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All the ideas for 'What is Logic?st1=Ian Hacking', 'Absolute Necessities' and 'The Passions of the Soul'

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26 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
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]
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]
10. Modality / A. Necessity / 2. Nature of Necessity
15086 Absolute necessity might be achievable either logically or metaphysically [Hale]
10. Modality / A. Necessity / 3. Types of Necessity
8261 Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale]
15081 A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale]
15080 'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale]
10. Modality / A. Necessity / 5. Metaphysical Necessity
15082 Metaphysical necessity says there is no possibility of falsehood [Hale]
10. Modality / A. Necessity / 6. Logical Necessity
15085 'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale]
15088 Logical necessities are true in virtue of the nature of all logical concepts [Hale]
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
15087 Conceptual necessities are made true by all concepts [Hale]
17. Mind and Body / A. Mind-Body Dualism / 2. Interactionism
3654 The pineal gland links soul to body, and unites the two symmetrical sides of the body [Descartes, by PG]
18. Thought / A. Modes of Thought / 3. Emotions / c. Role of emotions
4015 For Descartes passions are God-given preservers of the mind-body union [Descartes, by Taylor,C]
18. Thought / A. Modes of Thought / 3. Emotions / e. Basic emotions
4313 Are there a few primary passions (say, joy, sadness and desire)? [Descartes, by Cottingham]
23989 There are six primitive passions: wonder, love, hatred, desire, joy and sadness [Descartes, by Goldie]
20. Action / B. Preliminaries of Action / 2. Willed Action / b. Volitionism
20037 Merely willing to walk leads to our walking [Descartes]
22. Metaethics / B. Value / 2. Values / e. Death
16763 We don't die because the soul departs; the soul departs because the organs cease functioning [Descartes]
23. Ethics / C. Virtue Theory / 3. Virtues / a. Virtues
4016 Descartes makes strength of will the central virtue [Descartes, by Taylor,C]