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All the ideas for 'What is Logic?st1=Ian Hacking', 'Languages of Art (2nd edn)' and 'Truly Understood'

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21 ideas

2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
13834 Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
13835 Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
13845 The various logics are abstractions made from terms like 'if...then' in English [Hacking]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
13840 First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
13844 A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
13842 Second-order completeness seems to need intensional entities and possible worlds [Hacking]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
13837 With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
13839 Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
13843 If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
18. Thought / A. Modes of Thought / 6. Judgement / a. Nature of Judgement
12608 Concepts are distinguished by roles in judgement, and are thus tied to rationality [Peacocke]
18. Thought / D. Concepts / 3. Ontology of Concepts / c. Fregean concepts
12605 A sense is individuated by the conditions for reference [Peacocke]
12607 Fregean concepts have their essence fixed by reference-conditions [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / a. Conceptual structure
12609 Concepts have distinctive reasons and norms [Peacocke]
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
12604 Any explanation of a concept must involve reference and truth [Peacocke]
19. Language / C. Assigning Meanings / 4. Compositionality
12610 Encountering novel sentences shows conclusively that meaning must be compositional [Peacocke]
21. Aesthetics / B. Nature of Art / 1. Defining Art
20440 Art is a referential activity, hence indefinable, but it has a set of symptoms [Goodman]
21. Aesthetics / B. Nature of Art / 5. Art as Language
20439 Artistic symbols are judged by the fruitfulness of their classifications [Goodman, by Giovannelli]
21. Aesthetics / B. Nature of Art / 7. Ontology of Art
20438 A performance is only an instance of a work if there is not a single error [Goodman]
21. Aesthetics / C. Artistic Issues / 2. Copies of Art
20437 A copy only becomes an 'instance' of an artwork if there is a system of notation [Goodman]