Martin Heidegger (mär´tēn hī´dĕger), 1889–1976, German philosopher. As a student at Freiburg, Heidegger was influenced by the neo-Kantianism of Heinrich Rickert and the phenomenology of Edmund Husserl. In 1923 he became professor at Marburg, where he wrote and published the only completed part of his major work, Sein und Zeit (1927; tr. Being and Time, 1962). On the basis of this work Heidegger was called (1928) to Freiburg to succeed Husserl in the chair of philosophy, which he occupied until his retirement in 1951. He actively supported Adolf Hitler during the dictator's first years in power, and was a member of the National Socialist party from 1933 to 1945. After World War II he was banned from teaching and publishing for five years. Controversy has raged regarding nature and depth of Heidegger's Nazism and anti-Semitism and the degree to which they are reflective of his philosophical thinking.
Although generally considered a founder of existentialism, Heidegger vehemently rejected the association, just as he came to reject Husserl's phenomenology. Heidegger's fundamental concern, as announced in Sein und Zeit and developed in his subsequent works, is the problem of being. In Sein und Zeit, being is shown to be intimately linked with temporality; the relationship between them is investigated by means of an analysis of human existence. Strongly influenced by Sören Kierkegaard, Heidegger delineated various aspects of human existence, such as "care," "moods," and the individual's relationship to death, and related the authenticity of being, as well as the anguish of modern society, to the individual's confrontation with his own temporality. It was this work and its influence upon Jean-Paul Sartre that have led many critics to consider Heidegger an existentialist. In addition to its influence on Sartre, Heidegger's thought influenced both modern Protestant theology (through Paul Tillich and Rudolph Bultmann) and the work of Jacques Derrida and other advocates of deconstruction.
The ontological aspect of Heidegger's thought assumed greater prominence in his later writings, which included studies of poetry and of dehumanization in modern society. Heidegger considered himself the first thinker in the history of Western philosophy to have raised explicitly the question concerning the "sense of being," and he located the crisis of Western civilization in mass "forgetfulness of being." Among his other works are Kant and the Problem of Metaphysics (1929, tr. 1962), What Is Metaphysics? (1929, tr. 1949), An Introduction to Metaphysics (1953, tr. 1959), What Is Philosophy? (1956, tr. 1958), and The End of Philosophy (1956, tr. 1973).
See studies by T. Langan (1959), M. King (1964), J. M. Demske (1963, tr. 1970), L. M. Vail (1972), S. L. Binderman (1981), H. G. Wolz (1981), R. Wolin (1990; ed., 1993; and 2001), K. Lowith (tr. 1995), R. Safranski (1998), and P. E. Gordon (2010); V. Farias, Heidegger and Nazism (1987); E. Ettinger, Hannah Arendt, Martin Heidegger (1995) and D. Villa, Arendt and Heidegger: The Fate of the Political (1995).