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2 ideas
18743 | Wittgenstein says we want the grammar of problems, not their first-order logical structure [Wittgenstein, by Horsten/Pettigrew] |
Full Idea: For the later Wittgenstein what we should be after is the grammatical structure of philosophical problems, not the first-order logical structure of such problems. | |
From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2 | |
A reaction: This is the most sympathetic spin I have ever seen put on the apparent rather anti-philosophical later Wittgenstein. I nurse doubts about highly formal approaches to philosophy, and maybe 'grammar' (whatever that is) is our target. |
10896 | Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo] |
Full Idea: In propositional logic, any set containing ¬ and at least one of ∧, ∨ and → is expressively complete. | |
From: José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.8) |