Combining Philosophers

All the ideas for Anaxarchus, Christopher Peacocke and Wilfrid Hodges

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38 ideas

2. Reason / D. Definition / 7. Contextual Definition
The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W]
2. Reason / D. Definition / 13. Against Definition
Most people can't even define a chair [Peacocke]
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]
12. Knowledge Sources / B. Perception / 1. Perception
Perceptual concepts causally influence the content of our experiences [Peacocke]
12. Knowledge Sources / B. Perception / 6. Inference in Perception
Perception has proto-propositions, between immediate experience and concepts [Peacocke]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
Consciousness of a belief isn't a belief that one has it [Peacocke]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
Concepts are distinguished by roles in judgement, and are thus tied to rationality [Peacocke]
18. Thought / D. Concepts / 1. Concepts / b. Concepts in philosophy
Philosophy should merely give necessary and sufficient conditions for concept possession [Peacocke, by Machery]
Peacocke's account of possession of a concept depends on one view of counterfactuals [Peacocke, by Machery]
Peacocke's account separates psychology from philosophy, and is very sketchy [Machery on Peacocke]
18. Thought / D. Concepts / 2. Origin of Concepts / a. Origin of concepts
The concept 'red' is tied to what actually individuates red things [Peacocke]
18. Thought / D. Concepts / 3. Ontology of Concepts / a. Concepts as representations
If concepts just are mental representations, what of concepts we may never acquire? [Peacocke]
18. Thought / D. Concepts / 3. Ontology of Concepts / b. Concepts as abilities
Possessing a concept is being able to make judgements which use it [Peacocke]
A concept is just what it is to possess that concept [Peacocke]
Employing a concept isn't decided by introspection, but by making judgements using it [Peacocke]
18. Thought / D. Concepts / 3. Ontology of Concepts / c. Fregean concepts
A sense is individuated by the conditions for reference [Peacocke]
Fregean concepts have their essence fixed by reference-conditions [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / a. Conceptual structure
Concepts have distinctive reasons and norms [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
An analysis of concepts must link them to something unconceptualized [Peacocke]
Any explanation of a concept must involve reference and truth [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / f. Theory theory of concepts
Concepts are constituted by their role in a group of propositions to which we are committed [Peacocke, by Greco]
19. Language / B. Reference / 1. Reference theories
A concept's reference is what makes true the beliefs of its possession conditions [Peacocke, by Horwich]
19. Language / C. Assigning Meanings / 4. Compositionality
Encountering novel sentences shows conclusively that meaning must be compositional [Peacocke]