Combining Philosophers

All the ideas for Lynch,MP/Glasgow,JM, Wilfrid Hodges and Antiphon

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24 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 / 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 / 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 / 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 / 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
A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W]
Model theory studies formal or natural language-interpretation using set-theory [Hodges,W]
Models in model theory are structures, not sets of descriptions [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [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 / 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 / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
A 'set' is a mathematically well-behaved class [Hodges,W]
7. Existence / C. Structure of Existence / 3. Levels of Reality
A necessary relation between fact-levels seems to be a further irreducible fact [Lynch/Glasgow]
7. Existence / C. Structure of Existence / 5. Supervenience / c. Significance of supervenience
If some facts 'logically supervene' on some others, they just redescribe them, adding nothing [Lynch/Glasgow]
7. Existence / D. Theories of Reality / 6. Physicalism
Nonreductive materialism says upper 'levels' depend on lower, but don't 'reduce' [Lynch/Glasgow]
The hallmark of physicalism is that each causal power has a base causal power under it [Lynch/Glasgow]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
We should follow the law in public, and nature in private [Antiphon]
To gain the greatest advantage only treat law as important when other people are present [Antiphon]
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / e. Character
The way you spend your time will form your character [Antiphon]
24. Political Theory / D. Ideologies / 2. Anarchism
Nothing is worse for mankind than anarchy [Antiphon]