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All the ideas for 'What is Logic?st1=Ian Hacking', 'Summula philosophiae naturalis' and 'Action, Reasons and Causes'

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23 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]
7. Existence / B. Change in Existence / 4. Events / b. Events as primitive
7949 Varied descriptions of an event will explain varied behaviour relating to it [Davidson, by Macdonald,C]
7. Existence / E. Categories / 5. Category Anti-Realism
16608 Ockham was an anti-realist about the categories [William of Ockham, by Pasnau]
9. Objects / C. Structure of Objects / 4. Quantity of an Object
16599 Ockham says matter must be extended, so we don't need Quantity [William of Ockham, by Pasnau]
16681 Matter gets its quantity from condensation and rarefaction, which is just local motion [William of Ockham]
20. Action / A. Definition of Action / 2. Duration of an Action
20020 If one action leads directly to another, they are all one action [Davidson, by Wilson/Schpall]
20. Action / B. Preliminaries of Action / 1. Intention to Act / a. Nature of intentions
20072 We explain an intention by giving an account of acting with an intention [Davidson, by Stout,R]
20. Action / C. Motives for Action / 2. Acting on Beliefs / a. Acting on beliefs
20045 Acting for a reason is a combination of a pro attitude, and a belief that the action is appropriate [Davidson]
20. Action / C. Motives for Action / 3. Acting on Reason / c. Reasons as causes
23734 The best explanation of reasons as purposes for actions is that they are causal [Davidson, by Smith,M]
23737 Reasons can give purposes to actions, without actually causing them [Smith,M on Davidson]
20075 Early Davidson says intentional action is caused by reasons [Davidson, by Stout,R]
6664 Reasons must be causes when agents act 'for' reasons [Davidson, by Lowe]
3395 Davidson claims that what causes an action is the reason for doing it [Davidson, by Kim]