Combining Philosophers

All the ideas for Gorgias, Baruch Brody and Wilfrid Hodges

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32 ideas

2. Reason / D. Definition / 7. Contextual Definition
10476 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
10282 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
10478 Since first-order languages are complete, |= and |- have the same meaning [Hodges,W]
5. Theory of Logic / B. Logical Consequence / 4. Semantic Consequence |=
10477 |= 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
10283 A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W]
10284 There are three different standard presentations of semantics [Hodges,W]
10285 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
10474 |= should be read as 'is a model for' or 'satisfies' [Hodges,W]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10473 Model theory studies formal or natural language-interpretation using set-theory [Hodges,W]
10475 A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W]
10481 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
10288 Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W]
10289 Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W]
5. Theory of Logic / K. Features of Logics / 6. Compactness
10287 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
10480 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
10286 A 'set' is a mathematically well-behaved class [Hodges,W]
7. Existence / A. Nature of Existence / 3. Being / d. Non-being
18933 Not-Being obviously doesn't exist, and the five modes of Being are all impossible [Gorgias, by Diog. Laertius]
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
12132 Indiscernibility is a necessary and sufficient condition for identity [Brody]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
15834 Brody bases sortal essentialism on properties required throughout something's existence [Brody, by Mackie,P]
9. Objects / C. Structure of Objects / 2. Hylomorphism / a. Hylomorphism
12140 Modern emphasis is on properties had essentially; traditional emphasis is on sort-defining properties [Brody]
9. Objects / D. Essence of Objects / 5. Essence as Kind
11895 A sortal essence is a property which once possessed always possessed [Brody, by Mackie,P]
12141 Maybe essential properties are those which determine a natural kind? [Brody]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
12137 De re essentialism standardly says all possible objects identical with a have a's essential properties [Brody]
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
12142 Essentially, a has P, always had P, must have had P, and has never had a future without P [Brody]
12143 An object having a property essentially is equivalent to its having it necessarily [Brody]
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
12144 Essentialism is justified if the essential properties of things explain their other properties [Brody]
9. Objects / D. Essence of Objects / 12. Essential Parts
12139 Mereological essentialism says that every part that ensures the existence is essential [Brody]
9. Objects / E. Objects over Time / 12. Origin as Essential
12135 Interrupted objects have two first moments of existence, which could be two beginnings [Brody]
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
12130 a and b share all properties; so they share being-identical-with-a; so a = b [Brody]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
12138 Identity across possible worlds is prior to rigid designation [Brody]
19. Language / F. Communication / 1. Rhetoric
5864 Destroy seriousness with laughter, and laughter with seriousness [Gorgias]
9866 Gorgias says rhetoric is the best of arts, because it enslaves without using force [Gorgias, by Plato]