26 ideas
9193 | ZF set theory has variables which range over sets, 'equals' and 'member', and extensionality [Dummett] |
9194 | The main alternative to ZF is one which includes looser classes as well as sets [Dummett] |
9195 | Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett] |
9186 | First-order logic concerns objects; second-order adds properties, kinds, relations and functions [Dummett] |
9187 | Logical truths and inference are characterized either syntactically or semantically [Dummett] |
9191 | Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett] |
9192 | The number 4 has different positions in the naturals and the wholes, with the same structure [Dummett] |
15435 | If you think universals are immanent, you must believe them to be sparse, and not every related predicate [Lewis] |
15451 | I assume there could be natural properties that are not instantiated in our world [Lewis] |
15433 | Tropes are particular properties, which cannot recur, but can be exact duplicates [Lewis] |
15436 | Universals are meant to give an account of resemblance [Lewis] |
15438 | We can add a primitive natural/unnatural distinction to class nominalism [Lewis] |
15448 | The 'magical' view of structural universals says they are atoms, even though they have parts [Lewis] |
15449 | If 'methane' is an atomic structural universal, it has nothing to connect it to its carbon universals [Lewis] |
15439 | The 'pictorial' view of structural universals says they are wholes made of universals as parts [Lewis] |
15441 | The structural universal 'methane' needs the universal 'hydrogen' four times over [Lewis] |
15445 | Butane and Isobutane have the same atoms, but different structures [Lewis] |
15434 | Structural universals have a necessary connection to the universals forming its parts [Lewis] |
15437 | We can't get rid of structural universals if there are no simple universals [Lewis] |
15446 | Composition is not just making new things from old; there are too many counterexamples [Lewis] |
15440 | A whole is distinct from its parts, but is not a further addition in ontology [Lewis] |
15444 | Different things (a toy house and toy car) can be made of the same parts at different times [Lewis] |
17093 | Causation produces productive mechanisms; to understand the world, understand these mechanisms [Salmon] |
17492 | Salmon's interaction mechanisms needn't be regular, or involving any systems [Glennan on Salmon] |
15450 | Maybe abstraction is just mereological subtraction [Lewis] |
15443 | Mathematicians abstract by equivalence classes, but that doesn't turn a many into one [Lewis] |