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All the ideas for 'What is Logic?st1=Ian Hacking', 'Meaning and Necessity' and 'Vagueness: a global approach'

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22 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
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 / 6. Classical Logic
23548 Indeterminacy is in conflict with classical logic [Fine,K]
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 / I. Semantics of Logic / 1. Semantics of Logic
23539 Classical semantics has referents for names, extensions for predicates, and T or F for sentences [Fine,K]
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 / D. Theories of Reality / 10. Vagueness / a. Problem of vagueness
23544 Local indeterminacy concerns a single object, and global indeterminacy covers a range [Fine,K]
23540 Conjoining two indefinites by related sentences seems to produce a contradiction [Fine,K]
23546 Standardly vagueness involves borderline cases, and a higher standpoint from which they can be seen [Fine,K]
7. Existence / D. Theories of Reality / 10. Vagueness / c. Vagueness as ignorance
23542 Identifying vagueness with ignorance is the common mistake of confusing symptoms with cause [Fine,K]
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
23541 Supervaluation can give no answer to 'who is the last bald man' [Fine,K]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
23545 We do not have an intelligible concept of a borderline case [Fine,K]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / b. Self as mental continuity
23547 It seems absurd that there is no identity of any kind between two objects which involve survival [Fine,K]
19. Language / C. Assigning Meanings / 8. Possible Worlds Semantics
11968 The intension of a sentence is the set of all possible worlds in which it is true [Carnap, by Kaplan]
26. Natural Theory / D. Laws of Nature / 4. Regularities / a. Regularity theory
23543 We identify laws with regularities because we mistakenly identify causes with their symptoms [Fine,K]