Combining Texts

All the ideas for 'In Defence of Convention T', 'What is Logic?' and 'Pragmatism in Retrospect'

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15 ideas

2. Reason / D. Definition / 3. Types of Definition
A decent modern definition should always imply a semantics [Hacking]
3. Truth / E. Pragmatic Truth / 1. Pragmatic Truth
Peirce's theory offers anti-realist verificationism, but surely how things are is independent of us? [Horsten on Peirce]
Independent truth (if there is any) is the ultimate result of sufficient enquiry [Peirce]
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]
12. Knowledge Sources / D. Empiricism / 3. Pragmatism
Pragmatism is a way of establishing meanings, not a theory of metaphysics or a set of truths [Peirce]
19. Language / C. Assigning Meanings / 5. Fregean Semantics
A theory of meaning comes down to translating sentences into Fregean symbolic logic [Davidson, by Macey]