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Ideas for 'Axiomatic Theories of Truth (2005 ver)', 'What is it like to be a bat?' and 'Vagueness: a global approach'

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4 ideas

5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
Indeterminacy is in conflict with classical logic [Fine,K]
     Full Idea: I now believe that the existence of indeterminacy is in conflict with classical logic.
     From: Kit Fine (Vagueness: a global approach [2020], 3)
     A reaction: I think that prior to this Fine had defended classical logic. Presumably the difficulty is over Bivalence. Nietzsche spotted this problem, despite not being a logician. Logic has to simplify the world. Hence philosophy is quite different from logic.
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
We can use truth instead of ontologically loaded second-order comprehension assumptions about properties [Halbach]
     Full Idea: The reduction of 2nd-order theories (of properties or sets) to axiomatic theories of truth may be conceived as a form of reductive nominalism, replacing existence assumptions (for comprehension axioms) by ontologically innocent truth assumptions.
     From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.1)
     A reaction: I like this very much, as weeding properties out of logic (without weeding them out of the world). So-called properties in logic are too abundant, so there is a misfit with their role in science.
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
Instead of saying x has a property, we can say a formula is true of x - as long as we have 'true' [Halbach]
     Full Idea: Quantification over (certain) properties can be mimicked in a language with a truth predicate by quantifying over formulas. Instead of saying that Tom has the property of being a poor philosopher, we can say 'x is a poor philosopher' is true of Tom.
     From: Volker Halbach (Axiomatic Theories of Truth (2005 ver) [2005], 1.1)
     A reaction: I love this, and think it is very important. He talks of 'mimicking' properties, but I see it as philosophers mistakenly attributing properties, when actually what they were doing is asserting truths involving certain predicates.
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
Classical semantics has referents for names, extensions for predicates, and T or F for sentences [Fine,K]
     Full Idea: A precise language is often assigned a classical semantics, in which the semantic value of a name is its referent, the semantic value of a predicate is its extension (the objects of which it is true), and the value of a sentence is True or False.
     From: Kit Fine (Vagueness: a global approach [2020], 1)
     A reaction: Helpful to have this clear statement of how predicates are treated. This extensionalism in logic causes trouble when it creeps into philosophy, and people say that 'red' just means all the red things. No it doesn't.