Combining Texts

All the ideas for 'Philosophical Explanations', 'Recent Aesthetics in England and America' and 'Foundations of Geometry'

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8 ideas

6. Mathematics / A. Nature of Mathematics / 2. Geometry
Hilbert aimed to eliminate number from geometry [Hilbert, by Hart,WD]
     Full Idea: One of Hilbert's aims in 'The Foundations of Geometry' was to eliminate number [as measure of lengths and angles] from geometry.
     From: report of David Hilbert (Foundations of Geometry [1899]) by William D. Hart - The Evolution of Logic 2
     A reaction: Presumably this would particularly have to include the elimination of ratios (rather than actual specific lengths).
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid axioms concerns possibilities of construction, but Hilbert's assert the existence of objects [Hilbert, by Chihara]
     Full Idea: Hilbert's geometrical axioms were existential in character, asserting the existence of certain geometrical objects (points and lines). Euclid's postulates do not assert the existence of anything; they assert the possibility of certain constructions.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Charles Chihara - A Structural Account of Mathematics 01.1
     A reaction: Chihara says geometry was originally understood modally, but came to be understood existentially. It seems extraordinary to me that philosophers of mathematics can have become more platonist over the centuries.
Hilbert's formalisation revealed implicit congruence axioms in Euclid [Hilbert, by Horsten/Pettigrew]
     Full Idea: In his formal investigation of Euclidean geometry, Hilbert uncovered congruence axioms that implicitly played a role in Euclid's proofs but were not explicitly recognised.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2
     A reaction: The writers are offering this as a good example of the benefits of a precise and formal approach to foundational questions. It's hard to disagree, but dispiriting if you need a PhD in maths before you can start doing philosophy.
Hilbert's geometry is interesting because it captures Euclid without using real numbers [Hilbert, by Field,H]
     Full Idea: Hilbert's formulation of the Euclidean theory is of special interest because (besides being rigorously axiomatised) it does not employ the real numbers in the axioms.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Hartry Field - Science without Numbers 3
     A reaction: Notice that this job was done by Hilbert, and not by the fictionalist Hartry Field.
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
Maybe knowledge is belief which 'tracks' the truth [Nozick, by Williams,M]
     Full Idea: Nozick suggests that knowledge is just belief which 'tracks the truth' (hence leaving out justification).
     From: report of Robert Nozick (Philosophical Explanations [1981]) by Michael Williams - Problems of Knowledge Ch. 2
13. Knowledge Criteria / C. External Justification / 4. Tracking the Facts
A true belief isn't knowledge if it would be believed even if false. It should 'track the truth' [Nozick, by Dancy,J]
     Full Idea: Nozick says Gettier cases aren't knowledge because the proposition would be believed even if false. Proper justification must be more sensitive to the truth ("track the truth").
     From: report of Robert Nozick (Philosophical Explanations [1981], 3.1) by Jonathan Dancy - Intro to Contemporary Epistemology 3.1
     A reaction: This is a bad idea. I see a genuine tree in my garden and believe it is there, so I know it. That I might have believed it if I was in virtually reality, or observing a mirror, won't alter that.
21. Aesthetics / A. Aesthetic Experience / 1. Aesthetics
Aesthetics has risen and fallen with Romanticism [Scruton]
     Full Idea: The rise and fall (as we presently perceive them) of aesthetics have been contemporaneous with the rise and fall of Romanticism.
     From: Roger Scruton (Recent Aesthetics in England and America [1980], p.3)
     A reaction: Maybe it started a little before Romanticism, as part of the Englightenment aim of being rational about everything, and maybe it survives Romanticism because we want to be scientific about everything.
21. Aesthetics / A. Aesthetic Experience / 2. Aesthetic Attitude
Aesthetic experience informs the world with the values of the observer [Scruton]
     Full Idea: It is possible to conclude that aesthetic experience has a peculiar practical significance: it represents the world as informed by the values of the observer.
     From: Roger Scruton (Recent Aesthetics in England and America [1980], p.13)
     A reaction: An excellent remark. If you look at, or listen to, anything, you can make a conscious effort to drain away your personal values (objectivity; science?), or you can consciously flood them with values. But moral and aesthetic vision must differ...