Psychology is a science, and teaching is an art; and sciences never generate arts directly out of themselves.

The artist must be a child of the mystery.

数学是理解宇宙的钥匙。

The measure of our success is not just in tons extracted, but in communities uplifted.

幸福不是在外面等着我们去寻找。它不在外面的原因是因为它在我们的内心。