19 ideas
5893 | A wise man has integrity, firmness of will, nobility, consistency, sobriety, patience [Cicero] |
5891 | Philosophy is the collection of rational arguments [Cicero] |
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] |
14933 | Scientific properties are defined by the laws that embody them [Psillos, by Ladyman/Ross] |
5879 | The soul is the heart, or blood in the heart, or part of the brain, of something living in heart or brain, or breath [Cicero] |
5884 | How can one mind perceive so many dissimilar sensations? [Cicero] |
5887 | The soul has a single nature, so it cannot be divided, and hence it cannot perish [Cicero] |
5886 | Like the eye, the soul has no power to see itself, but sees other things [Cicero] |
5885 | Souls contain no properties of elements, and elements contain no properties of souls [Cicero] |
5890 | We should not share the distress of others, but simply try to relieve it [Cicero] |
5894 | All men except philosophers fear poverty [Cicero] |
5895 | If one despises illiterate mechanics individually, they are not worth more collectively [Cicero] |