19 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] |
| 21110 | An understanding of the most basic physics should explain all of the subject's mysteries [Krauss] |
| 21105 | In 1676 it was discovered that water is teeming with life [Krauss] |
| 7861 | Libet says the processes initiated in the cortex can still be consciously changed [Libet, by Papineau] |
| 6660 | Libet found conscious choice 0.2 secs before movement, well after unconscious 'readiness potential' [Libet, by Lowe] |
| 21109 | Space itself can expand (and separate its contents) at faster than light speeds [Krauss] |
| 21104 | General Relativity: the density of energy and matter determines curvature and gravity [Krauss] |
| 21107 | Uncertainty says that energy can be very high over very short time periods [Krauss] |
| 21106 | Most of the mass of a proton is the energy in virtual particles (rather than the quarks) [Krauss] |
| 21112 | Empty space contains a continual flux of brief virtual particles [Krauss] |
| 21108 | The universe is precisely 13.72 billion years old [Krauss] |
| 21111 | It seems likely that cosmic inflation is eternal, and this would make a multiverse inevitable [Krauss] |