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All the ideas for 'What is Logic?st1=Ian Hacking', 'Realism and Anti-Realism' and 'Non-Monotonic Logic'

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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]
2. Reason / E. Argument / 1. Argument
19115 You can 'rebut' an argument's conclusion, or 'undercut' its premises [Antonelli]
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 / E. Nonclassical Logics / 1. Nonclassical Logics
19119 We infer that other objects are like some exceptional object, if they share some of its properties [Antonelli]
4. Formal Logic / E. Nonclassical Logics / 12. Non-Monotonic Logic
19111 Reasoning may be defeated by new premises, or by finding out more about the given ones [Antonelli]
19114 Should we accept Floating Conclusions, derived from two arguments in conflict? [Antonelli]
19113 Weakest Link Principle: prefer the argument whose weakest link is the stronger [Antonelli]
19116 Non-monotonic core: Reflexivity, Cut, Cautious Monotonicity, Left Logical Equivalence, Right Weakening [Antonelli]
19117 We can rank a formula by the level of surprise if it were to hold [Antonelli]
19118 People don't actually use classical logic, but may actually use non-monotonic logic [Antonelli]
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]
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
19110 In classical logic the relation |= has Monotony built into its definition [Antonelli]
19112 Cautious Monotony ignores proved additions; Rational Monotony fails if the addition's negation is proved [Antonelli]
7. Existence / D. Theories of Reality / 2. Realism
15049 Metaphysical realists are committed to all unambiguous statements being true or not true [Dummett]