7 ideas
17833 | The first-order ZF axiomatisation is highly non-categorical [Hallett,M] |
17834 | Non-categoricity reveals a sort of incompleteness, with sets existing that the axioms don't reveal [Hallett,M] |
17837 | Zermelo allows ur-elements, to enable the widespread application of set-theory [Hallett,M] |
18758 | Validity is provable, but invalidity isn't, because the model is infinite [Church, by McGee] |
17836 | The General Continuum Hypothesis and its negation are both consistent with ZF [Hallett,M] |
1757 | The Electra: she knows this man, but not that he is her brother [Eucleides, by Diog. Laertius] |
3028 | The chief good is unity, sometimes seen as prudence, or God, or intellect [Eucleides] |