Online research in philosophy

This chapter traces the development of structural realism within the scientific realism debate and the wider current of structuralism that has swept the philosophy of the natural sciences in the twentieth century.1 The primary aim is to make perspicuous the many manifestations of structural realism and their underlying claims. Among other things, I will compare structural realism’s various manifestations in order to throw more light onto the relations between them. At the end of the chapter, I will identify the main objections raised against the epistemic form of structural realism. This last task will pave the way for the evaluation of the structural realist answer to the main epistemological question, an evaluation that will be central to the rest of this dissertation.

The subject of this essay is the relationship, within spacetime theories, between contemporary structural realism and Michael Friedman’s recent defense of the relativized a priori. Despite Friedman’s claims that the relativized a priori can account for the progress and rationality of science, such that the elements and structures of past successful theories will continue to be retained in future successful theories, our investigation will demonstrate that his theory does not have sufficient resources to make this guarantee. However, by exploiting the distinction between the epistemic and ontic versions of structural realism, the main content of Friedman’s relativized a priori can be retained within a structural realist position, and can thereby secure the successive progress and rationality of science without sacrificing the essential ideas put forward by Friedman.

The miracle argument for scientific realism can be cast in two forms: according to the miraculous theory argument, realism is the only position which does not make the empirical successes of particular theories miraculous. According to the miraculous choice argument, realism is the only position which does not render the fact that empirically successful theories have been chosen a miracle. A vast literature discusses the miraculous theory argument, but the miraculous choice argument has been unjustifiably neglected. I raise two objections to Richard Boyd's defense of the latter: (1) we have no miracle free account of the emergence of take-off theories and (2) the anti-realist can account for the non-miraculous choice of empirically successful theories by attributing mere empirical adequacy to background theory. I argue that the availability of extra-empirical criteria that are arguably truth conductive but not theory-laden suffices to answer (1), and the unavailability of extra-empirical criteria that are conductive to empirical adequacy but not necessarily to truth (and are also not theory-laden) constitutes to reply to (2). The prospects for a realist victory are at least somewhat promising, on a controversial assumption about the rate at which empirically successful theories emerge.

In this dissertation, I examine a view called ‘Epistemic Structural Realism’, which holds that we can, at best, have knowledge of the structure of the physical world. Put crudely, we can know physical objects only to the extent that they are nodes in a structure. In the spirit of Occam’s razor, I argue that, given certain minimal assumptions, epistemic structural realism provides a viable and reasonable scientific realist position that is less vulnerable to anti-realist arguments than any of its rivals.

The essay examines the relationship, within spacetime theories, between contemporary structural realism, Cassirer’s neo-Kantian structuralism, and Friedman’s defense of the relativized a priori. Despite Friedman’s claim that the relativized a priori can explain the progress of science, by using invariant theoretical elements/structures, our investigation will demonstrate that his theory cannot make this guarantee, nor may Cassirer’s earlier theory. However, as will be argued, the main content of both Cassirer’s and Friedman’s theories can be retained within an epistemic version of structural realism, thereby securing an account of scientific progress.

In recent years Structural Realism has been revived as a compromise candidate to resolve the long-standing question of scientific realism. Recent debate over structural realism originates with Worrall's (1989) paper "Structural Realism: The best of Both Worlds". However, critics such as Psillos contend that structural realism incorporates an untenable distinction between structure and nature, and is therefore unworkable. In this paper I consider three versions of structural realism that purport to avoid such criticism. The first is Chakravartty's "semirealism" which proceeds by trying to show that structural realism and entity realism entail one another. I demonstrate that this position will not work, but follow Chakravartty's contention that structural realism need not imply that scientific knowledge can only be of mathematical structure. I advance from this conclusion to sketch a version of structural realism that is consistent with recent deflationary approaches to the scientific realism question. Finally, I consider a third approach to structural realism Ladyman's "metaphysical structural realism" which tries to avoid the difficulties of earlier versions by taking structure to be ontologically primary. I show that the deflationary approach to structural realism undermines the rationale behind Ladyman's approach.

Are theories ‘underdetermined by the evidence’ in any way that should worry the scientific realist? I argue that no convincing reason has been given for thinking so. A crucial distinction is drawn between data equivalence and empirical equivalence. Duhem showed that it is always possible to produce a data equivalent rival to any accepted scientific theory. But there is no reason to regard such a rival as equally well empirically supported and hence no threat to realism. Two theories are empirically equivalent if they share all consequences expressed in purely observational vocabulary. This is a much stronger requirement than has hitherto been recognised—two such ‘rival’ theories must in fact agree on many claims that are clearly theoretical in nature. Given this, it is unclear how much of an impact on realism a demonstration that there is always an empirically equivalent ‘rival’ to any accepted theory would have—even if such a demonstration could be produced. Certainly in the case of the version of realism that I defend—structural realism—such a demonstration would have precisely no impact: two empirically equivalent theories are, according to structural realism, cognitively indistinguishable.

This paper examines whether structural realism entails an anti-realist thesis about natural kinds. Structural Realism is the view that the scientific realist can only support a realist claim about the structure of reality rather than its objects. Ladyman (1998) (2002) & French & Ladyman (2003) motivate the claim that ontic structural realism eliminates ‘objects’ as a distinct ontological category, thereby eliminating any possibility of a metaphysical account of individual objects. This is empirically motivated by fundamental physics. Those inclined towards realism about the rest of the sciences (chemistry, biology, the medical sciences, economics and so on) might think the appeal of structural realism as a general metaphysics for all of the sciences limited. Nevertheless, recent literature argues that mature special sciences e.g. economics, can be equally described by mathematical/syntactic models making the appeal of structural realism a more general one for the metaphysics of all of the sciences. {Ross (2006)}. Given a commitment to ontic structural realism, if natural kinds are kinds of “object”, then anti-realism about natural kinds should follow. However, I examine two realist theses about natural kinds and argue that a commitment to structural realism is not straightforwardly inconsistent with either.

In the debate over scientific realism, attention has been given recently to a realist position referred to as structural realism. In this essay, I offer a version of this position and indicate how it addresses two standard forms of underdetermination argument posed by the anti-realist.

Structural realism has been proposed as an epistemological position interpolating between realism and sceptical anti-realism about scientific theories. The structural realist who accepts a scientific theory thinks that is empirically correct, and furthermore is a realist about the ‘structural content’ of . But what exactly is ‘structural content’? One proposal is that the ‘structural content’ of a scientific theory may be associated with its Ramsey sentence (). However, Demopoulos and Friedman have argued, using ideas drawn from Newman's earlier criticism of Russell's structuralism, that this move fails to achieve an interesting intermediate position between realism and anti-realism. Rather, () adds little content beyond the instrumentalistically acceptable claim that the theory is empirically adequate. Here, I formulate carefully the crucial claim of Demopoulos and Friedman, and show that the Ramsey sentence () is true just in case possesses a full model which is empirically correct and satisfies a certain cardinality condition on its theoretical domain. This suggests that structural realism is not a position significantly different from the anti-realism it attempts to distinguish itself from. Introduction Technical framework Ramsification Empirical adequacy Ramsification empirical adequacy + cardinality constraint Conclusion.