The besetting sin of able men is impatience of contradiction and of criticism. Even those who do their best to resist the temptation, yield to it almost unconsciously and become the tools of toadies and flatterers. "Authorities," "disciples," and "schools" are the curse of science and do more to interfere with the work of the scientific spirit than all its enemies.

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

A good man: body serves his will and enjoys hard work, clear intellect that understands the truths of nature, full of passion for life but controlled by his will, well-developed conscience, loves beauty in art and nature, despises inferior morality, respects himself and others.

The child who has been taught to make an accurate elevation, plan, and section of a pint pot has had an admirable training in accuracy of eye and hand.

I would rather be the offspring of two apes than be a man and afraid to face the truth.

The only objections that have occurred to me are, 1st that you have loaded yourself with an unnecessary difficulty in adopting Natura non facit saltum so unreservedly. . . . And 2nd, it is not clear to me why, if continual physical conditions are of so little moment as you suppose, variation should occur at all. However, I must read the book two or three times more before I presume to begin picking holes.

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