11 ideas
| 22115 | Wise people should contemplate and discuss the truth, and fight against falsehood [Aquinas] |
| 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] |
| 20700 | Without God's influence every operation would stop, so God causes everything [Aquinas] |
| 16383 | Puzzled Pierre has two mental files about the same object [Recanati on Kripke] |
| 15202 | Eternity coexists with passing time, as the centre of a circle coexists with its circumference [Aquinas] |