Combining Texts

All the ideas for 'works', 'What is Logic?' and 'Russell's Ontological Development'

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16 ideas

1. Philosophy / H. Continental Philosophy / 3. Hermeneutics
An interpreter of a text, because of wider knowledge, can understand it better than its author [Schleiermacher, by Mautner]
Unity emerges from understanding particulars, so understanding is prior to seeing unity [Schleiermacher]
2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
2. Reason / D. Definition / 12. Paraphrase
Russell offered a paraphrase of definite description, to avoid the commitment to objects [Quine]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / d. Basic theorems of PL
'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking]
Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking]
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
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
First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking]
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
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
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
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
If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking]
19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning
Taking sentences as the unit of meaning makes useful paraphrasing possible [Quine]
Knowing a word is knowing the meanings of sentences which contain it [Quine]