Combining Philosophers

All the ideas for Archimedes, Richard Posner and Karl Weierstrass

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4 ideas

6. Mathematics / A. Nature of Mathematics / 5. The Infinite / k. Infinitesimals
18086 Weierstrass eliminated talk of infinitesimals [Weierstrass, by Kitcher]
     Full Idea: Weierstrass effectively eliminated the infinitesimalist language of his predecessors.
     From: report of Karl Weierstrass (works [1855]) by Philip Kitcher - The Nature of Mathematical Knowledge 10.6
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / l. Limits
18092 Weierstrass made limits central, but the existence of limits still needed to be proved [Weierstrass, by Bostock]
     Full Idea: After Weierstrass had stressed the importance of limits, one now needed to be able to prove the existence of such limits.
     From: report of Karl Weierstrass (works [1855]) by David Bostock - Philosophy of Mathematics 4.4
     A reaction: The solution to this is found in work on series (going back to Cauchy), and on Dedekind's cuts.
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
13007 Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz]
     Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points.
     From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13
     A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry.
24. Political Theory / D. Ideologies / 5. Democracy / a. Nature of democracy
21131 Democracy is competition for support of the people, guided by self-interest on all sides [Posner]
     Full Idea: Democratic politics is a competition among self-interested politicians, constituting a ruling class, for the support of the people, also assumed to be self-interested, and none too interested or well informed about politics.
     From: Richard Posner (Law, Pragmatism and Democracy [2003], p.144), quoted by Andrew Shorten - Contemporary Political Theory 05
     A reaction: This articulates the 'competitive' view of democracy, as simply a technique for establishing legitimacy. Posner is also an economist, and they also assume that everyone is wholly self-interested, which may be why they are so frequently wrong.