Combining Philosophers

All the ideas for Thales, Wilfrid Hodges and Scott Shalkowski

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28 ideas

1. Philosophy / B. History of Ideas / 2. Ancient Thought
Thales was the first western thinker to believe the arché was intelligible [Roochnik on Thales]
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
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]
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 / 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]
9. Objects / D. Essence of Objects / 1. Essences of Objects
Serious essentialism says everything has essences, they're not things, and they ground necessities [Shalkowski]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
Essences are what it is to be that (kind of) thing - in fact, they are the thing's identity [Shalkowski]
9. Objects / D. Essence of Objects / 13. Nominal Essence
We distinguish objects by their attributes, not by their essences [Shalkowski]
9. Objects / D. Essence of Objects / 15. Against Essentialism
Critics say that essences are too mysterious to be known [Shalkowski]
10. Modality / A. Necessity / 4. De re / De dicto modality
De dicto necessity has linguistic entities as their source, so it is a type of de re necessity [Shalkowski]
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Nothing is stronger than necessity, which rules everything [Thales, by Diog. Laertius]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Lewis must specify that all possibilities are in his worlds, making the whole thing circular [Shalkowski, by Sider]
19. Language / C. Assigning Meanings / 7. Extensional Semantics
Equilateral and equiangular aren't the same, as we have to prove their connection [Shalkowski]
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances
Thales said water is the first principle, perhaps from observing that food is moist [Thales, by Aristotle]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
Thales must have thought soul causes movement, since he thought magnets have soul [Thales, by Aristotle]
29. Religion / A. Polytheistic Religion / 2. Greek Polytheism
Thales said the gods know our wrong thoughts as well as our evil actions [Thales, by Diog. Laertius]