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Re: Question about Quine's New Foundations

Subject: Re: Question about Quine's New Foundations
From: Aatu Koskensilta
Date: Fri, 27 Oct 2006 01:58:18 +0300
Newsgroups: sci.logic
lugita15@xxxxxxxxx wrote:
That is, can you add a typical ambiguity scheme to ZFC which states that every wff phi is equivalent to the corresponding formula phi+ which results from increasing the ranks of all the variables in phi by 1?

No. Setting aside the fact that it's not clear what is meant by the "rank of a variable" in general, the formula "all sets of rank 0 are empty" is certainly not equivalent to "all sets of rank 1 are empty".

--
Aatu Koskensilta (aatu.koskensilta@xxxxxxxxx)

"Wovon man nicht sprechen kann, daruber muss man schweigen"
 - Ludwig Wittgenstein, Tractatus Logico-Philosophicus

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