I make it a rule not to clutter my mind with simple information that I can find in a book in five minutes.

If the moon, in the act of completing its eternal way around the earth, were gifted with self-consciousness, it would feel thoroughly convinced that it was traveling its way of its own accord on the strength of a resolution taken once and for all. So would a Being, endowed with higher insight and more perfect intelligence, watching man and his doings, smile about man's illusion that he was acting according to his own free will.

The height of stupidity is most clearly demonstrated by the individual who ridicules something he knows nothing about.

If you've never failed, you've never tried anything new.

Non-cooperation in military matters should be an essential moral principle for all true scientists.

Honestly, I cannot understand what people mean when they talk about the freedom of the human will. I have a feeling, for instance, that I will something or other; but what relation this has with freedom I cannot understand at all. I feel that I will to light my pipe and I do it; but how can I connect this up with the idea of freedom? What is behind the act of willing to light the pipe ? Another act of willing?

The truth isn't always a blinding light. Sometimes it's a deep and dazzling darkness, that illuminates - and burns - just as surely.