3 ideas
| 18465 | An 'equivalence' relation is one which is reflexive, symmetric and transitive [Kunen] |
| Full Idea: R is an equivalence relation on A iff R is reflexive, symmetric and transitive on A. | |
| From: Kenneth Kunen (The Foundations of Mathematics (2nd ed) [2012], I.7.1) |
| 12709 | Motion is not absolute, but consists in relation [Leibniz] |
| Full Idea: In reality motion is not something absolute, but consists in relation. | |
| From: Gottfried Leibniz (On Motion [1677], A6.4.1968), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 3 | |
| A reaction: It is often thought that motion being relative was invented by Einstein, but Leibniz wholeheartedly embraced 'Galilean relativity', and refused to even consider any absolute concept of motion. Acceleration is a bit trickier than velocity. |
| 7469 | There is no hereafter in the Book of Job [Anon (Job), by Watson] |
| Full Idea: The entire Book of Job is concerned with faith and suffering and inequality in a life where there is no hereafter (all the rewards promised to the Jews by their God are worldly). | |
| From: report of Anon (Job) (18: Book of Job [c.535 BCE]) by Peter Watson - Ideas Ch.5 | |
| A reaction: It is extraordinary how such ideas can creep into the great religions, and then become taken for granted, as if no one had ever doubted them. |