3 ideas
| 8920 | Equivalence relations are reflexive, symmetric and transitive, and classify similar objects [Lipschutz] |
| Full Idea: A relation R on a non-empty set S is an equivalence relation if it is reflexive (for each member a, aRa), symmetric (if aRb, then bRa), and transitive (aRb and bRc, so aRc). It tries to classify objects that are in some way 'alike'. | |
| From: Seymour Lipschutz (Set Theory and related topics (2nd ed) [1998], 3.9) | |
| A reaction: So this is an attempt to formalise the common sense notion of seeing that two things have something in common. Presumably a 'way' of being alike is going to be a property or a part |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |
| 22237 | The Greeks had a single word meaning both 'beautiful' and 'good' [Pormann] |
| Full Idea: The later Greeks coined the term 'kalokagathia' for the fact of being both beautiful [kalos] and good [agathos], thus linking moral and physical health. | |
| From: Peter E. Pormann (Medical Conceptions of Health pre-Renaissance [2019], p.44) | |
| A reaction: In their literature good people are often handsome, and bad people ugly. Socrates was famous for being an exception. |