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All the ideas for 'What is Logic?st1=Ian Hacking', 'Dialogue on human freedom and origin of evil' and 'Plural Quantification'

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25 ideas

2. Reason / D. Definition / 3. Types of Definition
13838 A decent modern definition should always imply a semantics [Hacking]
2. Reason / D. Definition / 12. Paraphrase
10633 'Some critics admire only one another' cannot be paraphrased in singular first-order [Linnebo]
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]
10638 A pure logic is wholly general, purely formal, and directly known [Linnebo]
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 / G. Quantification / 6. Plural Quantification
10635 Second-order quantification and plural quantification are different [Linnebo]
10641 Traditionally we eliminate plurals by quantifying over sets [Linnebo]
10640 Instead of complex objects like tables, plurally quantify over mereological atoms tablewise [Linnebo]
10636 Plural plurals are unnatural and need a first-level ontology [Linnebo]
10639 Plural quantification may allow a monadic second-order theory with first-order ontology [Linnebo]
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]
6. Mathematics / A. Nature of Mathematics / 2. Geometry
13163 Circles must be bounded, so cannot be infinite [Leibniz]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
10643 We speak of a theory's 'ideological commitments' as well as its 'ontological commitments' [Linnebo]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
10637 Ordinary speakers posit objects without concern for ontology [Linnebo]
16. Persons / F. Free Will / 6. Determinism / b. Fate
13162 Sloth's Syllogism: either it can't happen, or it is inevitable without my effort [Leibniz]
19. Language / C. Assigning Meanings / 3. Predicates
10634 Predicates are 'distributive' or 'non-distributive'; do individuals do what the group does? [Linnebo]
29. Religion / D. Religious Issues / 3. Problem of Evil / a. Problem of Evil
19339 Evil is a negation of good, which arises from non-being [Leibniz]
13164 God only made sin possible because a much greater good can be derived from it [Leibniz]