Every great advance in natural knowledge has involved the absolute rejection of authority.
Patience and tenacity are worth more than twice their weight of cleverness.
Teach a child what is wise, that is morality. Teach him what is wise and beautiful, that is religion!
The best men of the best epochs are simply those who make the fewest blunders and commit the fewest sins.
Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.
My business is to teach my aspirations to confirm themselves to fact, not to try and make facts harmonize with my aspirations.
The great tragedy of science - the slaying of a beautiful hypothesis by an ugly fact.
Economy does not lie in sparing money, but in spending it wisely.
If a little knowledge is dangerous, where is the man who has so much as to be out of danger?
The scientific imagination always restrains itself within the limits of probability.
Science and literature are not two things, but two sides of one thing.
The great thing in the world is not so much to seek happiness as to earn peace and self-respect.
The more rapidly truth is spread among mankind the better it will be for them. Only let us be sure that it is the truth.
My experience of the world is that things left to themselves don't get right.
No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.
Try to learn something about everything and everything about something.
Science reckons many prophets, but there is not even a promise of a Messiah.
Freedom and order are not incompatible... truth is strength... free discussion is the very life of truth.
Science is nothing, but trained and organized common sense.
The results of political changes are hardly ever those which their friends hope or their foes fear.
Science is organized common sense where many a beautiful theory was killed by an ugly fact.
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.
All truth, in the long run, is only common sense clarified.
In scientific work, those who refuse to go beyond fact rarely get as far as fact.
History warns us that it is the customary fate of new truths to begin as heresies and to end as superstitions.
No slavery can be abolished without a double emancipation, and the master will benefit by freedom more than the freed-man.
Proclaim human equality as loudly as you like, Witless will serve his brother.