display all the ideas for this combination of texts
3 ideas
| 8078 | Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin] |
| Full Idea: Modus ponens is just one of the five different inference rules identified by the Stoics. | |
| From: report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2 | |
| A reaction: Modus ponens strikes me as being more like a definition of implication than a 'rule'. Implication is what gets you from one truth to another. All the implications of a truth must also be true. |
| 6023 | Every proposition is either true or false [Chrysippus, by Cicero] |
| Full Idea: We hold fast to the position, defended by Chrysippus, that every proposition is either true or false. | |
| From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 38 | |
| A reaction: I am intrigued to know exactly how you defend this claim. It may depend what you mean by a proposition. A badly expressed proposition may have indeterminate truth, quite apart from the vague, the undecidable etc. |
| 9204 | Quine's arguments fail because he naively conflates names with descriptions [Fine,K on Quine] |
| Full Idea: Quine's logical argument against modality presupposes a naïve view of singular terms under which no significant distinction is to be drawn between the use of names and descriptions. | |
| From: comment on Willard Quine (Two Dogmas of Empiricism [1953]) by Kit Fine - Intro to 'Modality and Tense' p. 6 | |
| A reaction: See Idea 9201 for Quine's argument. The question is whether '9' and 'the number of planets' are names or descriptions. The 'number of planets' is not remotely descriptive of 9, so it must be referential. So '9' is a name? Hm. |