Man will do many things to get himself loved; he will do all things to get himself envied. – Mark Twain, Following the Equator, 1897

Man desired concord; but nature knows better what is good for his species; she desires discord. Man wants to live easy and content; but nature compels him to leave ease… and throw himself into roils and labors. – Immanuel Kant, Idea for a Universal History with a Cosmopolitan Purpose, 1787

In each generation the human mind in every man reverts to its starting-point; each new man is a primitive man. – Alexandre Vinet (1797–1847)

I demand of you, and of the whole world, that you show me a generic character… by which to distinguish between Man and Ape. I myself most assuredly know of none. – Carl Linnaeus, 1788