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] |
12219 | Whether a modal claim is true depends on how the object is described [Quine, by Fine,K] |
10829 | A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos] |
10922 | Objects are the values of variables, so a referentially opaque context cannot be quantified into [Quine] |
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] |
10923 | Aristotelian essentialism says a thing has some necessary and some non-necessary properties [Quine] |
10921 | Necessity can attach to statement-names, to statements, and to open sentences [Quine] |
10924 | Necessity is in the way in which we say things, and not things themselves [Quine] |
16713 | Philosophers are the forefathers of heretics [Tertullian] |
6610 | I believe because it is absurd [Tertullian] |