On the Possibility of Skeptical Scenarios

Abstract: It is generally accepted that skeptical scenarios must be possible to raise legitimate skeptical doubt. I argue that if the possibility in question is supposed to be genuine metaphysical possibility, the skeptic's reasoning does not straightforwardly succeed. I first motivate the metaphysical possibility requirement on skeptical scenarios: it's a plausible position that several authors accept and that a family of prominent views—sensitivity, safety, relevant alternatives—are committed to. I argue that plausible constraints in modal epistemology show that justification for believing that certain global skeptical scenarios are metaphysically possible rests on some justified beliefs about the external world, and that this undermines the skeptical argument. While there may still be local skeptical challenges, skeptics cannot appeal to the metaphysical possibility of skeptical scenarios to generate global external world skepticism.     

Naturalness in Context

According to proponents of one influential account of metaphysical naturalness, properties fall along a spectrum from perfectly natural to highly non-natural. The perfectly natural end of the spectrum is occupied by properties that appear in the laws of nature, account for resemblance and causal powers, and ground other properties, whereas the highly non-natural properties at the spectrum’s other end are not like this at all. However, there is another phenomenon that looks very much like metaphysical naturalness but is context-dependent. I call this phenomenon context-dependent naturalness. In this paper I describe two cases in which inappropriate use is made of metaphysical naturalness and argue that in such cases, the context-dependent importance of certain properties has been confused for the context-independent importance of those properties. I argue that in order to avoid such problems we should embrace context-dependent naturalness.     

Essentialism and the Necessity of the Laws of Nature

In this paper I discuss and evaluate different arguments for the view that the laws of nature are metaphysically necessary. I conclude that essentialist arguments from the nature of natural kinds fail to establish that essences are ontologically more basic than laws, and fail to offer an a priori argument for the necessity of all causal laws. Similar considerations carry across to the argument from the dispositionalist view of properties, which may end up placing unreasonable constraints on property identity across possible worlds. None of my arguments preclude the possibility that the laws may turn out to be metaphysically necessary after all, but I argue that this can only be established by a posteriori scientific investigation. I therefore argue for what may seem to be a surprising conclusion: that a fundamental metaphysical question – the modal status of laws of nature – depends on empirical facts rather than purely on a priori reasoning.     

There is a problem of change

Impostors are pseudo-problems masquerading as genuine problems. Impostors should be exposed. The problem of change appears genuine. But some, such as Hofweber (2009) and Rychter (2009), have recently denounced it as an impostor. They allege that it is mysterious how to answer the meta-problem of saying what problem it is: for even if any problem is genuinely about change per se, they argue, it is either empirical or trivially dissolved by conceptual analysis. There is indeed an impostor in our midst. But it is the meta-problem of change. I defend the appearance that the problem of change is a genuine metaphysical problem about change. This vindicates philosophers’ lasting interest in it. It also illuminates what makes a problem metaphysical, how metaphysics relates to other inquiries, and how best to respond to attempts to undermine metaphysical problems.     

Is backing grounding?

Separatists are grounding theorists who hold that grounding relations and metaphysical explanations are distinct, yet intimately connected in the sense that grounding relations back metaphysical explanations, just as causal relations back causal explanations. But Separatists have not elaborated on the nature of the ‘backing’ relation. In this paper, I argue that backing is a form of (partial) grounding. In particular, backing has many of the properties commonly attributed to grounding, and taking backing to be partial grounding allows Separatists to make the most of their position vis-à-vis their Unionist opponents.     

Actuality and the amodal perspective

In this paper, I examine our intuitive understanding of metaphysical contingency, and ask what features a metaphysical picture must possess in order to satisfy our intuitions about modal matters. After spelling out what I think are the central intuitions in this domain, I examine the debate between the two most widely held views on the nature of modality, namely, modal realism and modal actualism. I argue that while each of these views is able to accommodate some of our intuitions, it leaves others unsatisfied. I then present an alternative metaphysical picture, which I argue can accommodate our intuitions in a way that the traditional views cannot. More specifically, I argue that our intuitions about modality call for a pluralist view of the structure of reality—a view on which there is more than one ultimate ‘shape’ to the fundamental facts, each corresponding to a distinct metaphysically privileged perspective on reality.     

Essence and modal knowledge

During the last quarter of a century, a number of philosophers have become attracted to the idea that necessity can be analyzed in terms of a hyperintensional notion of essence. One challenge for proponents of this view is to give a plausible explanation of our modal knowledge. The goal of this paper is to develop a strategy for meeting this challenge. My approach rests on an account of modality that I developed in previous work, and which analyzes modal properties in terms of the notion of a metaphysical law (which is a generalization of the concept of an essential truth). I discuss what information about the metaphysical laws (including essential truths) is required for modal knowledge. Moreover, I describe two ways in which we might be able to acquire this information. The first way employs inference to the best explanation. The metaphysical laws, including the essential truths, play a crucial role in causal and grounding explanations and we can gain knowledge of these laws by abductive inferences from facts of which we have perceptual or a priori knowledge. The second way of gaining information about the metaphysical laws rests on knowledge that is partly constitutive of competence with the concepts that are needed to express the relevant information. Finally, I consider how knowledge of the metaphysical laws can be used to establish modal claims, paying special attention to the much-discussed connection between conceiving and possibility.

     

How can we come to know metaphysical modal truths?

Those who aim to give an account of modal knowledge face two challenges: the integration challenge of reconciling an account of what is involved in knowing modal truths with a plausible story about how we can come to know them, and the reliability challenge of giving a plausible account of how we could have evolved a reliable capacity to acquire modal knowledge. I argue that recent counterfactual and dispositional accounts of modal knowledge cannot solve these problems regarding specifically metaphysical modal truths—leaving us with the threat of skepticism about large portions of metaphysics, and certain other areas of philosophy. I argue, however, that both of these problems look insuperable only if we assume that metaphysical modal discourse serves a describing or tracking function. If we adopt instead a normativist approach to metaphysical modal discourse, which sees the basic function of modal discourse as giving us perspicuous ways of conveying, reasoning with, and renegotiating semantic rules, the problems show up very differently. The modal normativist can give a plausible response to both of the classic problems of how we can come to know metaphysical modal truths.

     

Modal Objectivity1

It is widely agreed that the intelligibility of modal metaphysics has been vindicated. Quine's arguments to the contrary supposedly confused analyticity with metaphysical necessity, and rigid with non‐rigid designators.² But even if modal metaphysics is intelligible, it could be misconceived. It could be that metaphysical necessity is not absolute necessity – the strictest real (non‐epistemic, non‐deontic) notion of necessity – and that no proposition of traditional metaphysical interest is necessary in every real sense. If there were nothing otherwise “uniquely metaphysically significant” about metaphysical necessity, then paradigmatic metaphysical necessities would be necessary in one sense of “necessary”, not necessary in another, and that would be it. The question of whether they were necessary simpliciter would be like the question of whether the Parallel Postulate is true simpliciter – understood as a pure mathematical conjecture, rather than as a hypothesis about physical spacetime. In a sense, the latter question has no objective answer. In this article, I argue that paradigmatic questions of modal metaphysics are like the Parallel Postulate question. I then discuss the deflationary ramifications of this argument. I conclude with an alternative conception of the space of possibility. According to this conception, there is no objective boundary between possibility and impossibility. Along the way, I sketch an analogy between modal metaphysics and set theory.     

Essence and Possibility in the Leibniz‐Arnauld Correspondence

In the 1680s, Gottfried Leibniz and Antoine Arnauld engaged in a philosophically rich correspondence. One issue they discuss is modal metaphysics – questions concerning necessity, possibility, and essence. While Arnauld's contributions to the correspondence are considered generally astute, his contributions on this issue have not always received a warm treatment. I argue that Arnauld's criticisms of Leibniz are sophisticated and that Arnauld offers his own Cartesian account in its place. In particular, I argue that Arnauld offers an account of possibility that is actualist (only actual things exist), modal actualist (modality is irreducible) and essence‐based (essences ground de re counterfactuals).     

Lockean Essentialism and the Possibility of Miracles

If the laws of nature are metaphysically necessary, then it appears that miracles are metaphysically impossible. Yet Locke accepts both essentialism, which takes the laws to be metaphysically necessary, and the possibility of miracles. I argue that the apparent conflict here can be resolved if the laws are by themselves insufficient for guaranteeing the outcome of a particular event. This suggests that, on Locke's view, the laws of nature entail how an object would behave absent divine intervention . While other views of laws also make miracles counterfactually dependent on God's will, I show how this view is consistent with the essentialist commitment to the view that the laws are metaphysically necessary. Further, I argue that Locke's view is a relatively attractive version of essentialism, in part, because it allows for the possibility of miracles.     

The Powerlessness of Necessity

This paper concerns anti‐Humean intuitions about connections in nature. It argues for the existence of a de re link that is not necessity. Some anti‐Humeans tacitly assume that metaphysical necessity can be used for all sorts of anti‐Humean desires. Metaphysical necessity is thought to stick together whatever would be loose and separate in a Hume world, as if it were a kind of universal superglue. I argue that this is not feasible. Metaphysical necessity might connect synchronically co‐existent properties—kinds and their essential features, for example—but it is difficult to see how it could also serve as the binding force for successions of events. That is, metaphysical necessity seems not to be fit for diachronic, causal affairs in which causal laws, causation, or dispositions are involved. A different anti‐Humean connection in nature has to do that job. My arguments focus mainly on a debate which has been the battleground for Humean vs. anti‐Humean intuitions for many decades—namely, the analysis of dispositional predicates—yet I believe (but do not argue here) that the arguments generalise to causation and causal laws straightforwardly.     

TWO KINDS OF POSSIBILITY

I defend a version of Kripke's claim that the metaphysically necessary and the knowable a priori are independent. On my version, there are two independent families of modal notions, metaphysical and epistemic, neither stronger than the other. Metaphysical possibility is constrained by the laws of nature. Logical validity, I suggest, is best understood in terms of epistemic necessity.     

What Do Easy Inferences Get Us?

In Ontology Made Easy (2015), I defend the idea that there are ‘easy’ inferences that begin from uncontroversial premises and end with answers to disputed ontological questions. But what do easy inferences really get us? Bueno and Cumpa (this journal, 2020) argue that easy inferences don’t tell us about the natures of properties—they don’t tell us what properties are. Moreover, they argue, by accepting an ontologically neutral quantifier we can also resist the conclusion that properties or numbers exist. Here I address these two issues in turn—in ways that help clarify both the scope and results of easy ontology. First, it is important to see that easy inferences were never intended to address modal questions. Modal questions are addressed by a different part of the total deflationary view—modal normativism. So understood, metaphysical modal questions nonetheless do not provide a remaining area for serious metaphysical inquiry. Second, I argue that we have reason to resist adopting an ontologically neutral quantifier, if we aim to answer ontological questions (without begging the question). Addressing these issues helps to clarify both what does (and does not) follow from easy inferences, and how they form part of a larger deflationary metametaphysical view.     

Validity and Necessity

In this paper I argue against the commonly received view that Kripke’s formal Possible World Semantics (PWS) reflects the adoption of a metaphysical interpretation of the modal operators. I consider in detail Kripke’s three main innovations vis-à-vis Carnap’s PWS: a new view of the worlds, variable domains of quantification, and the adoption of a notion of universal validity. I argue that all these changes are driven by the natural technical development of the model theory and its related notion of validity: they are dictated by merely formal considerations, not interpretive concerns. I conclude that Kripke’s model theoretic semantics does not induce a metaphysical reading of necessity, and is formally adequate independently of the specific interpretation of the modal operators.     

Capacities,explanation and the possibility of disunity

Nancy Cartwright argues that so-called capacities, not universal laws of nature, best explain the often complex way events actually unfold. On this view, science would represent a world that is fundamentally "dappled", or disunified, and not, as orthodoxy would perhaps have it, a world unified by universal laws of nature. I argue, first, that the problem Cartwright raises for laws of nature seems to arise for capacities too, so why reject laws of nature? Second, that in so far as there is a problem, it concerns the role of counterfactuals in explanation; I then briefly propose a simple model of counterfactual explanation. Finally, I investigate how a sophisticated version of the regularity theory of laws of nature (that of Ramsey-Lewis) can be neutral between the empirical hypotheses that the world is unified, and that the world is disunified.     

Objections and replies within the fifth meditation

Malebranche held that God acts only by general volitions and so is not constantly interfering in the world. The content of God's volitions appears to include the general laws of nature and the particular initial configuration of the created world, so that occasional or natural causes have an important explanatory role. It is clear that at the least Malebranche meant by a ‘general volition’ the willing of events which followed general laws. Steven Nadler argued that this is all we should understand by a ‘general volition’, and so we should think that general volitions are simply particular volitions which follow a general law.

I argue that this view is not the correct interpretation of Malebranche's general volitions, for it does not do justice to the theological doctrine of the Treatise, masks the genuine difference between Arnauld and Malebranche, and conflicts with what Malebranche says about practical volitions. I then argue that despite Malebranche's view of general volitions, there is still an important difference between his view and Leibniz's.     

Kant’s Regulative Metaphysics of God and the Systematic Lawfulness of Nature

In the “Appendix to the Transcendental Dialectic” of the Critique of Pure Reason, Kant contends that the idea of God has a positive regulative role in the systematization of empirical knowledge. But why is this regulative role assigned to this specific idea? Kant's account is rather opaque, and this question has also not received much attention in the literature. In this article, I argue that an adequate understanding of the regulative role of the idea of God depends on the specific metaphysical content Kant attributes to it in the Critique and other writings. I show that neither a heuristic principle of conceptual systematicity, nor conceiving God as a hypothesis of an intelligent designer, can satisfy the demands of reason to make the unity and necessity of the laws of nature intelligible. Regarding the positive account about the metaphysical content of the idea of God, I support my argument by referring to Kant's precritical discussion of the usefulness of the conception of God for the project of science, and by expounding Kant's critical account of the necessity of the laws of nature. Thus, my account sheds light on the continuity of Kant's conception of God and his appropriation of his own rationalistic metaphysics.     

Modal rationalism and the demonstrative reply to the scrutability argument against physicalism

According to the scrutability argument against physicalism, an a priori gap between the physical and conscious experience entails a lack of necessitation and the falsity of physicalism. This paper investigates the crucial premise of the scrutability argument: the inference from an a priori gap to a lack of necessitation. This premise gets its support from modal rationalism, according to which there are important, potentially constitutive, connections between a priori justification and metaphysical modality. I argue against the strong form of modal rationalism that underwrites the scrutability argument and suggest a more moderate rationalist view. I offer a novel demonstrative reply to the scrutability argument, according to which demonstratives play a vital role in the generation of meaning for our representations of conscious experience. This connection between conscious experience and demonstratives, rather than a metaphysical gap generated by the truth of dualism, is the source of the epistemic gap between consciousness and the physical.

     

Two Kinds of Logical Impossibility

In this paper, we argue that a distinction ought to be drawn between two ways in which a given world might be logically impossible. First, a world w might be impossible because the laws that hold at w are different from those that hold at some other world (say the actual world). Second, a world w might be impossible because the laws of logic that hold in some world (say the actual world) are violated at w. We develop a novel way of modelling logical possibility that makes room for both kinds of logical impossibility. Doing so has interesting implications for the relationship between logical possibility and other kinds of possibility (for example, metaphysical possibility) and implications for the necessity or contingency of the laws of logic.