Thought is the labor of the intellect, reverie is its pleasure.

Men have called me mad; but the question is not yet settled, whether madness is or is not the loftiest intelligence.

Intelligent people tend to have less friends than the average person. The smarter you are, the more selective you become.

I have always regarded that Constitution as the most remarkable work known to me in modern times to have been produced by the human intellect, at a single stroke (so to speak), in its application to political affairs.

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.

The first method of estimating the intelligence of a ruler is to look at the men he has around him.

In walking, the will and the muscles are so accustomed to working together and performing their task with so little expenditure of force that the intellect is left comparatively free.