of its composition into parts, each of which is free of this composition.” You may be told: This is false on that assumption, because if each of those parts differing in essence is an indivisible part—namely, an atom—it cannot then be composite or be resolved into further parts, for it has no composition whatsoever. The most you can say about it is what you said about the parts into which it is resolved: that it must be in contact with one thing on its right and another on its left.

But you may be told: First, this is false in the case of the indivisible part. Your statement, “But its right side is like its left; otherwise, it would itself be composite, whereas we have assumed it to be non-composite,” is self-contradictory: one part of it invalidates another. For if it has a right side and a left side, it is composite. Your statement that its right side is like its left—and two things that are alike are distinct—implies that it contains two distinct things. This too is composition. The resemblance between its two sides does not make it any less composite. Thus, your statement, “We have assumed it to be non-composite,” is a contradiction.

Likewise, your statement and claim that its right side resembles its left, since otherwise it would itself be composite, implies that when its two sides are alike, it is not