9 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] |
18189 | ZFC could contain a contradiction, and it can never prove its own consistency [MacLane] |
17837 | Zermelo allows ur-elements, to enable the widespread application of set-theory [Hallett,M] |
17836 | The General Continuum Hypothesis and its negation are both consistent with ZF [Hallett,M] |
17402 | Mendeleev saw three principles in nature: matter, force and spirit (where the latter seems to be essence) [Mendeleev, by Scerri] |
17399 | Elements don't survive in compounds, but the 'substance' of the element does [Mendeleev] |
17400 | Mendeleev focused on abstract elements, not simple substances, so he got to their essence [Mendeleev, by Scerri] |
17401 | Mendeleev had a view of elements which allowed him to overlook some conflicting observations [Mendeleev] |