Lewis (The Journal of Philosophy, 65(5), 113–126, 1968) attempts to provide an account of modal talk in terms of the resources of counterpart theory, a first-order theory that eschews transworld identity. First, a regimentation of natural language modal claims into sentences of a formal first-order modal language L is assumed. Second, a translation scheme from L-sentences to sentences of the language of the theory is provided. According to Hazen (The Journal of Philosophy, 76(6), 319–338, 1979) and Fara & Williamson (...) (Mind, 114(453), 1–30, 2005), the account cannot handle certain natural language modal claims involving a notion of actuality. The challenge has two parts. First, in order to handle such claims, the initial formal modal language that natural language modal claims are regimented into must extend L with something like an actuality operator. Second, certain ways that Lewis’ translation scheme for L might be extended to accommodate an actuality operator are unacceptable. Meyer (Mind, 122(485), 27–42, 2013) attempts to defend Lewis’ approach. First, Meyer holds that in order to handle such claims, the formal modal language L$$^*$$ ∗ that we initially regiment our natural language claims into need not contain an actuality operator. Instead, we can make do with other resources. Next, Meyer provides an alternative translation scheme from L$$^*$$ ∗ -sentences to sentences of an enriched language of counterpart theory. Unfortunately, Meyer’s approach fails to provide an appropriate counterpart theoretic account of natural language modal claims. In this paper, I demonstrate that failure. (shrink)

Counterpart theory is often advertised by its track record at solving metaphysical puzzles. Here I focus on puzzles of occasional identity, wherein distinct individuals at one world or time appear to be identical at another world or time. To solve these puzzles, the usual interpretation rules of counterpart theory must be extended beyond the simple language of quantified modal logic. I present a more comprehensive semantics that allows talking about specific times and worlds, that takes into account the (...) multiplicity and sortal-dependence of counterpart relations, and that does not require names to denote actual or present individuals. In addition, the semantics I defend does not identify ordinary individuals with world-bound or time-bound stages and thereby avoids the most controversial aspect of counterpart theory. Humphrey’s counterpart at other worlds or times is none other than Humphrey himself. (shrink)

Nonreductive physicalism faces serious problems regarding causal exclusion, causal heterogeneity, and the nature of realization. In this paper I advance solutions to each of those problems. The proposed solutions all depend crucially on embracing modal counterpart theory. Hence, the paper’s thesis: counterpart theory saves nonreductive physicalism. I take as my inspiration the view that mental tokens are constituted by physical tokens in the same way statues are constituted by lumps of clay. I break from other philosophers who have (...) pursued this line, however, in that I hold that constitution is identity. Much of the value of the comparison to statues and lumps is that it calls to mind the resources used to defend constitution-as-identity, most notably that of counterpart theory. Along the way, I discuss the virtues of a trope ontology, modal objections to token identity theories, the prospects of conditional analyses of causal powers, the subset account of realization, and the grounding problem. I also endorse a novel, empirical argument in favor of counterpart theory. (shrink)

The hole argument concludes that substantivalism about spacetime entails the radical indeterminism of the general theory of relativity (GR). In this paper, I amend and defend a response to the hole argument first proposed by Butterfield (1989) that relies on the idea of counterpart substantivalism. My amendment clarifies and develops the metaphysical presuppositions of counterpart substantivalism and its relation to various definitions of determinism. My defence consists of two claims. First, contra Weatherall (2018) and others: the hole argument (...) is not a blunder resulting from a mistaken view on how mathematical physics works, and requires a developed (meta)metaphysical response. Second, contra Melia (1999) and others: one can be content with a notion of determinism for GR which is not sensitive to merely haecceitistic differences. (shrink)

Actualist counterpart theory replaces David Lewis’s concrete possible worlds and individuals with ersatz worlds and individuals, but retains counterpart theory about de re modality. While intuitively attractive, this view has been rejected for two main reasons: the problem of indiscernibles and the Humphrey objection. I argue that in insisting that ersatz individuals play the same role as Lewisian individuals, actualists commit the particularist fallacy. The actualist should not require stand-ins for every Lewisian individual. Ersatz individuals should instead be (...) construed as representations of actually existing qualitative ways for individuals to be, or qualitative properties individuals can instantiate. This necessitates changes elsewhere. Non-instrumental uses of Kripke semantics and standard counterpart semantics also require stand-ins for particular non-actual individuals. I argue that the actualist should instead adopt a non-standard counterpart semantics that more clearly illuminates the role that actual properties and relations play in explaining de re possibilities and necessities. The result is an intuitive and forceful reply to both the problem of indiscernibles and the Humphrey objection. (shrink)

This paper presents and motivates a counterpart theoretic semantics for quantifi ed modal logic based on a fleshed out account of Lewis's notion of a `possibility.' According to the account a possibility consists of a world and some haecceitistic information about how each possible individual gets represented de re. A semantics for quanti ed modal logic based on evaluating formulae at possibilities is developed. It is shown that this framework naturally accommodates an actuality operator, addressing recent objections to (...) class='Hi'>counterpart theory, and is equivalent to the more familiar Kripke semantics for quanti fied modal logic with an actuality operator. (shrink)

I formulate a theory of groups based on pluralities and counterparts: roughly put, a group is a plurality of entities at a time. This theory comes with counterpart-theoretic semantics for modal and temporal sentences about groups. So this theory of groups is akin to the stage theory of material objects: both take the items they analyze to exist at a single time, and both use counterparts to satisfy certain conditions relating to the modal properties, temporal properties, and coincidence properties (...) of those items. (shrink)

One popular theodicy says that good can’t exist without evil, and so God must allow evil in order to allow good. Call this the counterpart theodicy. The counterpart theodicy relies on a metaphysical claim about existence—good cannot exist without evil. A second popular theodicy says that we would be unable to know/recognize/appreciate the good without evil, and so God is forced to allow evil in order to allow for such appreciation. Call this the appreciation theodicy. The appreciation theodicy (...) relies on an epistemological claim about recognition or appreciation—we are unable to know/recognize/appreciate good without evil (even if it is possible for good to exist without evil). Determining whether either of these theodicies is a success requires a careful discussion of whether either meets the conditions on a successful theodicy. I argue that both fail. (shrink)

David Lewis advised essentialists to judge his counterpart theory a false friend. He also argued that counterpart theory needs natural properties. This essay argues that natural properties are all essentialists need to find a true friend in counterpart theory. Section one explains why Lewis takes counterpart theory to be anti-essentialist and why he thinks it needs natural properties. Section two establishes the connection between the natural properties counterpart theory needs and the essentialist consequences Lewis disavows. (...) Section three answers two objections: the first attempts to block the consequences of adding natural properties to counterpart theory; the second grants the consequences, but denies that they amount to essentialism. –Correspondence to: [email protected]. (shrink)

Counterpart theory has many benefits, but few are happy to accept the metaphysical setting in which this account of de re modality was developed by its architect, David Lewis. I argue here that counterpart theory can be made acceptable by the lights of those who repudiate the existence of merely possible objects. To the "ersatz" counterpart theorist I offer two stories: one about the relate of the counterpart relation and one about the relation itself. With these (...) in place, I then defend ersatz counterpart theory from a number of objections that can be found in the literature. (shrink)

Fara and Williamson (Mind, 2005) argue that counterpart theory is unable to account for modal claims that use an actuality operator. This paper argues otherwise. Rather than provide a different counterpart translation of the actuality operator itself, the solution presented here starts out with a quantified modal logic in which the actuality operator is redundant, and then translates the sentences of this logic into claims of counterpart theory.

Counterpart theory affords an especially flexible form of essentialism. Gideon Rosen and the author suggested that by endowing the entire world with peculiar essences, they could likewise provide truth makers for negative existential propositions. Thus they avoid the need for states of affairs or non‐transferable tropes as truth makers. States of affairs are somehow constructed from particular things and the properties they instantiate. A legitimate counterpart relation can exist which validates only one direction of set‐theoretical essentialism, but under (...) which any counterpart of a state of affairs must be a state of affairs. States of affairs or tropes are not needed for purposes of truth making. But also, if we help ourselves to the flexibility of counterpart theory, the principal difficulties that stand in the way of using states of affairs or tropes as truth makers vanish. (shrink)

The paper investigates the link between the theory of modal occurrents (where individuals are allowed to stretch across possible worlds) and Lewis’s counterpart theory (where all individuals are world-bound but have counterparts in other worlds). First I show how to interpret modal talk extensionally within the theory of modal occurrents. Then I show that the assumption that worlds be pairwise discrete is all that is needed to reconstruct the bulk of counterpart theory (i.e., to define the concept of (...) a counterpart and to derive the standard postulates governing that concept) in terms of the theory of modal occurrents. Finally, I argue that this reconstruction allows us to view the indeterminacy of our modal intuitions as being part and parcel with the indeterminacy of our criteria for individuating modal occurrents, and that this indeterminacy is naturally explained in terms of linguistic (as opposed to ontic) vagueness. (shrink)

Many philosophers, following David Lewis, believe that we should look to counterpart theory, not quantified modal logic, as a means of understanding modal discourse. We argue that this is a mistake. Significant parts of modal discourse involve either implicit or explicit reference to what is actually the case, raising the question of how talk about actuality is to be represented counterpart-theoretically. By considering possible modifications of Lewis's counterpart theory, including actual modifications due to Graeme Forbes and Murali (...) Ramachandran, we argue that no coherent version of counterpart theory can provide a plausible representation of talk about actuality, and so, we conclude, counterpart theory should be rejected. (shrink)

This paper argues that a counterpart-theoretic treatment of events, combined with a counterfactual theory of causation, can help resolve three puzzles from the causation literature. First, CCT traces the apparent contextual shifts in our causal attributions to shifts in the counterpart relation which obtains in those contexts. Second, being sensitive to shifts in the counterpart relation can help diagnose what goes wrong in certain prominent examples where the transitivity of causation appears to fail. Third, CCT can help (...) us resurrect the much-maligned fragility response to the problems of late pre-emption by understanding fragility in counterpart-theoretic terms. Some reasons to prefer this CCT approach to rivals are discussed. (shrink)

David Lewis’s counterpart theory is often seen as involving a radical departure from the standard, Kripke-style semantics for modal logic, suggesting that we are dealing with deeply divergent accounts of our modal talk. However, CT captures but one version of the relevant semantic intuition, and does so on the basis of metaphysical assumptions that are ostensibly discretionary. Just as ML can be translated into a language that quantifies explicitly over worlds, CT may be formulated as a semantic theory in (...) which world quantification is purely metalinguistic. And just as Kripke-style semantics is formally compatible with the doctrine of world-boundedness, a counterpart-based semantics may in principle allow for cases of trans-world identity. In fact, one may welcome a framework that is general enough to include both Lewis’s counterpart-based account and Kripke’s identity-based account as distinguished special cases. There are several ways of doing so. The purpose of this paper is to outline a fully general option and to illustrate its philosophical significance, showing how the large variety of intermediate relations that lie between Lewisian counterparthood and Kripkean identity yield a corresponding variety of modal theories that would otherwise remain uncharted. (shrink)

In this paper, I argue that not only is metaphysical modal normativism an attractive view but that, as a matter of fact, many of us have, all along, been metaphysical modal normativists of a particular stripe. Namely, we have been the kinds of modal normativists, in the form of counterpart theorists, who are robust realists about possibility simpliciter. Having introduced modal normativism as Thomasson does in Norms and Necessity, I go on to recast it in somewhat different terms. With (...) this re-casting in place we can see that while the view offers a pleasingly deflationary account of metaphysical necessity and possibility it does so only against the backdrop of robust realism about possibility simpliciter. If that is right, then Lewis’ counterpart theory turns out to be a potent version of metaphysical modal normativism. So many of us have, all along, been metaphysical modal normativists, and so much the better for it. (shrink)

Standard accounts of counterfactuals with metaphysically impossible antecedents take them to by trivially true. But recent work shows that nontrivial countermetaphysicals are frequently appealed to in scientific modeling and are indispensable for a number of metaphysical projects. I focus on three recent discussions of counterpossible counterfactuals, which apply counterpossibles in both scientific and metaphysical modeling. I show that a sufficiently developed modal counterpart theory can provide a semantics for a wide range of counterpossibles without any inconsistent possibilities or other (...) forms of impossible worlds. But such a view faces problems: in order for the metaphysical views I discuss to bear weight, there must be a significant difference between the metaphysical possibilities and impossibilities. I will show how the counterpart-theoretic view delineates the possible from impossible, while still making room for the impossible. (shrink)

In this paper, the predicate counterparts, defined both axiomatically and semantically by means of Kripke frames, of the modal propositional logics $\textbf {GL}$, $\textbf {Grz}$, $\textbf {wGrz}$ and their extensions are considered. It is proved that the set of semantical consequences on Kripke frames of every logic between $\textbf {QwGrz}$ and $\textbf {QGL.3}$ or between $\textbf {QwGrz}$ and $\textbf {QGrz.3}$ is $\Pi ^1_1$-hard even in languages with three (sometimes, two) individual variables, two (sometimes, one) unary predicate letters, and a single (...) proposition letter. As a corollary, it is proved that infinite families of modal predicate axiomatic systems, based on the classical first-order logic and the modal propositional logics $\textbf {GL}$, $\textbf {Grz}$, $\textbf {wGrz}$ are not Kripke complete. Both $\Pi ^1_1$-hardness and Kripke incompleteness results of the paper do not depend on whether the logics contain the Barcan formula. (shrink)

In a recent article in Analysis, Graeme Hunter and William Seager (1981) attempt to rescue counterpart theory (CT) from some objections of Hazen 1979. They see these objections as arising from ‘uncritical use of the translation scheme originally proposed by Lewis’, and intend to meet them by refraining from use of that scheme. But they do not offer a new scheme; they say ‘…it is no more necessary to have one to capture the sense of modal idiom than it (...) is to capture the sense of quantificational idiom…Appeal to truth value is the single most important criterion of correct translation’ (Hunter and Seager 1981:72). Thus, where the scheme of Lewis (1968) translates a truth by a falsehood or conversely, Hunter and Seager simply produce a sentence which they claim to be a better translation, without articulating any structural principles they employ to arrive at their candidate. A friend of CT should not be happy with this procedure. Let Lm be first-order modal language and Lc be the language of counterpart theory. Sentences of Lc are intended to interpret or elucidate the meanings of Lm-sentences in the strong sense that they should be the outputs of an adequate theory of meaning, which we can formulate as a model theory, for Lm, written in Lc plus set theory. The interest of CT resides in its potential to provide an alternative approach to the model theory of modal logic, and from the clauses of any such alternative model theory we should be able to read off a translation scheme for Lm into Lc, just as we can in the standard case. If CT’s motivation is sound, which Hunter and Seager do not dispute, yet there is no translation scheme and so no counterpart-theoretic model theory, one might suspect some defect in the original language Lm. And in fact, Hunter and Seager find certain Lm-sentences multiply ambiguous with respect to Lc; but if a counterpart-theoretic model theory is possible, to say.. (shrink)

Kripke complained that counterpart theory makes modal claims be about counterparts and not about us, and that it is a misguided model of modality since we do not care about counterparts in the same way we care about ourselves. The first part of the complaint, I argue, has been met by Hazen and Lewis, while the second can be countered by observing that most of our modal concerns are about role‐fillers and that counterparts are well‐suited to such concerns. The (...) role‐filler analysis of modal concerns, however, does not seem to capture certain attitudes ‐ especially that of regret. Regret, however, I will argue, is not intrinsically modal and thus is no challenge to my general analysis of modal concerns. (shrink)

Kant's argument from incongruent counterparts for substantival space is examined; it is concluded that the argument has no force against a relationist. The argument does suggest that a relationist cannot give an account of enantiomorphism, incongruent counterparts and orientability. The prospects for a relationist account of these notions are assessed, and it is found that they are good provided the relationist is some kind of modal relationist. An illustration and interpretation of these modal commitments is given.

'Natural class' trope nominalism makes a trope's being of a certain sort--its nature--a matter of its membership in a certain natural class of actual tropes. It has been objected that on this theory had even a single member of the class of red tropes not existed, for example, then the type 'being red' would not have been instantiated and nothing would have been red. I argue that natural class trope nominalism can avoid this implication by way of counterpart theory (...) as applied to properties. (shrink)

Modal counterpart theory identifies a thing’s possibly being F with its having a counterpart that is F at another possible world; temporal counterpart theory, the stage view, according to which people and other ordinary objects are instantaneous stages, identifies a thing’s having been F or going to be F, with its having a counterpart that is F at another time. Both counterpart theories invite what has been called ‘the argument from concern’ (Rosen, G. 1990. “Modal (...) Fictionalism.” Mind 99 (395): 327–54). Why should I be concerned about my counterparts at other possible worlds or other times? I care about how things might have gone for me—not how they go for other people at other possible worlds; I care about my prospects—not the way go for other people at other times. Jiri Benovsky has argued that while modal counterpart theory can be defended against this style of argument, temporal counterpart theory cannot (Benovsky, J. 2015. “Alethic Modalities, Temporal Modalities, and Representation.” Kriterion: Journal of Philosophy 29: 18–34). I argue that temporal counterpart theory, like modal counterpart theory, resists the argument from concern. (shrink)

David Lewis’s counterpart-theoretic semantics for quantified modal logic is motivated originally by worries about identifying objects across possible worlds; the counterpart relation is grounded more cautiously on comparative similarity. The possibility of contingent identity is an unsought -- and in some eyes, unwelcome -- consequence of this approach. In this paper I motivate a Kripkean counterpart theory by way of defending the prior, pre-theoretical, coherence of contingent directness. Contingent identity follows for free. The theory is Kripkean in (...) that the counterpart relation is in a sense stipulated rather than grounded on similarity, and is such that no object has more than one counterpart at a world. This avoids a number of objections Fara and Williamson have recently levelled against counterpart theory generally; their other objections are addressed by enriching the theory with special quantifiers and actuality operators. (shrink)

Left and right hands are incongruent counterparts. Yet each replicates the intrinsic properties of the other. This suggests that differing relations to space make the difference. Kant's and Weyl's discussions of the problem are critically discussed. It emerges that spatial relationism fails to explain how its relations may be interpreted. An excursion into visual geometry explains the basis of handedness in the orientable structure of space.

Possible worlds represent you as being certain ways, as having a different lives, different hopes, and different friends. A foundational question in the philosophy of modality thus emerges: in virtue of what does a world represent you in these ways? In this paper, we focus on David Lewis's answer to this metarepresentational question: Counterpart Theory.

According to the Truthmaker Principle: every truth has a truthmaker. Attempts to come to grips with the Truthmaker Principle played a prominent role in Lewis’s metaphysical writings over the last fifteen years of his career. Although Lewis agreed that the truth of propositions must somehow be ontologically grounded, the Truthmaker Principle was too strong: it conflicted with two of Lewis’s most fundamental metaphysical assumptions, the uniqueness of composition and the Humean denial of necessary connections. Lewis endorsed instead a weaker principle: (...) Truth Supervenes on Being. But towards the end of his career, he changed course, noting that his critique of the Truthmaker Principle rested on essentialist assumptions that he, as a counterpart theorist, does not accept. Once freed from those assumptions, a counterpart theorist can accept the Truthmaker Principle after all without buying into unmereological composition and mysterious necessary connections. (shrink)

Counterpart theorists need not posit the counterpart relation in addition to the identity relations as an Additional relation relating objects across possible worlds. Identity can be viewed as a relation applicable to individuals within possible worlds, while the counterpart relation replaces identity in translations of ordinary utterances which correlate individuals in different possible worlds and, hence, in all modal utterances. CT is, in other words, a theory of modal discourse — it proposes a way of understanding all (...) modal predications. As such, it is not to be seen as providing a second ‘looser’ sense of identity across worlds, in addition to the ‘narrow’ sense. Perhaps Lewis' original formulation encourages this misunderstanding insofar as it (see, especially, P2) denies strict identity across possible worlds. Accordingly, I have suggested a modification of CT whereby syntactic restrictions upon variables eliminates any temptation to posit two parallel relations applicable to entities existing in different possible worlds. (shrink)

A claim by David K. Lewis (1986) that his counterpart theory provides a semantics for intensional languages is critiqued by showing that basic principles of modal logic fail to be valid in counterpart theory & by investigating problematic counterpart-theoretical translations of instances of universal instantiation. From Lewis's postulate that individuals inhabit only one world & have counterparts in other worlds, it follows that the relation between an object & its counterparts is nontransitive & nonsymmetric; consequently, an object (...) does not need to have exactly one counterpart in any world. The failure of modal principles in counterpart theory is ascribed to the possibility that an object has no counterpart in a given world, whereas universal instantiation becomes invalid when an object has more than one counterpart in a given world. 3 References. Adapted from the source document. (shrink)

Mereological nihilists are faced with a difficult challenge: explaining ordinary talk about material objects. Popular paraphrase strategies involve plurals, arrangements of particles, or fictions. In this paper, a new paraphrase strategy is put forward that has distinct advantages over its rivals: it is compatible with gunk and emergent properties of macro-objects. The only assumption is a commitment to a liberal view of the nature of simples; the nihilist must be willing to accept the possibility of heterogeneous extended simples. The author (...) suggests reinterpreting the parthood and composition relations as modal. According to this paraphrase, composition is a kind of counterpart relation. The author shows that one can accept that mereological nihilism is metaphysically necessary, while endorsing all the claims of classical mereology. As a result, the nihilists are in exactly the same position as the classical mereologist when it comes to explaining talk about ordinary objects, but without the additional ontology. (shrink)

It is shown that counterpart theory and the duplication account of intrinsicality —two key pieces of the Lewisian package—are incompatible. In particular, the duplication account yields the result that certain intuitively extrinsic modal properties are intrinsic. Along the way I consider a potentially more general worry concerning certain existential closures of internal relations. One conclusion is that, unless the Lewisian provides an adequate alternative to the duplication account, the reductive nature of their total theory is in jeopardy.

One of the primary burdens of the mereological nihilist is accounting for our ordinary intuitions about material objects. It certainly *seems* as if I am typing on a keyboard, which has particular keys and buttons as parts. But such intuitions are mistaken if mereological nihilism is right, leading to widespread error. So nihilists often propose paraphrases of our everyday utterances as compensation. Cotnoir aims to deliver a new paraphrase strategy on behalf of the nihilist: one that interprets parthood and composition (...) modally, and interprets (spatial) parts as (modal) counterparts. He advertises this view as the spatial analog of Sider’s stage-theoretic view. Unfortunately, I argue, it isn't. The spatial analog to the above views would be something like the following: individuals are region-bound spatial bits. Certain spatial claims about these objects may be true if the relevant spatial bits have the appropriate spatial counterparts. The table is flat iff the table (a spatial bit) has a spatial counterpart that is flat. That is, spatial *counterparts* make certain spatial claims true. Call this the *bit-theoretic* view. In this paper, I use the bit-theoretic view as a foil for highlighting certain aspects of Cotnoir’s proposal, as well as to show that the very ways in which Cotnoir’s view differs from the bit-theoretic view are ways in which it undermines advantages of nihilism. (shrink)

Recent pragmatic accounts of slurs argue that the offensiveness of slurs is generated by a speaker's free choice to use a slur opposed to a more appropriate and semantically equivalent neutral counterpart. I argue that the theoretical role of neutral counterparts on such views is overstated. I consider two recent pragmatic analyses, Bolinger (Noûs, 51, 2017, 439) and Nunberg (New work on speech acts, Oxford University Press, 2018), which rely heavily upon the optionality of slurs, namely, that a speaker (...) exercises a deliberate lexical choice to use a slur when they could have easily used a neutral counterpart instead. Against such views, I argue that across a range of different offensive uses of slurs, a speaker's choice to use a slur opposed to a neutral counterpart plays little to no role in accounting for why the slur generates offence. Such cases cast serious doubt upon the explanatory depth of these pragmatic analyses, and raise more general concerns for views which draw upon the relationship between a slur and its neutral counterpart. The main upshot is this: theorists should exercise caution in assuming that neutral counterparts play any fundamental or systemic role in explaining why slurs are offensive. (shrink)

We consider modal logics whose intermediate fragments lie between the logic of infinite problems [20] and the Medvedev logic of finite problems [15]. There is continuum of such logics [19]. We prove that none of them is finitely axiomatizable. The proof is based on methods from [12] and makes use of some graph-theoretic constructions (operations on coverings, and colourings).

Here I propose a coherent way of preserving the identity of material objects with the matter that constitutes them. The presentation is formal, and intended for RSL. An informal presentation is in preliminary draft! -/- Relative-sameness relations—such as being the same person as—are like David Lewis's "counterpart" relations in the following respects: (i) they may hold between objects that aren't identical (I propose), and (ii) there are a multiplicity of them, different ones of which may be variously invoked in (...) different contexts. They differ from counterpart relations, however, in that they are weak equivalence relations (transitive, symmetric and weakly reflexive). The likenesses to counterpart relations make them suitable for an analysis of de-re temporal and modal predications. The difference renders the resulting counterpart theory immune to standard criticisms of Lewis's Counterpart Theory (e.g., in Hazen 1979, and Fara and Williamson 2005). (shrink)

Suppose that reality consists of parallel universes of every variety imaginable. No path through space and time leads from one to another, and each universe is causally isolated from the rest. Some physicists believe a ‘multiverse’ hypothesis not terribly distant from this one simplifies quantum mechanics and provides an elegant explanation of why our universe has its particular laws. Suppose as science advances we come to accept the multiverse hypothesis, so construed.