17

15

The third proposition is that there is a number next greater than
any given number or taking any number
whatever, there is a number (namely, the next
greater one) such that taking any number you please
either this third number (being no greater than the first)
is used in counting every collection that the first is used
in counting or else (being as great as the next greater
number) is not used in counting any collection unless that
next greater is used in counting it.

[diagram]