Martin Heidegger's (1889–1976) relationship to existentialism is the subject of some controversy, not only because of his criticisms of Sartre's focus on consciousness and subjectivity in his 1945 essay “Letter on Humanism”, but also because of some substantive philosophical differences between his project and those of his French contemporaries. At the same time, there can be no doubting the extent of Heidegger's influence on existentialism. In fact, an adequate understanding of it would be impossible without at least some comprehension of his work, particularly his enormously influential Being and Time (1927), so we will shortly consider the aspects of his thought that have been important for existentialism: largely the material that he calls the “existential analytic”.

First, however, it is necessary to digress somewhat to consider Heidegger's broader philosophical project and there is no easy way to do this. Not only is Heidegger's language notoriously dense and difficult, and probably quite unlike anything that you will have encountered before, but the questions that guide and motivate his existential analytic are also, at first glance, highly abstract (the complication of his language is at least partly because of his attempts to escape the distorting effects of existing ways of thinking that Heidegger finds to be problematic). In the first few pages of this chapter, I hence attempt to lay out the basic impetus behind the more existential aspects of his work, as they are expressed in the “Introduction” in Being and Time, and his essay “What is Metaphysics?” Although readers might be tempted to skip this section of the chapter and begin with the more obviously existential material on “Dasein”, if this is done it is important eventually to return to these first few pages and, better yet, to the “Introduction” in Being and Time, as they problematize any too-quick conflation of Heidegger and existentialism.