"Man tends to increase at a greater rate than his means of subsistence."

"Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult—at least I have found it so—than constantly to bear this conclusion in mind."

"The highest possible stage in moral culture is when we recognize that we ought to control our thoughts."

"If I had my life to live over again, I would have made a rule to read some poetry and listen to some music at least once every week."

"I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection."