Patience and tenacity are worth more than twice their weight of cleverness.

The rung of a ladder was never meant to rest upon, but only to hold a man's foot long enough to enable him to put the other somewhat higher.

No slavery can be abolished without a double emancipation, and the master will benefit by freedom more than the freed-man.

Freedom and order are not incompatible... truth is strength... free discussion is the very life of truth.

Proclaim human equality as loudly as you like, Witless will serve his brother.

I do not say think as I think, but think in my way. Fear no shadows, least of all in that great spectre of personal unhappiness which binds half the world to orthodoxy.

The great thing in the world is not so much to seek happiness as to earn peace and self-respect.

It is one of the most saddening things in life that, try as we may, we can never be certain of making people happy, whereas we can almost always be certain of making them unhappy.

Science is simply common sense at its best, that is, rigidly accurate in observation, and merciless to fallacy in logic.

Science commits suicide when it adopts a creed.

The great tragedy of science - the slaying of a beautiful hypothesis by an ugly fact.

The man of science has learned to believe in justification, not by faith, but by verification.

Science and literature are not two things, but two sides of one thing.

Science is organized common sense where many a beautiful theory was killed by an ugly fact.

The improver of natural knowledge absolutely refuses to acknowledge authority, as such. For him, skepticism is the highest of duties; blind faith the one unpardonable sin.

If a little knowledge is dangerous, where is the man who has so much as to be out of danger?

The medieval university looked backwards; it professed to be a storehouse of old knowledge. The modern university looks forward, and is a factory of new knowledge.

Time, whose tooth gnaws away everything else, is powerless against truth.

It is not who is right, but what is right, that is of importance.

The only medicine for suffering, crime, and all other woes of mankind, is wisdom. Teach a man to read and write, and you have put into his hands the great keys of the wisdom box. But it is quite another thing to open the box.

In science, as in art, and, as I believe, in every other sphere of human activity, there may be wisdom in a multitude of counsellors, but it is only in one or two of them.

There is no sea more dangerous than the ocean of practical politics none in which there is more need of good pilotage and of a single, unfaltering purpose when the waves rise high.

Logical consequences are the scarecrows of fools and the beacons of wise men.

Learn what is true in order to do what is right.

Try to learn something about everything and everything about something.

The scientific imagination always restrains itself within the limits of probability.