16 ideas
| 7500 | Early Greeks cared about city and companions; later Greeks concentrated on the self [Foucault] |
| 17884 | Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner] |
| 17893 | 'Reflection principles' say the whole truth about sets can't be captured [Koellner] |
| 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] |
| 17894 | We have no argument to show a statement is absolutely undecidable [Koellner] |
| 13841 | Why should compactness be definitive of logic? [Boolos, by Hacking] |
| 17890 | There are at least eleven types of large cardinal, of increasing logical strength [Koellner] |
| 17887 | PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner] |
| 10833 | Many concepts can only be expressed by second-order logic [Boolos] |
| 17891 | Arithmetical undecidability is always settled at the next stage up [Koellner] |
| 7501 | Why couldn't a person's life become a work of art? [Foucault] |
| 7498 | Greeks and early Christians were much more concerned about food than about sex [Foucault] |