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All the ideas for 'What is Logic?st1=Ian Hacking', 'Positivism and Realism' and 'Propositions'

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22 ideas

1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
13737 The empiricist says that metaphysics is meaningless, rather than false [Schlick]
2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
3. Truth / A. Truth Problems / 5. Truth Bearers
13941 Are the truth-bearers sentences, utterances, ideas, beliefs, judgements, propositions or statements? [Cartwright,R]
13942 Logicians take sentences to be truth-bearers for rigour, rather than for philosophical reasons [Cartwright,R]
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]
9. Objects / F. Identity among Objects / 4. Type Identity
13945 A token isn't a unique occurrence, as the case of a word or a number shows [Cartwright,R]
19. Language / A. Nature of Meaning / 1. Meaning
13948 For any statement, there is no one meaning which any sentence asserting it must have [Cartwright,R]
13950 People don't assert the meaning of the words they utter [Cartwright,R]
19. Language / D. Propositions / 1. Propositions
13944 We can pull apart assertion from utterance, and the action, the event and the subject-matter for each [Cartwright,R]
13947 'It's raining' makes a different assertion on different occasions, but its meaning remains the same [Cartwright,R]
19. Language / D. Propositions / 4. Mental Propositions
13943 We can attribute 'true' and 'false' to whatever it was that was said [Cartwright,R]
13946 To assert that p, it is neither necessary nor sufficient to utter some particular words [Cartwright,R]
19. Language / F. Communication / 2. Assertion
13951 Assertions, unlike sentence meanings, can be accurate, probable, exaggerated, false.... [Cartwright,R]