You are never too old to set another goal or to dream a new dream.

Never underestimate the power of a simple idea executed well.

Psychology must be based on direct experience, not inference.

The best art is always on the edge of taste.

科学家研究自然并非因为它有用；他研究它是因为他从中获得乐趣，而他从中获得乐趣是因为它是美丽的。

The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.

"We are all in the gutter, but some of us are looking at the stars."