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.

There is a long-standing disagreement among Branching-Time theorists. Even though they all believe that the branching representation accurately grasps the idea that the future, contrary to the past, is open, they argue whether this representation is compatible with the claim that one among many possible futures is distinguished—the single future that will come to be. This disagreement is paralleled in an argument about the bivalence of future contingents. The single, privileged future is often called the Thin Red Line. I reconstruct (...) the history of the arguments for and against this idea. Then, I propose my own version of the Thin Red Line theory which is immune to the major objections found in the literature. I argue that the semantic disagreement is grounded in distinct metaphysical presuppositions. My solution is expressed in a conceptual framework proposed by John MacFarlane, who distinguishes semantics from postsemantics. I extend his distinction and introduce a new notion of presemantics to elucidate my idea. (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)

The best arguments for possible worlds as states of affairs furnish us with equally good arguments for impossible worlds of the same sort. I argue for a theory of impossible worlds on which the impossible worlds correspond to maximal inconsistent classes of propositions. Three objections are rejected. In the final part of the paper, I present a menu of impossible worlds and explore some of their interesting formal properties.

Truthmakers, truth conditions, and analyses are closely related, but distinct in rather important ways. A failure to properly appreciate their differences has led to some confusion regarding the role that possible worlds ought to play with respect to modality. Those philosophers who initially proposed the existence of possible worlds were understood as providing an analysis of modality. More recently, many have interpreted them as providing modal truthmakers. But, possible worlds are only suited to serve as truth conditions for modal truths. (...) My goals are as follows: First, to dispel this confusion by detailing the differences between these three concepts. Second, to apply the lesson learned to the famous Humphrey objection against possible worlds. While this objection, if successful, does undermine Lewisian modal realism, it only partially undermines ersatzism, and leaves available a route by which ersatzers may avoid the objection altogether. (shrink)

Ontological pluralism is the doctrine that there are different ways or modes of being. In contemporary guise, it is the doctrine that a logically perspicuous description of reality will use multiple quantifiers which cannot be thought of as ranging over a single domain. Although thought defeated for some time, recent defenses have shown a number of arguments against the view unsound. However, another worry looms: that despite looking like an attractive alternative, ontological pluralism is really no different than its counterpart, (...) ontological monism. In this paper, after explaining the worry in detail, I argue that considerations dealing with the nature of the logic ontological pluralists ought to endorse, coupled with an attractive philosophical thesis about the relationship between logic and metaphysics, show this worry to be unfounded. (shrink)

This paper proposes a new reductive theory of modality, called the moodless theory of modality. This theory, and not modal realism, is the closest modal analogue of the tenseless theory of time. So, if the tenseless theory is true, and the temporality–modality analogy is good, it is the moodless theory that follows. I also argue that the moodless theory, considered on its own, is better than modal realism: arguments often thought to be decisive against modal realism are weak against it.

The article deals with the charge of irrelevance levelled against D. Lewis’s modal realism, notably known as a reductionist account of modality. The charge of irrelevance is apparently one of the most popular objections to modal realism though it often seems that the debate surrounding this charge is not very fruitful since in this context it is common to appeal, implicitly or explicitly, to different criteria for theory choice. As a result, the article deals with the problem in a slightly (...) different manner. The article addresses arguments aimed to show that, contrary to what is often stated, modal realism does not violate our pre-theoretical intuitions, as well as arguments aimed to respond to the charge of irrelevance without appealing to criteria for theory choice at all but providing different reasons instead. However, the aim of this article is to show that all these arguments are rather unconvincing. (shrink)

Assuming minimal fine-individuation--that there are some necessarily equivalent intensional objects (e.g. propositions) that are nonetheless distinct objects, on standard actualist frameworks, the answer to our title question is "No". First I specify a fully cognitively accessible, purely qualitative maximal consistent state of affairs (MCS). (That there is an MCS that is either fully graspable or purely qualitative is in itself quite contrary to conventional dogma.) Then I identify another MCS, one necessarily equivalent to the first. It follows that there could (...) have been more than one obtaining MCS. I then argue that there is more than one obtaining MCS. So there is nothing answering to "the actual world", and the set of worlds is not the set of MCSs. I explore various patch-ups. Finally, I compare the actualist and modal realist notions of worlds, and I argue that even if the realist were right about concrete world ensembles, our reflections indicate that necessary truth is not truth in all worlds anyway, which undercuts the rationale for the realist's program. (shrink)

In this paper, I argue for a particular conception of impossible worlds. Possible worlds, as traditionally understood, can be used in the analysis of propositions, the content of belief, the truth of counterfactuals, and so on. Yet possible worlds are not capable of differentiating propositions that are necessarily equivalent, making sense of the beliefs of agents who are not ideally rational, or giving truth values to counterfactuals with necessarily false antecedents. The addition of impossible worlds addresses these issues. The kinds (...) of impossible worlds capable of performing this task are not mysterious sui generis entities, but sets of structured propositions that are themselves constructed out of possible worlds and relations. I also respond to a worry that these impossible worlds are unable to represent claims about the shape of modal space itself. (shrink)

The aim of this paper is to relate the debate about the status of S4 and S5 as modal logics for metaphysical modality to the debate about the identity of propositions. The necessary truth of the characteristic axioms of S4 and S5 (when interpreted in terms of metaphysical modality) is derived from a view about the identity of propositions, the view that necessarily equivalent propositions are identical.

In this article I defend a form of classical possibilism with an actualist foundation. As a matter of fact, I believe that this position is more in keeping with the classical metaphysical tradition. According to this form of possibilism, I construe possible objects as possible non-existing objects of an existing producing power. Consequently, they are nothing vis-à -vis the modality of their own actual being, although they do exist with regard to the modality of the producing power’s being. The actualist (...) requirement prescribed by the Frege-Quinean criterion of the quantification domain is thus fulfilled; indeed, really possible objects are not actual objects, but their possibility is actual. (shrink)

_ The Nature of Contingency _: _ Quantum Physics as Modal Realism _, by AlastairWilson. Oxford: Oxford University Press, 2020. Pp. xi + 219.

It is difficult to wander far in contemporary metaphysics without bumping into talk of possible worlds. And reference to possible worlds is not confined to metaphysics. It can be found in contemporary epistemology and ethics, and has even made its way into linguistics and decision theory. What are those possible worlds, the entities to which theorists in these disciplines all appeal? This paper sets out and evaluates a leading contemporary theory of possible worlds, David Lewis's Modal Realism. I note two (...) competing ambitions for a theory of possible worlds: that it be reductive and user-friendly. I then outline Modal Realism and consider objections to the effect that it cannot satisfy these ambitions. I conclude that there is some reason to believe that Modal Realism is not reductive and overwhelming reason to believe that it is not user-friendly. (shrink)

In this dissertation, I develop an interpretation of Leibniz on modality and free will. I do so for two reasons: first, I am attempting to revitalize the notion that Leibniz is the predecessor of contemporary modal semantics; second, I am using Leibniz's philosophical system to motivate responses to contemporary philosophical issues in modality and free will. In Chapter One, I argue that Leibniz's basic principles are plausible theoretical tools that ought to be used by contemporary philosophers in developing their philosophical (...) systems. In Chapter Two, I develop Leibniz's views on the nature of individuals. I argue that possible individuals are actually of the same sort as individuals in the actual world--possible individuals and actual individuals are complete creatures that do not differ ontologically from each other. In Chapter Three, I argue that Leibniz's views on possible individuals make him a modal realist and compare his view with contemporary modal realism in order to support this claim. I also argue that counterparts avoid many of the problems set for them by contemporary thinkers; I end with the ways that Leibniz's view differs from contemporary accounts. In Chapter Four, I argue that Leibniz provides two different analyses of modality. The first is an infinite analysis account; the second is a possible worlds account. I argue that these two accounts are compatible and amount to two different descriptions of the same theory of modality. I address objections to each account in order to show this. In Chapter Five, I argue that Leibniz is a compatibilist about free will. Importantly, I argue that it is precisely Leibniz's account of modality that allows for this compatibilism, as against a necessitarian like Spinoza. I then use Leibniz's account to challenge contemporary libertarians about free will on the basis of the principle of sufficient reason. I also show how Leibniz can help semicompatibilism avoid a worry concerning necessitarianism. At the end of the day, I claim that adopting elements of Leibniz's system can help us better understand modality and the freedom of the will and can be an aid in furthering contemporary philosophical theory. (shrink)

Can two objects occupy completely the same space for all of their careers? Yes, according to the standard theory, as long as they fall under different sortals; this happens when an object constitutes another. Nevertheless, to avoid spatio-temporally coincident objects many hypothesis have been proposed, none of which has reached consensus. An unexplored way of answering that question in the negative is to claim that if one object constitutes another only the constituted exists. This commits one to intermittent existence, which (...) plausibility is argued for in here and its foundations surveyed. This notion is to be based on the sub-sistence of the constituting object when only the constituted exists, and on the super-sistence on the constituted object when this no longer exists but the constituting does under certain conditions. (shrink)