4 ideas
15833 | Tell cleverness from answers, but wisdom from questions [Mahfouz] |
6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
11968 | The intension of a sentence is the set of all possible worlds in which it is true [Carnap, by Kaplan] |