For supposing that we really had to do with two contrary opinions, as Melissus thinks (for if there are many things, he says they must arise from what is not; and if this is impossible, what is, is not many; for, being ungenerated, anything which is, is unlimited, and therefore one), supposing this so, still, if we admit both propositions equally, unity is no more proved than multiplicity, and it is only if one proposition is more firm than the other, that the conclusions following from it are better proved.