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.

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)

It seems obvious that I could have failed to exist. My parents could easily never have met, in which case I should never have been conceived and born. The like applies to everyone. More generally, it seems plausible that whatever exists in space and time could have failed to exist. Events could have taken an utterly different course. Our existence, like most other aspects of our lives, appears frighteningly contingent. It is therefore surprising that there is a proof of my (...) necessary existence, a proof that generalizes to everything whatsoever. I will explain the proof and discuss what to make of it. A first reaction is that a ‘proof’ of such an outrageous conclusion must contain some dreadful fallacy. Yet the proof does not collapse under scrutiny. Further reflection suggests that, suitably interpreted, it may be sound. So interpreted, the conclusion is not outrageous, although it may not be the view you first thought of. (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. -/- .

There are many kinds of beings – stones, persons, artifacts, numbers, propositions – but are there also many kinds of being? The world contains a variety of objects, each of which exists – but do some objects exist in different ways? The historically popular answer is yes. This answer is suggested by the Aristotelian slogan that “being is said in many ways”, and according to some interpretations is Aristotle’s view.1 Variants of this slogan were championed by medieval philosophers, such as (...) Aquinas, who worried that God cannot be said to exist in the same sense (or in the same way?) as created things.2 Descartes alluded to the medievals’ worry, but extensive discussion of the problem of being disappeared from the central stage by the time of the modern period.3 However, in the early 20th century, friends of ways of being included Alexius Meinong (1910: 49- 62), G.E. Moore (1903: 161-163), Russell (1912: 91-100), Husserl (1901: 249-250), and Heidegger (1927).4 In what follows, I develop a meta-ontological theory based on the work of Martin Heidegger circa Being and Time. I take Heidegger’s work as my inspiration because of the historical importance of Heidegger’s philosophy, and because Heidegger provides a particularly clear statement of the doctrine that there are many ways to be. I begin by carefully discussing and then formulating the relevant aspects of Heidegger’s metaontological theory. Heidegger claims both that the word “being” has many meanings and that there are different ways in which things exist. Section 2 explicates the former thesis, as well as elucidates the connection between senses of “being” and quantification. Most contemporary analytic metaphysicians believe that the idea that different kinds of beings can enjoy different ways of being is metaphysically bankrupt, and probably even meaningless.5 They are mistaken. In section 3, I discuss the doctrine that there are ways of being, and show how we can understand this doctrine in terms of the meta-ontological framework defended by Theodore Sider.. (shrink)

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.).

According to David Lewis, a realist about possible worlds must hold that actuality is relative: the worlds are ontologically all on a par; the actual and the merely possible differ, not absolutely, but in how they relate to us. Call this 'Lewisian realism'. The alternative, 'Leibnizian realism', holds that actuality is an absolute property that marks a distinction in ontological status. Lewis presents two arguments against Leibnizian realism. First, he argues that the Leibnizian realist cannot account for the contingency of (...) actuality. Second, he argues that the Leibnizian realist cannot explain why skepticism about one's own actuality is absurd. In this paper, I mount a defense of Leibnizian realism. (shrink)

There is a common form of problem, to be found in many areas of philosophy, concerning the relationship between our perspective on reality and reality itself. We make statements (or form judgements) about how things are from a given standpoint or perspective. We make the statement ‘it is raining’ from the standpoint of the present time, for example, or the statement‘it is here’ from the standpoint of where we are, or the statement ‘I am glad’ from the standpoint of a (...) subject. In each of these cases, the statement has a certain ‘aspect’ or perspectival character in virtue of which its truth is capable of varying from one standpoint to another. Thus the statement ‘it is raining’ is tensed, the statement ‘it is here’ is ‘spatiocentric’ and the statement ‘I am glad’ is first-personal. The problem we then face is to determine whether this aspect is a feature of the reality which is described or merely a feature of the statement by which it is described. Is reality itself somehow tensed or spatiocentric or firstpersonal or is it merely that we describe a tenseless or spatially uncentered or impersonal reality from a tensed or spatiocentric or first-personal point of view? (shrink)

It is argued that just as there is a distinction between tensed and tenseless sentences so is there a distinction between worldly and unworldly sentences. This distinction has important implications for questions of possible non-existence, the nature of sortal concepts, such as man or set, and the different ways in which an object might exist.

There is a common form of problem, to be found in many areas of philosophy, concerning the relationship between our perspective on reality and reality itself. We make statements (or form judgements) about how things are from a given standpoint or perspective. We make the statement ‘it is raining’ from the standpoint of the present time, for example, or the statement‘it is here’ from the standpoint of where we are, or the statement ‘I am glad’ from the standpoint of a (...) subject. In each of these cases, the statement has a certain ‘aspect’ or perspectival character in virtue of which its truth is capable of varying from one standpoint to another. Thus the statement ‘it is raining’ is tensed, the statement ‘it is here’ is ‘spatiocentric’ and the statement ‘I am glad’ is first-personal. The problem we then face is to determine whether this aspect is a feature of the reality which is described or merely a feature of the statement by which it is described. Is reality itself somehow tensed or spatiocentric or firstpersonal or is it merely that we describe a tenseless or spatially uncentered or impersonal reality from a tensed or spatiocentric or first-personal point of view? (shrink)