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All the ideas for 'What is Logic?st1=Ian Hacking', 'Two Problems for Essentialism' and 'Philosophy of Science'

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21 ideas

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]
14. Science / A. Basis of Science / 6. Falsification
Why abandon a theory if you don't have a better one? [Gorham]
If a theory is more informative it is less probable [Gorham]
14. Science / B. Scientific Theories / 1. Scientific Theory
Is Newton simpler with universal simultaneity, or Einstein simpler without absolute time? [Gorham]
Structural Realism says mathematical structures persist after theory rejection [Gorham]
Structural Realists must show the mathematics is both crucial and separate [Gorham]
14. Science / B. Scientific Theories / 3. Instrumentalism
For most scientists their concepts are not just useful, but are meant to be true and accurate [Gorham]
Theories aren't just for organising present experience if they concern the past or future [Gorham]
14. Science / D. Explanation / 2. Types of Explanation / d. Consilience
Consilience makes the component sciences more likely [Gorham]
26. Natural Theory / A. Speculations on Nature / 1. Nature
Aristotelian physics has circular celestial motion and linear earthly motion [Gorham]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / e. Anti scientific essentialism
How can essences generate the right powers to vary with distance between objects? [Armstrong]