Crowell, Steven. "Existentialism." STANFORD ENCYCLOPEDIA OF PHILOSOPHY Updated January 23, 2010.

Like “rationalism” and “empiricism,” “existentialism” is a term that belongs to intellectual history. Its definition is thus to some extent one of historical convenience. The term was explicitly adopted as a self-description by Jean-Paul Sartre, and through the wide dissemination of the postwar literary and philosophical output of Sartre and his associates—notably Simone de Beauvoir, Maurice Merleau-Ponty, and Albert Camus—existentialism became identified with a cultural movement that flourished in Europe in the 1940s and 1950s. Among the major philosophers identified as existentialists (many of whom—for instance Camus and Heidegger—repudiated the label) were Karl Jaspers, Martin Heidegger, and Martin Buber in Germany, Jean Wahl and Gabriel Marcel in France, the Spaniards José Ortega y Gasset and Miguel de Unamuno, and the Russians Nikolai Berdyaev and Lev Shestov. The nineteenth century philosophers, Søren Kierkegaard and Friedrich Nietzsche, came to be seen as precursors of the movement. Existentialism was as much a literary phenomenon as a philosophical one. Sartre's own ideas were and are better known through his fictional works (such as Nausea and No Exit) than through his more purely philosophical ones (such as Being and Nothingness and Critique of Dialectical Reason), and the postwar years found a very diverse coterie of writers and artists linked under the term: retrospectively, Dostoevsky, Ibsen, and Kafka were conscripted; in Paris there were Jean Genet, André Gide, André Malraux, and the expatriate Samuel Beckett; the Norwegian Knut Hamsun and the Romanian Eugene Ionesco belong to the club; artists such as Alberto Giacometti and even Abstract Expressionists such as Jackson Pollock, Arshile Gorky, and Willem de Kooning, and filmmakers such as Jean-Luc Godard and Ingmar Bergman were understood in existential terms. By the mid 1970s the cultural image of existentialism had become a cliché, parodized in countless books and films by Woody Allen. It is sometimes suggested, therefore, that existentialism just is this bygone cultural movement rather than an identifiable philosophical position; or, alternatively, that the term should be restricted to Sartre's philosophy alone. But while a philosophical definition of existentialism may not entirely ignore the cultural fate of the term, and while Sartre's thought must loom large in any account of existentialism, the concept does pick out a distinctive cluster of philosophical problems and helpfully identifies a relatively distinct current of twentieth- and now twenty-first century philosophical inquiry, one that has had significant impact on fields such as theology (through Rudolf Bultmann, Paul Tillich, Karl Barth, and others) and psychology (from Ludwig Binswanger and Medard Boss to Otto Rank, R. D. Laing, and Viktor Frankl). What makes this current of inquiry distinct is not its concern with “existence” in general, but rather its claim that thinking about human existence requires new categories not found in the conceptual repertoire of ancient or modern thought; human beings can be understood neither as substances with fixed properties, nor as subjects interacting with a world of objects. On the existential view, to understand what a human being is it is not enough to know all the truths that natural science—including the science of psychology—could tell us. The dualist who holds that human beings are composed of independent substances—“mind” and “body”—is no better off in this regard than is the physicalist, who holds that human existence can be adequately explained in terms of the fundamental physical constituents of the universe. Existentialism does not deny the validity of the basic categories of physics, biology, psychology, and the other sciences (categories such as matter, causality, force, function, organism, development, motivation, and so on). It claims only that human beings cannot be fully understood in terms of them. Nor can such an understanding be gained by supplementing our scientific picture with a moral one. Categories of moral theory such as intention, blame, responsibility, character, duty, virtue, and the like do capture important aspects of the human condition, but neither moral thinking (governed by the norms of the good and the right) nor scientific thinking (governed by the norm of truth) suffices. “Existentialism”, therefore, may be defined as the philosophical theory which holds that a further set of categories, governed by the norm of authenticity, is necessary to grasp human existence. To approach existentialism in this categorial way may seem to conceal what is often taken to be its “heart” (Kaufmann 1968:12), namely, its character as a gesture of protest against academic philosophy, its anti-system sensibility, its flight from the “iron cage” of reason. But while it is true that the major existential philosophers wrote with a passion and urgency rather uncommon in our own time, and while the idea that philosophy cannot be practiced in the disinterested manner of an objective science is indeed central to existentialism, it is equally true that all the themes popularly associated with existentialism—dread, boredom, alienation, the absurd, freedom, commitment, nothingness, and so on—find their philosophical significance in the context of the search for a new categorial framework, together with its governing norm. . . . Read the rest here: http://plato.stanford.edu/entries/existentialism/.