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All the ideas for 'What is Logic?st1=Ian Hacking', 'The Limits of Reason' and 'fragments/reports'

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23 ideas

2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
18696 The vagueness of truthmaker claims makes it easier to run anti-realist arguments [Button]
3. Truth / D. Coherence Truth / 1. Coherence Truth
18701 The coherence theory says truth is coherence of thoughts, and not about objects [Button]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
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]
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [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 / 1. Logical Models
18694 Permutation Theorem: any theory with a decent model has lots of models [Button]
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]
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]
7. Existence / D. Theories of Reality / 2. Realism
18692 Realists believe in independent objects, correspondence, and fallibility of all theories [Button]
7. Existence / D. Theories of Reality / 4. Anti-realism
18693 Indeterminacy arguments say if a theory can be made true, it has multiple versions [Button]
18695 An ideal theory can't be wholly false, because its consistency implies a true model [Button]
13. Knowledge Criteria / D. Scepticism / 2. Types of Scepticism
18700 Cartesian scepticism doubts what is true; Kantian scepticism doubts that it is sayable [Button]
14. Science / A. Basis of Science / 4. Prediction
18698 Predictions give the 'content' of theories, which can then be 'equivalent' or 'adequate' [Button]
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
18697 A sentence's truth conditions are all the situations where it would be true [Button]
19. Language / F. Communication / 1. Rhetoric
9866 Gorgias says rhetoric is the best of arts, because it enslaves without using force [Gorgias, by Plato]
5864 Destroy seriousness with laughter, and laughter with seriousness [Gorgias]