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Ideas for 'On the Question of Absolute Undecidability', 'Moral Relativism' and 'Theories of Truth: a Critical Introduction'

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3 ideas

5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
In quantified language the components of complex sentences may not be sentences [Kirkham]
     Full Idea: In a quantified language it is possible to build new sentences by combining two expressions neither of which is itself a sentence.
     From: Richard L. Kirkham (Theories of Truth: a Critical Introduction [1992], 5.4)
     A reaction: In propositional logic the components are other sentences, so the truth value can be given by their separate truth-values, through truth tables. Kirkham is explaining the task which Tarski faced. Truth-values are not just compositional.
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
An open sentence is satisfied if the object possess that property [Kirkham]
     Full Idea: An object satisfies an open sentence if and only if it possesses the property expressed by the predicate of the open sentence.
     From: Richard L. Kirkham (Theories of Truth: a Critical Introduction [1992], 5.4)
     A reaction: This applies to atomic sentence, of the form Fx or Fa (that is, some variable is F, or some object is F). So strictly, only the world can decide whether some open sentence is satisfied. And it all depends on things called 'properties'.
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
We have no argument to show a statement is absolutely undecidable [Koellner]
     Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable.
     From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3)