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Ideas for 'Locke on Essences and Kinds', 'Transworld Heir Lines' and 'works'

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3 ideas

6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / c. Fregean numbers
If '5' is the set of all sets with five members, that may be circular, and you can know a priori if the set has content [Benardete,JA on Frege]
     Full Idea: There is a suspicion that Frege's definition of 5 (as the set of all sets with 5 members) may be infected with circularity, …and how can we be sure on a priori grounds that 4 and 5 are not both empty sets, and hence identical?
     From: comment on Gottlob Frege (works [1890]) by José A. Benardete - Metaphysics: the logical approach Ch.14
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Frege aimed to discover the logical foundations which justify arithmetical judgements [Frege, by Burge]
     Full Idea: Frege saw arithmetical judgements as resting on a foundation of logical principles, and the discovery of this foundation as a discovery of the nature and structure of the justification of arithmetical truths and judgments.
     From: report of Gottlob Frege (works [1890]) by Tyler Burge - Frege on Knowing the Foundations Intro
     A reaction: Burge's point is that the logic justifies the arithmetic, as well as underpinning it.
Eventually Frege tried to found arithmetic in geometry instead of in logic [Frege, by Friend]
     Full Idea: After the problem with Russell's paradox, Frege did not publish for fourteen years, and he then tried to re-found arithmetic in Euclidean geometry, rather than in logic.
     From: report of Gottlob Frege (works [1890], 3.4) by Michèle Friend - Introducing the Philosophy of Mathematics 3.4
     A reaction: I take it that his new road would have led him to modern Structuralism, so I think he was probably on the right lines. Unfortunately Frege had already done enough for one good lifetime.