On Wednesday, 30 October 2013 15:46:47 UTC+1, Robin wrote:
> He cannot distinguish for all x: there exists y: P(x,y) > from > there exists y: for all x: P(x,y)
The distinction is easy: The first sentence shows that every x is related to an y, the second sentence shows that not all x are related to the same y.
Conclusion: There are more than one y necessary such that all x are related to some y.
The same holds for naturals and FISONs: If not every natural is in one and the same FISON, then at least two FISONs are required to contain every natural - two or more or infinitely many. But everybody who claims that this is true should be able to name the first FISON of the required set of FISONs.
Since this is impossible because every FISON can be shown to be not required, the idea of the existence of more natural numbers than fit into one FISON is absurd.