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2 ideas
| 19215 | Arguers often turn the opponent's modus ponens into their own modus tollens [Merricks] |
| Full Idea: There is a seasoned method of turning your opponent's modus ponens into your own modus tollens. | |
| From: Trenton Merricks (Propositions [2015], 5.VII) | |
| A reaction: That is, they say 'if he's coming he'll be hear by now, and he's definitely coming', to which you say 'I'm afraid he's not here, so he obviously isn't coming after all'. They say if-A-then-B, and A, so B. You say not-B, so you're wrong about A. |
| 7933 | Don't assume that a thing has all the properties of its parts [Macdonald,C] |
| Full Idea: The fallacy of composition makes the erroneous assumption that every property of the things that constitute a thing is a property of the thing as well. But every large object is constituted by small parts, and every red object by colourless parts. | |
| From: Cynthia Macdonald (Varieties of Things [2005], Ch.5) | |
| A reaction: There are nice questions here like 'If you add lots of smallness together, why don't you get extreme smallness?' Colours always make bad examples in such cases (see Idea 5456). Distinctions are needed here (e.g. Idea 7007). |