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Ideas for 'fragments/reports', 'Logicism, Some Considerations (PhD)' and 'works'

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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 / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
An adequate account of a number must relate it to its series [Benacerraf]
     Full Idea: No account of an individual number is adequate unless it relates that number to the series of which it is a member.
     From: Paul Benacerraf (Logicism, Some Considerations (PhD) [1960], p.169)
     A reaction: Thus it is not totally implausible to say that 2 is several different numbers or concepts, depending on whether you see it as a natural number, an integer, a rational, or a real. This idea is the beginning of modern structuralism.