LET that of Heraclitus never be out of thy mind, that the death of earth, is water, and the death of water, is air; and the death of air, is fire; and so on the contrary. Remember him also who was ignorant whither the way did lead, and how that Reason being the thing, by which all things in the world are administered, and which men are continually and most inwardly conversant with: yet is the thing, which ordinarily they are most in opposition with, and how those things which daily happen among them, cease not daily to be strange unto them, and that we should not either speak, or do anything as men in their sleep, by opinion and bare imagination: for then we think we speak and do, and that we must not be as children, who follow their father's example; for best reason alleging barely this: As by tradition from our forefathers we have received it.
MARCUS AURELIUS. MEDITATIONS. Book xi. 3.