4 ideas
| 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] |
| 6552 | You can only explain the qualities of large objects using entities which lack those qualities [Heisenberg] |
| 4871 | A thing is free if it acts only by the necessity of its own nature [Spinoza] |