14 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] |
| 19393 | What is not active is nothing [Leibniz] |
| 2986 | Belief is the most important propositional attitude [Lyons] |
| 2978 | Consciousness no longer seems essential to intentionality [Lyons] |
| 2984 | Perceptions could give us information without symbolic representation [Lyons] |
| 2979 | Propositional attitudes require representation [Lyons] |
| 2987 | Folk psychology works badly for alien cultures [Lyons] |
| 2977 | All thinking has content [Lyons] |