Combining Texts

Ideas for 'fragments/reports', 'The Scientific Image' and 'Propositions'

unexpand these ideas     |    start again     |     choose another area for these texts

display all the ideas for this combination of texts

---

4 ideas

5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens

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.

5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle

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.

5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive

9455	Maybe proper names have the content of fixing a thing's category [Bealer]
	Full Idea: Some say that proper names have no descriptive content, but others think that although a name does not have the right sort of descriptive content which fixes a unique referent, it has a content which fixes the sort or category to which it belongs.
	From: George Bealer (Propositions [1998], §7)
	A reaction: Presumably 'Mary', and 'Felix', and 'Rover', and 'Smallville' are cases in point. There is a well known journalist called 'Manchester', a famous man called 'Hilary', a village in Hertfordshire called 'Matching Tie'... Interesting, though.

5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions

9454	The four leading theories of definite descriptions are Frege's, Russell's, Evans's, and Prior's [Bealer]
	Full Idea: The four leading theories of definite descriptions are Frege's, Russell's, Evans's, and Prior's, ...of which to many Frege's is the most intuitive of the four. Frege says they refer to the unique item (if it exists) which satisfies the predicate.
	From: George Bealer (Propositions [1998], §5)
	A reaction: He doesn't expound the other three, but I record this a corrective to the view that Russell has the only game in town.