Re: robinson arithmetic is not incomplete

rupert tells us that tarski gave a theory of truth

well this is what tarskis theory of truth amounts to

quote

http://en.wikipedia.org/wiki/Truth#Semantic_theory_of_truth

The semantic theory of truth has as its general case for a given
language:

'P' is true if and only if P

where 'P' is a reference to the sentence (the sentence's name), and P is
just the sentence itself.

Logician and philosopher Alfred Tarski developed the theory for formal
languages (such as formal logic). Here he restricted it in this way: no
language could contain its own truth predicate, that is, the expression is
true could only apply to sentences in some other language. The latter he
called an object language, the language being talked about. (It may, in
turn, have a truth predicate that can be applied to sentences in still
another language.) The reason for his restriction was that languages that
contain their own truth predicate will contain paradoxical sentences like
the Liar:


note

Bertrand Russell is credited with noticing the existence of such paradoxes
even in the best symbolic formalizations of mathematics in his day,

so please rupert
show us how tarski
tells us why
1+1=2 is true

it would seem from

'P' is true if and only if P

"1+1=2 is true" only if 1+1=2 is true

but then according to tarski

Here he restricted it in this way: no language could contain its own truth
predicate, that is, the expression is true could only apply to sentences in
some other language. The latter he called an object language, the language
being talked about


so mathematics cant contain its own truth predicate

so we have two languages to determine truth
the object ie mathematics and the other language
so what is this other language which deterimins the truth


and as i have asked you time and time again
tell us via tarski
why 1+1=2 is true


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