The relational interpretation of quantum mechanics proposes to solve the measurement problem and reconcile completeness and locality of quantum mechanics by postulating relativity to the observer for events and facts, instead of an absolute "view from nowhere". The aim of this paper is to clarify this interpretation, and in particular, one of its central claims concerning the possibility for an observer to have knowledge about other observer's events. I consider three possible readings of this claim (deflationist, relationist and relativist), and develop the most promising one, relativism, to show how it fares when confronted with the traditional interpretative problems of quantum mechanics. Although it provides answers to some problems, I claim that there is currently no adapted locality criterion to evaluate whether the resulting interpretation is local or not.

Structural realism (SR) has been suggested as the best compromise in the debate on scientific realism. It proposes that we should be realist about the relational structure of the world, not its nature. However, it faces an important objection, first raised by Newman against Russell: if relations are not qualified, then the position is either trivial or collapses into empiricism, but if relations are too strongly qualified, then it is no longer SR. A way to overcome this difficulty is to talk about modal, or nomological relations instead of purely extensional relations. I argue that this is insufficient, for then, SR collapses into modal empiricism (ME). I suggest, however, that ME could be the best position in the debate on scientific realism. 1Introduction2Objections to Structural Realism3How to Escape Newman’s Objection4Which Modal Relations Are Retained in Theory Change?5Are Modal Relations Real?6Relativity and Fundamentality7Is Modal Empiricism Really Empiricism?8Could Modal Empiricism Be the Best of Both Worlds?

Callender and Cohen have proposed to apply a “Gricean strategy” to the constitution problem of scientific representation. They suggest that scientific representation can be reduced to stipulation by epistemic agents. This account has been criticized for not making a distinction between symbolic and epistemic representation and not taking into account the communal aspects of representation. These criticisms would not apply if Grice’s actual strategy were properly employed. I transpose Grice’s strategy to epistemic representation. The main novelty of the resulting account is a distinction between contextual representational use and general representational status, which I address using the notion of indexicality.

Dans cet article, nous tentons d'explorer les liens possibles entre le réalisme structural et le problème de la mesure en mécanique quantique, et la façon dont ils peuvent s'éclairer mutuellement.

I critically examine the assumption that the theoretical structure that varies under theoretical symmetries is redundant and should be eliminated from a metaphysical picture of the universe, following a "symmetry to reality" inference. I do so by analysing the status of coordinate change symmetries taking a pragmatic approach. I argue that coordinate systems function as indexical devices, and play an important pragmatic role for representing concrete physical systems. I examine the implications of considering this pragmatic role seriously, taking what I call a perspectivist stance. My conclusion is that under a perspectivist stance, all symmetries (including local gauge symmetries) potentially have a direct empirical status: they point to dynamical aspects that are invariant under changes of operationalisation, and they constitute a guide not to reality, but to nomology and kinship.Note, however, that the authors concerned with the debate on DES present their case using the traditional formulation of physical theories, with all their "surplus structure." And that for a good reason: a reduced theory has no symmetry, so trivially, no symmetry of this theory can have DES. Galileo's ship would be represented by the same model in a reduced theory, or by the same sub-structure of a model, whether it is moving or not; a distinct part of a model encompassing the shore and the ship, representing the distance (or the region) between the two, would vary in the two situations, but the part that represents the ship would be identical. Arguably, reduced theories still explain why one cannot tell whether Galileo's ship is moving from the inside, but without appealing to symmetries: the explanation is simply that Galileo's ship is in the same state in both cases. Friederich (2015) draws the same conclusion with regards to local symmetries (in non-reduced theories), after arguing that they have no DES: "what appear to be two physically distinct yet empirically indistinguishable subsystem situations [. . . ] turns out to be one single physical subsystem situation." This conclusion comes out naturally with reduced theories.However, scientists do not use reduced theories either when representing concrete physical systems. This could be because reduced theories are more difficult to handle. But most of the time, they do not even use coordinate-free formulations of non-reduced theories, except in foundational discussions (Wallace 2019b). As remarked by Belot ( 2018), the received view, among scientists, is that translations and rotations applied to a model do represent a genuine physical change (or at least they can represent such a change).So, part of our original puzzle remains: if what is real is what is invariant under symmetry, and if the aim of science is to describe reality, why aren't scientists and philosophers doing away with coordinate systems or gauges when representing physical systems, or the universe as a whole? And why should we assume that any symmetry has empirical significance if, ultimately, theories without symmet...