That which endures is not one or another association of living forms, but the process of which the cosmos is the product, and of which these are among the transitory expressions.

What would become of the garden if the gardener treated all the weeds and slugs and birds and trespassers as he would like to be treated, if he were in their place?

Tolerably early in life I discovered that one of the unpardonable sins, in the eyes of most people, is for a man to go about unlabeled. The world regards such a person as the police do an unmuzzled dog.

Veracity is the heart of morality.

Every great advance in natural knowledge has involved the absolute rejection of authority.

A man who speaks out honestly and fearlessly that which he knows, and that which he believes, will always enlist the good will and the respect, however much he may fail in winning the assent, of his fellow men.

[Scientists] have learned to respect nothing but evidence, and to believe that their highest duty lies in submitting to it however it may jar against their inclinations.