“The Principle of Equivalence as a Criterion of Identity,” Synthese (2018), doi:10.1007/s11229-018-01897-w. (journal) (preprint)
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’s methodological significance resides in its motivation of a criterion of identity for the motions of freely falling frames and inertial frames. 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.
“There is No Conspiracy of Inertia,” British Journal for the Philosophy of Science 69, no. 4 (2018): 957-82. Published online May 18, 2017. (journal) (preprint)
Abstract: I examine two claims that arise in Harvey Brown’s account of inertial motion in Physical Relativity (2005). Brown claims there is something objectionable about the way in which the motions of free particles in Newtonian theory and special relativity are coordinated. Brown also claims that since a geodesic principle can be derived in Einsteinian gravitation the objectionable feature is explained away. I argue that there is nothing objectionable about inertia and that, while the theorems that motivate Brown’s second claim can be said to figure in a deductive-nomological explanation, their main contribution lies in their explication rather than their explanation of inertial motion.
“Friedman’s Thesis,” Studies in History and Philosophy of Modern Physics 52 (2015): 129-38. (journal) (preprint)
Abstract: This essay examines Michael Friedman’s recent approach to the analysis of physical theories. Friedman argues against Quine that the identification of certain principles as “constitutive” is essential to a satisfactory methodological analysis of physics. I explicate Friedman’s characterization of a constitutive principle, and I evaluate his account of the constitutive principles that Newtonian and Einsteinian gravitation presuppose for their formulation. I argue that something close to Friedman’s thesis is defensible.
“On Identifying Background-Structure in Classical Field Theories,” Philosophy of Science 78, no. 5 (2011): 1070-81. (journal) (revised and extended version (2013))
Abstract: I examine a property of theories called “background-independence” that Einsteinian gravitation is thought to exemplify. This concept has figured in the work of Rovelli (2001, 2004), Smolin (2006), Giulini (2007), and Belot (2011), among others. I propose and evaluate a few candidates for background-independence, and I show that there is something chimaerical about the concept. I argue, however, that there is a proposal that clarifies the feature of Einsteinian gravitation that motivates the concept.