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3 ideas
7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
Full Idea: Necessary implication is often called 'strict implication'. The sort of strict implication found in valid arguments, where the conjunction of the premises necessarily implies the conclusion, is often called 'entailment'. | |
From: Rod Girle (Modal Logics and Philosophy [2000], 1.2) | |
A reaction: These are basic concept for all logic. |
16974 | The nature of each logical concept is given by a collection of inference rules [Correia] |
Full Idea: The view presented here presupposes that each logical concept is associated with some fixed and well defined collection of rules of inference which characterize its basic logical nature. | |
From: Fabrice Correia (On the Reduction of Necessity to Essence [2012], 4) | |
A reaction: [He gives Fine's 'Senses of Essences' 57-8 as a source] He seems to have in mind natural deduction, where the rules are for the introduction and elimination of the concepts. |
7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
Full Idea: The truth trees method for establishing the validity of arguments and formulas is easy to use, and has the advantage that if an argument or formula is not valid, then a counter-example can be retrieved from the tree. | |
From: Rod Girle (Modal Logics and Philosophy [2000], 1.4) |