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All the ideas for 'What is Logic?st1=Ian Hacking', 'Particulars in Particular Clothing' and 'On the analysis of moral judgements'

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19 ideas

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 / B. Properties / 13. Tropes / a. Nature of tropes
18431 Internal relations combine some tropes into a nucleus, which bears the non-essential tropes [Simons, by Edwards]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
6968 Some people think there are ethical facts, but of a 'queer' sort [Ayer]
6972 A right attitude is just an attitude one is prepared to stand by [Ayer]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / d. Ethical theory
6973 Moral theories are all meta-ethical, and are neutral as regards actual conduct [Ayer]
6974 Moral judgements cannot be the logical consequence of a moral philosophy [Ayer]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / c. Ethical intuitionism
6971 I would describe intuitions of good as feelings of approval [Ayer]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
6969 Approval of historical or fictional murders gives us leave to imitate them [Ayer]
6970 Moral judgements are not expressions, but are elements in a behaviour pattern [Ayer]