4 ideas
16567 | Scientists know everything about nothing, philosophers nothing about everything [Sagan,D] |
18189 | ZFC could contain a contradiction, and it can never prove its own consistency [MacLane] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |