Be like a headland of rock on which the waves break incessantly: but it stands fast and around it the seething of the waters sinks to rest.

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Van Gogh, Vincent. Dear Theo: The Autobiography of Vincent Van Gogh, edited by Irving Stone and Jean Stone. Plume, 1995.

Phocylides. Quoted in Politics, written by Aristotle, translated by R. F. Stalley and Sir Ernest Barker. Oxford University Press, 2009, bk. 4.

Aristotle. Metaphysics, translated by Hugh Lawson-Tancred. Penguin Classics, 1999, book alpha.

Aristotle. Nicomachean Ethics, translated by Terence Irwin. Hackett Publishing, 2019, bk. 1.