4 ideas
10053 | Geometrical axioms imply the propositions, but the former may not be true [Russell] |
Full Idea: We must only assert of various geometries that the axioms imply the propositions, not that the axioms are true and therefore that the propositions are true. | |
From: Bertrand Russell (Foundations of Geometry [1897], Intro vii), quoted by Alan Musgrave - Logicism Revisited §4 | |
A reaction: Clearly the truth of the axioms can remain a separate issue from whether they actually imply the theorems. The truth of the axioms might be as much a metaphysical as an empirical question. Musgrave sees this as the birth of if-thenism. |
10052 | Geometry is united by the intuitive axioms of projective geometry [Russell, by Musgrave] |
Full Idea: Russell sought what was common to Euclidean and non-Euclidean systems, found it in the axioms of projective geometry, and took a Kantian view of them. | |
From: report of Bertrand Russell (Foundations of Geometry [1897]) by Alan Musgrave - Logicism Revisited §4 | |
A reaction: Russell's work just preceded Hilbert's famous book. Tarski later produced some logical axioms for geometry. |
15432 | Structural universals might serve as possible worlds [Forrest, by Lewis] |
Full Idea: Forrest proposed that structural universals should serve as ersatz possible worlds. | |
From: report of Peter Forrest (Ways Worlds Could Be [1986]) by David Lewis - Against Structural Universals 'Intro' | |
A reaction: I prefer powers to property universals. Perhaps a possible world is a maximal set of co-existing dispositions? |
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? |