13. When we have meat before us and such eatables, we receive the impression that this is the dead body of a fish, and this the dead body of a bird or of a pig; and again, that this Falernian is only a little grape-juice, and this purple robe some sheep's wool dyed with the blood of a shell-fish: such then are these impressions, and they reach the things themselves and penetrate them, and so we see what kind of things they are. Just in the same way ought we to act all through life, and where there are things which appear most worthy of our approbation, we ought to lay them bare and look at their worthlessness and strip them of all the words by which they are exalted. For outward show is a wonderful perverter of the reason, and when thou art most sure that thou art employed about things worth thy pains, it is then that it cheats thee most. Consider then what Crates says of Xenocrates himself.
Source: The Thoughts of the Emperor Marcus Aurelius Antoninus by Marcus Aurelius Antoninus, translated by George Long