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All the ideas for 'What is Logic?st1=Ian Hacking', 'Identity, Essence and Indiscernibility' and 'Why Medieval Philosophy Matters'

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20 ideas

1. Philosophy / E. Nature of Metaphysics / 4. Metaphysics as Science
22138 Science rests on scholastic metaphysics, not on Hume, Kant or Carnap [Boulter]
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]
8. Modes of Existence / D. Universals / 2. Need for Universals
22134 Thoughts are general, but the world isn't, so how can we think accurately? [Boulter]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
14381 A statue is essentially the statue, but its lump is not essentially a statue, so statue isn't lump [Yablo, by Rocca]
10. Modality / A. Necessity / 6. Logical Necessity
22150 Logical possibility needs the concepts of the proposition to be adequate [Boulter]
14. Science / A. Basis of Science / 3. Experiment
22139 Experiments don't just observe; they look to see what interventions change the natural order [Boulter]
14. Science / B. Scientific Theories / 1. Scientific Theory
22136 Science begins with sufficient reason, de-animation, and the importance of nature [Boulter]
15. Nature of Minds / C. Capacities of Minds / 1. Faculties
22135 Our concepts can never fully capture reality, but simplification does not falsify [Boulter]
19. Language / E. Analyticity / 3. Analytic and Synthetic
22152 Aristotelians accept the analytic-synthetic distinction [Boulter]
22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value
22156 The facts about human health are the measure of the values in our lives [Boulter]