Why we still need Heidegger — despite his Nazism

Heidegger's criticism of the history of Western thought is that since the time of Plato and Aristotle, philosophers have abandoned questioning in favor of proposing answers that have become dogmas that stand in the way of genuine thinking. (This is one reason why Heidegger called Socrates — who never wrote a word and spent his days antagonizing his fellow citizens with pesky questions — the "purest thinker in the West.")

Perhaps the most electrifying statement of this vision of philosophy can be found in a lecture course Heidegger taught in 1929-30:

Philosophy is the opposite of all comfort and assurance. It is turbulence, the turbulence into which man is spun, so as in this way alone to comprehend his existence without delusion. Precisely because the truth of this comprehension is something ultimate and extreme, it constantly remains in the perilous neighborhood of supreme uncertainty. No knower necessarily stands so close to the verge of error at every moment as the one who philosophizes. Whoever has not yet grasped this has never yet had any intimation of what philosophizing means.