Neo-Fregean foundations for real analysis: Some reflections on Frege’s constraint. (English) Zbl 1014.03012

Wright, Crispin

Notre Dame J. Formal Logic 41, No. 4, 317-334 (2000).

Summary: We now know of a number of ways of developing real analysis on a basis of abstraction principles and second-order logic. One, outlined by S. Shapiro in his contribution to this volume [ibid. 335-364 (2000; Zbl 1014.03013); see below], mimics Dedekind in identifying the reals with cuts in the series of rationals under their natural order. The result is an essentially structuralist conception of the reals. An earlier approach, developed by Hale in his “Reals by Abstraction” program differs by placing additional emphasis upon what I here term Frege’s Constraint, that a satisfactory foundation for any branch of mathematics should somehow so explain its basic concepts that their applications are immediate. This paper is concerned with the meaning of and motivation for this constraint. Structuralism has to represent the application of a mathematical theory as always posterior to the understanding of it, turning upon the appreciation of structural affinities between the structure it concerns and a domain to which it is to be applied. There is, therefore, a case that Frege’s Constraint has bite whenever there is a standing body of informal mathematical knowledge grounded in direct reflection upon sample, or schematic, applications of the concepts of the theory in question. It is argued that this condition is satisfied by simple arithmetic and geometry, but that in view of the gap between its basic concepts (of continuity and of the nature of the distinctions among the individual reals) and their empirical applications, it is doubtful that Frege’s Constraint should be imposed on a neo-Fregean construction of analysis.

MSC:

03A05	Philosophical and critical aspects of logic and foundations
00A30	Philosophy of mathematics
03F35	Second- and higher-order arithmetic and fragments
03B30	Foundations of classical theories (including reverse mathematics)
26A03	Foundations: limits and generalizations, elementary topology of the line

Keywords:

structuralism; foundations of real analysis; neo-Fregean program; abstraction principles; second-order logic

Citations:

Zbl 1014.03013

References:

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