The most difficult part about understanding something is that we understand it all.

Play is the highest from of research.

Never regard study as a duty, but as the enviable opportunity to learn

If most of us are ashamed of shabby clothes and shoddy furniture let us be more ashamed of shabby ideas and shoddy philosophies.

The time comes in life when we have read enough. It's time to stop reading. It's time to lay down the books and write.

I have not eaten enough of the tree of knowledge, though in my profession I am obligated to feed on it regularly.

Scientists believe that every occurrence, including the affairs of human beings, is due to the laws of nature. Therefore a scientist cannot be inclined to believe that the course of events can be influenced by prayer, that is, by a supernaturally manifested wish.