Plutarch, De communibus notitiis adversus Stoicos
Goodwin, Ed.

And this also is against sense, that there is not in the nature of bodies any thing either supreme or first or last, in which the magnitude of the body may terminate; but that there is always some phenomenon beyond the [p. 413] assumed body, and that this still going on carries the subject to infinity and undeterminateness. For one body cannot be imagined greater or less than another, if both of them may by their parts proceed in infinitum; but the nature of inequality is taken away. For of things that are esteemed unequal, the one falls short in its last parts, and the other goes on and exceeds. Now if there is no inequality, it follows that there is no unevenness nor roughness of bodies; for unevenness is the inequality of the same superficies with itself, and roughness is an unevenness joined with hardness; neither of which is left us by those who terminate no body in its last part, but extend them all by the multitude of their parts unto an infinity. And yet is it not evident that a man consists of more parts than a finger, and the world of more than a man? This indeed all men know and understand, unless they become Stoics; but if they are once Stoics, they on the contrary say and think that a man has no more parts than a finger, nor the world than a man. For division reduces bodies to an infinity; and of infinites neither is more or less or exceeds in multitude, or the parts of the remainder will cease to be divided and to afford a multitude of themselves.

LAMPRIAS. How then do they extricate themselves out of these difficulties?

DIADUMENUS. Surely with very great cunning and courage. For Chrysippus says: ‘If we are asked, if we have any parts, and how many, and of what and how many parts they consist, we are to use a distinction, making it a position that the whole body is compacted of the head, trunk, and legs, as if that were all which is enquired and doubted of. But if they extend their interrogation to the last parts, no such thing is to be undertaken, but we are to say that they consist not of any certain parts, nor yet of so many, nor of infinite, nor of finite.’ And I seem to [p. 414] myself to have used his very words, that you may perceive how he maintains the common notions, forbidding us to think of what or how many parts every body is compacted, and whether of infinite or finite. For if there were any medium between finite and infinite, as the indifferent is between good and evil, he should, by telling us what that is, have solved the difficulty. But if—as that which is not equal is presently understood to be unequal, and that which is not mortal to be immortal—we also understand that which is not finite to be immediately infinite, to say that a body consists of parts neither finite nor infinite is, in my opinion, the same thing as to affirm that an argument is compacted of positions neither true nor false....