Combining Texts

All the ideas for 'Good and Evil', 'Set Theory and the Continuum Hypothesis' and 'works'

unexpand these ideas     |    start again     |     specify just one area for these texts

---

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 / C. Sources of Mathematics / 10. Constructivism / a. Constructivism

14248	We could accept the integers as primitive, then use sets to construct the rest [Cohen]
	Full Idea: A very reasonable position would be to accept the integers as primitive entities and then use sets to form higher entities.
	From: Paul J. Cohen (Set Theory and the Continuum Hypothesis [1966], 5.4), quoted by Oliver,A/Smiley,T - What are Sets and What are they For?
	A reaction: I find this very appealing, and the authority of this major mathematician adds support. I would say, though, that the integers are not 'primitive', but pick out (in abstraction) consistent features of the natural world.

22. Metaethics / C. The Good / 1. Goodness / a. Form of the Good

22489	'Good' is an attributive adjective like 'large', not predicative like 'red' [Geach, by Foot]
	Full Idea: Geach puts 'good' in the class of attributive adjectives, such as 'large' and 'small', contrasting such adjectives with 'predicative' adjectives such as 'red'.
	From: report of Peter Geach (Good and Evil [1956]) by Philippa Foot - Natural Goodness Intro
	A reaction: [In Analysis 17, and 'Theories of Ethics' ed Foot] Thus any object can simply be red, but something can only be large or small 'for a rat' or 'for a car'. Hence nothing is just good, but always a good so-and-so. This is Aristotelian, and Foot loves it.