12 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] |
10245 | One geometry cannot be more true than another [Poincaré] |
10833 | Many concepts can only be expressed by second-order logic [Boolos] |
22179 | Explanatory facts also predict, and predictive facts also explain [Hempel, by Okasha] |
6755 | For Hempel, explanations are deductive-nomological or probabilistic-statistical [Hempel, by Bird] |
17083 | The covering-law model is for scientific explanation; historical explanation is quite different [Hempel] |
13052 | Hempel rejects causation as part of explanation [Hempel, by Salmon] |