26 ideas
14092 | Philosophers are often too fussy about words, dismissing perfectly useful ordinary terms [Rosen] |
14100 | Figuring in the definition of a thing doesn't make it a part of that thing [Rosen] |
10301 | The axiom of choice is controversial, but it could be replaced [Shapiro] |
10588 | First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro] |
10298 | Some say that second-order logic is mathematics, not logic [Shapiro] |
10299 | If the aim of logic is to codify inferences, second-order logic is useless [Shapiro] |
10300 | Logical consequence can be defined in terms of the logical terminology [Shapiro] |
10290 | Second-order variables also range over properties, sets, relations or functions [Shapiro] |
10590 | Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro] |
10296 | The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro] |
10297 | The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro] |
10292 | Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro] |
14096 | Explanations fail to be monotonic [Rosen] |
10294 | Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro] |
14097 | Things could be true 'in virtue of' others as relations between truths, or between truths and items [Rosen] |
14095 | Facts are structures of worldly items, rather like sentences, individuated by their ingredients [Rosen] |
14093 | An 'intrinsic' property is one that depends on a thing and its parts, and not on its relations [Rosen] |
10591 | Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro] |
14094 | The excellent notion of metaphysical 'necessity' cannot be defined [Rosen] |
14101 | Are necessary truths rooted in essences, or also in basic grounding laws? [Rosen] |
14099 | 'Bachelor' consists in or reduces to 'unmarried' male, but not the other way around [Rosen] |
17402 | Mendeleev saw three principles in nature: matter, force and spirit (where the latter seems to be essence) [Mendeleev, by Scerri] |
14098 | An acid is just a proton donor [Rosen] |
17399 | Elements don't survive in compounds, but the 'substance' of the element does [Mendeleev] |
17400 | Mendeleev focused on abstract elements, not simple substances, so he got to their essence [Mendeleev, by Scerri] |
17401 | Mendeleev had a view of elements which allowed him to overlook some conflicting observations [Mendeleev] |