20 ideas
8996 | If if time is money then if time is not money then time is money then if if if time is not money... [Quine] |
8995 | Definition by words is determinate but relative; fixing contexts could make it absolute [Quine] |
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
10064 | Quine quickly dismisses If-thenism [Quine, by Musgrave] |
20296 | Logic needs general conventions, but that needs logic to apply them to individual cases [Quine, by Rey] |
8998 | Claims that logic and mathematics are conventional are either empty, uninteresting, or false [Quine] |
8999 | Logic isn't conventional, because logic is needed to infer logic from conventions [Quine] |
9000 | If a convention cannot be communicated until after its adoption, what is its role? [Quine] |
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] |
8994 | If analytic geometry identifies figures with arithmetical relations, logicism can include geometry [Quine] |
8997 | There are four different possible conventional accounts of geometry [Quine] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
8993 | If mathematics follows from definitions, then it is conventional, and part of logic [Quine] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |