Skip to content
Carmelics
TopicsThinkersChangesContributorsLoading account…

    Carmelics

    A reasoning platform. Break down any belief into clear reasons, explore both sides, and weigh the evidence honestly.

    Navigate

    • Topics
    • Search
    • Recent Changes
    • Contribute
    • How It Works
    • Glossary
    • Thinkers
    • Contributors
    • About
    • Statistics
    • Terms
    • Privacy

    Database

    Statements
    —
    Perspectives
    —
    Topics
    —

    Press ? for keyboard shortcuts

    LoyalLoyalJusticeJustice
    Made withinDC&Austin
    Statements
    321,452
    Perspectives
    108,905
    Topics
    42
    Kreisel's categoricity argument holds that second-order P... — Carmelics
    Home
    HistoryEditSee Inverse

    Part of a larger discussion

    Challenges→Any sufficiently strong formal theory F satisfying the conditions of the first incompleteness theorem must possess non-standard models in addition to its intended standard model.

    Kreisel's categoricity argument holds that second-order Peano Arithmetic is categorical, uniquely determining the standard model up to isomorphism despite incompleteness results applying to its first-order fragments.

    ?Rate how convincing each reason is below to see the overall strength.

    No one has weighed in yet. Be the first to share reasons for or against this statement.

    Sign in or register to share your perspective on this statement.

    Key Terms

    First-order fragments(the weaker systems to which incompleteness applies)
    Simpler versions of a formal system that can only talk about individual objects, not about sets or properties of those objects.
    Incompleteness results(as used in mathematical logic)
    Mathematical theorems proving that in any logical system complex enough to describe math, there will always be true statements that the system cannot prove to be true.
    Kreisel(as a historical figure in logic and philosophy of mathematics)
    Georg Kreisel (1923–2015), a mathematical logician who studied how mathematical reasoning works and whether we can be certain about mathematical truths.
    Second-order Peano Arithmetic(the mathematical system being discussed)
    A formal system for describing the natural numbers (0, 1, 2, 3...) that is more powerful than the basic first-order version because it can quantify over sets and properties, not just individual numbers.

    Next step

    Based on where you are in your exploration

    Explore a random proposition
    Start fresh with something unrelated.
    categoricity(Joyce's term for the inescapable practical force of moral demands)
    The property of moral requirements whereby they apply to agents unconditionally, regardless of the agent's contingent desires, goals, or interests
    isomorphism(The strongest structural correspondence between two many-sorted structures.)
    An embedding between structures in which all defining maps are bijections.
    standard model(Contrasted with non-standard models that also satisfy the theory's axioms)
    The intended interpretation of an arithmetical theory, namely the structure of the natural numbers.

    Connections

    2 topics

    Truth & Knowledge1 linkedModality & Possibility1 linked

    Related

    Any sufficiently strong formal theory F satisfying the conditions of the first i...

    Details

    Type
    claim
    Perspectives
    0 (0 for, 0 against)
    Edits
    1 edit

    Open for perspectives

    This idea is waiting for its first supporting or challenging perspective.

    Share the first perspective