. It is this freedom and responsibility that, as for Kierkegaard, is the source of man's dread. Sartre's thought, as expressed in his novels and plays as well as in his more formal philosophical writings, strongly influenced a current in French literature, best represented by Albert Camus and Simone de Beauvoir. In France the most prominent exponent of a Christian existentialism was Gabriel Marcel, who developed his philosophy within the framework of the Roman Catholic Church. Aside from Heidegger, the leading German existentialist was Karl Jaspers, who developed the central Kierkegaardian insight along less theological lines. Various other theologians and religious thinkers such as Karl Barth, Martin Buber, Paul Tillich, and Reinhold Niebuhr are often included within the orbit of existentialism.
See J.-P. Sartre, Existentialism (1947); J. Macquarrie, Studies in Christian Existentialism (1966); R. C. Solomon, ed., Existentialism (1974); D. E. Cooper, Existentialism: A Reconstruction (1990); D. B. Raymond, ed., Existentialism and the Philosophical Tradition (1991).