Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Procedural republic and unencumbered self' and 'Sophistical Refutations'

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23 ideas

2. Reason / A. Nature of Reason / 1. On Reason
2676 Didactic argument starts from the principles of the subject, not from the opinions of the learner [Aristotle]
2. Reason / A. Nature of Reason / 4. Aims of Reason
2675 Reasoning is a way of making statements which makes them lead on to other statements [Aristotle]
2. Reason / C. Styles of Reason / 1. Dialectic
2677 Dialectic aims to start from generally accepted opinions, and lead to a contradiction [Aristotle]
2. Reason / C. Styles of Reason / 3. Eristic
2674 Competitive argument aims at refutation, fallacy, paradox, solecism or repetition [Aristotle]
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 / 2. Logical Connectives / d. and
16967 'Are Coriscus and Callias at home?' sounds like a single question, but it isn't [Aristotle]
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]
9. Objects / D. Essence of Objects / 10. Essence as Species
16149 Generic terms like 'man' are not substances, but qualities, relations, modes or some such thing [Aristotle]
9. Objects / F. Identity among Objects / 8. Leibniz's Law
11840 Only if two things are identical do they have the same attributes [Aristotle]
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]