Mere Possibilities: Metaphysical Foundations of Modal Semantics: 2 (Carl G. Hempel Lecture Series) - Hardcover

Stalnaker, Robert

Hardcover

ISBN 10: 0691147124 ISBN 13: 9780691147123

Publisher: Princeton University Press, 2012

Synopsis

It seems reasonable to believe that there might have existed things other than those that in fact exist, or have existed. But how should we understand such claims? Standard semantic theories exploit the Leibnizian metaphor of a set of all possible worlds: a proposition might or must be true if it is true in some or all possible worlds. The actualist, who believes that nothing exists except what actually exists, prefers to talk of possible states of the world, or of ways that a world might be. But even the actualist still faces the problem of explaining what we are talking about when we talk about the domains of other possible worlds. In Mere Possibilities, Robert Stalnaker develops a framework for clarifying this problem, and explores a number of actualist strategies for solving it.


Some philosophers have hypothesized a realm of individual essences that stand as proxies for all merely possible beings. Others have argued that we are committed to the necessary existence of everything that does or might exist. In contrast, Mere Possibilities shows how we can make sense of ordinary beliefs about what might and must exist without making counterintuitive metaphysical commitments. The book also sheds new light on the nature of metaphysical theorizing by exploring the interaction of semantic and metaphysical issues, the connections between different metaphysical issues, and the nature of ontological commitment.

About this title

About the Author

Robert Stalnaker is the Laurance S. Rockefeller Professor of Philosophy at Massachusetts Institute of Technology. He is the author of Our Knowledge of the Internal World,
Ways a World Might Be,
Context and Content, and Inquiry.

From the Back Cover

"This is a subtle, nuanced exploration of the metaphysical basis for talk of possible worlds and its far from straightforward relation to the version of formal semantics known as 'possible worlds semantics, ' both of which have been immensely influential in recent decades. Robert Stalnaker has been one of the major players in debates on these matters, and this book contains significant further developments of his ideas."--Timothy Williamson, University of Oxford

"This is a first-rate book and a model of the best kind of unfussy scholarly writing. Robert Stalnaker combines an admirable economy of presentation with clarity, rigor, and thoroughness in exposition and argument. This is a major contribution to the field, and one to which philosophers, logicians, and linguists with any serious interest in modality should attend."--Bob Hale, University of Sheffield

From the Inside Flap

"This is a subtle, nuanced exploration of the metaphysical basis for talk of possible worlds and its far from straightforward relation to the version of formal semantics known as 'possible worlds semantics,' both of which have been immensely influential in recent decades. Robert Stalnaker has been one of the major players in debates on these matters, and this book contains significant further developments of his ideas."--Timothy Williamson, University of Oxford

"This is a first-rate book and a model of the best kind of unfussy scholarly writing. Robert Stalnaker combines an admirable economy of presentation with clarity, rigor, and thoroughness in exposition and argument. This is a major contribution to the field, and one to which philosophers, logicians, and linguists with any serious interest in modality should attend."--Bob Hale, University of Sheffield

Excerpt. © Reprinted by permission. All rights reserved.

Mere Possibilities

Metaphysical Foundations of Modal SemanticsBy Robert Stalnaker

Princeton University Press

Copyright © 2012 Princeton University Press
All right reserved.
ISBN: 978-0-691-14712-3

Contents

Preface.........................................................................ix1 On What There Isn't (But Might Have Been)....................................12 Merely Possible Possible Worlds..............................................223 What Is Haecceitism, and Is It True?.........................................524 Disentangling Semantics from Metaphysics.....................................895 Modal Realism, Modal Rationalism, Modal Naturalism...........................126Appendix A Modeling Contingently Existing Propositions.........................136Appendix B Propositional Functions and Properties..............................139Appendix C A Model for a Mighty Language.......................................149Appendix D Counterpart Semantics for the Cheap Haecceitist.....................154References......................................................................157Index...........................................................................161

Chapter One

On What There Isn't (But Might Have Been)

The problem of ontology, Quine told us in his classic essay "On what there is," can be put in a simple question, "what is there?" and answered in a word: "everything." My question should be equally simple, and its answer should follow from Quine's: there is nothing that isn't. But of course as Quine went on to say, the problem gets harder when one tries to be more specific about what there is and what there isn't. Quine's concern was mainly with the problem of expressing disagreement about ontology—if I believe there are more things in Heaven and Earth than are dreamt of in your philosophy, how can you talk about what it is that I believe in, but you do not? But even when we agree about what there is, we may want to acknowledge that things might have been different—not just that things might have been differently arranged but that there might have been different things than there actually are. If we ask not just "what is there" but "what might there have been," the answer "everything" does not seem sufficiently inclusive. But what else is there that might be included?

The problem is sufficiently daunting to have driven many philosophers, in different ways, to deny there could have been anything other than what in fact exists, or that anything that exists could have failed to exist. (Three examples of philosophers who develop this idea in very different ways: Wittgenstein of the Tractatus, David Lewis, and Timothy Williamson.) Others have hypothesized actual surrogates for the nonexistent things—individual essences that are themselves necessary existents and that correspond one-to-one with all the "things" (as we are inclined to put it) that might exist. Still others think that because taking modality seriously forces us to such metaphysical extravagance, we should reject modal discourse as anything more than a façon de parler. But I think modal concepts are central to our understanding of the world—the actual world—and that understanding them should not require extravagant metaphysical commitments. My aim in this book is to sketch a framework that allows us to avoid extravagant metaphysical commitments and that is also compatible with intuitively natural beliefs about the way things might have been.

There are some philosophers who want to take modality seriously, and seek a theoretical account of modal discourse, but who think that we cannot take possible-worlds semantics, as an account of modality, seriously without making extravagant metaphysical commitments. Christopher Peacocke, for example, holds that "it is an unstable, indeed incoherent, position to think that you can at the same time use the Kripke-style semantics in the metalanguage to give absolute truth-conditions for modal sentences, count ... [the proposition that there could have been something that doesn't actually exist] as true, yet avoid commitment to the existence of nonactual objects." But I want to defend the metaphysical innocence not only of modal concepts but also of a theoretical account of them in terms of possible worlds. Whether my construal of possible-worlds semantics counts as a realistic one or not is open to debate, and I will concede that on one of the several ways of construing the term "possible world," the possible worlds posited by these semantic models are artifacts of the model and not entities whose existence is affirmed. But I will argue that on another way of understanding the term, we can affirm the existence of possible worlds, as well as the claim that the semantic theory provides "absolute truth conditions for modal sentences" and "avoids commitment to the existence of nonactual objects."

Here is my plan for this chapter: I will start, in section 1, with some preliminary methodological remarks—about the aim and value of reduction in philosophical analysis, about thinking of the evaluation of philosophical theses in terms of costs and benefits, and about the contrast between realistic and anti-realistic accounts of a philosophical theory. In section 2, I will say what I take possible worlds to be, and what, from the perspective of this account of possible worlds, the problem is about merely possible individuals. Possible worlds, on the account I want to defend, are (to a first approximation) properties, and the main point I want to make in this section is that properties (and so possible worlds) are not representations. In section 3, I take an extended look at some examples of properties that are simpler and easier to think about than possible worlds but that share some of the features of possible worlds, construed as properties. In this section and section 4, I will use the analogy I develop to motivate what I hope is a metaphysically innocent account of the domains of other possible worlds.

The view I will be defending is committed to making sense of the contingent existence of individuals and properties, of propositions, and even of possible worlds themselves. I will conclude, in section 4, by sketching a problem that an account of this kind faces, a problem that I will respond to in chapter 2.

1. Methodological Preliminaries

According to John Divers in his useful survey of the range of alternative philosophical accounts of possible worlds, "the primary question of conceptual application of the species of AR [actualist realism] is whether any affords a thoroughly non-modal analysis of the family of modal and intensional concepts." Divers acknowledges that "the proponents of AR typically do not claim that the favored version of AR affords thoroughly nonmodal analysis of the modal concepts," but he seems to assume that it would be a benefit (in the cost-benefit evaluation of the general view) if it did provide such an analysis. But my view is that if an account of modality were to meet this condition, that would be a sure sign that it was on the wrong track. Necessity and possibility are fundamental concepts, like truth and existence. What would you say to a philosopher who was seeking a thoroughly nonexistential analysis of quantificational concepts, or a thoroughly non-alethic analysis of truth, and related concepts? It is not that philosophers have not proposed such analyses (substitutional quantification, truth as warranted assertability or as what ideal believers will believe at the end of inquiry, for example). But even if an analysis of this kind were to be extensionally correct, at least according to someone's philosophical theory, it would only blur the distinction between semantic analysis and a substantive metaphysical thesis about what exists or what is true. Consider the nominalist who defines existence as having spatio-temporal location. Platonists will agree that if that is what you mean by "exist," than numbers, sets, and properties do not exist. They will need to find alternative means of describing their ontological beliefs.

I do not want to suggest that one can distinguish, on some pretheoretical a priori ground, which concepts are fit subjects for some kind of reductive analysis. It may be a contentious philosophical question, not only how to answer substantive questions but also which questions are substantive and which are semantic. So, for example, I am inclined to think not only that what is actual coincides with what exists but that this is because "actual" just means (more or less) real, or existent. The modal realist disagrees, and he might complain that by understanding "actual" in this way, I am blurring the line between metaphysical and terminological questions. I agree that my disagreement with the modal realist is a mix of semantic disagreement and disagreement about what there is in the world, and that to be clear, it is important to try to separate semantic from substantive questions, but it is not always easy to do so. I will discuss this issue in more detail and make some claims about how the two kinds of issues should be separated in chapter 4.

I have alluded to the cost-benefit, reflective equilibrium methodology that Lewis articulated and made fashionable, but I have my reservations about this way of thinking about the way philosophical alternatives are evaluated. This picture may be fine if it is taken simply as a reminder that in philosophy, as in science, political theory, or any other enterprise, everything is potentially criticizable; there are no absolute unquestionable dogmas. One should add that even judgments about what is a cost and what a benefit might be a proper subject of debate. But beyond the bland truism, the reflective equilibrium method does not offer much guidance. Even though anything might be epistemically relevant to anything else, one important task, in deciding between alternative philosophical views, is to isolate considerations of different kinds. There may be no absolutely neutral conceptual standpoint, but it is a virtue of a theoretical account of some concept or family of concepts (a benefit in the cost-benefit analysis) if it is able to fashion some tools that manage to remain neutral on issues in dispute—to provide resources to formulate alternative substantive views as coherently as possible. A more neutral account (of truth, existence, properties and relations, modality) may seem disappointing (it would be nice to have an account of truth that gave us a lot of information about what is true), but I think we should be suspicious of an account of modality that tells us too much about what there is or about what there might have been.

Consider this parody of the cost-benefit methodology, run amok: X says, "I have a beautiful, austere, and crystal clear theory of properties: they are just sets—no more and no less. The relation between a property and its exemplifications is just the relation between a set and its members." Y responds: "It is a beautiful theory, I agree, but unfortunately it is false—there are many obvious counterexamples. We don't need to consider exotic examples like renates and cordates. Consider any two uninstantiated properties like being a talking donkey and being a philosophizing cat [two of David Lewis's favorite examples]. It follows from your view that these two properties are one, which is obviously wrong." X replies: "Some who like my theory—perhaps a Quinean—would reply by rejecting your intuition that there are distinct properties here. But I am a commonsensical chap [as David Lewis liked to describe himself], and I agree with you that the properties you have described are distinct. Nevertheless, I am reluctant to give up my beautiful theory, since its benefits are great. I prefer to give up instead the belief that there are no talking donkeys and no philosophizing cats."

There is much more that X needs to say, for example, about how these ontological hypotheses are to be reconciled with apparent evidence to the contrary, but however X goes on, I think most of us will find this response suspicious, not just because the benefit of the beautiful theory is outweighed by the cost of the ugly facts, but because there is something suspect about using this kind of theoretical virtue to reach this kind of conclusion about what there is. (This is a parody, but it can be argued that my story of X and Y is just an uncharitable spin on the kind of consideration that actually motivated Lewis's modal realism. Lewis does hold this theory of properties, and getting the identity condition for properties right is a prime motivation for the hypothesis of a plurality of worlds. And it is the identification of properties with sets that rules out, for him, an actualist account of possible worlds.)

One final methodological remark before getting down to business: it is common to distinguish between "ontologically serious" applications of modal semantics and purely instrumental uses; the latter includes mathematical uses (for example, the construction of models to show the satisfiability, in a technical sense, of certain sets of sentences of a formal language) and heuristic uses that treat possible worlds discourse as "a vivid shorthand for sentences containing modal operators." It is often suggested that if we are to take possible-worlds semantics to be a theory that contributes to a project of philosophical explanation of modality, then we must specify a particular model—the intended model of metaphysical possibility. Jon Barwise and John Perry wrote, in criticizing possible-worlds semantics:

If the model-theoretic structures of possible worlds semantics, the ones that include a set of all possible worlds, are supposed to be a model of something, say super-reality, under some correspondence or other, then there ought to be one that is an intended or standard model, the one that really corresponds to super-reality.

I think this contrast is oversimplified. Taking possible-worlds semantics seriously as an explanatory account need not require the belief that there is one intended model any more than taking quantification theory, and its semantics, seriously requires the belief that the intended interpretation is in terms of a single domain of absolutely everything. There is controversy about whether it makes sense to quantify over absolutely everything, but whether it does or not, I think all should agree that we can take quantification theory as more than a mathematical tool or a heuristic device even while rejecting the idea of an absolute domain. And whether or not it makes sense to talk of an absolute, context-independent domain of all possible worlds, it is useful to separate the project of clarifying the framework for doing modal metaphysics from the project of saying, within that framework, what is really necessary and possible. (Just as Quine distinguished the project of getting clear about what ontological commitment is and how it is to be represented from the project of stating what one's ontological commitments are.) I agree that if we are to take possible-worlds semantics seriously, we must say something about the kind of thing that a possible world is and justify the claim that it is reasonable to think that there are such things as possible worlds. But my aim will be to vindicate the possible-worlds theory while making minimal commitments about substantive metaphysical questions, for example, about whether there are things, or properties, that exist only contingently, whether there are individual essences that are irreducible to qualitative properties, whether there could be distinct but qualitatively indiscernible worlds. In the balance of costs and benefits, I give positive weight to this kind of neutrality.

2. What Are Possible Worlds?

So what, on my view, are possible worlds (in the sense in which it is reasonable to say that there is a plurality of such things)? I take them to be properties—ways a world might be. Of course this leaves a lot open, since there are many different accounts of what properties are, but I take the significance of the categorization of possible states of the world as properties to be that it implies at least these two things. First, a possible world is the kind of thing that is, or can be, instantiated or exemplified. An actualist needs the distinction between existing and being exemplified in order to be able explain the sense in which a merely possible world exists (a property the world might have had exists) and the sense in which it does not (no world that is that way exists). But second—and this is the point I want to emphasize—if possible worlds are properties, they are not representations—not mental or linguistic entities. So the account of possible worlds I will defend rejects what Lewis calls linguistic ersatzism, as well as the other forms of ersatzism that Lewis considers, all of which treat possible worlds as representations. The significance of this point is that possible worlds are not the kind of thing that faces a problem of intentionality. About a representation (a name, a predicate, a picture, a scale model, a sentence) we can intelligibly ask, what is it about it in virtue of which it represents what it represents? (The following, for example, is a perfectly reasonable question: "What is it about the inscription or vocable 'triangular,' as it is used in a certain linguistic community, that makes it a word for the property of being triangular, rather than for the property of being square?") David Lewis, taking the actualist to be giving some kind of representational account of possible worlds, asks: What is it about a world in which there are talking donkeys that makes it a world in which there are talking donkeys, rather than a world in which there are philosophizing cats? But if possible worlds are properties, this is like the question, what is it about the property of being triangular that makes it that property rather than the property of being square? This I take to be an unintelligible question.

(Continues...)

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Edition details

• Publisher: Princeton University Press
• Publication date: 2012
• Language: English
• ISBN 10: 0691147124
• ISBN 13: 9780691147123
• Binding: Hardcover
• Number of pages: 184