Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'How to Read Foucault' and 'Intensions Revisited'

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18 ideas

1. Philosophy / H. Continental Philosophy / 6. Deconstruction
Post-structuralism focused on exterior determinants of thought, rather than the thinker [Oksala]
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]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
Quantified modal logic collapses if essence is withdrawn [Quine]
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]
9. Objects / D. Essence of Objects / 15. Against Essentialism
Essences can make sense in a particular context or enquiry, as the most basic predicates [Quine]
10. Modality / A. Necessity / 11. Denial of Necessity
Necessity is relative to context; it is what is assumed in an inquiry [Quine]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds are a way to dramatise essentialism, and yet they presuppose essentialism [Quine]
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
A rigid designator (for all possible worlds) picks out an object by its essential traits [Quine]
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
Beliefs can be ascribed to machines [Quine]