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2 ideas
18799 | Intuitionists can accept Double Negation Elimination for decidable propositions [Rumfitt] |
Full Idea: Double Negation Elimination is a rule of inference which the classicist accepts without restriction, but which the intuitionist accepts only for decidable propositions. | |
From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) | |
A reaction: This cures me of my simplistic understanding that intuitionists just reject the rules about double negation. |
18798 | It is the second-order part of intuitionistic logic which actually negates some classical theorems [Rumfitt] |
Full Idea: Although intuitionistic propositional and first-order logics are sub-systems of the corresponding classical systems, intuitionistic second-order logic affirms the negations of some classical theorems. | |
From: Ian Rumfitt (The Boundary Stones of Thought [2015], 1.1) |