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Chakravartty’s chapter is helpful in asking what naturalistic metaphysics might be and what might motivate it. He is sympathetic to what he takes to be the main motivation, viz. the great distance between analytic metaphys-ics and the empirical results of science. However, he doubts that there is currently a coherent and clear sense of naturalistic metaphysics, arguing that we cannot keep a priori metaphysics out of science because metaphysical notions such as cause inevitably arise in reporting scientific results; because there is at present no clear, non-trivializing way to distinguish metaphysics that is based on the a posteriori part of science from that which is not; and because metaphysical questions are underdetermined by the evidential base of science. Chakravartty ends with a positivefirst stab at characterizing the sense in which metaphysics might be‘grounded’ in empirical science, a standard but unclear naturalist claim. He spells out the idea in terms of

distance from experience running along a continuum from directly detect-able on one end to inferred or postulated on the other and in terms of Popperian riskiness. Many of the remaining chapters can be seen as provid-ing responses to Chakravartty’s position.

Humphreys focuses on the status of what he calls‘speculative ontology’

versus‘scientific ontology’. Scientific ontology gives us answers to ques-tions about what exists that are consistent with the well-established results and methods of science. Speculative ontology is not so constrained. His main target and the bulk of his chapter is the latter.

Humphreys identifies multiple problems with speculative ontology.

First he claims that it is sometimes directly inconsistent with well-estab-lished science. Since the science also is readily accessible and could be understood by philosophers, this kind of metaphysics is epistemically ‘irre-sponsible’. A second problem is the reliance on intuition in speculative metaphysics, since intuitions differ and have limited reliability. Where we have conflicting intuitions and no criteria to determine who are the experts, intuitions should be rejected as evidence in general, and thus as evidence in metaphysics. Echoing a common theme of the volume, Humphreys also argues that any analysis of common-sense concepts cannot legitimately place constraints on science but speculative ontology threatens precisely that. Finally, Humphreys suggests that we have reason to believe that the world is not scale invariant (a theme emphasized by Ladyman and Ross as well), making our ordinary concepts and intuitions of dubious project-ability beyond the domain of our own commonplace interactions with and manipulations of the world.

Melnyk in his chapter carefully sorts out key issues around what a naturalistic metaphysics would be like and what motivates it. A naturalistic metaphysics might show how claims of the special sciences hang together with fundamental physics as claimed by Ladyman and Ross, but why must it be restricted to unifying (as opposed to answering other questions), to identifying when unification is properly at issue, and to establishing unity with physics rather than with other parts of science?

Melnyk, like Humphreys, thinks naturalized a priori knowledge has not been ruled out. Intuitions may be reliable in some domains of inquiry. He also asks ‘What sort of priority does science have?’ The common-sense practices forfinding out about the world that science refines may none-theless still tell us some things about how the world is and so produce knowledge, at least where it is does not contradict well established

scientific results. Melnyk also asks whether a properly naturalized meta-physics could correct science, since on its advocates’ view it is part of science itself. These are good questions.

Dennett proposes that we think of standard analytic metaphysics as sorting out the common view of the world which he equates with Sellars’s notion of the‘manifest image’—the set of beliefs that ordinary humans have formed in their evolution so that they can get about in the world. On his view what drives much philosophy is negotiating between the scien-tific image and the manifest image, and it would be helpful to have an anthropology of the latter. This requires bracketing truth in favour of a careful delineation of its contours, producing a metaphysics of the manifest image.

This position bears some resemblance to ‘the Canberra project’ in metaphysics, which sees conceptual analysis as about determining the outline of folk theories. The Canberra project then wants to ask what in the world, if anything, corresponds to the elements of those theories.

Dennett, however, instead talks of the manifest image as a framework and invokes the idea of ontological relativity, trying to avoid the conclu-sion that the manifest image is false or in need of corrections. As he grants, this line of defense calls for further elaboration.

Ladyman and Ross focus their chapter around consideration of a recent book by Deutsch (2011). Deutsch, a physicist, develops a philosophy of science and metaphysics based on the goal of seeing how sciences as diverse as physics, the theory of computation, and evolutionary biology hang together. Thus he shares Ladyman and Ross’s (2007) thought that meta-physics in the form of unifying different scientific hypotheses is a worthy scientific project. He argues against reductionism because scientific results show that macro-level phenomena are often best explained in their own terms and that the scientific criterion for existence is information-theoretic—to be is to be a quasi-autonomous flow of information. These ideas are quite close to those of Ladyman and Ross (2007) and provide a context for them to further explain and clarify those claims in their chapter.

However, Deutsch in the end argues for an interpretation of quantum mechanics that presumes that irreducible stochasticity is scientifically unacceptable. For Ladyman and Ross, this move brings dogmatic, non-naturalized metaphysics into science. They propose instead a Pierceian understanding of the world such that it is the inherent stochasticity of

reality that explains the success of our statistical methods. The world is the totality of non-redundant statistics. They apply these ideas to debates about the interpretation of quantum mechanics in a way that is quite original and sophisticated and I will return to it in concluding the chapter.

Wilson presents his critique of the classical view of concepts and draws out the implications for what philosophy can and cannot do. The classical view of concepts—as found in Russell for example—asserts that once one has acquired language and the concepts it embodies then one can determine conceptual contents by introspection. On Wilson’s view much contempor-ary philosophy rests on an inchoate amalgam of classical and anticlassical themes. Scientific philosophy of the past was motivated by scientific prob-lems that required a conceptual freedom and creativity that did notfit well with the classical conception of concepts. However the positivist tradition bet on a wrong alternative to the classical notion, depending on the idea that set theory, logic, and axiomization would supply a curative. A real under-standing of ongoing scientific conceptual change in the last two centuries in mathematical physics, especially the physics relating mechanics to constitu-ents of matter, shows that‘science comes at us in pieces’ that invoke a variety of stratagems embodying applied mathematics, making for piecemeal local change to develop concepts that reliably track the data. As an illustration, Wilson discusses in detail the problem of explaining the motion of a bead on a string, Euler’s rule for doing so, and the obstacles and changes needed to make the rule reliable.

Much conceptual and inferential change in science is of this sort, making Wilson suspicious of axiomatizations and talk of overarching frameworks in science. Thus he is doubtful about projects, like that of Friedman (2001), according to which modern day scientific philosophy should be involved in creating the conceptual space for understanding and transforming contem-porary frameworks in science. He instead thinks the study of scientific concepts in practice in all their localized detail is the kind of work that someone trained in the analytic methods of philosophy can better under-take. This is a project far removed from the analysis of necessary and sufficient conditions based on armchair intuitions about meanings.

Friedman lays out his program for scientific philosophy as the identifi-cation and development of the constitutive representations of mathemat-ical physics. Like Wilson, he thinks that Quine’s holism encouraged overlooking important differences in the kinds of assumptions at work in scientific theories. He explains how identifying a priori elements of

scientific frameworks is necessary to fully understand them, helps make them possible, and provides for a kind of objectivity as intersubjective agreement via a relativized a priori.

Friedman argues that this project is orthogonal to the project pursued by Wilson. The kind of tension and change produced in trying to connect mechanics and matter theory were not ones that drove the historical change to relativity theory that is Friedman’s main case study. Einstein was careful to bracket issues in matter theory of the sort described by Wilson as he developed the theories of special and general relativity. So there is room for the study of concepts in the context of the fundamental presuppositions of theoretical frameworks and for the patchwork-like atlases of the application of physical concepts that Wilson produces. It is an interesting and open question how kinds of scientific activity aimed at modeling different aspects of systems might be interrelated.

Two questions about Friedman’s approach arise. Wilson in this volume doubts that there is such a unified framework in the first place. As he would put it, science comes at us in pieces as a patchwork of adjustments whose structure is not easily characterized as an n-tuple. Wilson’s Wandering Significance is a sustained argument backed up by countless detailed examples for this claim. So it unclear whether Wilson can ultimately accept Friedman’s proposed reconciliation of their two projects as orthogonal.

A second question concerns what Friedman’s view implies for the scope of metaphysics. The presuppositions of physics address issues about the nature of space, for example, but other metaphysical issues don't seem to have any direct connection.

Wilson in his second chapter turns to a variant of naturalized metaphysics that hefinds implausible, but I would also argue that his criticisms tell against strands of analytic metaphysics as well. He objects to the idea that we can adequately describe the physical world with only the kind terms of basic physics andfirst-order logical operations on those predicates, supporting the prospect that mathematics might be eliminated. The problem is that much mathematics is tangled up in specifying those predicates themselves, and applying them to reality involves determining a variety of other constructed physical quantities on a domain by domain basis. So clearly Wilson is a naturalist who is not committed to common forms of physical-ism. I think that his point generalizes to problems for analytic metaphysics, because innumerable debates about whether physical properties are funda-mental in various (obscure) senses take it for granted that we know what we

mean by‘physical property’ in the first place (and by ‘biological,’ ‘mental,’

or‘social’ properties for that matter). Debates framed in these terms are off to a bad start from the very beginning.

Following up on a comment from Dennett in Freedom Evolves that his own account might be improved by incorporating recent work on causal-ity from philosophy of science and computer science, Ismael discusses the scientific philosophy project in relation to the metaphysics of free will. On her view naturalistic metaphysics means there is no science-independent standpoint for inquiry and involves applying science to philosophical problems. For example, the naturalistic metaphysician takes her view of cause from science. The common-sense notion of cause may be of a force imposed from outside. Philosophers may think of the deterministic laws governing entire physical systems as determining their subsystems. But these ideas are undermined by our best scientific account of causal know-ledge. Ismael takes our best understanding to be based on the exciting developments originating in Pearl (2010) and Spirtes, Glymour, and Scheines (2001). They show that by working back from an explicit causal model meeting certain assumptions it is possible to deduce the conditional and unconditional dependencies that should be seen in the data if the model is the correct one, and give a semantics for graphical causal models that illuminates seemingly different empirical approaches to causation in the social, behavioural, and biomedical sciences. Ismael believes that this work shows among other things that what causes wefind depends on what we hold fixed, that we cannot get theories of local subsystems from dynamic laws that pertain to the whole, and that local modalities are richer than global ones. These understandings defuse the antecedent objection to basically compatibilist notions of free will.

Ismael points out that the work on causation that she invokes is not about conceptual analysis of our ordinary concepts but an explication of causal inference in science. Ismael also argues that the Pearl and Scheines et al. programme in graphical causal modelling sheds scientific light on the nature of causation. I might add that it does so by in part showing that what seemed to be diverse understandings of causation in scientific prac-tice are in effect reflections of one common underlying framework. This is a nice example of Ladyman and Ross’s interest in metaphysics as produc-ing scientific unification, although it does not involve physics in they way they would want (and with which Melnyk disagrees in his chapter).

It is worth expanding on this reading a bit to help clarify the versions of naturalistic metaphysics that predominate in this volume. Hall (2007), in a recent article on structural equation models and associated graphical expli-cations of causality, complains that they do not (could never?) handle causal preemption. However, this misunderstands the project encapsulated in graphical accounts of causal models. It is not to give necessary and sufficient conditions for our ordinary notion of cause. It is to give a unified account of how evidence is amassed for certain specified notions of cause that scientists antecedently understand. The causal evidence amassed is supposed to be conditional on an already specified causal model. The results generally are explicit that preemption is not handled by these methods—the standard faithfulness condition rules them out in that when preemption is present, incorrect inferences are made. The notion of causation that is best understood by these methods is that of individually sufficient independent causes that contribute to an effect (Kincaid, 2012b).

Pearl and company do not claim to handle all possible types of causation— necessary causes or effect modifiers do not easily fit into the framework. It is an empirical matter as to which kinds of scientific causal claims their models capture. Conceptual analysis in the sense of getting clear on how apparently different scientific methods and results hang together does go on but it is a quite different enterprise from conceptual analysis based on intuitions about our common-sense notion of cause. The unification achieved is not necessary for those practices to proceed but it is a uni fica-tion that increases our understanding of how different methods and the results they producefit together. It is quite different from the analytic metaphysical approach to causation. It gives no reason to think that kind of metaphysics is essential to science.

I want tofinish my discussion of the chapters by returning to Chakra-vartty’s chapter and making more explicit how and to what extent the chapters that follow answer his doubts about scientific metaphysics. There are various different and complementary responses to the claim that itional metaphysics is inevitable in science. Humphreys argues that trad-itional metaphysics in the guise of speculative ontology is unconstrained by scientific evidence and often flatly at odds with it, and is thus illegitimate.

However, scientific ontology goes beyond just what scientists explicitly are committed to because sometimes interpretations are underdetermined by the data as, for example, in quantum mechanics. However, those interpret-ations are still constrained by well-established results and widely accepted

standards of scientific evidence, unlike speculative ontology. So traditional metaphysics in the sense of speculative ontology has no place in an object-ive scientific understanding of the world.

Thus the underlying point is that‘metaphysics’ comes to several differ-ent things and understanding naturalized metaphysics requires staying clear about these differences. Friedman echoes this idea from another vantage point. The claims that derive from the necessary presuppositions required to tie theory to observation are quite specific and must be distinguished from other traditional metaphysical claims that do not play that role.

Ladyman and Ross have interesting things to say about the scientific ontology that Humphreys identifies with competing interpretations of the same data and that constitute one of Chakravartty’s reasons for thinking metaphysics cannot be naturalized. In Every Thing Must Go Ladyman and Ross deny that the status of questions that go beyond any possible evidence is an issue for science and thus a naturalistically respectable issue. The argument is not that such questions are meaningless, as positivists sometimes maintained. It is that science itself prohibits pursuing such questions, for they are not possible objects of‘objective inquiry’. Some of the kinds of underdetermination Humphreys has in mind may fall into this category.

In their chapter in this volume Ladyman and Ross address the interpret-ation of quantum mechanics directly and add interesting new content to their view on these issues, I believe. They point out that scientists can and should be strategic antirealists of the instrumentalist stripe on some occa-sions by refusing to take a stand on interpretations. They point out that working with a formalism that is given no preferred physical interpretation can lead to useful, novel, and compelling evidence supporting the structure behind the formalism. Such is the case with quantum mechanics.

Ismael’s comments about the progress in understanding causation coming from graphical approaches replies to Chakravartty’s claim that because scientists make causal claims, they are inevitably involved in metaphysical theorizing. As I pointed out earlier, the work of Pearl et al.

is not aboutfinding a general conception of causation in non-causal terms tested against intuition and common-sense counterexamples. Their work is showing how initially apparently different scientific ways of identifying causality can be brought under one formalism and improved thereby.

When scientists use the graphical approach to make causal claims, they are not taking a stand on the analytic metaphysics of causation, which is a debate that has little direct relevance to their empirical concerns.