However, I'd argue that it's not linear.

It has to be more than just not linear for that to solve it, it has to be so nonlinear that no finite number of specks at all can add up to the torture, since otherwise we could just ask the same question using the new number instead of 3^^^3.

If it's so nonlinear that no finite number of specks can add up to torture, then you find the maximum amount that a finite number of specks can add up to. Then there are two amounts (one slightly more than that and one slightly less) where one amount cannot be balanced by dust particles and one amount can, which doesn't really make any sense.