13 ideas
| 3067 | A philosopher should have principles ready for understanding, like a surgeon with instruments [Aurelius] |
| 6007 | If you know your father, but don't recognise your father veiled, you know and don't know the same person [Eubulides, by Dancy,R] |
| 6006 | If you say truly that you are lying, you are lying [Eubulides, by Dancy,R] |
| 6008 | Removing one grain doesn't destroy a heap, so a heap can't be destroyed [Eubulides, by Dancy,R] |
| 3072 | Everything is changing, including yourself and the whole universe [Aurelius] |
| 3066 | Nothing is evil which is according to nature [Aurelius] |
| 3071 | Justice has no virtue opposed to it, but pleasure has temperance opposed to it [Aurelius] |
| 3069 | The art of life is more like the wrestler's than the dancer's [Aurelius] |
| 3065 | Humans are naturally made for co-operation [Aurelius] |
| 17402 | Mendeleev saw three principles in nature: matter, force and spirit (where the latter seems to be essence) [Mendeleev, by Scerri] |
| 17399 | Elements don't survive in compounds, but the 'substance' of the element does [Mendeleev] |
| 17400 | Mendeleev focused on abstract elements, not simple substances, so he got to their essence [Mendeleev, by Scerri] |
| 17401 | Mendeleev had a view of elements which allowed him to overlook some conflicting observations [Mendeleev] |