If I fail, I try again, and again, and again. If YOU fail, are you going to try again? The human spirit can handle much worse than we realize. It matters HOW you are going to FINISH. Are you going to finish strong?

Don't let yesterday take up too much of today.

物理学的美丽不仅在于它提供的答案，还在于它揭示的奥秘。

The essence of mathematics lies in its freedom.

The consequences of this problem make themselves felt in bookshops. When you go to a large bookshop and look at the self-help sections, as I sometimes do -- if you analyze self-help book sproduced in the world today, there are basically two kinds. The first kind tells you, "You can do it! You can make it! Anything's possible!" The other kind tells you how to cope with what we politely call "low self-esteem," or impolitely call, "feeling very bad about yourself."

Innovation is not an option; it's a necessity for the survival of the coal industry.

Behavior, as such, is not to be regarded as a mere chain of muscular contractions, but rather as a purposive and cognitive affair.