30 ideas
21584 | A sense of timelessness is essential to wisdom [Russell] |
21572 | Philosophical disputes are mostly hopeless, because philosophers don't understand each other [Russell] |
21571 | Philosophical systems are interesting, but we now need a more objective scientific philosophy [Russell] |
21574 | Hegel's confusions over 'is' show how vast systems can be built on simple errors [Russell] |
21587 | Philosophers sometimes neglect truth and distort facts to attain a nice system [Russell] |
21582 | Physicists accept particles, points and instants, while pretending they don't do metaphysics [Russell] |
21573 | When problems are analysed properly, they are either logical, or not philosophical at all [Russell] |
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
21588 | Logic gives the method of research in philosophy [Russell] |
21586 | The logical connectives are not objects, but are formal, and need a context [Russell] |
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] |
21585 | The tortoise won't win, because infinite instants don't compose an infinitely long time [Russell] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
21684 | Atomic facts may be inferrable from others, but never from non-atomic facts [Russell] |
22316 | A positive and negative fact have the same constituents; their difference is primitive [Russell] |
21576 | With asymmetrical relations (before/after) the reduction to properties is impossible [Russell] |
21575 | When we attribute a common quality to a group, we can forget the quality and just talk of the group [Russell] |
21580 | Science condemns sense-data and accepts matter, but a logical construction must link them [Russell] |
21583 | When sense-data change, there must be indistinguishable sense-data in the process [Russell] |
21577 | Empirical truths are particular, so general truths need an a priori input of generality [Russell] |
21579 | Objects are treated as real when they connect with other experiences in a normal way [Russell] |
21578 | Global scepticism is irrefutable, but can't replace our other beliefs, and just makes us hesitate [Russell] |
6416 | Other minds seem to exist, because their testimony supports realism about the world [Russell, by Grayling] |
14494 | Epiphenomenalism is like a pointless nobleman, kept for show, but soon to be abolished [Alexander,S] |
21581 | We never experience times, but only succession of events [Russell] |