more from this thinker | more from this text
Full Idea
Gricean implicature theory might suggest that a disjunction is never assertable when a disjunct is (though actually the disjunction might be 'pertinent') - but the procedure is indispensable in mathematical practice.
Gist of Idea
Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths
Source
John P. Burgess (Philosophical Logic [2009], 5.2)
Book Ref
Burgess,John P.: 'Philosophical Logic' [Princeton 2009], p.102
A Reaction
He gives an example of a proof in maths which needs it, and an unusual conversational occasion where it makes sense.
| 21676 | Epicureans say disjunctions can be true whiile the disjuncts are not true [Epicurus, by Cicero] |
| 16479 | 'Or' expresses hesitation, in a dog at a crossroads, or birds risking grabbing crumbs [Russell] |
| 16481 | 'Or' expresses a mental state, not something about the world [Russell] |
| 16487 | Maybe the 'or' used to describe mental states is not the 'or' of logic [Russell] |
| 16483 | Disjunction may also arise in practice if there is imperfect memory. [Russell] |
| 16480 | A disjunction expresses indecision [Russell] |
| 16465 | In 'S was F or some other than S was F', the disjuncts need S, but the whole disjunction doesn't [Stalnaker] |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |