量子引力问题不仅是物理学的问题，也是科学哲学的问题。

整个有机体最复杂的反射就是所谓的本能。

The work of art is the result of a struggle between the artist and his material.

The chess-board is the world; the pieces are the phenomena of the universe; the rules of the game are what we call the laws of Nature.  

大海就是历史。