Combining Texts

All the ideas for 'fragments/reports', 'Ways Worlds Could Be' and 'Foundations of Geometry'

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4 ideas

5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism
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.
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
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.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
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?
21. Aesthetics / C. Artistic Issues / 7. Art and Morality
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?