Everything you always wanted to know about structural realism but were afraid to ask Content Type Journal Article Pages 227-276 DOI 10.1007/s13194-011-0025-7 Authors Roman Frigg, Department of Philosophy, Logic and Scientific Method, London School of Economics and Political Science, Houghton Street, London, WC2A 2AE UK Ioannis Votsis, Philosophisches Institut, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, Geb. 23.21/04.86, 40225 Düsseldorf, Germany Journal European Journal for Philosophy of Science Online ISSN 1879-4920 Print ISSN 1879-4912 Journal Volume Volume 1 Journal Issue Volume 1, Number 2.

Structural realism is the view that scientific theories give us knowledge only of the structure of the unobservable world. The view faces an influential objection that was first posed by Max Newman: if our knowledge of the unobservable world were strictly limited to its structure, our knowledge turns out to be trivial, for it amounts to nothing more than knowledge of the cardinality of the world. In this paper, I shall propose a response to Newman’s objection. It shall be argued (...) that in having epistemic access to the intrinsic nature of our conscious experiences—knowledge that structural realists allow for—we have knowledge of what it is to exist as concrete phenomena. With the plausible assumption that the relations of the unobservable world are also similarly concrete, one can address Newman’s objection. I shall further contrast this response to other similar responses that have been proposed, and also address the objection that this response is not available to structural realists. (shrink)

What is the ultimate nature of reality? This paper defends an answer in terms of informational realism (IR). It does so in three stages. First, it is shown that, within the debate about structural realism (SR), epistemic (ESR) and ontic (OSR) structural realism are reconcilable by using the methodology of the levels of abstractions. It follows that OSR is defensible from a structuralist-friendly position. Second, it is argued that OSR is also plausible, because not all related objects are logically prior (...) to all relational structures. The relation of difference is at least as fundamental as (because constitutive of) any relata. Third, it is suggested that an ontology of structural objects for OSR can reasonably be developed in terms of informational objects, and that Object Oriented Programming provides a flexible and powerful methodology with which to clarify and make precise the concept of “informational object”. The outcome is informational realism, the view that the world is the totality of informational objects dynamically interacting with each other.. (shrink)

Functionalism has become one of the predominant theories in the philosophy of mind, with its many merits supposedly including its capacity for precise formulation. The most common method to express this precise formulation is by means of the modified Ramsey sentence. In this article, I will apply work from the field of the philosophy of science to functionalism for the first time, examining how Newman’s objection undermines the Ramsey sentence as a means of formalising functionalism. I will also present a (...) formal variation on Newman’s objection through mathematical induction. Together, these proofs suggest that functionalism formalised by the Ramsey sentence trivially reduces to a kind of behaviourism plus a cardinality constraint on the number of relations holding between mental-relevant behaviours. As most functionalists see functionalism as a distinct theory of mind from behaviourism, this suggests that the modified Ramsey sentence cannot form a satisfactory formalism for functionalism. (shrink)

Structural realists claim that structure is preserved across instances of radical theory change, and that this preservation provides an argument in favor of realism about structure. In this paper, I use the shift from Newtonian gravity to Einstein’s general relativity as a case study for structural preservation, and I demonstrate that two prominent views of structural preservation fail to provide a solid basis for realism about structure. The case study demonstrates that (i) structural realists must be epistemically precise about the (...) concrete structure that is being preserved, and (ii) they must provide a metaphysical account of how structure is preserved through re-interpretation in light of a new theory. Regarding (i), I describe a means of epistemic access to the unobservable that I call “thick detection” of structure, which isolates the structure that will be preserved. Regarding (ii), I argue that thickly detectable structure is preserved across theory change through a process of extracting the old structure from the new structure, much like what has been done with geometrized versions of Newtonian gravity. With these two responses in hand, the structural realist can adequately account for the preservation of structure and can provide a strong argument in favor of structural realism. (shrink)

This is the revised version of an invited keynote lecture delivered at the "1st Australian Computing and Philosophy Conference". The paper is divided into two parts. The first part defends an informational approach to structural realism. It does so in three steps. First, it is shown that, within the debate about structural realism, epistemic and ontic structural realism are reconcilable. It follows that a version of OSR is defensible from a structuralist-friendly position. Second, it is argued that a version of (...) OSR is also plausible, because not all relata are logically prior to relations. Third, it is shown that a version of OSR is also applicable to both sub-observable and observable entities, by developing its ontology of structural objects in terms of informational objects. The outcome is informational structural realism, a version of OSR supporting the ontological commitment to a view of the world as the totality of informational objects dynamically interacting with each other. The paper has been discussed by several colleagues and, in the second half, ten objections that have been moved to the proposal are answered in order to clarify it further. (shrink)

In the literature over the Ramsey-sentence approach to structural realism, there is often debate over whether structural realists can legitimately restrict the range of the second-order quantifiers, in order to avoid the Newman problem. In this paper, I argue that even if they are allowed to, it won’t help: even if the Ramsey sentence is interpreted using such restricted quantifiers, it is still an implausible candidate to capture a theory’s structural content. To do so, I use the following observation: if (...) a Ramsey sentence did encode a theory’s structural content, then two theories would be structurally equivalent just in case they have logically equivalent Ramsey sentences. I then argue that this criterion for structural equivalence is implausible, even where frame or Henkin semantics are used. (shrink)

Newman’s objection can be used to argue that structuralism fails to specify a unique structure for the unobservable world, and hence, one can argue, it is ultimately a trivial task to determine the structure that the world ultimately has. Provided there are enough objects, any structure can be made compatible with that structure. We formulate a pragmatically enriched version of structuralism that avoids the Newman objection. For this purpose, we return to Carnap’s conception of founded relations, and provide a different (...) interpretation of them. According to Carnap, these are real, experienceable, physical relations. We argue that, when we specify a structural description of a given physical system, if we rely on such founded relations—provided they are properly understood—the threat of the Newman objection is avoided. However, pure structuralism has to be given up, and a form of empiricism can then be advanced. Finally, by using founded relations, we offer a framework in terms of which different conceptions can be articulated to avoid the Newman problem as well. (shrink)

This paper is a review of work on Newman's objection to epistemic structural realism (ESR). In Section 2, a brief statement of ESR is provided. In Section 3, Newman's objection and its recent variants are outlined. In Section 4, two responses that argue that the objection can be evaded by abandoning the Ramsey-sentence approach to ESR are considered. In Section 5, three responses that have been put forward specifically to rescue the Ramsey-sentence approach to ESR from the modern versions of (...) the objection are discussed. Finally, in Section 6, three responses are considered that are neutral with respect to one's approach to ESR and all argue (in different ways) that the objection can be evaded by introducing the notion that some relations/structures are privileged over others. It is concluded that none of these suggestions is an adequate response to Newman's objection, which therefore remains a serious problem for ESRists. Introduction Epistemic Structural Realism 2.1 Ramsey-sentences and ESR 2.2 WESR and SESR The Objection 3.1 Newman's version 3.2 Demopoulos and Friedman's and Ketland's versions Replies that Abandon the Ramsey-Sentence Approach to ESR 4.1 Redhead's reply 4.2 French and Ladyman's reply Replies Designed to Rescue the Ramsey-Sentence Approach 5.1 Zahar's reply 5.2 Cruse's reply 5.3 Melia and Saatsi's reply Replies that Argue that Some Structures/Relations are Privileged 6.1 A Carnapian reply 6.2 Votsis' reply 6.3 The Merrill/Lewis/Psillos reply Summary CiteULike Connotea Del.icio.us What's this? (shrink)

This unpublished paper, written in 2005 in the PhD philosophy program at Notre Dame, argues that algebraic structural realism faces a potentially fatal difficulty raised by the existence of inequivalent representations in quantum field theory.

Quantum theory offers mathematical descriptions of measurable phenomena with great facility and accuracy, but it provides absolutely no understanding of why any particular quantum outcome is observed. It is the province of genuine explanations to tell us how things actually work—that is, why such descriptions hold and why such predictions are true. Quantum theory is long on the what, both mathematically and observationally, but almost completely silent on the how and the why. What is even more interesting is that, in (...) some sense, this state of affairs seems to be a necessary consequence of the empirical adequacy of quantum descriptions. One of the most noteworthy achievements of quantum theory is the accurate prediction of phenomena that, on pain of experimental contradiction, have no physical explanation. It is the purpose of this essay to make clear why quantum mechanics and quantum field theory are complete physical descriptions that describe the metaphysical incompleteness of the physical world, then to press the negative implications of this fact for naturalistic metaphysics. (shrink)

Debates about scientific realism are closely connected to almost everything else in the philosophy of science, for they concern the very nature of scientific knowledge. Scientific realism is a positive epistemic attitude toward the content of our best theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences. This epistemic attitude has important metaphysical and semantic dimensions, and these various commitments are contested by a number of rival epistemologies of science, known collectively (...) as forms of scientific antirealism. This article explains what scientific realism is, outlines its main variants, considers the most common arguments for and against the position, and contrasts it with its most important antirealist counterparts. (shrink)

Russell's nonchalant response to Newman's apparently devastating critique of his structural realism presents a puzzle: if Russell conceded the point why did he not alter his theory or address the problem in print? I argue that Newman had merely pointed out an ambiguity in the formulation of Russell's theory in Analysis of Matter, and Russell already had the resources to avoid the problem through his contention that some relations are perceived. This concession gives his criterion of structural equivalence enough empirical (...) purchase to avoid Newman's triviality objection without the need to make stronger claims of knowledge of external relations than are present in Analysis of Matter. This provides a precise criterion of structural equivalence that explains exactly how the structural realist may escape Newman's objection by taking relations in intension. (shrink)

(i) Scientific realism is primarily a metaphysical doctrine about the existence and nature of the unobservables of science. (ii) There are good explanationist arguments for realism, most famously that from the success of science, provided abduction is allowed. Abduction seems to be on an equal footing, at least, with other ampliative methods of inference. (iii) We have no reason to believe a doctrine of empirical equivalence that would sustain the underdetermination argument against realism. (iv) The key to defending realism from (...) the pessimistic meta-induction is that we have greatly improved our capacity to understand the unobservable world over recent centuries. (shrink)

The paper is a kind of opinionated review paper on current issues in the debate about Structural Realism, roughly the view that we should be committed in the structural rather than object-like content of our best current scientific theories. The major thesis in the first part of the paper is that Structural Realism has to take structurally derived intrinsic properties into account, while in the second part key elements of aligning Structural Realism with a Humean framework are outlined.

When it comes to name-calling, structural realists have heard pretty much all of it. Among the many insults, they have been called ‘empiricist anti-realists’ but also ‘traditional scientific realists’. Obviously the collapse accusations that motivate these two insults cannot both be true at the same time. The aim of this paper is to defend the epistemic variety of structural realism against the accusation of collapse to traditional scientific realism. In so doing, I turn the tables on traditional scientific realists by (...) presenting them with a dilemma. They can either opt for a construal of their view that permits epistemic access to non-structural features of unobservables but then face the daunting task of substantiating a claim that seems to have little hope of being true or they can drop the requirement of epistemic access to non-structural features but then face a collapse to epistemic structural realism. There is thus only one well supported way to be a realist. No wonder then that many traditional scientific realists have over the years expressed views that are strikingly similar to epistemic structural realism. It is high time to let these epistemic structural realists out of the closet. (shrink)

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.

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. (shrink)

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. (shrink)

When it comes to name-calling, structural realists have heard pretty much all of it. Among the many insults, they have been called ‘empiricist anti-realists’ but also ‘traditional scientific realists’. Obviously the collapse accusations that motivate these two insults cannot both be true at the same time. The aim of this paper is to defend the epistemic variety of structural realism against the accusation of collapse to traditional scientific realism. In so doing, I turn the tables on traditional scientific realists by (...) presenting them with a dilemma. They can either opt for a construal of their view that permits epistemic access to non-structural features of unobservables but then face the daunting task of substantiating a claim that seems to have little hope of being true or they can drop the requirement of epistemic access to non-structural features but then face a collapse to epistemic structural realism. There is thus only one well supported way to be a realist. No wonder then that many traditional scientific realists have over the years expressed views that are strikingly similar to epistemic structural realism. It is high time to let these epistemic structural realists out of the closet. (shrink)

This paper considers whether, and how, the mind can be incorporated into structural realism. Section 1 begins with some definitions, and briefly reviews the main problems which beset structural realism. The existence of the mind is proffered as an additional problem, to which the rest of the paper is devoted. Three different philosophies of the mind are analysed, beginning with eliminative materialism, which is briefly reviewed in Section 2. The identity theory of the mind-brain relationship is critically analysed in Section (...) 3, and the notions of supervenience and emergentism are defined. In Section 4, the functionalist approach to the mind-brain relationship is introduced, and two specific functionalist approaches---the representational theory of the mind, and connectionism---are defined and appraised. It is argued that these approaches enable structural realism to be extended to include the mind. It is also argued that structural realism can be applied to the unconscious mind, and the paper concludes with the proposal that the distinction between epistemic structural realism and ontic structural realism is also valid in the case of the mind. (shrink)