17 ideas
| 9208 | Philosophers with a new concept are like children with a new toy [Fine,K] |
| 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] |
| 9210 | Possible objects are abstract; actual concrete objects are possible; so abstract/concrete are compatible [Fine,K] |
| 9211 | A non-standard realism, with no privileged standpoint, might challenge its absoluteness or coherence [Fine,K] |
| 9202 | Objects, as well as sentences, can have logical form [Fine,K] |
| 9206 | We must distinguish between the identity or essence of an object, and its necessary features [Fine,K] |
| 9205 | The three basic types of necessity are metaphysical, natural and normative [Fine,K] |
| 9209 | Metaphysical necessity may be 'whatever the circumstance', or 'regardless of circumstances' [Fine,K] |
| 9200 | Empiricists suspect modal notions: either it happens or it doesn't; it is just regularities. [Fine,K] |
| 18988 | Behind the bare phenomenal facts there is nothing [Wright,Ch] |
| 9207 | If sentence content is all worlds where it is true, all necessary truths have the same content! [Fine,K] |