This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.

It is my aim in this paper to show that the contemporary assimilation of essence to modality is fundamentally misguided and that, as a consequence, the corresponding conception of metaphysics should be given up. It is not my view that the modal account fails to capture anything which might reasonably be called a concept of essence. My point, rather, is that the notion of essence which is of central importance to the metaphysics of identity is not to be understood in (...) modal terms or even to be regarded as extensionally equivalent to a modal notion. The one notion is, if I am right, a highly refined version of the other; it is like a sieve which performs a similar function but with a much finer mesh. (shrink)

Kris McDaniel argues that there are different ways in which things exist. For instance, past things don't exist in the same way as present things. Numbers don't exist in the same way as physical objects; nor do holes, which are real, but less real than what they are in. McDaniel's theory of being illuminates a wide range of metaphysical topics.

If Pegasus existed, he would indeed be in space and time, but only because the word ‘Pegasus’ has spatio-temporal connotations, and not because ‘exists’ has spatio-temporal connotations. If spatio-temporal reference is lacking when we affirm the existence of the cube root of 27, that is simply because a cube root is not a spatio-temporal kind of thing.

Ontological Pluralism is the view that there are different modes, ways, or kinds of being. In this paper, I characterize the view more fully (drawing on some recent work by Kris McDaniel) and then defend the view against a number of arguments. (All of the arguments I can think of against it, anyway.).

Ontological pluralism is the doctrine that there are different ways or modes of being. In contemporary guise, it is the doctrine that a logically perspicuous description of reality will use multiple quantifiers which cannot be thought of as ranging over a single domain. Although thought defeated for some time, recent defenses have shown a number of arguments against the view unsound. However, another worry looms: that despite looking like an attractive alternative, ontological pluralism is really no different than its counterpart, (...) ontological monism. In this paper, after explaining the worry in detail, I argue that considerations dealing with the nature of the logic ontological pluralists ought to endorse, coupled with an attractive philosophical thesis about the relationship between logic and metaphysics, show this worry to be unfounded. (shrink)

In this paper I argue that presentism —the view that only present objects exist—can be motivated, at least to some degree, by virtue of the fact that it is more quantitatively parsimonious than rival views.

A-theorists think there is a fundamental difference between the present and other times. This concern shows up in what kinds of properties they take to be instantiated, what objects they think exist and how they formalize their views. Nearly every contemporary A-theorist assumes that her metaphysics requires a tense logic – a logic with operators like and. In this paper, I show that there is at least one viable A-theory that does not require a logic with tense operators. And I (...) will argue that three common indispensability arguments for tense operators are unsound. (shrink)

Eternalists say that non-present entities (for instance dinosaurs) exist; presentists say that they do not. But some sceptics deny that this debate is genuine, claiming that presentists simply represent eternalists' quantifiers over non-present entities in different notation. This scepticism may be refuted on purely logical grounds: one of the leading candidate ‘presentist quantifiers’ over non-present things has the inferential role of a quantifier. The dispute over whether non-present objects exist is as genuine and non-verbal as the dispute over whether there (...) is life on other planets. (shrink)

The Razor commands us not to multiply entities without necessity. I argue for an alternative principle—The Laser—which commands us not to multiply fundamental entities without necessity.

I examine three ‘anti-object’ metaphysical views: nihilism, generalism, and anti-quantificationalism. After setting aside nihilism, I argue that generalists should be anti-quantificationalists. Along the way, I attempt to articulate what a ‘metaphysically perspicuous’ language might even be.

In this paper, I motivate the view that quantitative parsimony is a theoretical virtue: that is, we should be concerned not only to minimize the number of kinds of entities postulated by our theories (i. e. maximize qualitative parsimony), but we should also minimize the number of entities postulated which fall under those kinds. In order to motivate this view, I consider two cases from the history of science: the postulation of the neutrino and the proposal of Avogadro's hypothesis. I (...) also consider two issues concerning how a principle of quantitative parsimony should be framed. (shrink)

Logical realism is the view that there is logical structure in the world. I argue that, if logical realism is true, then we are deeply ignorant of that logical structure: either we can’t know which of our logical concepts accurately capture it, or none of our logical concepts accurately capture it at all. I don’t suggest abandoning logical realism, but instead discuss how realists should adjust their methodology in the face of this ignorance.

Counterfactuals is David Lewis' forceful presentation of and sustained argument for a particular view about propositions which express contrary to fact conditionals, including his famous defense of realism about possible worlds and his theory of laws of nature.

"Matter" may be defined, according to the Oxford English Dictionary, as "The substance, or the substances collectively, out of which a physical object is made or of which it consists". And while the O.E.D. is not the ultimate authority on words, nor is it, I believe, far wrong in this particular case. The definition is, as I shall argue in this paper, in substantial harmony with a tradition of some antiquity, according to which material objects do not constitute a somehow (...) 'fundamental category' for ontology; and it is in conflict with a more contemporary view which maintains precisely that they do. (shrink)

Parsimony is a virtue of empirical theories. Is it also a virtue of philosophical theories? I review four contemporary accounts of the virtue of parsimony in empirical theorizing, and consider how each might apply to two prominent appeals to parsimony in the philosophical literature, those made on behalf of physicalism and on behalf of nominalism. None of the accounts of the virtue of parsimony extends naturally to either of these philosophical cases. This suggests that in typical philosophical contexts, ontological simplicity (...) has no evidential value. (shrink)

Theories that posit metaphysical structure are able to do much work in philosophy. Some, however, find the notion of ‘metaphysical structure’ unintelligible. In this paper, I argue that their charge of unintelligibility fails. There is nothing distinctively problematic about the notion. At best, their charge of unintelligibility is a mere reiteration of previous complaints made toward similar notions. In developing their charge, I clarify several important concepts, including primitiveness, intelligibility, and the Armstrong-inspired “ontologism” view of the world. I argue that, (...) ultimately, their charge is best understood as an objection whose central premise is that the notion of ‘structure’ runs contrary to an important presupposition of contemporary metaphysics. But that central premise is, on closer inspection, implausible. I respond to the objection by identifying three popular metaphysical theories that violate the alleged presupposition but are still generally regarded as intelligible. The objection thus fails to show that a theory that posits metaphysical structure is unintelligible. (shrink)

Metaphysicians now typically distinguish between a theory’s ontology and its ideology. But besides a few cursory efforts, no one has explained the role of ideology in theory choice. In this paper I develop a framework for discussing how differing approaches to ideology impact metaphysical disputes. I first provide an initial characterization of ideology and develop two contrasting types of criteria used to evaluate its quality. In using externalist criteria, we judge the quality of a theory’s ideology by its relation to (...) external features of the world. In contrast, in using internalist criteria, we judge the quality of a theory’s ideology by features internal to the theory and the theorizer, e.g. the intelligibility of the terminology employed. I then argue for an unrestricted application of externalist criteria, what I call maximal realism. According to maximal realism, we ought to apply externalist criteria to the entirety of a theory’s ideology—to not only predicates but also to quantifiers and logical operators. I defend maximal realism from what I take to be the best objection to it: that the view leads to bad questions. As part of my defense, I argue that those who would restrict their application of externalist criteria either adopt an unjustified partition of ideology or reject seemingly benign questions. Finally, I apply my discussion of ideology to two extant metaphysical disputes. (shrink)

We naturally think of the material world as being populated by a large number of individuals . These are things, such as my laptop and the particles that compose it, that we describe as being propertied and related in various ways when we describe the material world around us. In this paper I argue that, fundamentally speaking at least, there are no such things as material individuals. I then propose and defend an individual-less view of the material world I call (...) “generalism”. (shrink)

The theoretical virtue of parsimony values the minimizing of theoretical commitments, but theoretical commitments come in two kinds : ontological and ideological. While the ontological commitments of a theory are the entities it posits, a theory’s ideological commitments are the primitive concepts it employs. Here, I show how we can extend the distinction between quantitative and qualitative parsimony, commonly drawn regarding ontological commitments, to the domain of ideological commitments. I then argue that qualitative ideological parsimony is a theoretical virtue. My (...) defense proceeds by demonstrating the merits of qualitative ideological parsimony and by showing how the qualitative conception of ideological parsimony undermines two notable arguments from ideological parsimony: David Lewis’ defense of modal realism and Ted Sider’s defense of mereological nihilism. (shrink)

Metaphysicians frequently appeal to the idea that theoretical simplicity is truth conducive in metaphysics, in the sense that, all other things being equal, simpler metaphysical theories are more likely to be true. In this paper I defend the notion that theoretical simplicity is truth conducive in metaphysics, against several recent objections. I do not give any direct arguments for the thesis that simplicity is truth conducive in metaphysics, since I am aware of no such arguments. I do argue, however, that (...) there is no special problem with the notion that simplicity is truth conducive in metaphysics. More specifically, I argue that if you accept the idea that simplicity is truth conducive in science, then it would be objectionably arbitrary to reject the idea that simplicity is truth conducive in metaphysics. (shrink)

Mereological nihilism is the thesis that composite objects—objects with proper parts—do not exist. Nihilists generally paraphrase talk of composite objects F into talk of there being “xs arranged F-wise” . Recently several philosophers have argued that nihilism is defective insofar as nihilists are either unable to say what they mean by such phrases as “there are xs arranged F-wise,” or that nihilists are unable to employ such phrases without incurring significant costs, perhaps even undermining one of the chief motivations for (...) nihilism. In this paper I defend nihilism against these objections. A key theme of the paper is this: if nihilists need to employ such phrases as “there are xs arranged F-wise,” non-nihilists will need to do so as well. Accordingly, any costs incurred by the nihilist when she employs such phrases will be shared by everyone else. What’s more, such phrases are intelligible when employed by the nihilist, as well as when they are employed by the non-nihilist, insofar as analyses of such phrases will not essentially involve mereological concepts incompatible with nihilism. (shrink)

Mereological nihilism (henceforth just "nihilism") is the thesis that composition never occurs. Nihilism has often been defended on the basis of its theoretical simplicity, including its ontological simplicity and its ideological simplicity (roughly, nihilism's ability to do without primitive mereological predicates). In this paper I defend nihilism on the basis of the theoretical unification conferred by nihilism, which is, roughly, nihilism's capacity to allow us to take fewer phenomena as brute and inexplicable. This represents a respect in which nihilism enjoys (...) greater theoretical simplicity than its rivals which has not yet been explored, and which is immune to many of the objections which have been leveled against previous arguments for nihilism from nihilism's theoretical simplicity. Composition as identity might be thought to confer a similar degree of theoretical unification as nihilism. I end the paper by arguing that this is not the case. (shrink)

Many explanations in science make use of mathematics. But are there cases where the mathematical component of a scientific explanation is explanatory in its own right? This issue of mathematical explanations in science has been for the most part neglected. I argue that there are genuine mathematical explanations in science, and present in some detail an example of such an explanation, taken from evolutionary biology, involving periodical cicadas. I also indicate how the answer to my title question impacts on broader (...) issues in the philosophy of mathematics; in particular it may help platonists respond to a recent challenge by Joseph Melia concerning the force of the Indispensability Argument. (shrink)

Philosophers have long been tempted by the idea that objects and properties are abstractions from the facts. But how is this abstraction supposed to go? If the objects and properties aren't 'already' there, how do the facts give rise to them? Jason Turner develops and defends a novel answer to this question: The facts are arranged in a quasi-geometric 'logical space', and objects and properties arise from different quasi-geometric structures in this space.

Ross P. Cameron argues that the flow of time is a genuine feature of reality. He suggests that the best version of the A-Theory is a version of the Moving Spotlight view, according to which past and future beings are real, but there is nonetheless an objectively privileged present. Cameron argues that the Moving Spotlight theory should be viewed as having more in common with Presentism than with the B-Theory. Furthermore, it provides the best account of truthmakers for claims about (...) what was or will be the case. Cameron goes on to defend an account of the open future, and argues that this is a better account than that available to the Growing Block theory. (shrink)

In order to perfectly describe the world, it is not enough to speak truly. One must also use the right concepts - including the right logical concepts. One must use concepts that "carve at the joints", that give the world's "structure". There is an objectively correct way to "write the book of the world". Much of metaphysics, as traditionally conceived, is about the fundamental nature of reality; in the present terms, this is about the world's structure. Metametaphysics - inquiry into (...) the status of metaphysical questions - turns on structure. The question of whether ontological, causal, or modal questions are "substantive" is in large part a question of whether the world has ontological, causal, and modal structure - whether quantifiers, causal relations, and modal operators carve at the joints. (shrink)

This volume concerns the status and ambitions of metaphysics as a discipline.

The paper is an extended discussion of what I call the ‘dismissive attitude’ towards metaphysical questions. It has three parts. In the first part, I distinguish three quite different versions of dismissivism. I also argue that there is little reason to think that any of these positions is correct about the discipline of metaphysics as a whole; it is entirely possible that some metaphysical disputes should be dismissed and others should not be. Doing metametaphysics properly requires doing metaphysics first. I (...) then put two particular disputes on the table to be examined in the rest of the paper: the dispute over whether composite objects exist, and the dispute about whether distinct objects can be colocated. In the second part of the paper, I argue against the claim that these disputes are purely verbal disputes. In the third part of the paper, I present a new version of dismissivism, and argue that it is probably the correct view about the two disputes in question. They are not verbal disputes, and the discussion about them to date has not remotely been a waste of time. At this stage, however, our evidence has run out. I argue that neither side of either dispute is simpler than the other, and that the same objections in fact arise against both sides. (For example, the compositional nihilist does not in fact escape the problem of the many, and the one-thinger does not in fact escape the grounding problem.). (shrink)

Mereological nihilism says that there do not exist (in the fundamental sense) any objects with proper parts. A reason to accept it is that we can thereby eliminate 'part' from fundamental ideology. Many purported reasons to reject it - based on common sense, perception, and the possibility of gunk, for example - are weak. A more powerful reason is that composite objects seem needed for spacetime physics; but sets suffice instead.

There are different ways to be. This paper explicates and defends this controversial thesis. Special attention is given to the meta-ontology of Martin Heidegger. -/- .

Some argue that Lewisian realism fails as a reduction of modality because in order to meet some criterion of success the account needs to invoke primitive modality. I defend Lewisian realism against this charge; in the process, I hope to shed some light on the conditions of success for a reduction. In §1 I detail the resources the Lewisian modal realist needs. In §2 I argue against Lycan and Shalkowski’s charge that Lewis needs a modal notion of ‘world’ to ensure (...) that worlds correspond to possibilities. In §3 I respond to Divers and Melia’s objection that Lewis needs to invoke primitive modality to give a complete account of what worlds there are. In §4 I ask what it is for a notion to ‘involve’ modality. I conclude that the question is either in bad standing or at best offers little traction on the debate, and propose a different way of assessing when materials are appropriately included in a reductive base. (shrink)