Peter E. Gordon at the New York Review of Books:
Heidegger was one of the most influential thinkers of the modern era. He was also a convinced Nazi. During his brief term as rector at the University of Freiburg (1933–1934) he worked to advance the process of Gleichschaltung, or coordination, that brought the university into alignment with the official policies of the Third Reich. Apologists for Heidegger have occasionally sought to underplay the gravity of this political record. They note that he stepped down from his post after less than a year, and they add that many of his academic contemporaries, such as Ernst Krieck and Alfred Baeumler, were both more zealous and more effective in their collaboration. The difference, however, is that few today take those other men seriously as scholars. Heidegger, meanwhile, continues to be read, and his permanent place in the pantheon of Continental philosophy seems more or less secure.
How, then, can one study his philosophy without taking some cognizance of his ignominious past? One strategy for resolving the dilemma has been to insist on a neat distinction: Heidegger was good at philosophy but bad at politics. An elegant defense along these lines was developed by Hannah Arendt, his erstwhile student, whose essay “Martin Heidegger at Eighty” (published in these pages in 1971) compared Heidegger to Thales, the ancient philosopher who grew so absorbed in contemplating the heavens that he stumbled into the well at his feet.