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All the ideas for 'What is Logic?st1=Ian Hacking', 'Philosophy of Language' and 'fragments/reports'

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27 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]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
15163 The interest of quantified modal logic is its metaphysical necessity and essentialism [Soames]
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 / F. Referring in Logic / 2. Descriptions / a. Descriptions
15158 Indefinite descriptions are quantificational in subject position, but not in predicate position [Soames]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
15157 Recognising the definite description 'the man' as a quantifier phrase, not a singular term, is a real insight [Soames]
5. Theory of Logic / G. Quantification / 7. Unorthodox Quantification
15156 The universal and existential quantifiers were chosen to suit mathematics [Soames]
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]
5. Theory of Logic / L. Paradox / 4. Paradoxes in Logic / a. Achilles paradox
1507 We don't have time for infinite quantity, but we do for infinite divisibility, because time is also divisible [Aristotle on Zeno of Elea]
5109 The fast runner must always reach the point from which the slower runner started [Zeno of Elea, by Aristotle]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / b. The Heap paradox ('Sorites')
1512 Zeno is wrong that one grain of millet makes a sound; why should one grain achieve what the whole bushel does? [Aristotle on Zeno of Elea]
5. Theory of Logic / L. Paradox / 7. Paradoxes of Time
1508 Zeno's arrow paradox depends on the assumption that time is composed of nows [Aristotle on Zeno of Elea]
10. Modality / A. Necessity / 5. Metaphysical Necessity
15161 There are more metaphysically than logically necessary truths [Soames]
15162 We understand metaphysical necessity intuitively, from ordinary life [Soames]
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
15152 To study meaning, study truth conditions, on the basis of syntax, and representation by the parts [Soames]
15153 Tarski's account of truth-conditions is too weak to determine meanings [Soames]
19. Language / D. Propositions / 4. Mental Propositions
15154 We should use cognitive states to explain representational propositions, not vice versa [Soames]
26. Natural Theory / A. Speculations on Nature / 1. Nature
454 If there are many things they must have a finite number, but there must be endless things between them [Zeno of Elea]
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
455 That which moves, moves neither in the place in which it is, nor in that in which it is not [Zeno of Elea]
27. Natural Reality / C. Space / 5. Relational Space
1511 If everything is in a place, what is the place in? Place doesn't exist [Zeno of Elea, by Simplicius]