From fundamental theories to metaphysics

Belot, G. (1998). Understanding electromagnetism. The British Journal for the Philosophy of Science 49 (4), 531-555:

there is a very straightforward sense in which a false — but eminently useful — theory like electromagnetism can tell us about our world: it makes empirical predictions which are very accurate within a certain circumscribed domain of applicability. But it seems strange to say that the interpretation of such a theory tells us about our world. To interpret a theory is to describe the possible worlds about which it is the literal truth. Thus, an interpretation of electromagnetism seems to tell us about a possible world which we know to be distinct from our own. On the other hand, whatever world electromagnetism is true of, it is not one which contains quantum electrons. So it is difficult to see how a quantum-mechanical effect can teach us anything about the interpretation of electromagnetism. Of course, quantum mechanics itself is false (being nonrelativistic). So our world is one about which neither electromagnetism nor quantum mechanics is true. None the less, I maintain, we learn something about our own world when we study the interpretative interaction between these two false theories.


I distinguish three components of a physical theory: the formalism, the interpretation, and the application. The formalism is some (more or less rigorous) mathematics. This might be of interest to a mathematician with no interest whatsoever in physics. The application is a set of practices which allow one to derive and to test the empirical consequences of the theory. The interpretation consists of a set of stipulations which pick out a putative ontology for the possible worlds correctly described by the theory. Schematically, we can imagine the physical theory being taught in a course for undergraduates : the formalism is developed on the blackboard during lectures; the application is worked out in problem sets and in the lab; the interpretation is fixed via verbal asides which give the students a heuristic grasp of the content of the theory. A command of all three components will be essential for any student who aspires to full understanding of the theory.

The articulation of the content of our physical knowledge is one of the chief tasks of philosophy of physics. Much of this work is interpretative in nature. Naively, one seeks the correct interpretation of a given physical theory X. But, of course, all extant physical theories are false — none is both fully relativistic and fully quantum. What sense does it make to speak of the correct interpretation of a false theory?

A better picture would be this. We can begin by thinking of the content of a physical theory as consisting of the set of worlds at which it is true. This provides only a first approximation to the notion of physical content: we certainly do not view each interpretation as being on a par. So we should think of the content of a physical theory as the set of worlds described by the theory together with some additional structure which encodes our evaluation of the relative merits of each of the possible interpretations. Interpretation is the articulation of this further structure. Sometimes, as in electromagnetism, there will be a single most preferred interpretation. We may, if we like, think of this interpretation as being the 'correct' one. We will, of course, reserve the right to revise such judgements.

The formalism of the theory picks out the set of possible worlds which underlies the content of the theory. What determines the further structure? Here purely metaphysical views will play some role. But surely our beliefs about the structure of our own world make a large contribution here. We feel that there is a sense in which a world containing a physically real ether is less like our own than one in which fields are free-standing. This contributes to our sense that some interpretations of electromagnetism are more far-fetched than others. To the extent that such interpretative judgements place constraints on our beliefs about where the actual world might sit in the space of possible worlds, they are indeed judgements about our world. There is a clear sense, then, in which the interpretation of false theories teaches us about this world. Our beliefs about our world are reflected in our understanding of our false physical theories; so getting clear on the content of a false theory is one way to make explicit our beliefs about our world. Admittedly, this is a strange way to learn about the world. But it is also a fruitful one for us: in the absence of a true theory, our false theories provide much of our understanding of the structure of the world.

Laura Ruetsche, Interpreting Quantum Field Theory, Philosophy of Science Vol. 69, No. 2 (June 2002), pp. 348-378:

While I do not claim that the construal of interpretative projects offered here is the only, or even the best, construal of such projects, I do suggest that many archetypal interpretative questions are interpretative questions in this section's sense, and that many prominent and probing criticisms of interpretations call those interpretations to task for violating constraints this section announces.

One business of philosophers of physics is the interpretation of physical theories. The interpreter asks: “Under what conditions is this theory true? What does it say the world is like?” (Van Fraassen 1991, 242). A standard sort of answer (see Van Fraassen 1989, ch. 9 and references therein) proceeds in two stages. At the first, structure‐specifying, stage, the interpreter characterizes the structures by which the theory would represent physical reality.4 At the second, semantic, stage, the interpreter characterizes the physical worlds which model the theory so structured. Thus an interpretation of a theory identifies the physical worlds possible according to the theory.

Halvorson and Clifton, No Place for Particles in Relativistic Quantum Theories?:

if we believe that the assumptions of Malament’s theorem must hold for any theory that is descriptive of our world, then it follows that our world cannot be correctly described by a particle theory. On the other hand, if we believe that our world can be correctly described by a particle theory, then one (or more) of the Malament’s assumptions must be false.
Since our world is presumably both relativistic and quantum-theoretic, these results show that there are no localizable particles

Clifton and Halvorson, "Are Rindler Quanta Real? Inequivalent Particle Concepts in Quantum Field Theory":

All we have tried to determine… is how the world could possibly be if both the Rindler and Minkowski representations were 'true'.

Kuhlmann, Meinard, "Quantum Field Theory", The Stanford Encyclopedia of Philosophy (Spring 2009 Edition), Edward N. Zalta (ed.):

it thus appears to be impossible that our world is composed of particles when we assume that localizability in some finite region of space-time is a necessary ingredient of the particle concept

Belot, G. (2003, June). Symmetry and gauge freedom. Studies In History and Philosophy of Science Part B: Studies In History and Philosophy of Modern Physics 34 (2), 189-225.:

My worry here is not simply that our world is not fundamentally described by classical Yang–Mills theories. Indeed, I think we are in general entirely reasonable in debating the correct interpretation of less-than-fundamental theories. Understanding how this could be so is an outstanding philosophical problem. But this much, I suppose, is uncontentious: judgments about the interest and correctness of interpretations of theories which are (in the strictest sense) false must rest ultimately upon judgments about the extent to which various interpretations of a given theory contribute to, and integrate smoothly with, our understanding of the world. Here the following sorts of considerations play a role: background metaphysical commitments and hopes; judgments about the relative perspicuity of various alternative formulations of the theory that we are interested in, and about the links between variant formulations and competing interpretations; and considerations—operating at the technical, conceptual, and metaphysical levels—that arise when we consider how our theory is related to neighboring theories, both more and less fundamental.