Animals, whom we have made our slaves, we do not like to consider our equal.
It is a cursed evil to any man to become as absorbed in any subject as I am in mine.
A moral being is one who is capable of reflecting on his past actions and their motives - of approving of some and disapproving of others.
I am turned into a sort of machine for observing facts and grinding out conclusions.
To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact.
Man is descended from a hairy, tailed quadruped, probably arboreal in its habits.
The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an agnostic.
I cannot persuade myself that a beneficent and omnipotent God would have designedly created parasitic wasps with the express intention of their feeding within the living bodies of Caterpillars.
An American monkey, after getting drunk on brandy, would never touch it again, and thus is much wiser than most men.
A man's friendships are one of the best measures of his worth.
In the long history of humankind (and animal kind, too) those who learned to collaborate and improvise most effectively have prevailed.
A man who dares to waste one hour of time has not discovered the value of life.
What a book a devil's chaplain might write on the clumsy, wasteful, blundering, low, and horribly cruel work of nature!
On the ordinary view of each species having been independently created, we gain no scientific explanation.