17 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] |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| 4061 | The right to life is not a right not to be killed, but not to be killed unjustly [Thomson] |
| 4057 | A newly fertilized ovum is no more a person than an acorn is an oak tree [Thomson] |
| 4695 | Maybe abortion can be justified despite the foetus having full human rights [Thomson, by Foot] |
| 4059 | It can't be murder for a mother to perform an abortion on herself to save her own life [Thomson] |
| 4696 | The foetus is safe in the womb, so abortion initiates its death, with the mother as the agent. [Foot on Thomson] |
| 4058 | Is someone's right to life diminished if they were conceived by a rape? [Thomson] |
| 4060 | The right to life does not bestow the right to use someone else's body to support that life [Thomson] |
| 4062 | No one is morally required to make huge sacrifices to keep someone else alive for nine months [Thomson] |