Re: Relative Cardinality



Virgil wrote:


>
> Which infinity is a number according to Cantor? There are all sorts of
> infinities, and they need not all be numbers.
>
Every kind of actual infinity is a number by Cantor, ordinals and
cardinals. But potential infinity is not a numbers but a variable, dx
as well as n. Both must be distinguished if one wants to convince.
Perhaps that is the reason why modern set theory is not convincing.
Cantor, letter to Illgens, 16.5.1886: Will man in der Materie des
Unendlichen überzeugend wirken, so muß man vor allem zwischen dem
potenzialen und actualen Unendlichen so streng unterscheiden, dass
keinerlei Verwechslung dabei vorkommen kann.

Regards, WM

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