Jessica M. Wilson

Here I compare two accounts of metaphysical indeterminacy (MI): first, the 'meta-level' approach described by Elizabeth Barnes and Ross Cameron in the companion to this paper, on which every state of affairs (SOA) is itself precise/determinate, and MI is a matter of its being indeterminate which determinate SOA obtains; second, my preferred 'object-level' determinable-based approach, on which MI is a matter of its being determinate---or just plain true---that an indeterminate SOA obtains, where an indeterminate SOA is one whose constitutive object has a determinable property, but no unique determinate of that determinable. In S1, I first note an important difference between our accounts, concerning whether MI is taken to induce propositional indeterminacy; in S2, I highlight and defend certain advantages of my account; in S3, I address certain of Barnes and Cameron's objections to my account.

The nonlinearity of a composite system, whereby certain of its features (including powers and behaviors) cannot be seen as linear or other broadly additive combinations of features of the system's composing entities, has been frequently seen as a mark of metaphysical emergence, coupling the dependence of a composite system on an underlying system of composing entities with the composite system's ontological autonomy from its underlying system. But why think that nonlinearity is a mark of emergence, and moreover, of metaphysical rather than merely epistemological emergence? Are there diverse ways in which nonlinearity might enter into an account of properly metaphysical emergence? And what are the prospects for there actually being phenomena that are metaphysically emergent in any available sense? Here I explore the mutual bearing of nonlinearity and metaphysical emergence, with an eye towards answering these and related questions.

Relativized Metaphysical Modality (RMM: Murray and Wilson, 'Relativized metaphysical modality', Oxford Studies in Metaphysics, 2012; Murray, Perspectives on Modal Metaphysics, 2017) exploits 'two-dimensionalist' resources to metaphysical, rather than epistemological, ends: the second dimension offers perspective-dependence without contingency, diverting attacks on 'Classical' analyses of modals (in effect, analyses validating S5 and the Barcan Formulae). Here, we extend the RMM program in two directions. First, we harvest resources for RMM from Lewis's 1980 'Context--Index' (CI) framework: (a) the ban in CI on binding into context-arguments (akin to Kaplan's 'monstrosity' ban) projects a bright line between perspective-dependence and contingency; and (b) CI-postulated connections among meaning, content, truth, argument-structure, context, and modality collectively generate a 'Generalized Humphrey Problem' for any non-Classical analysis (examples covered include appeals to accessibility, contingent domains, and counterpart relations). Second, we sharpen the tools of RMM-based metaphysical analysis, and extend their domain of coverage across familiar anomalies for Classical modals: we revisit earlier RMM-based bulwarks for S5 (against 'Chisholm's Paradox' for moderate flexibility of essence, and nomological necessitarianism); and we now similarly shore up the Barcan Formulae (against the apparent contingency of existence and nonexistence).

In Meaning and Necessity (1947/1950), Carnap advances an intensional semantic framework on which modal claims are true in virtue of semantical rules alone, and so are a priori. In 'Empiricism, Semantics, and Ontology' (1950), Carnap advances an epistemic-ontological framework on which metaphysical claims are either trivial or meaningless, since lacking any means of substantive confirmation. Carnap carried out these projects two decades before Kripke influentially argued, in Naming and Necessity (1972/1980), that some modal claims are true a posteriori. How should a neo-Carnapian respond to Kripke's results? Some (notably, Chalmers and Jackson, in their 2001) have suggested that an extension of intensional semantics along lines of "epistemic two-dimensionalism" can accommodate Kripke's results while largely preserving commitment to the semantics-based a priority of modal claims. Here we consider how best to implement this suggestion, and how the resulting semantics fits with Carnap's second project. We find that the most promising (and most Carnapian!) post-Kripke version of Carnap’s semantics---abductive two-dimensionalism---presupposes an epistemology which undermines Carnap's metaphysical anti-realism.

Hume argued that experience could not justify commonly held beliefs in singular causal effcacy, according to which individual or singular causes produce their effects or make their effects happen. Hume's discussion has been influential, as motivating the view that Causal reductionism (denying that causal efficacy is an irreducible feature of natural reality) requires Causal generalism (according to which causal relations are metaphysically constituted by patterns of events). Here I argue that causal reductionists---indeed, Hume himself---have previously unappreciated resources for making sense of Causal singularism, associated with a relation that has been curiously underexploited in the causation debates: resemblance. The core idea I explore here is that causation may be metaphysically and epistemologically indicated by the coming-to-be of a resemblance. Comings-to-be of resemblances are epistemically available in the singular instance, even by Hume's strict lights, and, I argue, can justify (albeit fallibly) belief in the holding of singular causal relations; hence Hume's general argument for generalism fails. More to the contemporary metaphysical point, comings-to-be of resemblances provide valuable resources for existing singularist accounts: while neither changes (Ducasse) nor transfers of physical quantities (Fair, Dowe, Salmon) provide a suffciently fine-grained basis for the individuation of causes, either changes or transfers, in combination with comings-to-be of resemblances, can do so.

Humeans and non-Humeans reasonably agree that there may be necessary connections between entities that are identical or merely partly distinct—between, e.g., sets and their individual members, fusions and their individual parts, instances of determinates and determinables, members of certain natural kinds and certain of their intrinsic properties, and (especially among physicalists) certain physical and mental states. Humeans maintain, however, that as per “Hume’s Dictum”, there are no necessary connections between entities that are wholly distinct;1 and in particular, no necessary causal connections between such entities (even when the background conditions requisite for causation are in place). The Humean’s differential treatment appears principled, in reflecting that commonly accepted necessary connections involve constitutional relations, whereas wholly distinct entities (notably, causes and effects) do not constitute each other. I’ll argue, however, that the appearance of principle is not genuine, as per the following conditional: Constitutional→Causal: If one accepts certain constitutional necessities, one should accept certain causal necessities. This result provides needed leverage in assessing the two main frameworks in the metaphysics of science, treating natural kinds, causes, laws of nature, and the like. These frameworks differ primarily on whether Hume’s Dictum is taken as a working constraint on theorizing; and it has proved difficult for either side to criticize the other without presupposing their preferred stance on the dictum, hence talking past one another. The arguments for Constitutional→Causal are based, however, in general and independent considerations about what facts in the world might plausibly warrant our beliefs in certain constitutional necessities involving broadly scientific entities. The Humean can respond to these arguments, which reveal a deep tension in their view, at attendant costs of implausibilty and adhocery. The non-Humean framework doesn’t face any such tension between constitutional and causal necessities, however, and so in this respect comes out ahead.

I address the question of whether there is any role for metaphysics to play on which it is both non-redundant and capable of genuinely illuminating whatever subject matter is at issue. I first argue that metaphysical methodology itself obliges metaphysicians to take this question seriously. I then argue that the currently popular “hands-off” conception of metaphysical theorizing is unable to provide a satisfactory answer to the question of metaphysics. Third, I present my preferred “embedded” conception of metaphysics, and say why it makes good sense of metaphysics as a non-redundant discipline, capable of producing intelligible and illuminating results.

Arguably no concept is more fundamental to science than that of causality, for investigations into cases of existence, persistence, and change in the natural world are largely investigations into the causes of these phenomena. Yet the metaphysics and epistemology of causality remain unclear. For example, the ontological categories of the causal relata have been taken to be objects (Hume 1739), events (Davidson 1967), properties (Armstrong 1978), processes (Salmon 1984), variables (Hitchcock 1993), and facts (Mellor 1995). (For convenience, causes and effects will usually be understood as events in what follows.) Complicating matters, causal relations may be singular (Socrates’s drinking hemlock caused Socrates’s death) or general (Drinking hemlock causes death); hence the relata might be tokens (e.g., instances of properties) or types (e.g., types of events) of the category in question. Other questions up for grabs are: Are singular causes metaphysically and/or epistemologically prior to general causes or vice versa (or neither)? What grounds the intuitive asymmetry of the causal relation? Are macro-causal relations reducible to micro-causal relations? And perhaps most importantly: Are causal facts (e.g., the holding of causal relations) reducible to non-causal facts (e.g., the holding of certain spatiotemporal relations)?

Both the special sciences and ordinary experience suggest that there are metaphysically emergent entities and features: macroscopic goings-on (including mountains, trees, humans, and sculptures, and their characteristic properties) which depend on, yet are distinct from and distinctively efficacious with respect to, lower-level physical configurations and features. These appearances give rise to two key questions. First, what is metaphysical emergence, more precisely? Second, is there any metaphysical emergence, in principle and moreover in fact? Metaphysical Emergence provides clear and systematic answers to these questions. Wilson argues that there are two, and only two, forms of metaphysical emergence of the sort seemingly at issue in the target cases: 'Weak' emergence, whereby a dependent feature has a proper subset of the powers of the feature upon it depends, and 'Strong' emergence, whereby a dependent feature has a power not had by the feature upon which it depends. Weak emergence unifies and illuminates seemingly diverse accounts of non-reductive physicalism; Strong emergence does the same as regards seemingly diverse anti-physicalist views positing fundamental novelty at higher levels of compositional complexity. After defending the in-principle viability of each form of emergence, Wilson considers whether complex systems, ordinary objects, consciousness, and free will are actually metaphysically emergent. She argues that Weak emergence is quite common, and that there is Strong emergence in the important case of free will.

In Calosi and Wilson (Phil Studies 2019/2018), we argue that on many interpretations of quantum mechanics (QM), there is quantum mechanical indeterminacy (QMI), and that a determinable-based account of metaphysical indeterminacy (MI), as per Wilson 2013 and 2016, properly accommodates the full range of cases of QMI. Here we argue that this approach is superior to other treatments of QMI on offer, both realistic and deflationary, in providing the basis for an intelligible explanation of the interference patterns in the double-slit experiment. We start with a brief overview of the motivations for QMI and for a determinable-based account of MI (§1). We then apply a developed 'glutty' implementation of determinable-based QMI to the superposition-based QMI present in the double-slit experiment, and positively compare the associated explanation of double-slit interference with that available on a metaphysical supervaluationist account of QMI (§2). We then present and respond to objections, due to Glick (2017) and Torza (2017), either to QMI (§3) or to our specific account of QMI (§4); in these sections we also positively compare our treatment of double-slit interference to that available on Glick's deflationary treatment of QMI. We conclude with some dialectical observations (§5).

Mary Shepherd (1777–1847) was a fierce and brilliant critic of Berkeley and Hume, who moreover offered strikingly original positive views about the nature of reality and our access to it which deserve much more attention (and credit, since she anticipates many prominent views) than they have received thus far. By way of illustration, I focus on Shepherd's 1824 Essay Upon the Relation of Cause and Effect, Controverting the Doctrine of Mr. Hume, Concerning the Nature of that Relation (ERCE). After a brief setup, I canvas certain of her trenchant objections to Hume’s argumentation; I then present the positive core of her response to Hume, which consists in providing novel accounts of how reason alone or reason coupled with experience can justify, first, that every effect must have a cause, and second, that it is necessary that like causes produce like effects. Among other contributions here, Shepherd provides a distinctively metaphysical argument for the claim that nothing can begin to exist 'of itself' (going beyond an appeal to the Principle of Sufficient Reason, in particular), and leverages difference-making considerations to make the case that a single 'experimentum crucis' can justify causal belief (anticipating Mill's 'method of difference'). I close by highlighting salient features of Shepherd's metaphysics of causation, whereby causation is singularist and local (anticipating Ducasse and Anscombe) and involves synchronic interactions (anticipating Mill's and certain contemporary accounts), and according to which objects are essentially characterized by their causes and effects (anticipating contemporary causal or dispositional essentialist positions).

The debate between exceptionalists and anti-exceptionalists about logic is often framed as concerning whether the justification of logical theories is a priori or a posteriori (for short: whether logic is a priori or a posteriori). As we substantiate (S1), this framing more deeply encodes the usual anti-exceptionalist thesis that logical theories, like scientific theories, are abductively justified, coupled with the common supposition that abduction is an a posteriori mode of inference, in the sense that the epistemic value of abduction is (and, indeed, must be) a posteriori. In past work, however, we have argued that this common supposition is incorrect: abduction is an a priori mode of inference, in the sense that the epistemic value of abduction is (and indeed, must be) a priori (Biggs and Wilson 2017a, 2017b, 2019). After sketching our two main argumentative strategies for this conclusion (S2), we go on (S3) to consider its import on the proper understanding of anti-exceptionalism about logic.

Is there a need for a distinctively diachronic conception of metaphysical emergence? Here I argue to the contrary. In the main, my strategy consists in considering a representative sample of accounts of purportedly diachronic metaphysical emergence, and arguing that in each case, the purportedly diachronic emergence at issue either can (and should) be subsumed under a broadly synchronic account of metaphysical emergence, or else is better seen as simply a case of causation. In addition, I consider and argue against the suggestion that 'in-principle unpredictability' accounts of diachronic emergence support there being distinctively diachronic metaphysical emergence.

This correction reflects that I forgot to cite Stephan Leuenberger's unpublished work in the paragraph beginning "More promising, perhaps, is the orthodox view ..." in Section 5. The overall argument of Section 5 is a development of an argument I gave in footnote 27 of 'No Work for a Theory of Grounding' (Inquiry, 2014). At issue in the relevant sections of 'No Work...' and 'Grounding-based Formulations...' is whether a proponent of Grounding has resources to accommodate strongly emergent phenomena, where strong emergence is understood as contrasting with physicalism. In 'No Work...', after arguing in the text that an account of strong emergence as involving a failure of full Grounding would not accommodate the live possibility that strongly emergent goings-on might be partially but not completely metaphysically dependent on physical goings on, I considered in note 27 whether strong emergence, again understood as contrasting with physicalism, could be characterized by appeal to a Finean notion of partial Grounding, as the view that strongly emergent goings-on are partially but not fully Grounded in physical goings-on, and I argued that assuming that the notion of partial Grounding was taken to be primitive, then (since there were no prospects of defining full Grounding in terms of primitive partial Grounding along lines of defining a general notion of parthood in terms of primitive proper parthood or identity), such an approach would require that full Grounding also be taken as primitive, with possibly yet another primitive connecting partial and full Grounding. I heard Leuenberger's talk 'Emergence and Failures of Supplementation' in May 2015; for purposes of developing my previous argument (as per Section 5 in 'Grounding-based Formulations...') this talk was helpful since Leuenberger correctly argued that there were also no prospects for implementing the partial Grounding-based strategy by taking full Grounding to be primitive and defining partial Grounding in terms of full Grounding, since that would import a weak supplementation structure that might not be present in cases of strong emergence. I wrote to Leuenberger asking for his slides so that I could reference him and his work (which again is presented in the paragraph beginning "More promising, perhaps, is the orthodox view..."), but somehow forgot to include a citation to his talk, for which I sincerely apologize. One last thing: the erratum is a bit misleading about my use of Leuenberger's work. My discussion of whether a primitivist (i.e., 'non-orthodox') understanding of Finean partial Ground serves as a suitable basis for a partial Grounding-based approach to strong emergence stems from footnote 27 of my 2014, not Leuenberger's 2015 talk, and in both 'No Work...' and 'Grounding-based Formulations...' I argue that such an approach would be problematic, not "suitable", since involving two or three primitives. Also worth noting is that I do not claim or argue that the orthodox conception of partial Grounding as defined in supplementary fashion in terms of full Grounding is *incompatible* with strong emergence. Again, at issue in both 'No Work...' and in 'Grounding-based Formulations...' is strong emergence understood as contrasting with physicalism, so the relevant application of a partial Grounding-based strategy, whether or not involving an 'orthodox' account of partial Grounding as definable in terms of full Grounding, is in my papers one according to which strongly emergent goings-on are partially but not fully Grounded in *physical* goings-on. So far as I can tell, there might be cases of strong emergence that *do* obey supplementation, and which would be compatible with a partial Grounding-based account of strong emergence, where the operative notion of partial Grounding is 'orthodox' (non-primitive). For my purposes, what is important is that cases of strong emergence might not obey supplementation.

I discuss certain representative accounts of metaphysical emergence falling into three broad categories, assessing their prospects for satisfying certain criteria; the ensuing dialectic has a bit of the Goldilocks fable about it. At one end of the spectrum are what I call ‘scientistic’ accounts, which characterize metaphysical emergence by appeal to one or another specific feature commonly registered in scientific descriptions of seeming cases of emergence; such accounts, I argue, typically fail to provide a clear basis for ensuring incompatibility with ontological reduction, and thus fail to guarantee satisfaction of the criterion of appropriate contrast (§2). At the other end of the spectrum are what I call ‘abstractionist’ accounts, which characterize emergence in terms floating free of scientific notions; such accounts, I’ll argue, typically fail to guarantee satisfaction of the criterion of illuminating contrast (§3). I’ll then look at several accounts of metaphysical emergence that are what I call ‘substantive’, in appealing to familiar relations or posits which are properly metaphysical, while being intelligibly connected to scientific relations and posits. As we’ll see, the resources of such accounts are up to the tasks of blocking ontological reduction and of enabling investigations into metaphysical emergence to proceed in an illuminating way (§4). I close with some methodological morals (§5)

I argue that the best explanation of the multiplicity of available frameworks for treating any given philosophical topic is that philosophy currently (though not insuperably) lacks fixed standards; I then go on to identify three barriers to philosophical progress associated with our present epistemic situation. First is that the lack of fixed standards encourages what I call “intra‐disciplinary siloing,” and associated dialectical and argumentative failings; second is that the lack of fixed standards makes room for sociological factors (including elite influence and disciplinary inertia) to be determinative of which philosophical frameworks are embraced; third is that the lack of fixed standards encourages (implicit and/or explicit) bias. I close by offering some suggestions about how to move beyond these barriers, even in the absence of fixed standards.

Many contemporary philosophers accept a strong generalization of Hume's denial of necessary causal connections, in the form of Hume's dictum (HD), according to which there are no metaphysically necessary connections between distinct, intrinsically typed entities. Hume's version of his dictum occurs during his investigation into the source of the idea of causal connection. The most powerful role that HD plays in Lewis's system concerns its providing a basis for, as Lewis puts it, a "principle of plentitude" that will guarantee "that the worlds are abundant, and logical space is somehow complete". Lewis's combinatorialism promises to provide a principled, extensionally adequate, and reductive generator of metaphysical modal space. Beyond combinatorialism, there are many other accounts of metaphysical modality that need to be considered, not just with an eye to extensional adequacy but also to the clear desideratum to provide an account of the space of metaphysical modality that is principled.

Physicalism is the thesis that all entities are nothing over and above physical entities. Here I investigate into whether and how physicalism might be formulated so as to substantively contrast with its best traditional rivals---including and especially emergentism. Formulating physicalism requires making sense of both the physical/non-physical distinction and the nothing/something over and above distinction. It has been argued that no distinction between the physical and the non-physical exists, that can serve as the basis for a sub stantive physicalism. But such arguments miss the mark, for participants to the physicalism debates do not disagree about the boundary of the physical, which, while roughly drawn is clear enough for debate to proceed. Rather, participants disagree on whether there are any entities over and above those entities they agree are physical. Hence the viability of physicalism primarily depends on the over and above distinction. ;I argue that existing accounts of over and aboveness are inadequate, for the key class of cases where two properties are instanced in a single subject, and one property is supposed to necessitate the other, with at least nomological necessity. I go on to provide an adequate account of over and aboveness, by reference to the notion of a fundamental force . We can formulate physicalism and emergentism using Force-relative Over and Aboveness: according to physicalism, all causal powers bestowed by all properties are grounded only in fundamental physical forces; according to emergentism, some causal powers are grounded in a new fundamental force, different from any physical force. ;Understanding over and aboveness as involving fundamental forces is not new. But arguments against forces have lately been accepted; hence the notable absence of forces from contemporary philosophizing. I distinguish two uses of 'force', and show that these arguments do not tell against fundamental forces. I then give positive arguments for admitting fundamental forces, stemming from the reasonable hypothesis that fundamental forces are collections of interacting fields. Forces, so understood, are ontologically defensible; and thus can serve as the needed basis for formulating physicalism and emergentism