18 ideas
| 16123 | Whenever you perceive a community of things, you should also hunt out differences in the group [Plato] |
| 16125 | To reveal a nature, divide down, and strip away what it has in common with other things [Plato] |
| 16124 | No one wants to define 'weaving' just for the sake of weaving [Plato] |
| 14249 | Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley] |
| 10830 | Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems [Boolos] |
| 10829 | A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos] |
| 10832 | '∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos] |
| 10834 | Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences [Boolos] |
| 13841 | Why should compactness be definitive of logic? [Boolos, by Hacking] |
| 10833 | Many concepts can only be expressed by second-order logic [Boolos] |
| 22518 | The actual must be possible, because it occurred [Aristotle] |
| 5961 | The soul gets its goodness from god, and its evil from previous existence. [Plato] |
| 283 | The question of whether or not to persuade comes before the science of persuasion [Plato] |
| 282 | Non-physical beauty can only be shown clearly by speech [Plato] |
| 16566 | Poetry is more philosophic than history, as it concerns universals, not particulars [Aristotle] |
| 281 | The arts produce good and beautiful things by preserving the mean [Plato] |
| 22559 | Democracy is the worst of good constitutions, but the best of bad constitutions [Plato, by Aristotle] |
| 279 | Only divine things can always stay the same, and bodies are not like that [Plato] |