5 ideas
| 9987 | An aggregate in which order does not matter I call a 'set' [Bolzano] |
| Full Idea: An aggregate whose basic conception renders the arrangement of its members a matter of indifference, and whose permutation therefore produces no essential difference, I call a 'set'. | |
| From: Bernard Bolzano (Paradoxes of the Infinite [1846], §4), quoted by William W. Tait - Frege versus Cantor and Dedekind IX | |
| A reaction: The idea of 'sets' was emerging before Cantor formalised it, and clarified it by thinking about infinite sets. Nowadays we also have 'ordered' sets, which rather contradicts Bolzano, and we also expect the cardinality to be determinate. |
| 10856 | A truly infinite quantity does not need to be a variable [Bolzano] |
| Full Idea: A truly infinite quantity (for example, the length of a straight line, unbounded in either direction) does not by any means need to be a variable. | |
| From: Bernard Bolzano (Paradoxes of the Infinite [1846]), quoted by Brian Clegg - Infinity: Quest to Think the Unthinkable §10 | |
| A reaction: This is an important idea, followed up by Cantor, which relegated to the sidelines the view of infinity as simply something that could increase without limit. Personally I like the old view, but there is something mathematically stable about infinity. |
| 13745 | Supervenience is not a dependence relation, on the lines of causal, mereological or semantic dependence [Kim] |
| Full Idea: It is a mistake, or at least misleading, to think of supervenience itself as a special and distinctive type of dependence relation, alongside causal dependence, mereological dependence, semantic dependence, and others. | |
| From: Jaegwon Kim (Postscripts on supervenience [1993], 2) | |
| A reaction: The point, I take it, is that supervenience is something which requires explanation, rather than being a conclusion to the debate. Why are statues beautiful? Why do brains generate minds? |
| 13746 | Supervenience is just a 'surface' relation of pattern covariation, which still needs deeper explanation [Kim] |
| Full Idea: Supervenience itself is not an explanatory relation, not a 'deep' metaphysical relation; rather it is a 'surface' relation that reports a pattern of property covariation, suggesting the presence of an interesting dependency relation that might explain it. | |
| From: Jaegwon Kim (Postscripts on supervenience [1993], 2) | |
| A reaction: I think the underlying idea here is that supervenience appeals to the Humean view of physical laws as mere regularities, but it is no good for those who seek underlying mechanisms to explain the patterns and regularities. Humeans are wrong. |
| 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? |