"Every sentence I utter must be understood not as an affirmation, but as a question."

"Some subjects are so serious that one can only joke about them."

"Every valuable human being must be a radical and a rebel, for what he must aim at is to make things better than they …"

"Two sorts of truth: profound truths recognized by the fact that the opposite is also a profound truth, in contrast to…"

"It is a great pity that human beings cannot find all of their satisfaction in scientific contemplativeness."

"Anyone who is not shocked by quantum theory has not understood it."

"We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a cha…"

"Physics is to be regarded not so much as the study of something a priori given, but rather as the development of meth…"

"How wonderful that we have met with a paradox. Now we have some hope of making progress."

"Truth and clarity are complementary."