No slavery can be abolished without a double emancipation, and the master will benefit by freedom more than the freed-man.
Economy does not lie in sparing money, but in spending it wisely.
Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.
The scientific imagination always restrains itself within the limits of probability.
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.
It is not who is right, but what is right, that is of importance.
Science reckons many prophets, but there is not even a promise of a Messiah.
If a little knowledge is dangerous, where is the man who has so much as to be out of danger?
My business is to teach my aspirations to confirm themselves to fact, not to try and make facts harmonize with my aspirations.
Every great advance in natural knowledge has involved the absolute rejection of authority.
The great tragedy of science - the slaying of a beautiful hypothesis 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.
Patience and tenacity are worth more than twice their weight of cleverness.
Try to learn something about everything and everything about something.
Learn what is true in order to do what is right.
The best men of the best epochs are simply those who make the fewest blunders and commit the fewest sins.
Science is organized common sense where many a beautiful theory was killed by an ugly fact.
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.