display all the ideas for this combination of texts
2 ideas
| 10455 | Free logic at least allows empty names, but struggles to express non-existence [Bach] |
| Full Idea: Unlike standard first-order logic, free logic can allow empty names, but still has to deny existence by either representing it as a predicate, or invoke some dubious distinction such as between existence and being. | |
| From: Kent Bach (What Does It Take to Refer? [2006], 22.2 L1) |
| 9967 | 'Impure' sets have a concrete member, while 'pure' (abstract) sets do not [Jubien] |
| Full Idea: Any set with a concrete member is 'impure'. 'Pure' sets are those that are not impure, and are paradigm cases of abstract entities, such as the sort of sets apparently dealt with in Zermelo-Fraenkel (ZF) set theory. | |
| From: Michael Jubien (Ontology and Mathematical Truth [1977], p.116) | |
| A reaction: [I am unclear whether Jubien is introducing this distinction] This seems crucial in accounts of mathematics. On the one had arithmetic can be built from Millian pebbles, giving impure sets, while logicists build it from pure sets. |