Combining Philosophers

All the ideas for Pindar, Gerhard Gentzen and Anil Gupta

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23 ideas

2. Reason / D. Definition / 1. Definitions
11223 Definitions usually have a term, a 'definiendum' containing the term, and a defining 'definiens' [Gupta]
11215 Notable definitions have been of piety (Plato), God (Anselm), number (Frege), and truth (Tarski) [Gupta]
2. Reason / D. Definition / 2. Aims of Definition
11225 A definition needs to apply to the same object across possible worlds [Gupta]
11227 The 'revision theory' says that definitions are rules for improving output [Gupta]
2. Reason / D. Definition / 3. Types of Definition
11224 Traditional definitions are general identities, which are sentential and reductive [Gupta]
11226 Traditional definitions need: same category, mention of the term, and conservativeness and eliminability [Gupta]
11221 A definition can be 'extensionally', 'intensionally' or 'sense' adequate [Gupta]
2. Reason / D. Definition / 4. Real Definition
11217 Chemists aim at real definition of things; lexicographers aim at nominal definition of usage [Gupta]
2. Reason / D. Definition / 6. Definition by Essence
11216 If definitions aim at different ideals, then defining essence is not a unitary activity [Gupta]
2. Reason / D. Definition / 10. Stipulative Definition
11218 Stipulative definition assigns meaning to a term, ignoring prior meanings [Gupta]
2. Reason / D. Definition / 11. Ostensive Definition
11220 Ostensive definitions look simple, but are complex and barely explicable [Gupta]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
14965 Truth rests on Elimination ('A' is true → A) and Introduction (A → 'A' is true) [Gupta]
3. Truth / F. Semantic Truth / 2. Semantic Truth
14968 A weakened classical language can contain its own truth predicate [Gupta]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
11222 The ordered pair <x,y> is defined as the set {{x},{x,y}}, capturing function, not meaning [Gupta]
5. Theory of Logic / A. Overview of Logic / 2. History of Logic
11022 Gentzen introduced a natural deduction calculus (NK) in 1934 [Gentzen, by Read]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
11065 The inferential role of a logical constant constitutes its meaning [Gentzen, by Hanna]
11023 The logical connectives are 'defined' by their introduction rules [Gentzen]
11213 Each logical symbol has an 'introduction' rule to define it, and hence an 'elimination' rule [Gentzen]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
13832 Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
14964 The Liar reappears, even if one insists on propositions instead of sentences [Gupta]
14969 Strengthened Liar: either this sentence is neither-true-nor-false, or it is not true [Gupta]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
10067 Gentzen proved the consistency of arithmetic from assumptions beyond arithmetic [Gentzen, by Musgrave]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
6017 Nomos is king [Pindar]