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Ideas for 'On Motion', 'Plural Quantification' and 'A Tour through Mathematical Logic'

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16 ideas

5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
A pure logic is wholly general, purely formal, and directly known [Linnebo]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS]
First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS]
5. Theory of Logic / G. Quantification / 6. Plural Quantification
Second-order quantification and plural quantification are different [Linnebo]
Traditionally we eliminate plurals by quantifying over sets [Linnebo]
Instead of complex objects like tables, plurally quantify over mereological atoms tablewise [Linnebo]
Plural plurals are unnatural and need a first-level ontology [Linnebo]
Plural quantification may allow a monadic second-order theory with first-order ontology [Linnebo]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS]
First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS]
Model theory reveals the structures of mathematics [Wolf,RS]
Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
The LST Theorem is a serious limitation of first-order logic [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 4. Completeness
If a theory is complete, only a more powerful language can strengthen it [Wolf,RS]
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS]