23 ideas
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] |
10294 | Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro] |
10591 | Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro] |
18890 | Putnam smuggles essentialism about liquids into his proof that water must be H2O [Salmon,N on Putnam] |
7705 | The Twin Earth theory suggests that intentionality is independent of qualia [Jacquette on Putnam] |
4099 | If Twins talking about 'water' and 'XYZ' have different thoughts but identical heads, then thoughts aren't in the head [Putnam, by Crane] |
12026 | We say ice and steam are different forms of water, but not that they are different forms of H2O [Forbes,G on Putnam] |
3208 | Does 'water' mean a particular substance that was 'dubbed'? [Putnam, by Rey] |
3893 | Often reference determines sense, and not (as Frege thought) vice versa [Putnam, by Scruton] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
11191 | The hidden structure of a natural kind determines membership in all possible worlds [Putnam] |
11192 | If causes are the essence of diseases, then disease is an example of a relational essence [Putnam, by Williams,NE] |
11190 | Archimedes meant by 'gold' the hidden structure or essence of the stuff [Putnam] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |