4 ideas
21548 | The null class is the class with all the non-existents as its members [MacColl, by Lackey] |
10247 | We have no adequate logic at the moment, so mathematicians must create one [Veblen] |
13165 | Geometrical proofs do not show causes, as when we prove a triangle contains two right angles [Proclus] |
9569 | The origin of geometry started in sensation, then moved to calculation, and then to reason [Proclus] |