25 ideas
7460 | The great moments are the death of Aristotle, Machiavelli, and Romanticism [Berlin, by Watson] |
7662 | Romanticism is the greatest change in the consciousness of the West [Berlin] |
10476 | The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W] |
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
10478 | Since first-order languages are complete, |= and |- have the same meaning [Hodges,W] |
10477 | |= in model-theory means 'logical consequence' - it holds in all models [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] |
10474 | |= should be read as 'is a model for' or 'satisfies' [Hodges,W] |
10473 | Model theory studies formal or natural language-interpretation using set-theory [Hodges,W] |
10475 | A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W] |
10481 | Models in model theory are structures, not sets of descriptions [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] |
10480 | First-order logic can't discriminate between one infinite cardinal and another [Hodges,W] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
7665 | Most Enlightenment thinkers believed that virtue consists ultimately in knowledge [Berlin] |
6004 | The cardinal virtues are theoretical (based on knowledge), and others are 'non-theoretical' [Hecato, by Dorandi] |
7676 | If we are essentially free wills, authenticity and sincerity are the highest virtues [Berlin] |
7664 | The Greeks have no notion of obligation or duty [Berlin] |
7677 | Central to existentialism is the romantic idea that there is nothing to lean on [Berlin] |
20544 | Berlin distinguishes 'negative' and 'positive' liberty, and rejects the latter [Berlin, by Swift] |
7663 | Judaism and Christianity views are based on paternal, family and tribal relations [Berlin] |