Plutarch, De communibus notitiis adversus Stoicos
Goodwin, Ed.

DIADUMENUS. You perhaps have suffered the same things with some of the vulgar. But if you believe the poets, who say that the ancient city Sipylus was overthrown by the providence of the Gods when they punished Tantalus, believe also the companions of the Stoa saying that Nature, not by chance but by divine providence, brought forth Chrysippus, when she had a mind to turn things upside down and alter the course of life; for which purpose never any man was fitter than he. But as Cato said of Caesar, that never any but he came to the management of public affairs sober and considerately resolved on the ruin of the state; so does this man seem to me with the greatest diligence and eloquence to overturn and demolish custom, as they who magnify the man testify, when they dispute against him concerning the sophism called Pseudomenos (or the Liar). For to say, my best friend, that a conclusion drawn from contrary positions is not manifestly false, and again to say that some arguments having true premises and true inductions may yet moreover have the contrary to their conclusions true, what conception of demonstration or what presumption of faith does it not overthrow? They [p. 374] say, that the polypus in the winter gnaws his own claws; but the logic of Chrysippus, taking away and cutting off its own chiefest parts and principles,—what other notion has it left unsuspected of falsehood? For the superstructures cannot be steady and sure, if the foundations remain not firm but are shaken with so many doubts and troubles. But as those who have dust or dirt upon their bodies, if they touch or rub the filth that is upon them, seem rather to increase than remove it; so some men blame the Academics, and think them guilty of the faults with which they show themselves to be burdened. For who do more pervert the common conceptions than the Stoics? But if you please, let us leave accusing them, and defend ourselves from the things with which they charge us.