From the title and the original question in the article I expected something like a proof in a system of formal arithmetic, maybe a discussion of the Peano axioms or a discussion of different possible representations of the natural numbers using sets (like von Neumann ordinal numbers) and the really interesting question if numbers are sets.<p><a href="http://en.wikipedia.org/wiki/Peano_axioms" rel="nofollow">http://en.wikipedia.org/wiki/Peano_axioms</a>