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.

Recently, I’ve championed the doctrine that fundamentally different sorts of things exist in fundamentally different ways.1 On this view, what it is for an entity to be can differ across ontological categories.2 Although historically this doctrine was very popular, and several important challenges to this doctrine have been dealt with, I suspect that contemporary metaphysicians will continue to treat this view with suspicion until it is made clearer when one is warranted in positing different modes of existence.3 I address this (...) concern here. The question of when to posit ways of being is closely related to a more general question: when should one think that some philosophically interesting expression is analogous? Accordingly, my strategy here is as follows. First, I briefly explain my interpretation of ontological pluralism, the doctrine that there are ways of being.4 Second, I introduce the notion of an analogous term, and show how, on most ways of implementing ontological pluralism, “existence” is analogous. Third, I discuss two sufficient conditions for when one is warranted in claiming that a philosophically interesting term is analogous. Fourth, I present a series of ontological schemes, each of which satisfies at least one of the sufficient conditions. The upshot is this: if you are attracted to one of these ontologies, you have reason to believe in ways of being. The careful reader will have noted the apparent modesty of my conclusion. Unfortunately, I do not believe that one could ever be rationally required to believe in ways of being. Still, in general a metaphysic is a live option to the extent that it is shown to be rationally permissible to believe. Since the apparent consensus among contemporary analytic metaphysicians is that believing that things can exist in different ways is silly or confused, establishing the rational permissibility of belief in ways of being is a non-trivial task. Let us begin. (shrink)

Surveys and extens work that has been done in the past two years on 'tense logic' and is a sequel to the author's book, Time and Modality.

But Findlay's remark, like so much that has been written on the subject of time in the present century, was provoked in the first place by McTaggart's ...

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)

Ontological pluralism is the view that there are ways of being. Ontological pluralism is enjoying a revival in contemporary metaphysics. We want to say that there are numbers, fictional characters, impossible things, and holes. But, we don’t think these things all exist in the same sense as cars and human beings. If they exist or have being at all, then they have different ways of being. Fictional characters exist as objects of make‐believe and holes exist as absences in objects. But, (...) human beings and cars exist in a much more robust sense. What are ways of being? Why should be believe in them and what should we believe about them? This short essay provides an overview of the recent revival of ways of being and explores some of the surrounding issues. (shrink)

It seems intuitively obvious that what I am doing right now is more real than what I did just one second ago, and it seems intuitively obvious that what I did just one second ago is more real than what I did forty years ago. And yet, remarkably, every philosopher of time today, except for the author, denies this obvious fact about reality. What went wrong? How could philosophers get so far away from what is the most experientially evident fact (...) about reality? (shrink)

Precis of my book by this title, for a symposium.

Persistence through time is like extension through space. A road has spatial parts in the subregions of the region of space it occupies; likewise, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies. This view — known variously as four dimensionalism, the doctrine of temporal parts, and the theory that objects “perdure” — is opposed to “three dimensionalism”, the doctrine that things “endure”, or are “wholly present”.1 I will (...) attempt to resolve this dispute in favor of four dimensionalism by means of a novel argument based on considerations of vagueness. But before argument in this area can be productive, I believe we must become much clearer than is customary about exactly what the dispute is, for the usual ways of formulating the dispute are flawed, especially where three dimensionalism is concerned. (shrink)

I am attracted to ontological pluralism, the doctrine that some things exist in a different way than other things.1 For the ontological pluralist, there is more to learn about an object’s existential status than merely whether it is or is not: there is still the question of how that entity exists. By contrast, according to the ontological monist, either something is or it isn’t, and that’s all there is say about a thing’s existential status. We appear to be to be (...) ontological committed to what I will call almost nothings. Examples of almost nothings include holes, cracks, and shadows; almost nothings thrive in the absence of ‘positive’ entities such as donuts, walls, and sunlight. Let’s focus on holes, since the literature on them is voluminous.2 We quantify over holes, and even count them: we say, for example, that there are some holes in the cheese, seven to be precise. We ascribe features to them and talk as though they stand in relations: that hole is three feet wide, much wider than that tire over there. Holes apparently persist through time, as evidenced by the fact that my sweater has the same hole in it as the last time you saw me wear it. We even talk as though holes are causally efficacious: my ankle was badly sprained because I stepped in that hole in the sidewalk.3 It seems then that we believe in holes. If our beliefs are true, holes must enjoy some kind of reality. This puts the ontological monist in an uncomfortable position. According to her, everything that there is enjoys the same kind of reality, which is the kind of reality enjoyed by full-fledged concrete entities such as ourselves. She is committed to the unpleasant claim that holes are just as real as concretia, a claim that is apt to be met with incredulous stares by those not acquainted with contemporary metaphysics. Roy Sorensen (2008, p. 19) notes the tension almost nothings generate for ontological monists: ‘… it feels paradoxical to say that absences exist—but no better to say that absences do not exist’.. (shrink)

Ted Sider’s book makes a beautifully presented and compellingly argued case for four dimensionalism. Most of the arguments for four dimensionalism to be found in the literature seem to me to be uncompelling. Ted’s argument from vagueness, given in the last section of chapter 4, is a notable exception. After discussing that argument I will respond to his objections in section 5 chapter 5 to my own temporary identity view.

Three plausible views—Presentism, Truthmaking, and Independence—form an inconsistent triad. By Presentism, all being is present being. By Truthmaking, all truth supervenes on, and is explained in terms of, being. By Independence, some past truths do not supervene on, or are not explained in terms of, present being. We survey and assess some responses to this.

Four- Dimensionalism defends the thesis that the material world is composed of temporal as well as spatial parts. This defense includes a novel account of persistence over time, new arguments in favour of the four-dimensional ontology, and responses to the challenges four- dimensionalism faces." "Theodore Sider pays particular attention to the philosophy of time, including a strong series of arguments against presentism, the thesis that only the present is real. Arguments offered in favour of four- dimensionalism include novel arguments based (...) on time travel, the debate between spacetime substantivalists and relationalists, and vagueness. Also included is a comprehensive discussion of the paradoxes of coinciding material objects, and a novel resolution of those paradoxes based on temporal counterpart theory. In conclusion Sider replies to prominent objections to four- dimensionalism, including discussion of the problem of the rotating homogenous disk. (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.

Let us agree that everything that there is exists, and that to be, to be real, and to exist are one and the same. Does everything that there is exist to the same degree? Or do some things exist more than others? Are there gradations of being? I argue that some entities exist more than others. Moreover, many of the notions in play in contemporary metaphysical discourse, such as fundamentality, perfect naturalness, and grounding ought to be cashed out in terms (...) of degree of existence. (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.

In , Peter van Inwagen asked a good question. (Asking the right question is often the hardest part.) He asked: what do you have to do to some objects to get them to compose something---to bring into existence some further thing made up of those objects? Glue them together or what?1 Some said that you don’t have to do anything.2 No matter what you do to the objects, they’ll always compose something further, no matter how they are arranged. Thus we (...) learned of the fusion of the coins in our pockets and the Eiffel tower. (shrink)

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. -/- .