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

It is wrong for a man to say that he is certain of the objective truth of any proposition unless he can produce evidence which logically justifies that certainty.

Mix salt and sand, and it shall puzzle the wisest of men, with his mere natural appliances, to separate all the grains of sand from all the grains of salt; but a shower of rain will effect the same object in ten minutes.

The vast results obtained by Science are won by no mystical faculties, by no mental processes other than those which are practicedby every one of us, in the humblest and meanest affairs of life. A detective policeman discovers a burglar from the marks made by his shoe, by a mental process identical with that by which Cuvier restored the extinct animals of Montmartre from fragments of their bones.

The thief and the murderer follow nature just as much as the philanthropist.

Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.

To persons uninstructed in natural history, their country or seaside stroll is a walk through a gallery filled with wonderful works of art, nine-tenths of which have their faces turned to the wall.