Combining Texts

All the ideas for 'Foundations of Geometry', 'Brains and Behaviour' and 'Letters to Hugo Boxel'

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6 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.
17. Mind and Body / B. Behaviourism / 4. Behaviourism Critique
Superactors and superspartans count against behaviourism [Putnam, by Searle]
     Full Idea: Putnam proposed the superactor/superspartan objection to behaviourism.
     From: report of Hilary Putnam (Brains and Behaviour [1963]) by John Searle - The Rediscovery of the Mind Ch. 2.II
     A reaction: This is a beautiful compression of the obvious counterexamples, which are behaviour-wth-no-experience, and experience-with-no-behaviour. Presumably, though, Spartans are disposed to go 'aagh!' when they get home, and there are no 'super' actors.
21. Aesthetics / A. Aesthetic Experience / 5. Natural Beauty
The most beautiful hand seen through the microscope will appear horrible [Spinoza]
     Full Idea: The most beautiful hand seen through the microscope will appear horrible.
     From: Baruch de Spinoza (Letters to Hugo Boxel [1674], 1674?)
     A reaction: Spinoza offers this nicely expressed point to support his view that beauty is strictly relative to observers, but I am unconvinced. If the outline of the hand is its key aesthetic feature, the viewer through the microscope cannot see it.