16 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] |
| 10289 | Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W] |
| 10288 | Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [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] |
| 21339 | We want the ontology of relations, not just a formal way of specifying them [Heil] |
| 21349 | Two people are indirectly related by height; the direct relation is internal, between properties [Heil] |
| 21340 | Maybe all the other features of the world can be reduced to relations [Heil] |
| 21348 | In the case of 5 and 6, their relational truthmaker is just the numbers [Heil] |
| 21351 | Truthmaking is a clear example of an internal relation [Heil] |
| 21344 | If R internally relates a and b, and you have a and b, you thereby have R [Heil] |
| 21350 | If properties are powers, then causal relations are internal relations [Heil] |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |