There is but one right, and the possibilities of wrong are infinite..

There is the greatest practical benefit in making a few failures early in life..

Action is the catalyst that creates accomplishments. It is the path that takes us from uncrafted hopes to realized dreams..

I'd rather have an ape for an ancestor than a bishop..

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

Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle. ... Positively the p….

Of the few innocent pleasures left to men past middle life, the jamming of common sense down the throats of fools is perhaps the keenest..

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

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

The chess-board is the world, the pieces are the phenomena of the universe, the rules of the game are what we call the laws of Nature. The player on ….

Perhaps the most valuable result of all education is the ability to make yourself do the thing you have to do, when it ought to be done, whether you ….

It is far better for a man to go wrong in freedom than to go right in chains..

Skepticism is the highest duty and blind faith the one unpardonable sin..

Not far from the invention of fire we must rank the invention of doubt..

The foundation of all morality is to have done, once and for all, with lying; to give up pretending to believe that for which there is no evidence, a….

Try to learn something about everything and everything about something..

The secret of genius is to carry the spirit of childhood into maturity..

Economy does not lie in sparing money, but in spending it wisely..

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

God give me strength to face a fact though it slay me..

Science commits suicide when it adopts a creed..