many in Germany and elsewhere were feeling as they beheld what looked like a failed experiment in liberalism and capitalism. (The American stock market began to crash on October 24, 1929.)
But to judge from his journals, known as the Black Notebooks, Heidegger himself might prefer to think of the change in his thought in terms of the requirements of philosophy itself as a risky adventure. He writes, at the outset of the thirties, “Only if we actually err—go into errancy—can we run up against ‘truth’” (GA 94: 13/11 tm). Thinkers must learn “long useless straying”; “the history of philosophy is in itself an erring” (GA 95: 227/176).
In trying to understand Heidegger’s transition into the thirties, we should not wipe out this element of experimentation and risk. The transition should not be smoothed over in retrospect and turned into a logical extension of his earlier thought. However, we can identify some crucial spurs that urged him to think differently. One is the question of the origin of our temporality. Others include the themes of emergency and shared selfhood, which were present in Being and Time but become more urgent.
As for the end of the “thirties,” it is more gradual. Heidegger draws back from his political or quasi-political discourse of leaping, deciding, and founding. His enthusiasm for struggle and power cools. During the Second World War, he moves toward a nonwillful letting-be.
Although the transition to Heidegger’s “late” thought was incremental, it eventually led to a stark personal and philosophical collapse. After the defeat of Germany and his removal from teaching, he experienced a depressive crisis from which he had to recover in a sanitarium. He had to build a new, humbled way of thinking on the ruins of his former thought, trying to describe “things” in a deliberately simple, unpresumptuous way, as if he were seeing the world anew.6 Philosophically, the collapse of the “thirties” could be highlighted in two dramatic reversals. In a lecture from 1945, “Poverty,” he defines Not (urgent need or emergency) as being forced to focus on what we require for survival, and claims that freedom lies in Not-wendigkeit, turning away from such compulsion (GA 73.1: 878–79). Emergency is no longer a requirement for appropriate existence. The other reversal is a postwar passage in the Black Notebooks that says the “talk of the history of beyng is an embarrassment and a euphemism” (GA 97: 382). With such statements, one can say that the “thirties” have been left behind.
To be sure, Heidegger still understands the West as suffering from a certain crisis that must be understood in terms of its entire history. And short of certain extreme breaks, one does not simply become a new person—or a new philosopher. Several themes and concerns run throughout sixty years of Heidegger’s thinking, and a case can be made for a unified interpretation of his trajectory.7