8 ideas
| 18189 | ZFC could contain a contradiction, and it can never prove its own consistency [MacLane] |
| 10496 | Monothetic categories have fixed defining features, and polythetic categories do not [Ellen] |
| 10497 | In symbolic classification, the categories are linked to rules [Ellen] |
| 10494 | Several words may label a category; one word can name several categories; some categories lack words [Ellen] |
| 10495 | Continuous experience sometimes needs imposition of boundaries to create categories [Ellen] |
| 10498 | Classification is no longer held to be rooted in social institutions [Ellen] |
| 5845 | Niceratus learnt the whole of Homer by heart, as a guide to goodness [Xenophon] |
| 5833 | Education is the greatest of human goods [Xenophon] |