He who has extensive knowledge is not a wise man.

I keep six honest serving men (they taught me all I knew); Their names are What and Why and When And How and Where and Who.

One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another.

There is nothing so absurd or ridiculous that has not at some time been said by some philosopher.

The possession of knowledge does not kill the sense of wonder and mystery. There is always more mystery.

Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind.

The desire of power in excess caused the angels to fall; the desire of knowledge in excess caused man to fall.

A wise man proportions his belief to the evidence.

I hope our wisdom will grow with our power, and teach us, that the less we use our power the greater it will be.

We should be careful to get out of an experience only the wisdom that is in it—and stop there; lest we be like the cat that sits down on a hot stove lid. She will never sit down on a hot stove lid again—and that is well; but also she will never sit down on a cold one any more.

I was wise enough to never grow up while fooling most people into believing I had.

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

All things are filled full of signs, and it is a wise man who can learn about one thing from another.