Curiosity is one of the most permanent and certain characteristics of a vigorous intellect.

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

It is not reason which is the guide of life, but custom.

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.

I've always felt that a person's intelligence is directly reflected by the number of conflicting points of view he can entertain simultaneously on the same topic.

It doesn't matter how smart you are unless you stop and think.

The most crucial use of knowledge and education is to understand the importance of developing a good heart.

The opinion of 10,000 men is of no value if none of them know anything about the subject.

Knowledge rests not upon truth alone, but upon error also.

When you know a thing, to hold that you know it; and when you do not know a thing. To allow that you do not know it—this is knowledge.

There is a wisdom in this beyond the rules of physic. A man’s own observation, what he finds good of and what he finds hurt of, is the best physic to preserve health.

Opinion is the medium between knowledge and ignorance.

Knowing your own darkness is the best method for dealing with the darknesses of other people.