He preferred smart questions to smart answers.

It was clear that he didn't remember me from one day to the next. The note clipped to his sleeve simply informed him that it was not our first meeting, but it could not bring back the memory of the time we had spent together.

—Mais, quelle que soit l'importance de l'événement, dès qu'il est écrit sur le papier, il ne fait plus qu'une ou deux lignes. "Mes yeux ne voyaient plus" ou "je n'avais plus un sou", il suffit d'une dizaine ou d'une vingtaine de lettres de l'alphabet. C'est pourquoi, quand on calligraphie des autobiographies, il arrive qu'on soit soulagé. On se dit que ce n'est pas la peine de trop réfléchir à tout ce qui se passe dans le monde.

Solving a problem for which you know there’s an answer is like climbing a mountain with a guide, along a trail someone else has laid. In mathematics, the truth is somewhere out there in a place no one knows, beyond all the beaten paths. And it’s not always at the top of the mountain. It might be in a crack on the smoothest cliff or somewhere deep in the valley.

Disappeared' is the only way to describe it-it was as if he dissolved into thin air without so much as a whimper. I wouldn't have believed that a human being with a brain, a heart, with arms and legs and the power of speech could have simple vanished like that. There was nothing about him that suggested he would disappear.

The Professor never really seemed to care whether we figured out the right answer to a problem. He preferred our wild, desperate guesses to silence, and he was even more delighted when those guesses led to new problems that took us beyond the original one. He had a special feeling for what he called the "correct miscalculation," for he believed that mistakes were often as revealing as the right answers.