"Beyond Economics: Essays on Society, Religion, and Ethics" by Kenneth E. Boulding (p. 141), as quoted in "Evolutionary Economics and Human Nature" by John Laurent, (p. 175), 2003.
Thomas Hobbes (1750). “The Moral and Political Works of Thomas Hobbes of Malmesbury: Never Before Collected Together : To which is Prefixed, the Author's Life, Extracted from that Said to be Written by Himself, ...”, p.114