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All the ideas for 'What is Logic?st1=Ian Hacking', 'The Human Body is a sort of Machine' and 'The Nature of Judgement'

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16 ideas

1. Philosophy / C. History of Philosophy / 5. Modern Philosophy / b. Modern philosophy beginnings
Moore's 'The Nature of Judgement' (1898) marked the rejection (with Russell) of idealism [Moore,GE, by Grayling]
1. Philosophy / F. Analytic Philosophy / 1. Nature of Analysis
Analysis for Moore and Russell is carving up the world, not investigating language [Moore,GE, by Monk]
2. Reason / D. Definition / 3. Types of Definition
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
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking]
'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
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
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
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
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
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
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
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
19. Language / D. Propositions / 3. Concrete Propositions
Moor bypassed problems of correspondence by saying true propositions ARE facts [Moore,GE, by Potter]
19. Language / D. Propositions / 5. Unity of Propositions
Hegelians say propositions defy analysis, but Moore says they can be broken down [Moore,GE, by Monk]
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / b. Limited purposes
A machine is best defined by its final cause, which explains the roles of the parts [Leibniz]