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All the ideas for 'What is Logic?st1=Ian Hacking', 'Meaning and Necessity' and 'Causal and Metaphysical Necessity'

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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 / 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 / 3. Logical Truth
15091 Restrict 'logical truth' to formal logic, rather than including analytic and metaphysical truths [Shoemaker]
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]
8. Modes of Existence / B. Properties / 1. Nature of Properties
15095 A property's causal features are essential, and only they fix its identity [Shoemaker]
15097 I claim that a property has its causal features in all possible worlds [Shoemaker]
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
15094 I now deny that properties are cluster of powers, and take causal properties as basic [Shoemaker]
10. Modality / A. Necessity / 5. Metaphysical Necessity
15099 If something is possible, but not nomologically possible, we need metaphysical possibility [Shoemaker]
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
15101 Once you give up necessity as a priori, causal necessity becomes the main type of necessity [Shoemaker]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
15098 Empirical evidence shows that imagining a phenomenon can show it is possible [Shoemaker]
15100 Imagination reveals conceptual possibility, where descriptions avoid contradiction or incoherence [Shoemaker]
14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem
15096 'Grue' only has causal features because of its relation to green [Shoemaker]
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 / 5. Laws from Universals
15093 We might say laws are necessary by combining causal properties with Armstrong-Dretske-Tooley laws [Shoemaker]