The problem of theoretical equivalence is traditionally understood as the problem of specifying when superficially dissimilar accounts of the world are reformulations of a single underlying theory. One important strategy for answering this question has been to appeal to formal relations between theoretical structures. This article presents two reasons to think that such an approach will be unsuccessful and suggests an alternative account of theoretical equivalence, based on the notion of interpretive equivalence, in which the problem is merely an instance (...) of a broader problem in the philosophy of physics. I thus conclude that there is no distinctive problem of theoretical equivalence at all. Two difficulties my approach raises for realist replies to the threat of underdetermination are then discussed, with particular emphasis on a recent reply by Norton. 1 Introduction2 Methodological Confusion3 Asymmetrical Equivalence3.1 Maxwell’s field equations3.2 Classical Lagrangian dynamics4 Formal Approaches: Quine and Glymour5 Theoretical Equivalence as Interpretive Equivalence6 Theoretical Equivalence without Interpretive Judgement?7 Lessons for Underdetermination. (shrink)

Einstein claimed that the fundamental dynamical insight of special relativity was the equivalence of mass and energy. I disagree. Not only are mass and energy not equivalent but talk of such equivalence obscures the real dynamical insight of special relativity, which concerns the nature of 4-forces and interactions more generally. In this paper I present and defend a new ontology of special relativistic particle dynamics that makes this insight perspicuous and I explain how alleged cases of mass–energy conversion can be (...) accommodated within that ontology. (shrink)

This document is a synopsis of discussions at the workshop prepared by Nicholaos Jones and Kevin Coffey, with remarks added by by Chuang Liu, John D. Norton, John Earman, Gordon Belot, Mark Wilson, Bob Batterman and Margie Morrison. The program is included in an appendix.

It is sometimes said there are two ways of formulating Newtonian gravitation theory. On the first, matter gives rise to a gravitational field deflecting bodies from inertial motion within flat spacetime. On the second, matter’s accelerative effects are encoded in dynamical spacetime structure exhibiting curvature and the field is ‘geometrized away’. Are these accounts of Newtonian gravitation theoretically equivalent? Conventional wisdom within philosophy of physics is that they are, and recently several philosophers have made this claim explicit. In this paper (...) I develop an alternative approach to Newtonian gravitation on which the equivalence claim fails, and in the process identify an important but largely overlooked consideration for interpreting physical theories. I then apply this analysis to (a) put limits on the uses of Newtonian gravitation within the methodology of science, and (b) defend the interpretive approach to theoretical equivalence against formal approaches, including the recently popular criterion of categorical equivalence. (shrink)