3 ideas
18189 | ZFC could contain a contradiction, and it can never prove its own consistency [MacLane] |
13547 | Limitation of Size is weak (Fs only collect is something the same size does) or strong (fewer Fs than objects) [Boolos, by Potter] |
19699 | A Gettier case is a belief which is true, and its fallible justification involves some luck [Hetherington] |