Combining Texts

All the ideas for 'Law and Causality', 'Model Theory' and 'Letters to Voetius'

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14 ideas

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]
10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
Ramsey's Test: believe the consequent if you believe the antecedent [Ramsey, by Read]
10. Modality / B. Possibility / 8. Conditionals / e. Supposition conditionals
Asking 'If p, will q?' when p is uncertain, then first add p hypothetically to your knowledge [Ramsey]
14. Science / B. Scientific Theories / 8. Ramsey Sentences
Mental terms can be replaced in a sentence by a variable and an existential quantifier [Ramsey]
26. Natural Theory / D. Laws of Nature / 4. Regularities / b. Best system theory
All knowledge needs systematizing, and the axioms would be the laws of nature [Ramsey]
Causal laws result from the simplest axioms of a complete deductive system [Ramsey]
28. God / C. Attitudes to God / 5. Atheism
Atheism is an atrocious and intolerable crime in any country [Descartes]