[FOM] Indispensability of the natural numbers

[Steven Ericsson-Zenith]

Vladimir Sazonov said:
>  Mathematicians do not need to have
> a metatheory. They just deduce their theorems (with the help
> of some intuition, of course).

...
and then said:

> Whatever are our beliefs, the mental concept of the natural numbers
> is something vague, anyway. It is only illusion of something solid.

I would like to understand how you sustain this position since the 
first appears - at least to me - to contradict the second position.

A metatheory would seem essential if you are to resolve the 
inadequacies of "illusion" - for example, what *exactly* do you mean 
by "illusion"?

Sincerely,
Steven
--
Dr. Steven Ericsson Zenith