 A further argument depends on thinking that opposite properties must have opposite characteristics: if ‘many’ or ‘large’ things have infinite parts, it is argued, then ‘few’ or ‘small’ things must have only a finite number of parts. It is then concluded that there must be a magnitude without parts, apparently so that it is not further divisible and thus composed of an infinite number of parts. The last argument depends on the idea that mathematicians talk of commensurable lines, and posit a single unit of measurement: this would not be possible if the unit were divisible, because the parts of the unit, if measured, would be measured by the unit measure and it would then turn out to contain multiple units within itself.