15 ideas
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
10283 | A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W] |
10284 | There are three different standard presentations of semantics [Hodges,W] |
10285 | I |= φ means that the formula φ is true in the interpretation I [Hodges,W] |
10288 | Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W] |
10289 | Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W] |
10287 | If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
22868 | The value and truth of knowledge are measured by success in activity [Dewey] |
22865 | Habits constitute the self [Dewey] |
22871 | The good people are those who improve; the bad are those who deteriorate [Dewey] |
22876 | Democracy is the development of human nature when it shares in the running of communal activities [Dewey] |
22875 | Democracy is not just a form of government; it is a mode of shared living [Dewey] |
22874 | Individuality is only developed within groups [Dewey] |
5470 | The idea of laws of nature arose in the Middle Ages [Hall,AR, by Ellis] |