Combining Texts

All the ideas for 'fragments/reports', 'Empiricism, Semantics and Ontology' and 'Model Theory'

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20 ideas

1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
No possible evidence could decide the reality of numbers, so it is a pseudo-question [Carnap]
2. Reason / D. Definition / 7. Contextual Definition
The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
Since first-order languages are complete, |= and |- have the same meaning [Hodges,W]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
|= in model-theory means 'logical consequence' - it holds in all models [Hodges,W]
5. Theory of Logic / I. Semantics of Logic / 4. Satisfaction
|= should be read as 'is a model for' or 'satisfies' [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory studies formal or natural language-interpretation using set-theory [Hodges,W]
A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W]
Models in model theory are structures, not sets of descriptions [Hodges,W]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / i. Cardinal infinity
First-order logic can't discriminate between one infinite cardinal and another [Hodges,W]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Questions about numbers are answered by analysis, and are analytic, and hence logically true [Carnap]
Logical positivists incorporated geometry into logicism, saying axioms are just definitions [Carnap, by Shapiro]
7. Existence / A. Nature of Existence / 4. Abstract Existence
Internal questions about abstractions are trivial, and external ones deeply problematic [Carnap, by Szabó]
7. Existence / D. Theories of Reality / 1. Ontologies
Existence questions are 'internal' (within a framework) or 'external' (concerning the whole framework) [Carnap]
7. Existence / D. Theories of Reality / 3. Reality
To be 'real' is to be an element of a system, so we cannot ask reality questions about the system itself [Carnap]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
A linguistic framework involves commitment to entities, so only commitment to the framework is in question [Carnap]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
We only accept 'things' within a language with formation, testing and acceptance rules [Carnap]
12. Knowledge Sources / D. Empiricism / 1. Empiricism
Empiricists tend to reject abstract entities, and to feel sympathy with nominalism [Carnap]
12. Knowledge Sources / D. Empiricism / 3. Pragmatism
New linguistic claims about entities are not true or false, but just expedient, fruitful or successful [Carnap]
14. Science / B. Scientific Theories / 3. Instrumentalism
All linguistic forms in science are merely judged by their efficiency as instruments [Carnap]
21. Aesthetics / C. Artistic Issues / 7. Art and Morality
Musical performance can reveal a range of virtues [Damon of Ath.]