15 ideas
| 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] |
| 19271 | No rule can be fully explained [Kripke] |
| 19269 | 'Quus' means the same as 'plus' if the ingredients are less than 57; otherwise it just produces 5 [Kripke] |
| 7305 | Kripke's Wittgenstein says meaning 'vanishes into thin air' [Kripke, by Miller,A] |
| 19270 | If you ask what is in your mind for following the addition rule, meaning just seems to vanish [Kripke] |
| 11076 | Community implies assertability-conditions rather than truth-conditions semantics [Kripke, by Hanna] |
| 11075 | The sceptical rule-following paradox is the basis of the private language argument [Kripke, by Hanna] |
| 1474 | Moral evil may be acceptable to God because it allows free will (even though we don't see why this is necessary) [Plantinga, by PG] |
| 1475 | It is logically possible that natural evil like earthquakes is caused by Satan [Plantinga, by PG] |