Metaphysics as Fairness

Abstract

What are the rules of the metaphysical game? And how are the rules, what-ever they are, to be justified? Above all, the rules should be fair. They shouldbe rules that we metaphysicians would all accept, and thus should be justifi-able to all rational persons engaged in metaphysical inquiry. Borrowing fromRawls’s conception of justice as fairness, I develop a model for determining andjustifying the rules of metaphysics as a going concern.

1 Introduction

METAPHYSICS is a norm-governed enterprise. But are there, or do there need tobe, rules for doing ‘good’ metaphysics?1 I believe so, for three reasons. First,

there is substantial disagreement over what the norms of metaphysics are. Whetherwe ought to obey Ockham’s razor, whether we should use intuitions as evidence,whether we are obliged to render metaphysics continuous with science, are all nor-mative issues that engender a great deal of dispute. Such disagreement is troubling.Debates in metaphysics that rely on these norms are likely to stall until some de-termination has been made concerning what the norms of metaphysics should be.Determining what the norms should be, however, is partly a matter of identifyingthose rules that express the right norms for doing good metaphysics, and legislatingaccordingly.

1The distinction of interest between ‘rules’ and ‘norms’ is between the norms as they actually existand rules that express possible norms, which may be legislated to ensure compliance with some ideal.For instance, it may be that themanner in whichwealth is distributed within a society is unfair, despitebeing norm-governed. Accordingly, if fairness in wealth distribution is valued, then the norms mustbe overturned for a set of rules that do better. The situation is similar in metaphysics. Metaphysicshas aims. Exactly what these aims are depends on what metaphysics is. I won’t take a stand on thisissue yet (though see §3.1). The point is just this: for a given set of aims we can imagine variousrules, each of which expresses a possible norm geared toward ensuring the e�cient achievement ofdefined metaphysical ends. We may then wonder whether the norms of metaphysics best ensure thesuccessful attainment of those ends, or whether there is some possible set of rules that would do better.

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Second, it is a common refrain that metaphysics makes no progress, or at leastprogresses very little. As I see it, there are (roughly) three possible explanations forwhy metaphysics makes no progress: (i) what it is trying to do is extremely di�cult;(ii) what it is trying to do is impossible; (iii) there’s something wrong with the man-ner in which it’s being done. There is substantial pressure on the metaphysician torule out explanations (ii) and (iii). One way to rule out (iii) is to identify rules fordoing ‘good’ metaphysics and check to see if they express the norms that currentlyexist. If they do, then (iii) is not a plausible explanation. If they do not, then wemay be forced to legislate. Of course, progress within metaphysics – in some senseof ‘progress’ – may be achieved with a merely arbitrary set of rules. What we want,however, is real progress in metaphysics, rather than pseudo-progress, and to do thatwe need to come up with the right set of rules.

Finally, we need a rule-book for metaphysics because sometimes when a move ismade in the context of a metaphysical debate it feels like cheating, despite the absenceof any prohibition against the move. For instance, invoking deities at certain pointsin a debate, or taking certain concepts to be intuitively primitive, seems to be funda-mentally parochial in this sense: one thereby excludes, from subsequent discussion,those who give low credence to deities or those who don’t share the relevant intu-itions about conceptual primitivity. Cheating in metaphysics, however, only makessense against the backdrop of a set of rules, and so the question arises: what are thoserules?

The rules of metaphysics should not, themselves, be parochial; they must be rulesthat would be endorsed by all fair-minded, truly disinterested fans of rational col-lective inquiry. Furthermore, the rules should be in the best interests of metaphysicsas a discipline. In what follows I advance a model for determining the rules of meta-physics as a going concern, one that is built on the foundations of justifiability. Myaim, however, is not to come up with a definitive list of rules, and thus to outlinethe rule-book for metaphysics. That is a much larger project. My aim, rather, isthe more modest one of developing a framework within which this more generalproject can be profitably developed. Although developing such a framework is myprimary focus, I will nevertheless briefly apply the framework and o�er advice onwhat some of the rules of metaphysics might be.2

The framework draws heavily on the work of John Rawls. Rawls (1999) out-lines a model for identifying the principles of justice that we as rational, mutuallydisinterested agents would agree to be bound by. The Rawlsian framework, thoughpowerful in its own right, is also quite flexible: a similar framework can, in principleat least, be developed for any system of practices involving rational agents, where

2The Rawslian model is not an account of what the methods of metaphysics are and so does notcompete with any such account; it is rather a decision procedure for selecting a set of methodologicalnorms.

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those agents possess motivations appropriate to the system in question. In particular,as I will demonstrate, the framework can be extended to determine and ultimatelyjustify the rules of good metaphysics.

While I focus on the rules of metaphysics, I recognise that it is somewhat artificialto do so. There may not be any rules peculiar to metaphysics that are not simply rulesof philosophy more generally. While I believe that metaphysics does require its ownparticular rules I admit that not everyone will agree. In the event that there are norules peculiar to metaphysics, the framework developed in this paper has merit asa toy model, one that provides the foundations for producing a larger method forjustifying and determining the rules of philosophy tout court.

I foresee two further benefits of the Rawlsian approach. First, the lack of anexplicit account of the rules of metaphysics, along with an account of why we shouldfollow them, may contribute to the existence of ‘stalemates’. Stalemated debates inmetaphysics are often intractable in a way that stalemated debates in, say, scienceare not. One reason for this, perhaps, is that such stalemates are a direct result ofquestionable moves made by one or both sides; moves that have not been properlycriticised for being unfair in the context of the enterprise in which they occur. Thisis not to say that all stalemated debates are like this; but I believe that some are,3 andso determining the rules of metaphysics promises to provide new tools for reassessingold, deadlocked disputes.4

Second, care for the rules of metaphysical inquiry is good for the health of thediscipline.5 Metaphysics as a practice is increasingly scrutinised by scientists; by thepublic; by university administrators looking to make funding cuts; by grant bodieslooking for cutting edge research and, of course, by philosophers outside of meta-physics looking to make their mark. If we metaphysicians can’t agree on the normsof metaphysics, then it appears we are at a relative disadvantage. Without the re-sources to properly defend our discipline, we are thus apt to find ourselves squirmingunder the increased scrutiny of others. A rule-book for metaphysics would thereforeconstitute a bedrock for addressing sceptism about metaphysics as a discipline.

3Debates that may be stalemated include the debate between presentism and eternalism; the debateover persistence and the debate over unrestricted versus restricted composition. I discuss some of thesedebates in §4.

4A similar point is made by Wilson (forthcoming).5As Wilson (forthcoming) notes, our understanding of metaphysical methodology is still rudi-

mentary. Of course, inroads have been made. There is an important project investigating the roleof scientific virtues in metaphysical theory choice (Baker (2003), Nolan (1997, forthcoming)). Thereis also a recent debate over the status of methodology in ontology (see Scha�er (2009)). And thereis the project of defending metaphysics against positivist and neo-positivist scepticism (for the latestincarnation of this debate, see Ladyman and Ross (2007) and Maclaurin and Dyke (2012, 2013)).This work does not, however, speak to the development of a framework for justifying the norms ofmetaphysics. Rather, the literature cited focuses on the relationship between science and metaphysicsand/or on whether or not metaphysics is a legitimate form of investigation.

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2 Justice as FairnessAlthough many will be familiar with the Rawlsian picture, its uptake has not beenuniversal and so I’ll start there. I should note, though, that in considering Rawls’sview I will outline only those features of his theory of justice that are relevant to theissue at hand, and that are thus transferable to the case of metaphysics. In particular, Iwill focus on themodel that he develops for determining and justifying the principlesof justice, extracting its core features. I will thus, with some regret, set aside thericher details of Rawls’s position.

Themodel begins with the original position. The original position is a hypothet-ical scenario, in which agents come together to make agreements about the princi-ples by which society will be organised. Principles are put forward, discussed andvoted upon. The aim of the original position is unanimity: agents must unanimouslyagree on the principles of justice, since it is only then that the principles will be jus-tifiable to everyone and thus fair. In addition, agents in the original position aresubject to certain epistemic limitations; they are behind a veil of ignorance. Theyare ignorant of their social status; class position; fortune in the distribution of naturalassets; abilities; intelligence; strength and so on. Agents are not entirely ignorant,however. They still possess general information. In particular, they know whatevergeneral facts are needed to make decisions about principles of justice. They thereforeknow general facts about human society; about political a�airs and economics; thebasis of social organization; the laws of human psychology and general informationabout laws and theories.

The veil of ignorance is crucial. It is only by stripping agents of particular knowl-edge about their position in society that they are guaranteed to arrive at agreementsnot based on natural contingencies, which are irrelevant from the standpoint of jus-tice. As Rawls (1999, p. 17) puts the point:

The aim [of the veil of ignorance] is to rule out those principles that it would berational to propose for acceptance, however little the chance of success, only ifone knew certain things that are irrelevant from the standpoint of justice. Forexample, if a man knew that he was wealthy, he might find it rational to ad-vance the principle that various taxes for welfare measures be counted unjust; ifhe knew that he was poor, he would most likely propose the contrary principle.To represent the desired restrictions one imagines a situation in which everyoneis deprived of this sort of information.

If we do not abstract away from this information then the principles o�ered as prin-ciples of justice by agents in the original position, and thus the principles that havethe potential to gain acceptance, are unlikely to be justifiable to everybody. The

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rich person’s principles of justice won’t be acceptable to the poor person and viceversa. Agents must therefore agree on principles of justice that they would agree tobe bound by regardless of the actual position in society that they ultimately come tooccupy, once the veil of ignorance is lifted.

Agents in the original position are rational and mutually disinterested. They areconcerned to maximise their own share of the primary social goods. These are thegoods that a rational person would desire regardless of whatever else she desires:rights, liberties, opportunities, income and wealth. A rational agent in the originalposition is only interested in her own gains. She remains neutral on the gains orlosses of other agents. As such, she does not seek to maximize or minimize thedi�erence between her gains and the gains of others. Rather, she seeks only to getfor herself as much as possible. Put in terms of a game, a mutually disinterestedrational agent seeks to attain the highest possible score. As Rawls (1999, p. 125)notes, the analogy with a game is imperfect, as mutually disinterested agents do notseek to win. Winning implies the attainment of a higher score than other players,and agents in the original position are not interested in other players’ scores.

Rational, mutually disinterested agents must choose the principles of justice thatthey would agree to be bound by, once the veil of ignorance is lifted, from a list ofpossible principles of justice.6 Rawls’s central contention is that rational, mutuallydisinterested agents would agree upon a single, unique set of principles from behindthe veil of ignorance. It is these principles, then, that are the principles of justice thatwe ought to follow. According to Rawls, agents within the original position wouldselect two principles of justice in particular, over all other alternatives. These twoprinciples are stated as follows (Rawls 1999, p. 53):

(1) Each person is to have an equal right to the most extensive scheme of equalbasic liberties compatible with a similar scheme of liberties for others.

(2) Social and economic inequalities are to be arranged so that they are both(a) reasonably expected to be to everyone’s advantage, and (b) attached topositions and o�ces open to all.

One useful way to think of the hypothetical scenario that Rawls asks us to con-sider is in terms of optimisation. Optimality models include three components: thething one is trying to optimise, the options for optimisation, and any relevant con-straints on the situation. So, for example, consider the evolutionary optimality modelof why it is that hive-bees produce hexagonal honeycomb (see, for discussion, Lyon

6Ideally, individuals would have a list of all possible principles of justice. For obvious reasons,however, Rawls (1999, pp. 126–127) restricts his statement of the original position to a list of themost likely principles of justice.

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and Colyvan (2008) and Baker (2012)). The reason that hive-bees produce hexago-nally structured honeycomb is that partitioning the surface of the honeycomb usinghexagons will allow the swarm to produce the largest nectar-storing cells, for theleast expenditure of energy in producing wax. This, in turn, will enable those beesto outcompete other swarms and so honeybees have evolved to exploit this optimalsolution. This outcome is predicted by an optimality model in which one seeks tomaximise the amount of nectar stored for the least energy expended. The constraintson the model are typical environmental constraints on hive-bees and the choices in-volve di�erent regular and irregular polygons.

Similarly, the two principles of justice outlined above can be seen as optimal solu-tions to an optimisation problem, one that Rawls models using the original position.Rawls seems to suggest this interpretation when he writes:

Suppose, for example, that it is rational for the persons in the original position toprefer a society with the greatest equal liberty. And suppose further that whilethey prefer social and economic advantages to work for the common good theyinsist that they mitigate the ways in which men are advantaged or disadvantagedby natural and social contingencies. If these two features are the only relevantones ... the two principles are the optimum solution. (Rawls 1999, pp. 106–107)

The model stated in this quotation is a simplified version of the case at hand,since it assumes only that rational, mutually disinterested agents are concerned tooptimise two features (i) the equal liberty in society and (ii) the degree to whichany advantages serve the common good. The choices in this simplified case are, asbefore, potential principles of justice (see Rawls (1999 pp. 126–127) for the relevantoptions), and the central constraint is that the optimisation must mitigate the advan-tages or disadvantages a�orded by natural and social contingencies. It is thus becauseprinciples (1) and (2) represent the optimal solution to this problem, that they wouldbe selected by rational mutually disinterested agents in the original position. It isbecause they would be so selected that they are justifiable to everybody.

I raise the parallel between Rawls’ hypothetical scenario and optimisation merelyas a heuristic for better understanding the scenario in question. What really mat-ters for present purposes is that the scenario can be distilled into three core features,which I set out as follows:

Motivation Agents in the original position are rational and mutuallydisinterested, and are thus motivated to achieve the great-est share of primary social goods for themselves as possible,without trying to maximize or minimize the di�erences be-tween themselves and others.

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Ignorance Agents in the original position are ignorant of their socialstatus; class position; fortune in the distribution of naturalassets; abilities; intelligence; strength and so on.

Justifiability Agents in the original position must agree upon those prin-ciples of justice that are justifiable to everyone. This is rep-resented through unanimous agreement on the principles inquestion.

It is these features of the model that will become important as I seek to extend theRawlsian paradigm to metaphysics.

3 Metaphysical not PoliticalLet us call a rule that constrains the manner in which metaphysics qua practice iscarried out, a principle of metaphysics. In order to extend Rawls’s model for deter-mining and justifying the principles of justice to the principles of metaphysics, anoriginal position for this particular set of practices must be elucidated. As before,the original position is a hypothetical scenario. In this case, however, it is a sce-nario in which metaphysicians come together in order to determine the principles bywhich metaphysics will proceed. As such, for the sake of clarity, let us call this: themetaphysical original position.

3.1 The MetaphysiciansWho exactly are the metaphysicians? One way to answer this question is by citingcanonical examples. Current candidates include Elizabeth Barnes, Sally Haslanger,Carrie Jenkins, Kit Fine, Kristie Miller, Laurie Paul, Jonathan Scha�er and TedSider. Looking back: Anscombe, Foot, Lewis, Russell and Quine surely count asmetaphysicians (if meta-ethicists) in some sense. And in the early twentieth cen-tury, we find De Beauvoir, Heidegger, McTaggart, Neitszche, Hegel and Husserl.The early modern period boasts (at least) Berkeley, Cavendish, Descartes, Locke,and Kant and in ancient times: Hypatia, Plato, Socrates and Aristotle. Now, I’msure my canon is going to raise a few eyebrows: many of the names cited would notplay well together. Still, all of these philosophers have at least some claim to the title‘metaphysician’.

Citing canonical examples can take us quite far: we all know a metaphysicianwhen we see one and so we roughly know who’s coming to the party. Knowingwho’s coming to the party, even roughly, is perhaps enough for the Rawlsian model

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I outline below to gain dialectical traction. The trouble, however, with my canonis that it is quite tightly tied to the institutional arrangement of disciplines, in thissense: the ‘default’ metaphysicians are ‘o�cially’ philosophers. Not everyone whoshould qualify as a metaphysician must be o�cially a philosopher, however. Manyscientists are metaphysicians too. So it behoves me to say a little more.

Very roughly, a metaphysician is a rational agent who is motivated to achievethe aims of metaphysics and who is disposed to act upon those motivations. Exactlywho counts as a metaphysician on this account therefore depends entirely on whatmetaphysics is, since an adequate account of the nature of metaphysical inquiry willbe one that has a story to tell about its aims. I make two assumptions about thenature of metaphysics. First, I assume that metaphysics is a single discipline, distinctto other forms of rational investigation, and possessing a single, unified set of aims.Second, following Paul (2012) I assume that whatever else metaphysics might be, itis the search for general and fundamental truths about reality.7 These assumptionsproduce a crisp account of who the metaphysicians are. Paul, herself, would clearlycount as a metaphysician, and so would the rest of the canonical examples citedabove. The advantage, however, is that we are no longer limited to those who are‘o�cially’ philosophers. Anyone engaged in the relevant search counts, regardlessof where they find themselves inside (or outside) the academy.

Identifying the metaphysicians with the set of agents who engage in the searchfor fundamental and general truths does not seem all that controversial. What iscontroversial is the idea that there might be unifying methodological themes amongthe various di�erent sub-sets of agents engaged in this broader practice. For it seemsthat metaphysicians diverge quite significantly in their views on how the search isto be done.8 For Ladyman and Ross (2007) the project is that of unifying our bestscientific theories. For others, it is the Ramsay-Lewis-Carnap project of conceptualanalysis (see also Kant (1943), Dummett (1991), Strawson (2011) amd Jackson (1998).And on it goes.9 Now, if the goal of this paper were to provide a complete accountof what metaphysics is, then I would have to sort this divergence out. More detailwould be needed about what metaphysics is in the business of doing, and the starkdi�erences between the sorts of things that di�erent groups of metaphysicians dowould have to be addressed. However, these issues are beyond the scope of the

7The model outlined below is not beholden to these assumptions. The model may be run withany set of participants selected for their common epistemic aims. Still, these simplifying assumptionswill be necessary in §4 when the model is applied.

8If metaphysics is pseudo-artistic, then the metaphysicians won’t be definable in terms of whatthey are trying to know. I do not, however, have the space to discuss non-epistemic versions of themetaphysical original position here.

9While I find it plausible that the Ladyman and Ross project and the Ramsay-Lewis-Carnapproject both fall under the broader disciplinary practice of searching for general and fundamentaltruths, this could be denied. Denying this would force one toward the idea that metaphysics is reallya group of sub-disciplines connected by a family resemblance relation, as discussed briefly in fn. 10.

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current discussion and so can be reasonably set to one side. A fairly coarse-grainedunderstanding of what metaphysics is – along the lines sketched by Paul – will do.10

3.2 The ModelI make two further assumptions about the metaphysical original position. First, Iassume a veil of ignorance. The veil of ignorance in this case does not involve igno-rance about social status. Rather, it factors out information about an agent’s beliefsand opinions on metaphysical issues. In addition, agents in the metaphysical originalposition do not know what theories they will end up defending once the veil of ig-norance is lifted. Nor do they know what philosophical intuitions they might have.They do not knowwho has defended which theories in the past. Finally, because theline between scientific knowledge and metaphysical speculation can be quite thin insome places, it is also necessary to abstract away from any knowledge that agentshave concerning their own views on scientific disputes (assuming that this knowl-edge, and knowledge like it, fosters bias over which principles of metaphysics areo�ered in the metaphysical original position, and accepted).11 As before, agents inthe original position are not completely ignorant. They know general facts aboutwhat metaphysical theories there are; what scientific theories there are; what scien-tific evidence exists; what philosophical methodologies there are and what method-

10It could be argued that these more fine-grained issues about the nature of metaphysics cannot beso easily set aside. Apparent disagreement among metaphysicians about the best way to search for thefundamental and general truths may, in the end, reveal that metaphysics is a cluster of sub-disciplines,each of which is both distinct from each other and distinct from other forms of rational investigation,and each of which possesses its own unique set of aims. If metaphysics is a cluster of sub-disciplines,then it is doubtful that there is a single class of individuals who are the metaphysicians. That said,we can still make sharp distinctions between individuals based on the sub-discipline of metaphysicsin which they are involved, and based on each peculiar motivational set. We can, that is, identifythe metaphysicians1, the metaphysicians2 ... the metaphysiciansn. Each group will then attend itsown metaphysical original position in order to determine the rules for metaphysics1, metaphysics2... metaphysicsn respectively. As we shall see below, that’s fine. The model I outline is flexibleenough to allow for its use across a range of sub-disciplinary instances of metaphysics just as easilyas if metaphysics were a single discipline, though the results in each instance of the model may varysubstantially from one another.

11One might worry that too much information has been occluded. Perhaps it is necessary to knowone’s opinions on some metaphysical disputes in order to be in a position to make decisions aboutthe norms of metaphysics. If so, then the model can be made more specific, by focusing in on aparticular metaphysical dispute: D. The norms of D are to be determined by abstracting away fromthe knowledge agents have of their opinions on that dispute. Opinions on other disputes are, however,allowed. The trouble with this way of proceeding, however, is that many metaphysical disputes arestrongly connected to one another (at least at some level). So information about disputes other thanD might be inadmissible.

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ologies there are available to agents engaged in rational inquiry more generally.12In short, they know whatever general facts might be relevant to the development ofprinciples of metaphysics.13

The veil of ignorance in the metaphysical original position is required for similarreasons to the veil of ignorance that Rawls introduces. The aim of the veil here is torule out those principles of metaphysics that it might be rational to propose for ac-ceptance, however little the chance of success, only if one knows certain things thatare irrelevant from the standpoint of general metaphysical methodology. To putthe point another way, in both the Rawlsian original position and the metaphysi-cal original position we’re looking to identify and agree upon rules with which toconduct ourselves when we come across predictable (and predictably unresolvable)disagreement. The central thought, then, is that if we metaphysicians can predictthe details of the roles that we play in these disagreements, there will be a strongtemptation to develop ground rules in a biased way.

For example, if an agent knows that she is defending the A-theory of time (theview according to which, roughly, temporal passage is an objective feature of real-ity), she might find it rational to advance the anti-naturalistic principle that meta-physics should not seek compatibility with empirical science. This is for the simplereason that the A-theory is at odds with some of our best available scientific theories(namely, the special and general theories of relativity) and so ruling out appeals toscience serves the A-theorist’s interests. Conversely, if a person knows that she is de-fending the B-theory of time (the view according to which, again roughly, temporalpassage is not an objective feature of reality), she might find it rational to advance theprinciple that one ought not appeal to common sense in support of a metaphysicaltheory, since common sense intuitions are thought, by some, to provide evidence forthe A-theory (see e.g. Zimmerman (2008)). Principles of metaphysical methodol-ogy that are developed in this way, in the service of a particular theory, are unlikelyto be fair. They ‘stack the deck’ against certain metaphysical positions, by ruling out

12What about logic? When the agents are arguing from within the original position to whateverprinciples of metaphysics they ultimately accept, they must be deploying some rules of inference. Butwhich rules? It is tempting to say: the one correct logic, whatever that might be! But that won’t flywith anti-realists about the one correct logic, and they are sometimes metaphysicians too. So, better:agents in the original position have knowledge of all the logics, and use whichever logic they all agreeis most apt for their current argument about the normative principles of metaphysics.

13I have focused here on general scientific and metaphysical knowledge. It may be that, in orderto make informed decisions about the methodology of metaphysics, all of human knowledge mustbe included, assuming that there is knowledge outside of these two domains (e.g. moral knowledge,political knowledge and so on). Widening the knowledge that agents have within the metaphysicaloriginal position in this way will make it more di�cult to get methodological naturalism out as aprinciple of metaphysics (see §4.1 below), since it may be that we have to unify with more thanjust science. Still, something like the weak naturalism I consider should be recoverable even in thissituation.

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particular methodologies. As such, in the interests of developing those metaphysicalprinciples that are justifiable to all we must abstract away from this information.

In addition to a veil of ignorance, I assume that agents engaged in metaphysicsare rational and that they have particular motivations. For Rawls, agents in the orig-inal position are rational and mutually disinterested. As such, they are motivatedto maximise their own share in the primary social goods. This motivation is rele-vant to the contractarian approach to society in which Rawls is interested. It is not,however, the appropriate kind of motivation for metaphysics. We are not trying tobuild a society in the same sense. We are, rather, trying to determine how a field ofinquiry can be profitably developed, and thus to determine the rules of associationthat bind parties within that field. The motivations in this case must therefore beones that are relevant to the practice of metaphysics as a going concern. We mustbe careful, however, to abstract away from those motivations that one might havein virtue of knowing information occluded by the veil of ignorance. One cannot,for example, assume that all agents are motivated to defend a particular metaphys-ical theory. What we can assume, however, is that the agents in the metaphysicaloriginal position are ideally motivated to do the best metaphysics they possibly can.

With this in mind, it is possible to identify three motivations that agents in themetaphysical original position are likely to share. First, it is reasonable to supposethat such agents are motivated by the ideal of progress. Metaphysicians want tomaximise the progress that metaphysics as a discipline makes, though exactly whatcounts as progress in metaphysics will depend in large part upon what one thinksmetaphysics is in the business of doing. But, for now at least, I will continue toassume that metaphysics aims to discover the fundamental and general truths andthat progress in metaphysics is progress toward this aim.

Second, agents in the metaphysical original position are motivated by the ideal ofunification. Metaphysicians see the work that they do as contributing in some wayto the development of a grand, unified philosophical theory. This is not to say thatall metaphysicians are motivated to develop their own unified theory. It is, rather,to say that all metaphysicians seek to contribute something to the project of devel-oping such a theory, whatever that theory might be. More precisely, agents in themetaphysical original position seek to maximise the contribution that metaphysicsmakes to this ideal.

The third motivation is di�cult to articulate, but it is something like the follow-ing. Agents in the metaphysical original position seek to maximise the ‘accessibility’or ‘transparency’ of their theories. They want metaphysics (as far as possible) to besuch that one need not be inducted into metaphysics in order to be able to take ametaphysical theory seriously. More precisely, metaphysicians in the original posi-tion do not want it to be the case that one must be a metaphysician in order to acceptthe evidence o�ered in support of any given metaphysical theory as evidence. Or that

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one has to be a metaphysician in order to find the assumptions in a metaphysical ar-gument compelling, assuming that one has understood the argument and is awareof the putative basis for the relevant assumptions. The reason for this motivationis that, without transparency, metaphysics runs the risk of becoming irrelevant. Ifmetaphysics is convincing only to metaphysicians because it trades on implicit be-liefs that only they hold in virtue of being metaphysicians, then it is hard to seewhat place metaphysics has in rational investigation more generally. For instance,to return to the A-theory/B-theory example used above, suppose that only meta-physicians take common sense intuition seriously as a guide to theory choice. Folksoutside of metaphysics – e.g. scientists – are going to look askance at metaphysics aspracticed. The onus is therefore on the metaphysician to show that common senseintuition is transparent in the above sense: that it has a positive evidential status bothinside and outside of metaphysics.

As in the Rawlsian original position, agents in the metaphysical original positionmust, from behind the veil of ignorance, agree upon a principle or set of princi-ples about how metaphysics should be carried out. In particular, they must identifythose principles that best satisfy the three motivations mentioned above. Becausethese principles are based on general motivations that all such metaphysicians have,and because they are not based on contingent knowledge of the position within themetaphysical ‘game’ that any one metaphysician occupies, such principles will bejustifiable to all and, as such, will be fair. As before, it is possible to construe this asan optimisation problem: what sorts of principles ought we to adopt in order to max-imise the ideals of progress, unification and transparency? The optimal solution tothis problem is the one that everyone from within the metaphysical original positionwill be willing to agree upon.14 As before, the focus on optimality is a heuristic.

The metaphysical original position can be distilled into three core features:

Motivation Agents in the metaphysical original position are motivatedto maximise the ideals of progress, unification and trans-parency in metaphysics.

Ignorance Agents in the metaphysical original position are ignorant oftheir beliefs and opinions about metaphysical issues; the the-ories they will end up defending; what philosophical intu-itions they might have and exactly who has defended which

14There’s a general epistemic problem here. The basic principles of metaphysics are the ones wewould all agree to in the metaphysical original position. But you might think that such a state isepistemically inaccessible: how do we know what we would all agree to? Perhaps our judgementsabout this are being filtered through the same biases that the original position is supposed to remove.So our very judgements about the original position cannot be trusted. That’s a problem, but it’s aproblem for Rawls too and so I set it aside for now.

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theories in the past (mutatis mutandis for scientific disputes).

Justifiability Agents in themetaphysical original positionmust agree uponthose principles of metaphysics that are justifiable to every-one. This is represented through unanimous agreement onthe principles in question.

A great deal hangs on the motivations that I have attributed to rational agents inthe metaphysical original position. It is these motivations that, ultimately, inform thedecisions that are made regarding the principles of metaphysics. I have attempted toidentify a set of uncontroversial motivations that jibe with metaphysics as it is ac-tually practiced, and with the sorts of things that metaphysicians are likely to sayif questioned on the topic. Still, one might worry about the list as I have compiledit. Consider, for instance, the ideal of unification. As has been pointed out to me,metaphysicians as a matter of fact di�er greatly in the extent to which they valueconsistency across metaphysical theories, or indeed across metaphysics and science.Accordingly, it may well be that unification is just not a motivation that all meta-physicians in the original position are likely to share.

There are two things to say here. First, it may be useful to draw a distinctionbetween ideal and non-ideal metaphysicians. If the participants to the metaphysicaloriginal position are idealised then while it may be true that many actual metaphysi-cians are not motivated by unification, it may still turn out that the ideal metaphysi-cian will be. Of course, this idealising move is just as slippery here as it is in Rawls’stheory of justice and so I won’t make too much of it. Second, it is important to keepsight of the two assumptions made in §3.1. I am assuming that the goal of meta-physics is to discover the fundamental and general truths about reality. Given thisway of understanding metaphysics and thus who the metaphysicians are, unificationseems quite important. For it seems plausible that the full set of fundamental andgeneral truths is to be found only in the most unified philosophical theory and sometaphysicians of this ilk are likely to have a unificationist bent. This is especially soif the search for general and fundamental truths is to be carried out by unifying ourbest scientific theories.

That said, there may well be accounts of what metaphysics is according to whichmetaphysicians so defined are notmotivated to unify. So I admit that I may bewrongabout the importance of unification, and about the list of motivations more gener-ally. It might be that some competing list of motivations is a better contender forcharacterising the motivations of metaphysicians behind the veil of ignorance. Butthat’s fine. I’m not wedded to the list I have compiled. What matters is that there aresome general motivations shared by all metaphysicians in the original position thatare relevant to the way in which metaphysics is practiced, and that these motivations

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can be ultimately used to constrain the norms of metaphysical methodology.Of course, it may be the that there are no such universal motivations for every

metaphysician simply because metaphysicians do not share a common set of epis-temic aims. In that situation, the first assumption made in §3.1 is false: if di�erentaims really do dictate completely di�erent motivations with no overlap at all, thenwhat seems to be a di�erence in aim is really a di�erence in practice. In such a situa-tion, the reasonable thing to do is to split metaphysics into a number of sub-domains,each interested in di�erent things and each governed by its own rules. If that is howthings must go, then I am inclined to say: lesson learned. Such a lesson does notmake a di�erence to my goal here: whether we have one practice with several aims,or many practices with distinct aims, so long as these aims can be used to definethe motivations of agents in the metaphysical original position, it will be possible touse a Rawlsian method for determining the principles of metaphysics. It is worthemphasising, however, two things. First, some accounts of what metaphysics is mayultimately pick out something much broader than metaphysics and so the rules thatare determined may bleed o� into other domains. Second, candidate sub-disciplinesfor metaphysics are potentially quite disparate and so may yield quite di�erent resultswhen run through the Rawlsian model.15

At any rate, what I am stressing is really the flexibility of the method that I amproposing, and it is the method that matters. The flexibility of the method is due

15It could turn out that there is no single, unified discipline that is metaphysics and no set of sub-disciplines that are crisply delineable either. One manner in which metaphysics may fail to be adistinct discipline or a distinct set of sub-disciplines is if there turns out to be no strong way to splitthe di�erence between scientific and metaphysical investigation. For instance, it may be that thereis no residue for metaphysics over and above a certain clutch of debates in the special sciences. Inthis situation, the model developed here could either be applied to science, or it could be applied tophilosophy more generally, if the relevant debates within science are ones that philosophers, and notscientists, should take on. Note that for the model to be applied to philosophy, an account of whatphilosophy ismust be given, at which point the same options become available: philosophy is a singlediscipline, a set of sub-disciplines, or no distinct discipline at all. If pressed to take the last option, thenwe may be forced to fall back again and again, until we reach a point where the goal is to determinethe rules of all rational investigation. Presumably, in this scenario, the rule-makers will be (somethinglike) the class of individuals who are motivated to gain knowledge about the world.Being pushed all the way back to the class of individuals whose goal it is to learn about the world

may be no bad thing. For I am confident that with work (much more work than I can carry out in asingle paper), the model outlined below will apply even here, at the limit and that once it is applied,rules will flow on down to whatever is left of metaphysical investigation. Indeed, applying the modelat these giddy heights of abstract generalisation opens up quite an exciting prospect. Once we’vepushed the boundaries of the model all the way out to the class of individuals who are motivatedto gain knowledge about the world we may find a deep unification with Rawls’s theory of justice.In both cases the driving force behind the original position may turn out to be rational self-interest.Rational self-interest, for Rawls, dictactes the decisions made about distribution of wealth. It may alsodictate decisions about the best way to generate knowledge, since that is a commodity like any otherto be desired and used; justice and epistemology may enjoy justificatory integration in the abstract.

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to its modularity. By substituting in one’s preferred motivations, aims and evenepistemic restrictions, one can produce a model that may then be used to elucidateand justify the rules that govern the practice of metaphysics. This flexibility makesthe method quite powerful. It also highlights the way in which the method feedsback into a much larger research project, one that seeks to illuminate the aims andmotivations behind metaphysics as practiced.16

Of course, it may be that the method ultimately fails to deliver up a general setof rules, upon which everyone can agree. This is a concern also for the Rawlsianoriginal position: there may be disagreement behind the veil of ignorance and, assuch, no general principles of justice that are justifiable to everybody. If that wereright in the metaphysical case, it would be an important result. For if no principlesof metaphysics are justifiable to everybody from within the metaphysical originalposition then it follows that one cannot do metaphysics without begging the ques-tion against somebody, methodologically speaking. That would pose a substantialproblem for metaphysics as a practice and would constitute a novel, and quite sig-nificant meta-philosophical objection. For my part, I am optimistic that there aregeneral rules of metaphysics that we can all get behind, and that the Rawlsian modelwill deliver them (or, at least, point us in the right direction). But I doubt that ev-eryone will share this optimism.17 To the pessimist, I can only say that minimisingmethodological question begging, or at least minimising the harm done by questionbegging of this kind, is still worthwhile and that a useful way to minimise this harmis to abstract away as far as possible from any biases we might have regarding meta-physics, and aim for principles that can be justified to every metaphysician, even if

16Alongside the social-justice-like structure of determining the principle of metaphysics, thereare also the actual social justice issues of metaphysical methodology. Who do we take seriously asmetaphysicians, and how do we come to take them seriously in this way? Which topics fall under therubric of ‘general metaphysics’? And which topics count as ‘specialised metaphysics’? Which booksget reviewed, and by whom? Which articles get responded to and why? Who is treated how atworkshops and who is invited to which selective conferences and why? A method for determiningthe ground rules for metaphysical methodology ought to also get a handle on these issues. TheRawlsian paradigm is well-placed to do so.

17Here’s a reason to be pessimistic: suppose that I develop a metaphysical theory using classicallogic. My opponent claims that I am being unfair, because they endorse a non-classical logic. I shiftmy ground: all I need is consistency. But it turns out my opponent is a dialethist. So I am still beingunfair. I shift my ground again: I just require the one-true logic! But my opponent is also an anti-realist about the one true logic. So on it goes. On the one hand, that the model can be applied evento a case such as this is impressive. On the other hand, I worry that there will be no way to settle onthe most basic of methodological principles: namely, which logic to use. But here is the beginning ofa solution: for most disputes we can, for the purposes of argumentation, settle on a logic acceptableto both sides. So that is what we ought to do. It is only when what’s at stake is the very logic beingused that matters become di�cult. Even here, though, we can perhaps agree on a logic to use for thepurposes of argumentation; a ladder that we can ultimately kick away if we need to, when all is saidand done.

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one cannot, ultimately, get hold of any such principles.

4 ApplicationThat, then, is the proposal: in order to determine and justify the principles of meta-physics, we place ourselves into the metaphysical original position. Those principlesthat we as metaphysicians would all agree upon from behind a veil of ignorance(one that, roughly, occludes our theoretical and pre-theoretical commitments) arethe principles that are justifiable to everyone working in metaphysics and ipso factothe principles that ought to govern metaphysical practice. I recognise, however, thatthe proof here is in the pudding: the model must be applicable. Accordingly, I nowdemonstrate the practical utility of the model by using it to identify three principlesof metaphysical methodology that I believe are likely to be agreed upon by everyonefrom within the metaphysical original position.

Before proceeding, however, two points of clarification are in order. First, mygoal in applying the Rawlsian model to metaphysics is primarily to show how themethod works, and how it can be used to gain traction on existing metaphysicaldisputes. So the focus is really on the method; I am less concerned to defend theparticular principles of metaphysics that I outline below. Second, I will continue toassume a particular view about the aims and motivations of metaphysicians, namelythat it aims at uncovering fundamental and general truths, and that the motivationsare as described above. What I say is therefore provisory, and subject to revisionshould these further issues be decided di�erently. That said I would very much liketo get the principles of metaphysics discussed below out of the model. As such, therelevant principles can be thought of as constituting a wish list. No doubt others willhave their own wish lists, and so I encourage everybody to consider how it is thatthe principles on their lists can be justified using the method outlined.

4.1 Methodological NaturalismThe first principle of metaphysics might be called ‘methodological naturalism’. Bymethodological naturalism I have something quite particular in mind, and some-thing that is perhaps a bit weaker than the viewmost often referred to by this phrase.Methodological naturalism in my sense is the idea that metaphysicians ought to de-velop metaphysical theories in a manner that is informed by our best science; that issensitive to empirical developments and evidence; and that seeks wherever possibleto integrate our metaphysical theories with our best scientific theories. It is also theidea that metaphysicians ought to deploy scientific methods where appropriate forany aspects of their theories that have empirical content. This means, among otherthings, that practicing metaphysicians ought to be up to speed with contemporary

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scientific theories andmethods. Of course, not every metaphysical theory is going tobe informed by science, and so not every theorywill be one inwhichmethodologicalnaturalismwill come into play. But many theories are so informed andmethodolog-ical naturalism as a norm of metaphysics exerts pressure on metaphysicians to lookfor connections with science and develop them wherever possible.18

Methodological naturalism competes with a number of other principles, the mostextreme of which is that metaphysicians are required to develop their theories withoutpaying attention to science. Call this principle: methodological anti-naturalism. Inthe space between methodological naturalism and methodological anti-naturalismwe find a range of principles that permit varying degrees of contact with science;however none of these principles require a metaphysician to develop her theory in ascientifically informed manner other than methodological naturalism. Methodolog-ical naturalism is (or is at least supposed to be) the weakest principle of metaphysicsthat exerts this requirement.

Methodological naturalism, as a principle of metaphysical methodology, is morelikely than competing principles to maximise the motivational ideals identified in §3.Consider, first, the ideal of unification. As noted, this is the idea that metaphysiciansare motivated by the ideal of maximising the contribution that metaphysics makesto the development of a unified philosophical theory, in this case: a theory of funda-mental reality. Since such a theory is very likely to include all of our current science,the best way to contribute to this goal is to proceed in a scientifically informed man-ner. Indeed, if one does not proceed in this way, then one runs the risk of developingone’s metaphysical theories in a way that is ultimately incompatible or otherwise dif-ficult to integrate with our best science. That would ultimately cut against the idealof unification and so if we are to maximise that ideal, then we should adopt a nat-uralistic approach to metaphysics. One might demur: unification will not speak infavour of methodological naturalism if science is compatible with many metaphysi-cal systems. Even here, however, unification gains traction. For presumably scienceis not compatible with all possible metaphysical systems. Accordingly, metaphysi-cians who aim to develop a metaphysical system should ensure that their favouredsystem falls within the class of systems compatible with science. To do that, how-ever, they must defend their theories in a scientifically informed way, which is all

18Methodological naturalism in my sense is not the view that science trumps all. Nor does it ruleout non-natural metaphysics tout court. It only does so when the relevant metaphysics is scientifi-cally naive. Endorsing methodological naturalism does not thereby immediately commit one to aLadyman and Ross-type vision of naturalized metaphysics, according to which metaphysics is in thebusiness of unifying science. Rather, the naturalized metaphysics imagined here is weaker than that:it is merely required to render itself compatible with science and to integrate scientific and metaphys-ical theories wherever possible. There is plenty of scope within this weaker conception of naturalizedmetaphysics for metaphysics that is independent of science; not so for Ladyman and Ross. If Lady-man and Ross’s account of metaphysics is used to set up the metaphysical original position somethingmuch stronger than the methodological naturalism proposed here would likely fall out.

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that methodological naturalism of the kind discussed here demands.Consider, second, the ideal of progress. If we do not develop our metaphysical

theories in line with methodological naturalism, then because we run the risk ofdeveloping theories that are at odds with our best science, we also run the risk ofdeveloping theories that must be abandoned for reasons of empirical inadequacy.Which is to say that metaphysics developed in this way may result in a great deal ofwork being poured into metaphysical theories that must eventually be abandoned.Now, of course, this might happen regardless of how closely we attend to science,but the point is that methodological naturalism will minimise this possibility andthus minimise the possibility that metaphysicians will proceed up blind alleys. This,in turn, maximises the chances of genuine progress in metaphysics.

Finally, methodological naturalism is likely to contribute something toward theideal of transparency. If metaphysicians are motivated to produce arguments that areconvincing to those outside of metaphysics, then they should not produce argumentsthat are empirically naive. Such arguments are likely to contain hidden empirical as-sumptions about which science has an opinion, and one that has not been properlytaken into account. Such arguments are therefore unlikely to be convincing to any-one but other, similarly naive metaphysicians. The most transparent theories, then,are ones that are developed in a scientifically informed way.

Methodological naturalism helps to maximise the ideals of progress, unificationand transparency, when compared to various anti-naturalistic principles that do notexert a requirement to engage with science. As a principle of metaphysics, then, itis a principle that is likely to be justifiable to all, within the metaphysical originalposition. The Rawlsian framework developed here thus furnishes methodologicalnaturalism with added normative force. Of course, as before, whether the Rawlsianmodel delivers the normative force at issue depends very much on the inputs. Ifone is in the business of attempting to discover the fundamental and general truthsabout reality by unifying science, then it is relatively clear that progress toward thatend will be maximised by adopting a naturalistic approach. If, however, one takesmetaphysics to be in the business of discovering fundamental and general truths byconducting conceptual analysis, then the link to naturalism is less clear. Still, even inthe case of conceptual analysis, if we really want to know what the structure of ourconcepts is, it seems reasonable to suppose that an empirical understanding of thoseconcepts is required and thus that some dialogue with empirical psychology is in thebest interests of the project. Perhaps this result is at odds with what those engaged inconceptual analysis are actually doing, but such is the divide between is and ought.

At any rate, let us briefly consider two cases where the added normative force ofmethodological naturalism comes into play, to gain a flavour for the kind of workthat notion can do once properly justified. First, consider the debate over the exis-tence of God. In this debate there is a tendency by some metaphysicians to defend

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theism in a manner that requires rejecting a great deal of science. I have in mindhere those who defend intelligent design in such a way that they end up rejectingevolutionary theory. Many believe that defending the existence of God in this wayis troubling. We can now see why: metaphysicians who defend the existence ofGod by appealing to intelligent design of the kind that is incompatible with our bestscience are cheating. They are cheating because they shirk the rules of metaphysicsthat they themselves would agree upon, from within the metaphysical original po-sition. The case is therefore analogous to slavery in Rawls’s theory of justice. Whileslavery might benefit the slaveholders, it is a practice that they themselves wouldrule out from behind the veil of ignorance. They would rule it out because it is nota practice that is justifiable to everybody. Analogously, while ignoring science mayfurther the aims and interests of metaphysicians who are theists, it is a practice thatthey themselves would rule out from behind the veil of ignorance.

Similar considerations apply to the second example. As briefly noted above, thereis a debate in the philosophy of time over the compatibility between the A-theoryand the special and general theories of relativity. Some A-theorists have attempted toavoid this incompatibility by recommending a return to pre-Einsteinian notions ofrelativity. Craig (2000), for instance, argues that we should reject special relativity –one of our most well-confirmed scientific theories – because of this incompatibility,and embrace an aether theory of the kind defended by Lorentz. The debate on thistopic is rather technical, but, for now at least, the details are not important. Whatmatters is that scientists consider Lorentz’s theory to be a failed physical theory. It istherefore di�cult to see how the recommendation to return to pre-Einsteinian me-chanics properly accords with methodological naturalism. Recommending a failedscientific theory on metaphysical grounds does not satisfy the requirement to de-velop one’s metaphysical theories in a scientifically informed way. So Craig is cheat-ing: he is failing to obey the rules of metaphysics that he himself would agree to bebound by from within the metaphysical original position.

Now, I have no doubt that anti-naturalists will find it outrageous to suppose thatflouting methodogical naturalism constitutes a form of cheating. The worry, as itever is with any Rawlsian approach such as this, is that it is implausible to get so muchout without implicitly putting it in. However, consider an analogous issue in the caseof distributive justice. Consider, in particular, a conservative who rejects Rawls’smethodology of the original position because the two principles outlined in §2 aretoo ideologically substantive to follow from a mere methodological suggestion. Tobe convincing, that is not how the conservative should argue against those principlesand the associated theory of justice. Rather, shemust produce arguments to the e�ectthat the rule-makers behind the veil of ignorance would not reach consensus, andthus there would be deep disagreement within the original position, or that theywould reach consensus but would not converge on the di�erence principle. In the

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same vein, an anti-naturalist whowants to attackmethodological naturalism as I havedefended it here should not do so by denying that anything quite so substantive canfollow from mere methodology. Rather, she should provide an argument to thee�ect that metaphysicians in the original position would not converge on anything,or would converge on a rule for metaphysics that permits at least sometimes ignoringbest (relevant) science. I have no doubt that such arguments could be developed,and so I do not view methodological naturalism to be unassailable. But developingarguments of this kind would be a substantial undertaking, and that’s all I aim toshow.

Here’s a sketch of one such argument for anti-naturalism. Above I mentioned theidea that science might be compatible with a number of metaphysical systems anddismissed the idea that it is compatible with all. Perhaps this was too quick however.For suppose that all scientific theories were compatible with all possible metaphysicalsystems and that this could be shown. If that is information that metaphysiciansin the original position have available to them, then it is doubtful that they wouldlegislate in favour of any kind of naturalism. Indeed, a vehement anti-naturalism,whereby metaphysics is developed independently of science, would seem to be theorder of the day. Now, to be clear, I am not defending the idea that science iscompatible with all possiblemetaphysical systems. I ammerely trying to demonstratethe kind of argument that must be produced by the anti-naturalist as a response tothe proposed Rawlsian derivation of naturalism. I leave it to the anti-naturalist totake the argument further.

4.2 Reasons For AllThe second and third principles of metaphysics are less general than methodologicalnaturalism, in the following sense. These principles are required to maximise indi-vidual motivational ideals only. The second principle is targeted, in particular, at theideal of transparency, and can be stated in maxim form as follows: the reasons thatare provided in favour of a metaphysical theory ought to be reasons for all suitablyempirically informed rational agents. That is, the reasons provided in favour of ametaphysical theory ought not to be reasons that trade on implicit beliefs that onlysome rational agents hold. They should, rather, be compelling to everybody as rea-sons and, as such, in so far as they rely on implicit beliefs at all, they ought to rely onbeliefs that pretty much every empirically informed rational agent is likely to have.

This principle is more likely to maximise the ideal of transparency than the alter-natives. Again, to see this, we require some sense of the alternatives. The alternativesin this case correspond to a class of principles, each of which allows some scope too�er reasons in support of one’s view, where the status of those reasons as reasons issomething that not every suitable empirically informed rational agent would accept.At one end of this spectrum sits a principle which requires metaphysicians to o�er

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highly idiosyncratic reasons in support of their views, reasons that very few suchagents, if any, would accept as reasons. As we move away from this position, eachalternative principle renders metaphysics more transparent than the principle iden-tified above. This is clearest for the extremal case. In the extremal case, metaphysicsas practiced appears to be irrelevant to anyone except for a very select few. Eachweakening of this extremal principle will render metaphysics more transparent tosome degree, making it more relevant to other empirically informed rational agents.However, it is not until we come to the other end of the spectrum, and thus to theprinciple outlined above, that we reach a principle that maximises this ideal.

As with methodological naturalism, this principle can be used to catch cheats.Here’s a toy example. Consider, again, the debate over the existence of God. Inarguing for the existence of God one may cite, as evidence, testimony in favour ofthe existence of miracles. Many cite claims by persons to have special experiences ofawareness of the divine. But not every empirically informed rational agent will agreeon the evidential status of such testimony. Rather, manywill maintain that testimonyin favour of miracles is not to be trusted as evidence; and nor is testimony of specialexperiences of the divine. Similarly, suppose one takes the bible to be evidence infavour of the existence of God. Again, the status of the bible as evidence is verymuch up for debate. Now, the claim that there is something untoward about the useof these items of evidence as a basis for belief in the existence of God is nothing new.Nor, even, is the idea that this strategy of arguing for the existence of God amountsto a kind of cheating. What is new is that we now have a further sense of why thisis cheating. It is cheating because it flouts a principle that even those metaphysicianswho are theists would accept from behind the veil of ignorance. There is thereforea sense in which such metaphysicians are cheating by their own (ideal) lights.

Similar considerations apply to various versions of supernaturalism inmeta-ethics.Suppose Alice and Bob are two metaphysicians disagreeing about whether there areobjective moral facts. Suppose that Bob o�ers, as evidence for the existence of ob-jective moral facts, God’s existence. Alice can legitimately criticise Bob’s dialecticalmove as unfair. Bob has provided reasons in favour of his view that rely on holdingmetaphysical beliefs that not every empirically informed rational agent is likely toshare. Alice can therefore demand of Bob that he provide further evidence in favourof the existence of moral facts, evidence that does not require Alice to become atheist in order to take it seriously.

Of course, if Alice is already a theist, then perhaps it is legitimate for Bob tomake the move that he does. As such, perhaps a caveat is in order. The principleo�ered above, namely that the reasons provided in favour of a metaphysical theoryought to be reasons for all, is sensitive to the context of a dispute. If every agentengaged in a particular metaphysical dispute accepts p as a basic assumption of thedebate, then perhaps it is legitimate to provide reasons for or against a theory that

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presupposes p, even if p is not universally accepted. However, ultimately p itself mustbe argued for, and in a way that is accessible to all (or if p is not accessible to all andrelies on q, then it is q that must receive this treatment, and so on). In short, at somelevel, all metaphysical claims must be supported by reasons that rely only on widelyheld beliefs, in order to maximise the ideal of transparency. Metaphysical debatescannot bottom out, as it were, in evidence, the status of which as evidence relies oncontroversial assumptions.

4.3 Don’t Go PrimitiveWe come now to the third principle of metaphysics, which is the final principle Iwill discuss. The third principle speaks primarily to the ideal of progress. I havealready discussed a principle that is required to maximise progress in metaphysics:methodological naturalism. But there is a further, less general principle needed toachieve this goal as well. Sometimes in the course of a metaphysical debate, someonemight take something as primitive. While we want to allow the use of primitiveswithin the context of a metaphysical theory – everyone is allowed some primitivityin their theories, to spread around wherever they like – at times the use of primitivesseems questionable. I have in mind here the introduction of some new primitive inorder to solve a problem for one’s theory, or the taking of something as primitiveto the same end, where (i) the primitive is tailored specifically to solve the problemand (ii) there is no other reason for adopting the primitive than to solve the problemat hand. I will outline an example of this in a moment but first we need to get clearon the relationship between this kind of manoeuvre and the ideal of progress inmetaphysics.

The trouble with introducing new primitives to solve a problem for a metaphys-ical theory where (i) and (ii) apply is that pretty much any problem with any theorycan be addressed using a variant of this strategy. Suppose a theory has some kindof metaphysical shortfall: there is something that we need the theory to do that itcannot, and for many that is a reason to doubt the view. In response to this problemone can, in principle at least, introduce some new primitive and simply stipulate thatit does the relevant work. Or suppose that a theory maintains, on pain of inconsis-tency, that x and y are distinct, but cannot give a good account of the distinctness ofthese two things. One can simply stipulate that x and y are primitively distinct. Inshort, the move of taking something as primitive or introducing some new primi-tive into one’s theory is extremely powerful. If one is allowed to ‘go primitive’ in thisfashion, then it will be all too easy to make our metaphysical theories impervious tocriticism. Moreover, the temptation to do so will be significant, since going primi-tive in this way is an easy solution to one’s problems. It is also a lasting solution, sinceby its very nature it prevents further questions being asked (because one is invokingprimitives), and thus further objections from being raised.

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If going primitive is easy to do then progress in metaphysics will be di�cult.The situation won’t be quite as bad as one in which all metaphysical theories areon a par, and so there is no way to choose between them, but it will be close. Itwon’t be quite this bad, because one can always call on parsimony considerations asa way of choosing between theories. Those theories that require going primitive lessfrequently than others will be the stand out theories, since it is better for a theory toreduce the number of primitives it has wherever possible. Even then, parsimony willonly take us so far because it can only rule out a handful of theories. In the situationwhere going primitive is allowed, most theories will have a range of primitives tailor-made to render each theory viable, and somost of these theories will be on a par fromthe standpoint of parsimony. Once we have identified those theories, there will benothing left for metaphysics to do and so the entire enterprise will grind to a haltwell short of its stated aims.

In order to maximise the progress that can be made in metaphysics, we mustminimise the use of primitives. Now, one might want to rule out the use of prim-itives completely to solve problems with a metaphysical theory, but that strikes meas a bit extreme. At any rate, it is the more moderate position that I will focus onhere. This moderate position speaks in favour of a principle of metaphysics wherebysome condition is placed on the use of primitives. It is not entirely obvious whatthe condition needs to be, but at the very least it should be strong enough to avertthe scenario discussed above. Here’s one stab at formulating such a principle. Oneought not appeal to primitives in order to solve a problem for one’s view unless onehas very strong independent reasons for doing so, where ‘independent’ here means:independent of the problem at hand. Exactly what counts as a very strong inde-pendent reason is going to vary on a case by case basis, but the basic idea is that onemust show that the primitives at issue do more work than merely solving a particularproblem for one’s theory. This sanction against the use of primitives is a corollaryof a more general principle, one that restricts the use of ad hoc assumptions in gen-eral. I suspect that the more general principle can also be justified using the Rawlsianmodel. But, for now at least, I will focus only on the invocation of primitives since Ibelieve the notion of ad hocness hides complexities that I cannot adequately engagewith here.

As before, it is useful to consider an example. Presentism, a popular view inthe philosophy of time, is the view according to which only present entities exist.Presentists find it di�cult to satisfy the demands of truthmaker theory. Truthmakingrequires, roughly, that for any proposition P , there exists some entity E such thatE’s existence makes P true. But now consider some proposition about the past, suchas <dinosaurs existed>. For the presentist, past entities do not exist. So <dinosaursexisted> cannot be made true by the existence of any dinosaurs. But it is far fromobvious what else might make this proposition true, given presentism. If nothing

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can be found to make the proposition true, however, then presentists are forced toaccept that <dinosaurs existed> (and, indeed, all claims about the past) is false, anoutcome that is generally thought to be unattractive.

In order to satisfy the demands of truthmaker theory, then, presentists must findsome further truthmakers for propositions about the past. In response to this de-mand, Bigelow (1996) invokes a certain kind of property, possessed by the worlditself: a tensed property. Tensed properties are primitive, unanalysable propertiesof the world that, in some primitive sense, ‘point’ toward the past and, in virtue ofso pointing, serve as the truthmakers for past-directed propositions. So, for exam-ple, the proposition <dinosaurs existed> is made true by the presently instantiatedworld-property having been such that there were dinosaurs, the existence of which guar-antees that dinosaurs existed.

Appealing to primitive tensed properties to solve the truthmaking problem forpresentism is thought by many to constitute a kind of cheating. The manner inwhich this charge of cheating is developed, however, is usually metaphysical andnot methodological. The move of introducing primitive tensed properties quamoveis not itself questioned. Sider (2001), for instance, argues that tensed properties arehypothetical properties – properties that point beyond their instances – and so shouldbe disallowed for this reason. Similarly, Cameron (2011) argues that tensed prop-erties do not make an intrinsic di�erence to their bearers and, as such, are meta-physically contentious posits. In so far as a methodological worry has been pressedat all, the worry has been one of parsimony: invoking new primitives in this way ismetaphysically profligate.

There is, however, something troubling about the move that Bigelowmakes thatis unrelated to worries about parsimony. Tensed properties are introduced for thesole purpose of addressing a certain kind of objection against presentism. Moreover,this is a job that the relevant tensed properties are tailor-made to do. Their use astruthmakers does not receive independent motivation by Bigelow, and nor does theidea that these properties exist. One cannot help but feel, then, that Bigelow’s so-lution to the truthmaking problem has been achieved far too easily. The principleof metaphysics outlined above, concerning primitives, does justice to this intuitionand, moreover, tells us what’s wrong with the move. Because no independent moti-vation for invoking these primitives has been given; because we are given no reasonto believe in the existence of the relevant primitives, other than that they can be usedto solve a particular metaphysical problem for presentism, the appeal to primitives inthis context has failed to meet the right normative standards.

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5 ConclusionHere, then, are three putative principles of metaphysics:

Methodological Naturalism Metaphysicians ought to develop metaphys-ical theories in a manner that is informed byour best science.

Reasons for All The reasons provided in favour of a meta-physical theory ought to be reasons for allempirically informed rational agents.

Don’t Go Primitive One ought not to appeal to primitives in or-der to solve a problem for one’s view unlessone has very strong independent reasons fordoing so.

As noted, I o�er these three principles in a provisory mood, as instances of howto apply a particular Rawlsian framework to the methodology of metaphysics. Whatreally matters is the method used to justify these principles. The basic idea behindthis method is to abstract away from the particular metaphysical disputes in whichwe are engaged and place ourselves in the metaphysical original position. From themetaphysical original position we attempt to agree on the principles of methodologyby which metaphysics will be bound, once a veil of ignorance is lifted; a veil which,in this case, occludes pertinent information that might influence the sorts of decisionswe make about which principles to adopt.

This Rawlsian approach to determining and justifying the principles of meta-physics promises to deliver a set of principles that are justifiable to everybody en-gaged in metaphysical inquiry, and that are therefore fair. Moreover, because theseprinciples are determined by the motivations of agents determined to do the bestmetaphysics they can, they are also likely to be in the best interests of metaphysics asa discipline. The refinement and application of the method developed here is there-fore a worthwhile project in meta-metaphysics. At best, it will produce a rule-bookfor metaphysics as an end product, a guide that can be used to do real work withinfirst-order debates, at worst it will tell us why no such guide is forthcoming. Thereis also the possibility that something like this method can be extended to other dis-ciplines. One might, for instance, use this method to motivate and justify the normsof science, or of history. It is interesting indeed to consider just how far the Rawlsianparadigm can be pushed.

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Acknowledgements I am very grateful to Jamin Asay, Christopher Daly, ThomasDougherty, Raamy Majeed, David Ripley and three anonymous referees for this jour-nal for comments on earlier drafts of the paper. I am also grateful to Miri Albahari,John Bigelow, David Braddon-Mitchell, Rachael Briggs, Mark Colyvan, Mauro Do-rato, Peter Evans, Suzy Killmister, Kristie Miller, Bradley Monton, James Norton, GregRestall, Michael Rubin, Caroline West, Robbie Williams and the audience at the 2012Australasian Association of Philosophy Conference for extremely useful discussion onthe ideas behind “Metaphysics as Fairness”.

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