Citation

Samaroo R. Synthese 2020; 197(8): 3481-3505.

Copyright

(Copyright © 2020, Holtzbrinck Springer Nature Publishing Group)

DOI

10.1007/s11229-018-01897-w

PMID

32801399 PMCID

Abstract

In 1907 Einstein had the insight that bodies in free fall do not "feel" their own weight. This has been formalized in what is called "the principle of equivalence." The principle motivated a critical analysis of the Newtonian and special-relativistic concepts of inertia, and it was indispensable to Einstein's development of his theory of gravitation. A great deal has been written about the principle. Nearly all of this work has focused on the content of the principle and whether it has any content in Einsteinian gravitation, but more remains to be said about its methodological role in the development of the theory. I argue that the principle should be understood as a kind of foundational principle known as a criterion of identity. This work extends and substantiates a recent account of the notion of a criterion of identity by William Demopoulos. Demopoulos argues that the notion can be employed more widely than in the foundations of arithmetic and that we see this in the development of physical theories, in particular space-time theories. This new account forms the basis of a general framework for applying a number of mathematical theories and for distinguishing between applied mathematical theories that are and are not empirically constrained.

Language: en

Keywords

Criterion of identity; Einstein; Foundations of space-time theories; Frege; Newton; Principle of equivalence