Psychology must study the adaptive functions of thought and behavior.

The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.

I have so much admiration for women who are married with children and work. I don’t know how you all do it.

圆的周长大于任何内接等边多边形的周长，小于任何外切多边形的周长。

A great truth is a truth whose opposite is also a great truth.

Patriotism is your conviction that this country is superior to all other countries because you were born in it.

To understand humanity, we must first understand our origins.