4 ideas
| 9879 | NF has no models, but just blocks the comprehension axiom, to avoid contradictions [Quine, by Dummett] |
| 22363 | You have only begun to do real science when you can express it in numbers [Kelvin] |
| 19216 | Propositions (such as 'that dog is barking') only exist if their items exist [Williamson] |
| 20644 | Energy has progressed from a mere formula, to a principle pervading all nature [Kelvin] |