Crucial to Hilary Putnam’s realism in the philosophy of mathematics is to maintain the objectivity of mathematics without the commitment to the existence of mathematical objects. Putnam’s indispensability argument was devised as part of this conception. In this paper, I reconstruct and reassess Putnam’s argument for the indispensability of mathematics, and distinguish it from the more familiar, Quinean version of the argument. Although I argue that Putnam’s approach ultimately fails, I develop an alternative way of implementing (...) his form of realism about mathematics that, by using different resources than those Putnam invokes, avoids the difficulties faced by his view. (shrink)

Recent debates about mathematical ontology are guided by the view that Platonism's prospects depend on mathematics' explanatory role in science. If mathematics plays an explanatory role, and in the right kind of way, this carries ontological commitment to mathematical objects. Conversely, the assumption goes, if mathematics merely plays a representational role then our world-oriented uses of mathematics fail to commit us to mathematical objects. I argue that it is a mistake to think that mathematical representation is necessarily ontologically innocent (...) and that there is an argument from mathematics' representational capacity to Platonism. Given that it is common ground between the Platonist and nominalist that mathematics plays a representational role in science, this representationalist argument is to be preferred over the explanatory, or enhanced, indispensability argument. (shrink)

ABSTRACT:This essay describes three commitments that have become central to the author's philosophical outlook, namely, to liberal naturalism, to metaphysical realism, and to the epistemic and ontological objectivity of normative judgments.Liberal naturalismis contrasted with familiar scientistic versions of naturalism and their project of forcing explanations in every field into models derived from one or another particular science. The form ofmetaphysical realismthat the author endorses rejects every form of verificationism, including the author's one-time ‘internal realism’, and insists that our claims (...) about the world are true or false and not just epistemically successful or unsuccessful and that the terms they contain typically refer to real entities. ‘Representationalism is no sin’. The central part of the essay is an account oftruthbased on a detailed analysis of Tarski's theory of truth and of the insights we can get from it as well as of the respects in which Tarski is misleading. The account ofthe objectivity of the normativein this essay draws on insights from Dewey as well as Scanlon. (shrink)

Much recent discussion in the philosophy of mathematics has concerned the indispensability argument—an argument which aims to establish the existence of abstract mathematical objects through appealing to the role that mathematics plays in empirical science. The indispensability argument is standardly attributed to W. V. Quine and Hilary Putnam. In this paper, I show that this attribution is mistaken. Quine's argument for the existence of abstract mathematical objects differs from the argument which many philosophers of mathematics ascribe to him. Contrary (...) to appearances, Putnam did not argue for the existence of abstract mathematical objects at all. I close by suggesting that attention to Quine and Putnam's writings reveals some neglected arguments for platonism which may be superior to the indispensability argument. (shrink)

Recently, nominalists have made a case against the Quine–Putnam indispensability argument for mathematical Platonism by taking issue with Quine’s criterion of ontological commitment. In this paper I propose and defend an indispensability argument founded on an alternative criterion of ontological commitment: that advocated by David Armstrong. By defending such an argument I place the burden back onto the nominalist to defend her favourite criterion of ontological commitment and, furthermore, show that criterion cannot be used to formulate (...) a plausible form of the indispensability argument. (shrink)

The ramifications are explored of taking physical theories to commit their advocates only to ‘physically real’ entities, where ‘physically real’ means ‘causally efficacious’ (e.g., actual particles moving through space, such as dust motes), the ‘physically significant’ (e.g., centers of mass), and the merely mathematical—despite the fact that, in ordinary physical theory, all three sorts of posits are quantified over. It's argued that when such theories are regimented, existential quantification, even when interpreted ‘objectually’ (that is, in terms of satisfaction via variables, (...) rather than by substitution-instances) need not imply any ontological commitments. (shrink)

Indispensability arguments for realism about mathematical entities have come under serious attack in recent years. To my mind the most profound attack has come from Penelope Maddy, who argues that scientific/mathematical practice doesn't support the key premise of the indispensability argument, that is, that we ought to have ontological commitment to those entities that are indispensable to our best scientific theories. In this paper I defend the Quine/Putnam indispensability argument against Maddy's objections.

Discourse carries thin commitment to objects of a certain sort iff it says or implies that there are such objects. It carries a thick commitment to such objects iff an account of what determines truth-values for its sentences say or implies that there are such objects. This paper presents two model-theoretic semantics for mathematical discourse, one reflecting thick commitment to mathematical objects, the other reflecting only a thin commitment to them. According to the latter view, for example, the semantic role (...) of number-words is not designation but rather the encoding of cardinality-quantifiers. I also present some reasons for preferring this view. (shrink)

I revisit my 1993 paper on Putnam and mathematical realism focusing on the indispensability argument and how it has fared over the years. This argument starts from the claim that mathematics is an indispensable part of science and draws the conclusion, from holistic considerations about confirmation, that the ontology of science includes abstract objects as well as the physical entities science deals with.

In this brief book one of the most distinguished living American philosophers takes up the question of whether ethical judgments can properly be considered objective--a question that has vexed philosophers over the past century. Reviewing what he deems the disastrous consequences of ontology's influence on analytic philosophy--in particular, the contortions it imposes upon debates about the objective of ethical judgments--Putnam proposes abandoning the very idea of ontology.

"The first two lectures place the alternative I defend -- a kind of pragmatic realism -- in a historical and metaphysical context. Part of that context is provided by Husserl's remark that the history of modern philosophy begins with Galileo -- that is, modern philosophy has been hypnotized by the idea that scientific facts are all the facts there are. Another part is provided by the analysis of a very simple example of what I call 'contextual relativity'. The position I (...) defend holds that truth depends on conceptual scheme and it is nonetheless 'real truth'. "In my third lecture I turn to the Kantian antecedents of this view, explaining what I think should be retained of the Kantian idea of autonomy as the central theme of morality, and extracting from Kant's work a 'moral image of the world' that connects the ideals of equality and intellectual liberty. In this lecture I defend the idea that moral images are an indispensible part of our moral and cultural heritage. "In the final lecture I defend the idea of moral objectivity. I compare our epistemological positions in ethics, history, analysis of human character, and science, and I argue that in no area can we hope for a 'foundation' which is more ultimate than the beliefs that actually, at a given time, function as foundational in the area, the beliefs concerning which one has to say 'this is where my spade is turned'. In ethics such beliefs are represented in moral images of the world.". (shrink)

First published in 1971, Professor Putnam's essay concerns itself with the ontological problem in the philosophy of logic and mathematics - that is, the issue of whether the abstract entities spoken of in logic and mathematics really exist. He also deals with the question of whether or not reference to these abstract entities is really indispensible in logic and whether it is necessary in physical science in general.

First published in 1971, Professor Putnam's essay concerns itself with the ontological problem in the philosophy of logic and mathematics - that is, the issue of whether the abstract entities spoken of in logic and mathematics really exist. He also deals with the question of whether or not reference to these abstract entities is really indispensible in logic and whether it is necessary in physical science in general.

The article discusses the relevance of ontology, the metaphysical study of being, in social sciences through a comparison of three distinct outlooks: Roy Bhaskar's version of critical realism, a pragmatic realist approach the most renowned representatives of which are Rom Harré and Hilary Putnam, and the authors’ own synthesis of the pragmatist John Dewey's and the neopragmatist Richard Rorty's ideas, here called methodological relationalism. The Bhaskarian critical realism is committed to the heavy ontological furniture of metaphysical transcendentalism, resting (...) on essentialist presumptions of causality and social structures, tacitly creating a dualism between individuals and society. Pragmatic realists, for their part, carry much lighter metaphysical baggage than critical realists and, much in a pragmatist vein, accept the idea that social scientists should study society by studying social life—the interwoven activities of individuals. Nevertheless, pragmatic realists only reluctantly, if at all, renounce the subject–object dualism and its ontological implications. Drawing on the ideas of Donald Davidson and Richard Rorty, the writers outline their own antirepresentationalist, antiessentialist approach to social sciences. The proposed methodological relationalism is a pragmatist approach of Deweyan origin. Based on a Darwinian understanding of human beings as organisms trying to cope with their environment, it emphasises the insight that one can neither step outside one's own action, nor withdraw from the actor's point of view, just as one cannot cognitively step outside language. (shrink)

The Quine-Putnam indispensability argument runs as follows: We have reason to believe in Fs if Fs are indispensable to our best available science. Mathematical entities are indispensable to our best available science. Therefore, we have reason to believe in mathematical entities.According to the standard understanding, in order to refute the argument the nominalist has to show that mathematical entities are dispensable by providing an at least as good theory of the same phenomena that is not ontologically committed to mathematical (...) entities. Most philosophers who write in this area, including John Burgess, Mark Colyvan, Hartry Field, Penelope Maddy, and Gideon Rosen, accept the standard understanding. Many nominalists who accept the standard understanding propose nominalistic paraphrases or alternatives, claiming that these are either equally good or better than our current scientific theories. Platonists deny that they are either equally good or better. (shrink)

It has been maintained by such philosophers as Quine and Goodman that purely ‘extensional’ language suffices for all the purposes of properly formalized scientific discourse. Those entities that were traditionally called ‘universals’ — properties, concepts, forms, etc. — are rejected by these extensionalist philosophers on the ground that ‘the principle of individuation is not clear’. It is conceded that science requires that we allow something tantamount to quantification over non-particulars (or, anyway, over things that are not material objects, not space-time (...) points, not physical fields, etc.), but, the extensionalists contend, quantification over sets serves the purposes nicely. The ‘ontology’ of modern science, at least as Quine formalizes it, comprises material objects (or, alternatively, space-time points), sets of material objects, sets of sets of material objects,... but no properties, concepts,or forms. Let us thus examine the question: Can the principle of individuation for properties ever be made clear? (shrink)

According to Quine’s indispensability argument, we ought to believe in just those mathematical entities that we quantify over in our best scientific theories. Quine’s criterion of ontological commitment is part of the standard indispensability argument. However, we suggest that a new indispensability argument can be run using Armstrong’s criterion of ontological commitment rather than Quine’s. According to Armstrong’s criterion, ‘to be is to be a truthmaker (or part of one)’. We supplement this criterion with our own brand of (...) metaphysics, 'Aristotelian (...) realism', in order to identify the truthmakers of mathematics. We consider in particular as a case study the indispensability to physics of real analysis (the theory of the real numbers). We conclude that it is possible to run an indispensability argument without Quinean baggage. (shrink)

A metaphysically robust, as opposed to lightweight, Platonism with respect to uncreatable abstract objects is theologically unacceptable because it fatally compromises creatio ex nihilo and divine aseity. The principal argument for Platonism is the so-called Indispensability Argument based on the ontological commitments required by singular terms and existential quantifiers in true sentences. Different varieties of Nominalism challenge each of the argument’s premises. Fictionalism accepts the assumed criterion of ontological commitment but rejects the truth of the relevant sentences. Neutralism (...) accepts the truth of the relevant sentences but denies the assumed criterion of ontological commitment. Both of these perspectives, but especially the last, are plausible routes available for the Christian theist. (shrink)

In this article I consider what it would take to combine a certain kind of mathematical Platonism with serious presentism. I argue that a Platonist moved to accept the existence of mathematical objects on the basis of an indispensability argument faces a significant challenge if she wishes to accept presentism. This is because, on the one hand, the indispensability argument can be reformulated as a new argument for the existence of past entities and, on the other hand, if one accepts (...) the indispensability argument for mathematical objects then it is hard to resist the analogous argument for the existence of the past. (shrink)

In this article I consider what it would take to combine a certain kind of mathematical Platonism with serious presentism. I argue that a Platonist moved to accept the existence of mathematical objects on the basis of an indispensability argument faces a significant challenge if she wishes to accept presentism. This is because, on the one hand, the indispensability argument can be reformulated as a new argument for the existence of past entities and, on the other hand, if one accepts (...) the indispensability argument for mathematical objects then it is hard to resist the analogous argument for the existence of the past. (shrink)

In this paper, I examine Putnam’s nuanced views in the philosophy of mathematics, distinguishing three proposals: modalism, quasi-empirical realism, and an indispensability view. I argue that, as he shifted through these views, Putnam aimed to preserve a semantic realist account of mathematics that avoids platonism. In the end, however, each of the proposals faces significant difficulties. A form of skepticism then emerges.

The author of “Parsimony and inference to the best mathematical explanation” argues for platonism by way of an enhanced indispensability argument based on an inference to yet better mathematical optimization explanations in the natural sciences. Since such explanations yield beneficial trade-offs between stronger mathematical existential claims and fewer concrete ontological commitments than those involved in merely good mathematical explanations, one must countenance the mathematical objects that play a theoretical role in them via an application of the relevant mathematical results. (...) The nominalist’s challenge is thus to undermine the platonistic force of such explanations by way of alternative nominalistic ones. The author’s contention is that such nominalistic explanations should provide a paraphrase of the proofs of the mathematical results being applied. There are reasons to doubt that proofs, construed here as formal derivations, actually contribute to the platonistc force to be undermined and, by parity, that nominalized proofs should bear responsability for the corresponding undermining. A discussion of two examples and of associated arguments by Lange, Pincock, Steiner and Tallant, point to a a wealth of worries concerning the construal of this explanatory role. Among those figure the distinction between the weak and strong role of proofs, the distinction between causal or “ordinary” explanations and genuine mathematical ones, and the unifying role of optimization explanations. More generally, the very idea that the explanatory advantages yielded by applied mathematical claims may be construed as gradual or progressive and the associated notion that the feasibility of their nominalistic paraphrases decreases as the generality and force of these claim increases, deserves a closer attention. (shrink)

In this paper, I argue against Michael Gorman’s objection to Tim Crane’s view of intentional objects. Gorman (“Talking about Intentional Objects,” 2006), following Searle (Intentionality, 1983), argues that intentional content can be cashed out solely in terms of conditions of satisfaction. For Gorman, we have reason to prefer his more minimal satisfaction-condition approach to Crane’s be- cause we cannot understand Crane’s notion of an intentional object when applied to non-existent objects. I argue that Gorman’s criticism rests on a misunderstanding of (...) Crane’s position. I also discuss the importance of keeping track of the distinction between the intentional objects of intentional states and the referents of such states. I do agree with Gorman that conditions of satisfaction are needed to cash out propositional intentional content, but we cannot get these conditions of satisfaction right if we do not capture how the subject takes the world to be. And we cannot properly capture how the subject takes the world to be without commitment to intentional objects. I argue that Crane’s notion of an intentional object is one that avoids questionable ontological commitments. So, in the end we have a view of intentional objects with a respectable metaphysics and ontology that can properly capture the intentional content of subjects’ intentional states. (shrink)

I will contrast two conceptions of the nature of mathematical objects: the conception of mathematical objects as preconceived objects, and heavy duty platonism. I will argue that friends of the indispensability argument are committed to some metaphysical theses and that one promising way to motivate such theses is to adopt heavy duty platonism. On the other hand, combining the indispensability argument with the conception of mathematical objects as preconceived objects yields an unstable position. The conclusion is that the metaphysical commitments (...) of the indispensability argument should be carefully scrutinized. (shrink)

What in our theoretical pronouncements commits us to objects? The Quinean standard for ontological commitment involves (nearly enough) commitments when we utter “there is” or “there are” statements without hope of eliminating these by paraphrase. Coupled with the indispensability of the truth of applied mathematical doctrine, the result is that the ontologically hard-nosed scientist is a Platonist—haplessly commited to abstracta. In this book Azzouni offers a way around the Quinean straitjacket: ontological commitment turns on how theories are (nearly (...) enough) nailed to the world. The specifics of how theories are applied indicates which among the posits of a theory are mere mathematical garb and which are genuine connections to items out there. In the first part of the book Azzouni undercuts the arguments, both actual and possible, in support of Quine’s criterion. An alternative criterion for what exists—ontological independence—is offered, one in sturdy accord with ordinary folk views on the matter. In the second part of the book, a beginning is made of bringing this alternative to bear upon scientific theories with a rich mathematical component. Along the way, old philosophical issues about absolute space and time versus relative space and time, the status of mathematical posits, such as spatial and temporal points, and so on, are illuminated. (shrink)

Platonists in mathematics endeavour to prove the truthfulness of the proposal about the existence of mathematical objects. However, there have not been many explicit proofs of this proposal. One of the explicit ones is doubtlessly Baker’s Enhanced Indispensability Argument, formulated as a sort of modal syllogism. We aim at showing that the purpose of its creation – the defence of Platonist viewpoint – was not accomplished. Namely, the second premise of the Argument was imprecisely formulated, which gave space for various (...) interpretations of the EIA. Moreover, it is not easy to perceive which of the more precise formulations of the above-mentioned premise would be acceptable. For all these reasons, it is disputable whether the EIA can be used to defend Platonist outlook. At the beginning of this century, Baker has shown that the so-called Quine-Putnam Indispensability Argument can not provide “full” platonism - a guarantee of the existence of all mathematical objects. It turns out, however, that the EIA has a similar disadvantage. (shrink)

In this paper I do two things: (1) I support the claim that there is still some confusion about just what the Quine-Putnam indispensability argument is and the way it employs Quinean meta-ontology and (2) I try to dispel some of this confusion by presenting the argument in a way which reveals its important meta-ontological features, and include these features explicitly as premises. As a means to these ends, I compare Peter van Inwagen’s argument for the existence of (...) properties with Putnam’s presentation of the indispensability argument. Van Inwagen’s argument is a classic exercise in Quinean meta-ontology and yet he claims – despite his argument’s conspicuous similarities to the Quine-Putnam argument – that his own has a substantially different form. I argue, however, that there is no such difference between these two arguments even at a very high level of specificity; I show that there is a detailed generic indispensability argument that captures the single form of both. The arguments are identical in every way except for the kind of objects they argue for – an irrelevant difference for my purposes. Furthermore, Putnam’s and van Inwagen’s presentations make an assumption that is often mistakenly taken to be an important feature of the Quine-Putnam argument. Yet this assumption is only the implicit backdrop against which the argument is typically presented. This last point is brought into sharper relief by the fact that van Inwagen’s list of the four nominalistic responses to his argument is too short. His list is missing an important – and historically popular – fifth option. (shrink)

What are the ontological commitments of a sentence? In this paper I offer an answer from the perspective of the truthmaker theorist that contrasts with the familiar Quinean criterion. I detail some of the benefits of thinking of things this way: they include making the composition debate tractable without appealing to a neo-Carnapian metaontology, making sense of neo-Fregeanism, and dispensing with some otherwise recalcitrant necessary connections.

Indispensability-based arguments for mathematical platonism are typically motivated by drawing an analogy between abstract mathematical objects and concrete scientific posits. In this paper, I argue that mathematics can sometimes help to reduce our concrete ontological, ideological, and structural commitments. My focus is on optimization explanations, and in particular the case study involving periodical cicadas. I argue that in this case, stronger mathematical apparatus yields explanations that have fewer concrete commitments. The nominalist cannot accept these more parsimonious explanations without embracing (...) the stronger mathematics, and this poses a challenge for the nominalist position. (shrink)

This is a dissertation of philosophy of mathematics, in the analytical tradition, about the Quine-Putnam mathematical indispensability argument, that we ought to have ontological commitment to mathematical entities that are indispensable to our best scientific theories. It is an argument for the metaphysical mathematical realism supported by Quinean doctrines such as naturalism and holism. My overall aim is to make a discussion of the argument. The argument will be defended against generic objections or some of its detractors such (...) as Azzouni, Maddy, Cheyne and Balaguer. Matters connected with the indispensability of mathematics, such as the epistemic problem of Benacerraf and the agnosticist view of Balaguer, will be discussed. Primarily, the discussion is ontological; secondarily, the discussion is epistemological and metaphysical. (shrink)

This book does three main things. First, it defends mathematical platonism against the main objections to that view (most notably, the epistemological objection and the multiple-reductions objection). Second, it defends anti-platonism (in particular, fictionalism) against the main objections to that view (most notably, the Quine-Putnam indispensability objection and the objection from objectivity). Third, it argues that there is no fact of the matter whether abstract mathematical objects exist and, hence, no fact of the matter whether platonism or anti-platonism is (...) true. (shrink)

This research is aimed at explaining and analyzing the ontological status of semantical objects of religious language. This ontological status concern how every term in religious language refers to an object and how we interpret those terms, whether it represents the object itself or merely its sensual or constructive properties. This finding lies in the disputation between religious realism and non-realism. The results of this research are (1) every believer is exactly a realist because he or she has (...) the ontological commitment to the object of the utterance, but (2) God exists independently from human thought and consciousness, (3) it is possible to put God as the object of intentional and semantic but only represents sensible qualities of the real object, and (4) the meaning of religious language depends on believer's ontological commitment on God's existence. (shrink)

I discuss Putnam’s conception of logical truth as grounded in his picture of mathematical practice and ontology. i begin by comparing Putnam’s 1971 Philosophy of Logic with Quine’s homonymous book. Next, Putnam’s changing views on modality are surveyed, moving from the modal pre-formal to the de-modalized formal characterization of logical validity. Section three suggests a complementary view of Platonism and modalism underlying different stages of a dynamic mathematical practice. The final section argues for the pervasive platonistic conception (...) of the working mathematician. (shrink)

Enhanced indispensability arguments claim that Scientific Realists are committed to the existence of mathematical entities due to their reliance on Inference to the best explanation. Our central question concerns this purported parity of reasoning: do people who defend the EIA make an appropriate use of the resources of Scientific Realism to achieve platonism? We argue that just because a variety of different inferential strategies can be employed by Scientific Realists does not mean that ontological conclusions concerning which things we (...) should be Scientific Realists about are arrived at by any inferential route which eschews causes, and nor is there any direct pressure for Scientific Realists to change their inferential methods. We suggest that in order to maintain inferential parity with Scientific Realism, proponents of EIA need to give details about how and in what way the presence of mathematical entities directly contribute to explanations. (shrink)

Introduction: I lay out the broad contours of my thesis: a defence of mathematical nominalism, and nominalism more generally. I discuss the possibility of metaphysics, and the relationship of nominalism to naturalism and pragmatism. Chapter 2: I delineate an account of abstractness. I then provide counter-arguments to claims that mathematical objects make a di erence to the concrete world, and claim that mathematical objects are abstract in the sense delineated. Chapter 3: I argue that the epistemological problem with abstract objects (...) is not best understood as an incompatibility with a causal theory of knowledge, or as an inability to explain the reliability of our mathematical beliefs, but resides in the epistemic luck that would infect any belief about abstract objects. To this end, I develop an account of epistemic luck that can account for cases of belief in necessary truths and apply it to the mathematical case. Chapter 4: I consider objections, based on metaphysical considerations and linguistic data, to the view that the existential quantifier expresses existence. I argue that these considerations can be accommodated by an existentially committing quantifier when the pragmatics of quantified sentences are properly understood. I develop a semi-formal framework within which we can define a notion of nominalistic adequacy. I show how our notion of nominalistic adequacy can show why it is legitimate for the nominalist to make use of platonistic “assumptions” in inference-making. Chapter 5: I turn to the application of mathematics in science, including explanatory applications, and its relation to a number of indispensability arguments. I consider also issues of realism and anti-realism, and their relation to these arguments. I argue that abstraction away from pragmatic considerations has acted to skew the debate, and has obscured possibilities for a nominalistic understanding of mathematical practices. I end by explaining the notion of a pragmatic meta-vocabulary, and argue that this notion can be used to carve out a new way of locating our ontological commitments. Chapter 6: I show how the apparatus developed in earlier chapters can be utilised to roll out the nominalist project to other domains of discourse. In particular, I consider propositions and types. I claim that a unified account of nominalism across these domains is available. Conclusion: I recapitulate the claims of my thesis. I suggest that the goal of mathematical enquiry is not descriptive knowledge, but understanding. (shrink)

The subject with which Mark Colyvan's book deals is timely indeed. While discussions of mathematical ontology have been a mainstay in philosophy of mathematics for the last century (at least), for the last thirty years or so this discussion has begun with (and often not left) the Quine/Putnam indispensability argument. Though the argument is widely cited, to my knowledge this is the first book-length project exclusively dedicated to articulating and defending the Quine/Putnam indispensability argument for mathematical platonism. In (...) the first section below, I shall run through a summary of the book (following its chapter layout) with a few critical remarks. In the second section I shall raise a few critical issues organized topically. (shrink)

Chihara introduces this book as a response to critics of his last book, which gave an account of mathematical objects in terms of possible constructions of open sentences. Several reviewers charged him with exchanging an ontology of platonistic mathematical objects for an equally extravagant ontology of possible entities. In this book Chihara replies with an extended account how one can use modal logic, and even the notions of possible worlds semantics, without accepting merely possible worlds or objects. A final chapter (...) extends his anti-platonist arguments about philosophy of mathematics, directed primarily against Penelope Maddy and the “Indispensibility” argument associated with Quine and Putnam. (shrink)

This book is an exploration and defense of the coherence of classical theism’s doctrine of divine aseity in the face of the challenge posed by Platonism with respect to abstract objects. A synoptic work in analytic philosophy of religion, the book engages discussions in philosophy of mathematics, philosophy of language, metaphysics, and metaontology. It addresses absolute creationism, non-Platonic realism, fictionalism, neutralism, and alternative logics and semantics, among other topics. The book offers a helpful taxonomy of the wide range of options (...) available to the classical theist for dealing with the challenge of Platonism. It probes in detail the diverse views on the reality of abstract objects and their compatibility with classical theism. It contains a most thorough discussion, rooted in careful exegesis, of the biblical and patristic basis of the doctrine of divine aseity. Finally, it challenges the influential Quinean metaontological theses concerning the way in which we make ontological commitments. (shrink)

Several non-naturalist philosophers look for ways to maintain the objectivity of morals without making any ontological commitments. Recently Derek Parfit proposed an account of non-ontologically existing irreducible moral properties. My first aim in this paper is to outline that such an account is doomed to fail. My second aim in this paper is to argue that irreducible moral properties can be integrated with adaptions into an ontological framework such as E.J. Lowe’s four-category ontology. If it can be shown (...) that irreducible moral properties have a proper place in such an ontology, then there is no need to distinguish between an ontological and non-ontological mode of existence, which, in turn helps to eschew the obscurities that this distinction brings in its wake. (shrink)

Possible-worlds semantics proved itself as a strong tool in analysing the statements of actuality, possibility, contingency and necessity. But impossible phenomena go beyond the expressive power of the apparatus. The proponents of possible-worlds apparatus thus owe us at least three stories. The first one is the story about ontological nature of possible worlds, the second one is the story about the theoretical role such entities play and the third one is the story about the impossible. Modal Realism (MR) provides (...) us with a positive story regarding the first and the second, but denies impossible worlds. Extended Modal Realism (EMR) adds a positive story about the third point too. This book is an attempt to paraphrase extended modal realism in different metaphysical frameworks. In Chapter I, I outline the theory of modal realism, its systematic account of modality and its ontological commitments. I also motivate an impossible-worlds discourse as well as a systematic appeal of extending the picture beyond the possible. I then propose several definitions of the concept of ‘impossible world’ (or impossible possible world). Finally, I discuss a particular metaphysics behind the concept - extended modal realism. Chapter II considers the epistemological worry associated with (MR) and (EMR) and concludes that although the worry is justified, there can be epistemological justification of the theory. Next, I outline the so-called indispensability argument for the legitimacy of mathematical Platonism. Finally, I argue that the argument, if accepted, can be applied to metaphysics in general, to the existence of concrete possibilia (and impossibilia) in particular. Chapter III focuses on the analysis of (EMR). To be more precise, I present a so-called advanced modalizing problem which seems to be infecting every genuinely realistic theory of modality. In this chapter, I propose a way of treating extraordinary modal claims by means of plurality of logical spaces. The next three chapters provide different ways of understanding (EMR). Namely, Chapter IV develops and defends Extended Modal Dimensionalism (EMD). (EMD) is realism about spaces, times and worlds—metaphysical indices that make objects spatial, temporal and modal, respectively. Metaphysical indices play the role of alethic relativisers, i.e. items to which matters of truth are relativized. The chapter examines several arguments against modal dimensionalism and shows that it offers a feasible way to understand (EMR). Chapter V offers a structural approach to possible and impossible worlds: Extended Modal Structuralism (EMS). In particular, I consider whether it makes sense to think of logical models in isolation from the concrete world but without their being divorced from all spatiotemporal totalities. The metaphysics of structure developed in this chapter assumes that structural properties of possible and impossible worlds are primitive and objective. However, I provide some characterisations of their logical and metaphysical behaviour, as well as guidelines for talking about them. Finally, Chapter VI proposes yet another metaphysical framework of hybrid modal realism. I present theories of (MR), (EMR) and modal fictionalism respectively, their advantages and drawbacks. Finally, I propose a so-called hybrid view. Roughly, the view is that one might be a modal realist when it comes to possibilia, but turn into fictionalism regarding impossibilia. The approach is dubbed Extended Modal Fictionalism (EMF) a version of fictionalism according to which claims made within a certain discourse are better to be understood as a sort of ‘fiction’, rather than as a literal truth. (shrink)

Disagreement over what exists is so fundamental that it tends to hinder or even to block dialogue among disputants. The various controversies between believers and atheists, or realists and nominalists, are only two kinds of examples. Interested in contributing to the intelligibility of the debate on ontology, in 1939 Willard van Orman Quine began a series of works which introduces the notion of ontological commitment and proposes an allegedly objective criterion to identify the exact conditions under which a theoretical (...) discourse signals an assumption of existence. I intend to present the concept of ontological commitment and the Quinean criterion, to expose and evaluate some of the many criticisms to which the criterion has subject and to situate it in the context of Quine’s philosophy. As a product of such analyses, I hope to contribute to the discussion on the application and relevance of the notion of ontological commitment. (shrink)

I propose a way of thinking aboout content, and a related way of thinking about ontological commitment. (This is part of a series of four closely related papers. The other three are ‘On Specifying Truth-Conditions’, ‘An Actualist’s Guide to Quantifying In’ and ‘An Account of Possibility’.).

Modal Platonism utilizes "weak" logical possibility, such that it is logically possible there are abstract entities, and logically possible there are none. Modal Platonism also utilizes a non-indexical actuality operator. Modal Platonism is the EASY WAY, neither reductionist nor eliminativist, but embracing the Platonistic language of abstract entities while eliminating ontological commitment to them. Statement of Modal Platonism. Any consistent statement B ontologically committed to abstract entities may be replaced by an empirically equivalent modalization, MOD(B), not so ontologically committed. (...) This equivalence is provable using Modal/Actuality Logic S5@. Let MAX be a strong set theory with individuals. Then the following Schematic Bombshell Result (SBR) can be shown: MAX logically yields [T is true if and only if MOD(T) is true], for scientific theories T. The proof utilizes Stephen Neale's clever model-theoretic interpretation of Quantified Lewis S5, which I extend to S5@. (shrink)

The Quine/Putnam indispensability argument is regarded by many as the chief argument for the existence of platonic objects. We argue that this argument cannot establish what its proponents intend. The form of our argument is simple. Suppose indispensability to science is the only good reason for believing in the existence of platonic objects. Either the dispensability of mathematical objects to science can be demonstrated and, hence, there is no good reason for believing in the existence of platonic objects, or (...) their dispensability cannot be demonstrated and, hence, there is no good reason for believing in the existence of mathematical objects which are genuinely platonic. Therefore, indispensability, whether true or false, does not support platonism. (shrink)

According to the indispensability argument, the fact that we quantify over numbers, sets and functions in our best scientific theories gives us reason for believing that such objects exist. I examine a strategy to dispense with such quantification by simply replacing any given platonistic theory by the set of sentences in the nominalist vocabulary it logically entails. I argue that, as a strategy, this response fails: for there is no guarantee that the nominalist world that go beyond the set of (...) sentences in the nominalist language such theories entail. However, I argue that what such theories show is that mathematics can enable us to express possibilities about the concrete world that may not be expressible in nominalistically acceptable language. While I grant that this may make quantification over abstracta indispensable, I deny that such indispensability is a reason for accepting them into our ontology. I urge that the nominalist should be allowed to quantify over abstracta whilst denying their existence and I explain how this apparently contradictory practice (a practice I call 'weaseling') is in fact coherent, unproblematic and rational. Finally, I examine the view that platonistic theories are simpler or more attractive than their nominalistic reformulations, and thus that abstract ought to be accepted into our ontology for the same sorts of reasons as other theoretical objects. I argue that, at least in the case of numbers, functions and sets, such arguments misunderstand the kind of simplicity and attractiveness we seek. (shrink)

Some forms of analytic reconstructivism take natural language (and common sense at large) to be ontologically opaque: ordinary sentences must be suitably rewritten or paraphrased before questions of ontological commitment may be raised. Other forms of reconstructivism take the commitment of ordinary language at face value, but regard it as metaphysically misleading: common-sense objects exist, but they are not what we normally think they are. This paper is an attempt to clarify and critically assess some common limits of these (...) two reconstructivist strategies. (shrink)

The Quine-Putnam indispensability argument urges us to place mathematical entities on the same ontological footing as (other) theoretical entities of empirical science. Recently this argument has attracted much criticism, and in this paper I address one criticism due to Elliott Sober. Sober argues that mathematical theories cannot share the empirical support accrued by our best scientific theories, since mathematical propositions are not being tested in the same way as the clearly empirical propositions of science. In this paper I (...) defend the Quine-Putnam argument against Sober's objections. (shrink)

Some platonists truly agonize over the ontological commitments which their platonism demands of them. Peter van Inwagen, for example, confesses candidly,I am happy to admit that I am uneasy about believing in the existence of ‘causally irrelevant’ objects. The fact that abstract objects, if they exist, can be neither causes or [sic] effects is one of the many features of abstract objects that make nominalism so attractive. I should very much like to be a nominalist, but I don't see (...) how to be one …. (shrink)

In this paper I present an argument for belief in inconsistent objects. The argument relies on a particular, plausible version of scientific realism, and the fact that often our best scientific theories are inconsistent. It is not clear what to make of this argument. Is it a reductio of the version of scientific realism under consideration? If it is, what are the alternatives? Should we just accept the conclusion? I will argue (rather tentatively and suitably qualified) for a positive answer (...) to the last question: there are times when it is legitimate to believe in inconsistent objects. (shrink)

From Parmenides to the present, philosophers have been attracted by characterizations of being as being uttered or utterable, formulated or formulable. But what for Parmenides was presumably a valid co-entailment between antecedently understood concepts reappears in contemporary thought as a proffered explication of what it is to be. Without presuming to discredit Parmenidean views in general, my purpose here is to examine certain members of a modern family of theories of existence that fall into place around Quine’s. Depending on the (...) methodology of explication espoused, the theories in this family are either semantic commentaries on ideal languages, or they are themselves interpreted formalized languages. The former may be called, after Quine, theories of ontological commitment. The theories of the latter sort I wish to consider are called, after Karel Lambert, free logics, i.e., logic systems the singular terms of which are free of existential import. My conclusion about theories of both kinds is that, while unexceptionable on their own terms, from a broader point of view they beg the question of what it is to be. In arguing that these theories thus fail to clarify the concept of existence, I believe I am not so much propounding a new insight as articulating an objection many thinkers have felt in the face of views akin to Quine’s. (shrink)