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    Feferman (1960) demonstrated that the choice of provabili... — Carmelics
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    Challenges→Rosser's provability predicate cannot be used to formalize the consistency claim in the second incompleteness theorem.

    Feferman (1960) demonstrated that the choice of provability predicate is conventional, since differently defined but extensionally equivalent predicates yield divergent unprovability results.

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    1 reason for
    1 reason against

    Reasons For

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    Reason for
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    • 1.Extensionally equivalent predicates can differ in syntactic structure, enabling different Gödel sentences with divergent provability statuses.
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    • 2.Provability is not a direct physical property but a formal relation, so its definition depends on representational choices within formal systems.
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    • 3.If two predicates prove identical sentences yet yield different unprovability results, then unprovability cannot be a purely objective mathematical fact.
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    Reasons Against

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    Reason against
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    • 1.Divergent unprovability results from different predicates indicate they are not truly extensionally equivalent, suggesting Feferman's premise is flawed.
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    • 2.Unprovability relative to a *specific system* is objective once the system is fixed; conventionality of representation doesn't undermine this objectivity.
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    • 3.Mathematical facts about what is unprovable in PA remain invariant regardless of how we notate provability—convention affects expression, not truth.
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    Key Terms

    Divergent(describing how these three confirmation measures give conflicting results)
    Moving in different directions; disagreeing or coming to different conclusions.
    Feferman(as a historical figure in logic and philosophy of mathematics)
    Solomon Feferman (1928–2016), a logician and philosopher who studied the foundations of mathematics and how different formal systems relate to each other.
    Provability predicate(mathematical logic)
    A mathematical tool that checks whether a statement can be proven true within a formal system, like a built-in function that answers 'yes' or 'no' to 'can this be proven?'
    Unprovability results(as the divergent outcomes produced by different provability predicates)
    The conclusions you reach when you demonstrate that certain statements cannot be proven true within a logical system—basically, proof of what can't be proven.
    conventional(social ontology)
    In ordinary usage, 'conventional' may mean merely that a phenomenon is social, or that something about it is arbitrary or a matter of choice. In social ontology, however, 'conventional' is understood more precisely, following variants of David Lewis's 1969 analysis or analyses that challenge Lewis's approach.
    extensionally equivalent(Applied to Church's thesis and Turing's thesis regarding functions of positive integers)
    Two theses are extensionally equivalent when they are about one and the same class of functions

    Connections

    2 topics

    Truth & Knowledge1 linkedPhilosophy of Language1 linked

    Related

    Divergent unprovability results from different predicates indicate they are not ...Extensionally equivalent predicates can differ in syntactic structure, enabling ...

    Details

    Type
    claim
    Perspectives
    2 (1 for, 1 against)
    Edits
    1 edit
    If two predicates prove identical sentences yet yield different unprovability re...
    Mathematical facts about what is unprovable in PA remain invariant regardless of...
    +3 moreShow less
    Provability is not a direct physical property but a formal relation, so its defi...Rosser's provability predicate cannot be used to formalize the consistency claim...Unprovability relative to a *specific system* is objective once the system is fi...