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All the ideas for 'What is Logic?st1=Ian Hacking', 'Thinking and Experience' and 'talk'

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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 / 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 / C. Powers and Dispositions / 2. Powers as Basic
14329 Some dispositional properties (such as mental ones) may have no categorical base [Price,HH]
15. Nature of Minds / B. Features of Minds / 3. Privacy
5210 We could know what a lion thinks by mapping both its brain patterns and its experiences [Douglas,A]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
9032 Before we can abstract from an instance of violet, we must first recognise it [Price,HH]
9034 There may be degrees of abstraction which allow recognition by signs, without full concepts [Price,HH]
9035 If judgement of a characteristic is possible, that part of abstraction must be complete [Price,HH]
9036 There is pre-verbal sign-based abstraction, as when ice actually looks cold [Price,HH]
9037 Intelligent behaviour, even in animals, has something abstract about it [Price,HH]
18. Thought / A. Modes of Thought / 1. Thought
9033 Recognition must precede the acquisition of basic concepts, so it is the fundamental intellectual process [Price,HH]
18. Thought / E. Abstraction / 1. Abstract Thought
9030 Abstractions can be interpreted dispositionally, as the ability to recognise or imagine an item [Price,HH]
9029 If ideas have to be images, then abstract ideas become a paradoxical problem [Price,HH]
18. Thought / E. Abstraction / 2. Abstracta by Selection
9031 The basic concepts of conceptual cognition are acquired by direct abstraction from instances [Price,HH]