Combining Texts

All the ideas for 'What is Logic?st1=Ian Hacking', 'Causation' and 'Against the Logicians (two books)'

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18 ideas

1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
22764 Ordinary speech is not exact about what is true; we say we are digging a well before the well exists [Sext.Empiricus]
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]
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]
9. Objects / D. Essence of Objects / 9. Essence and Properties
22762 Some properties are inseparable from a thing, such as the length, breadth and depth of a body [Sext.Empiricus]
13. Knowledge Criteria / A. Justification Problems / 1. Justification / b. Need for justification
22759 Fools, infants and madmen may speak truly, but do not know [Sext.Empiricus]
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
22760 Madmen are reliable reporters of what appears to them [Sext.Empiricus]
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
8406 Not all explanations are causal, but if a thing can be explained at all, it can be explained causally [Sanford]
18. Thought / D. Concepts / 2. Origin of Concepts / b. Empirical concepts
22763 We can only dream of a winged man if we have experienced men and some winged thing [Sext.Empiricus]
26. Natural Theory / C. Causation / 8. Particular Causation / c. Conditions of causation
8407 A totality of conditions necessary for an occurrence is usually held to be jointly sufficient for it [Sanford]