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All the ideas for 'What is Logic?st1=Ian Hacking', 'Procedural republic and unencumbered self' and 'Replies on 'Limits of Abstraction''

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30 ideas

1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
10571 Concern for rigour can get in the way of understanding phenomena [Fine,K]
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
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]
13833 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / e. Iterative sets
10565 There is no stage at which we can take all the sets to have been generated [Fine,K]
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
10564 We might combine the axioms of set theory with the axioms of mereology [Fine,K]
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 / G. Quantification / 5. Second-Order Quantification
10569 If you ask what F the second-order quantifier quantifies over, you treat it as first-order [Fine,K]
5. Theory of Logic / I. Semantics of Logic / 1. Semantics of Logic
10570 Assigning an entity to each predicate in semantics is largely a technical convenience [Fine,K]
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 / 3. Nature of Numbers / b. Types of number
10573 Dedekind cuts lead to the bizarre idea that there are many different number 1's [Fine,K]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / i. Reals from cuts
10575 Why should a Dedekind cut correspond to a number? [Fine,K]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / l. Zero
10574 Unless we know whether 0 is identical with the null set, we create confusions [Fine,K]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory
10560 Set-theoretic imperialists think sets can represent every mathematical object [Fine,K]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
10568 Logicists say mathematics can be derived from definitions, and can be known that way [Fine,K]
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / b. Levels of abstraction
10563 A generative conception of abstracts proposes stages, based on concepts of previous objects [Fine,K]
18. Thought / E. Abstraction / 7. Abstracta by Equivalence
10561 Abstraction-theoretic imperialists think Fregean abstracts can represent every mathematical object [Fine,K]
10562 We can combine ZF sets with abstracts as urelements [Fine,K]
10567 We can create objects from conditions, rather than from concepts [Fine,K]
23. Ethics / D. Deontological Ethics / 2. Duty
22262 Kant's moral law has no foundation - because that would undermine its priority [Sandel]
24. Political Theory / D. Ideologies / 5. Democracy / d. Representative democracy
22264 Modern liberal rights in democracies protect individuals against the majority [Sandel]
24. Political Theory / D. Ideologies / 6. Liberalism / a. Liberalism basics
22261 Liberals say rights always come first, and justice is neutral on social values [Sandel]
24. Political Theory / D. Ideologies / 6. Liberalism / b. Liberal individualism
22263 Liberal justice means the withdrawal of the self, as transcendental or as unencumbered [Sandel]
24. Political Theory / D. Ideologies / 7. Communitarianism / a. Communitarianism
22805 Liberalism concerns rights, and communitarianism concerns the common good [Sandel, by Avineri/De-Shalit]