Combining Texts

All the ideas for 'Semantic Necessity', 'First-Order Logic' and 'Abstraction Reconsidered'

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19 ideas

5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
Theories in logic are sentences closed under consequence, but in truth discussions theories have axioms [Fine,K]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
There are three different standard presentations of semantics [Hodges,W]
I |= φ means that the formula φ is true in the interpretation I [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
5. Theory of Logic / K. Features of Logics / 6. Compactness
If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
A 'set' is a mathematically well-behaved class [Hodges,W]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
Abstraction from objects won't reveal an operation's being performed 'so many times' [Geach]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
The role of semantic necessity in semantics is like metaphysical necessity in metaphysics [Fine,K, by Hale/Hoffmann,A]
15. Nature of Minds / C. Capacities of Minds / 5. Generalisation by mind
If concepts are just recognitional, then general judgements would be impossible [Geach]
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
For abstractionists, concepts are capacities to recognise recurrent features of the world [Geach]
18. Thought / E. Abstraction / 8. Abstractionism Critique
The abstractionist cannot explain 'some' and 'not' [Geach]
Only a judgement can distinguish 'striking' from 'being struck' [Geach]
19. Language / C. Assigning Meanings / 2. Semantics
Semantics is either an assignment of semantic values, or a theory of truth [Fine,K]
Semantics is a body of semantic requirements, not semantic truths or assigned values [Fine,K]
19. Language / C. Assigning Meanings / 7. Extensional Semantics
Referential semantics (unlike Fregeanism) allows objects themselves in to semantic requirements [Fine,K]
19. Language / E. Analyticity / 4. Analytic/Synthetic Critique
The Quinean doubt: are semantics and facts separate, and do analytic sentences have no factual part? [Fine,K]