Édouard Levé said this quote
“ You used to give yourself over to endless sessions of doubt. You would claim to be an expert on the subject. But doubting would tire you so much that you would end up doubting doubt itself. I saw you one day at the end of an afternoon of solitary speculation. You were unmoving and petrified. Running several kilometers in a deep forest full of ravines and pitfalls would have exhausted you less. ”