A man who dares to waste one hour of time has not discovered the value of life.
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.
The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an agnostic.
I love fools' experiments. I am always making them.
I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection.
Man is descended from a hairy, tailed quadruped, probably arboreal in its habits.
The highest possible stage in moral culture is when we recognize that we ought to control our thoughts.
False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for every one takes a salutary pleasure in proving their falseness.
Animals, whom we have made our slaves, we do not like to consider our equal.
I am turned into a sort of machine for observing facts and grinding out conclusions.
The very essence of instinct is that it's followed independently of reason.
Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.
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.
We must, however, acknowledge, as it seems to me, that man with all his noble qualities... still bears in his bodily frame the indelible stamp of his lowly origin.
We can allow satellites, planets, suns, universe, nay whole systems of universes, to be governed by laws, but the smallest insect, we wish to be created at once by special act.
My mind seems to have become a kind of machine for grinding general laws out of large collections of facts.
I have tried lately to read Shakespeare, and found it so intolerably dull that it nauseated me.
How paramount the future is to the present when one is surrounded by children.
It is a cursed evil to any man to become as absorbed in any subject as I am in mine.