Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', '06: Epistle to the Romans' and 'Ancient Philosophy: very short introduction'

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17 ideas

1. Philosophy / C. History of Philosophy / 2. Ancient Philosophy / b. Pre-Socratic philosophy
12036 Xenophanes began the concern with knowledge [Annas]
1. Philosophy / C. History of Philosophy / 2. Ancient Philosophy / c. Classical philosophy
12046 Plato was the first philosopher who was concerned to systematize his ideas [Annas]
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]
12. Knowledge Sources / A. A Priori Knowledge / 3. Innate Knowledge / a. Innate knowledge
5052 When Gentiles follow the law, they must have the law written in their hearts [Paul]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / b. Rational ethics
12037 Euripides's Medea is a key case of reason versus the passions [Annas]
23. Ethics / C. Virtue Theory / 1. Virtue Theory / a. Nature of virtue
12040 Virtue is a kind of understanding of moral value [Annas]
24. Political Theory / D. Ideologies / 10. Theocracy
7572 Power is ordained by God, so anyone who resists power resists God, and will be damned [Paul]