Reasoning about situations we take to be impossible is useful for a variety of theoretical purposes. Furthermore, using a device of impossible worlds when reasoning about the impossible is useful in the same sorts of ways that the device of possible worlds is useful when reasoning about the possible. This paper discusses some of the uses of impossible worlds and argues that commitment to them can and should be had without great metaphysical or logical cost. The paper then provides an (...) account of reasoning with impossible worlds, by treating such reasoning as reasoning employing counterpossible conditionals, and provides a semantics for the proposed treatment. (shrink)

This article focuses on the main methods used in analytic metaphysics. It first considers five important sources of constraints on metaphysical theorizing: linguistic and conceptual analysis, consulting intuitions, employing the findings of science, respecting folk opinion, and applying theoretical virtues in metaphysical theory choice such as preferring simpler theories, or preferring more explanatory theories. It then examines the role of formal methods in metaphysics as well as the role of metaphysical communities, traditions, and the place of the history of metaphysics (...) in contemporary work. It also discusses the issue of whether metaphysics should be seen as an enterprise that will yield knowledge of metaphysical matters or whether it should have more modest epistemic goals. Finally, it explores the question of how much of metaphysics is a priori. (shrink)

Thought experiments are common where infinitely many entities acting in concert give rise to strange results. Some of these cases, however, can be generalized to yield almost omnipotent systems from limited materials. This paper discusses one of these cases, bringing out one aspect of what seems so troubling about "New Zeno" cases. -/- This paper is in memory of Josh Parsons.

This paper responds to commentaries by Kaiserman and Magidor, and Hawthorne. The case of the infinite clowns can teach us several things.

Zurvanism was an ancient variant of Zoroastrianism. According to Zurvanism, the great powers of good and evil, Ahura Mazda and Angra Mainyu, were the sons of a greater god Zurvan, associated with time. According to Eudemus of Rhodes, some Persian thinkers, presumably Zurvanists, took there to be three great principles underlying the world: light, darkness, and greatest of all time (or perhaps, according to Eudemus, space). This paper explores what metaphysics might underlie these doctrines, and what contemporary options we have (...) for making sense of a metaphysics where time is the ultimate principle. Among the options explored is the option that despite appearance many of the entities of the concrete world are identical to stretches of time, or are somehow aspects of stretches of time; that they include times as parts, or are included in times as parts; that they are somehow properties of time; or hylomorphic compounds of which time is the matter; that the world is somehow a mixture of time, light, and dark; or that somehow the ends or teloi of everyday objects and processes are to be found among good, evil, and time. (shrink)

Methodological naturalism arises as a topic in metaethics in two ways. One is the issue of whether we should be methodological naturalists when doing our moral theorising, and another is whether we should take a naturalistic approach to metaethics itself. Interestingly, these can come apart, and some naturalist programs in metaethics justify a non-scientific approach to our moral theorising. This paper discusses the range of approaches that fall under the general umbrella of methodological naturalism, and how naturalists view the role (...) of science in ethics and metaethics. It discusses how naturalism interacts with the use of intuitions, using conceptual analysis, and reflective equilibrium methods. Finally, it discusses some ways using scientific investigation can make distinctive contributions to ethics and metaethics. (shrink)

This paper makes a case that we should believe in the existence of worldly states of affairs.

A lot of philosophers engage in debates about what claims are “metaphysically necessary”, and a lot more assume with little argument that some classes of claims have the status of “metaphysical necessity”. I think we can usefully replace questions about metaphysical necessity with five other questions which each capture some of what people may have had in mind when talking about metaphysical necessity. This paper explains these five other questions, and then discusses the question “how much of metaphysics is metaphysically (...) necessary?”, and each of its five replacements. (shrink)

As is well known, Aristotelian natural philosophy, and many other systems of natural philosophy since, have relied heavily on teleology and teleological causation. Somehow, the purpose or end of an obj ect can be used to predict and explain what that object does: once you know that the end of an acorn is to become an oak, and a few things about what sorts of circumstances are conducive to the attainment of this end, you can predict a lot about the (...) sprouting of the acorn and the subsequent behaviour of the piece of vegetation that results. Once you know that a rock seeks to move towards the centre of the Earth, you gain some insight into why it falls when released, and why it deforms the carpet or foot that it lands on. Once you know that the rabbit seeks to preserve itself, you can predict it will run from the fox. And so on. There are at least three features of Aristotle’s teleology, and more generally of an Aristotelian frame of mind about teleology, that may induce suspicion. One is that an end can serve as a "cause": as well as the sort of causation we all recognize, efficient causation, there are other forms, one of which is teleological causation. However, this can look less odd if we think of causes as things that figure in "because" answers to "why" questions. Whether or not self-preservation, or the rabbit’s continued existence, or something similar, causes the rabbit to run, the reply "because it seeks to continue in existence" certainly makes sense as an answer, or part of an answer, to a question about why it ran from the fox. (At present we are only. (shrink)

It is almost universally believed that some infinite regresses are vicious, and also almost universally believed that some are benign. In this paper I argue that regresses can be vicious for several different sorts of reasons. Furthermore, I claim that some intuitively vicious regresses do not suffer from any of the particular aetiologies that guarantee viciousness to regresses, but are nevertheless so on the basis of considerations of parsimony. The difference between some apparently benign and some apparently vicious regresses, then, (...) turns out to be a matter of a more general assessment of costs and benefits, making viciousness of regresses in some cases less of a local matter than is usually thought. (shrink)

This paper examines both creepiness and the distinctive reaction had to creepiness, being “creeped out.” The paper defends a response-dependent account of creepiness in terms of this distinctive reaction, contrasting our preferred account to others that might be offered. The paper concludes with a discussion of the value of detecting creepiness.

Possible worlds have found many applications in contemporary philosophy: from theories of possibility and necessity, to accounts of conditionals, to theories of mental and linguistic content, to understanding supervenience relationships, to theories of properties and propositions, among many other applications. Almost as soon as possible worlds started to be used in formal theories in logic, philosophy of language, philosophy of mind, metaphysics, and elsewhere, theorists started to wonder whether impossible worlds should be postulated as well. In many applications, possible worlds (...) face limitations that can be dealt with through postulating impossible worlds as well. This chapter examines some of the uses of impossible worlds, and philosophical challenges theories of impossible worlds face. (shrink)

In the last few decades of the twentieth century there was a revolution in metaphysics: the intensional revolution. Many metaphysicians rejected the doctrine, associated with Quine and Davidson, that extensional analyses and theoretical resources were the only acceptable ones. Metaphysicians embraced tools like modal and counterfactual analyses, claims of modal and counterfactual dependence, and entities such as possible worlds and intensionally individuated properties and relations. The twenty-first century is seeing a hypterintensional revolution. Theoretical tools in common use carve more finely (...) than by necessary equivalence: two pieces of language can apply to the same entities across all possible worlds but not be equivalent; thoughts can be necessarily equivalent in truth value but not synonymous. This paper argues that hyperintensional resources are valuable in metaphysics outside theories of representation, and discusses some promising areas of hyperintensional metaphysics. (shrink)

This introduction to the roles infinity plays in metaphysics includes discussion of the nature of infinity itself; infinite space and time, both in extent and in divisibility; infinite regresses; and a list of some other topics in metaphysics where infinity plays a significant role.

An overview of hyperintensionality is provided. Hyperintensional languages have expressions with meanings that are more fine-grained than necessary equivalence. That is, the expressions may necessarily co-apply and yet be distinct in meaning. Adequately accounting for theories cast in hyperintensional languages is important in the philosophy of language; the philosophy of mind; metaphysics; and elsewhere. This entry presents a number of areas in which hyperintensionality is important; a range of approaches to theorising about hyperintensional matters; and a range of debates that (...) attention to hyperintensional constructions has generated. (shrink)

In this paper, I motivate the view that quantitative parsimony is a theoretical virtue: that is, we should be concerned not only to minimize the number of kinds of entities postulated by our theories (i. e. maximize qualitative parsimony), but we should also minimize the number of entities postulated which fall under those kinds. In order to motivate this view, I consider two cases from the history of science: the postulation of the neutrino and the proposal of Avogadro's hypothesis. I (...) also consider two issues concerning how a principle of quantitative parsimony should be framed. (shrink)

David Lewis's work is of fundamental importance in many areas of philosophical inquiry and there are few areas of Anglo-American philosophy where his impact has not been felt. Lewis's philosophy also has a rare unity: his views form a comprehensive philosophical system, answering a broad range of questions in metaphysics, philosophy of mind, philosophy of language, philosophy of action and many other areas. This breadth of Lewis's work, however, has meant that it is difficult to know where to start in (...) Lewis's work and a casual reader may often miss some of the illuminating connections between apparently quite disparate pieces of Lewis's work. This book aims to make this body of work more accessible to a general philosophical readership, while also providing a unified overview of the many contributions Lewis has made to contemporary Anglo-American philosophy. The book can be divided into four parts. The first part examines Lewis's metaphysical picture - one of the areas where he has had the greatest impact and also the framework for the rest of his theories. The second section discusses Lewis's important contributions in the philosophy of mind, language and meaning. The third part explores some of Lewis's work in decision theory, metaethics and applied ethics, areas where his work in not necessarily as widely appreciated, but in which he has done a range of work that is both accessible and important. The final section focuses on Lewis's distinctive philosophical method, perhaps one of his most significant legacies, which combines naturalism with "common-sense" theorizing. (shrink)

Philosophers have found postulating possible worlds to be very useful in a number of areas, including philosophy of language and mind, logic, and metaphysics. Impossible worlds are a natural extension to this use of possible worlds, and can help resolve a number of difficulties thrown up by possible‐worlds frameworks.

This encylopedia entry describes the "Canberra Plan" approach to conceptual analysis, a method closely related to the Ramsey-Carnap-Lewis approach to analysing the meaning of theoretical terms.

Liberals agree that free speech should be protected, where speech is understood broadly to include all forms of intentional communication, including actions and pictures, not merely the spoken or written word. A surprising view about free speech in some liberal and legal circles is that communications should be protected on free-speech grounds only if the communications are mentally mediated. By “mentally mediated communication” we mean speech which communicates its message in such a way that the message can be rationally evaluated (...) by hearers, and causes the hearers to believe it, when it does, through the mechanism of those hearers employing their rational capacity to judge that it is correct. The mental-mediation or persuasion principle, as it is sometimes called, has some important legal and public policy implications. It has been applied to argue that certain forms of expression, despite being forms of speech or expression, lack even a prima facie claim to protection on free speech grounds. -/- Our central aim is to show why the mental mediation principle is mistaken. Liberals should think that some speech which is not mentally mediated deserves protection for the very same reasons that speech which is mentally mediated is often thought to deserve protection. (shrink)

In this paper we introduce a distinct metaethical position, fictionalism about morality. We clarify and defend the position, showing that it is a way to save the 'moral phenomena' while agreeing that there is no genuine objective prescriptivity to be described by moral terms. In particular, we distinguish moral fictionalism from moral quasi-realism, and we show that fictionalism possesses the virtues of quasi-realism about morality, but avoids its vices.

This book discusses a range of important issues in current philosophical work on the nature of possible worlds. Areas investigated include the theories of the nature of possible worlds, general questions about metaphysical analysis and questions about the direction of dependence between what is necessary or possible and what could be.

This paper explores a special kind of loop of grounding: cosmic loops. A cosmic loop is a loop that intuitively requires us to go "around" the entire universe to come back to the original ground. After describing several kinds of cosmic loop scenarios, I will discuss what we can learn from these scenarios about constraints on grounding; the conceivability of cosmic loops; the possibility of cosmic loops; and the prospects for salvaging local reflexivity, asymmetry and transitivity of grounding in a (...) world containing a cosmic loop of ground. The considerations raised in this paper also bear on what we should think about relations that are meant to support grounding relations: in particular, revisions to theories of the part-whole relation are discussed. (shrink)

Impossible fictions are valuable evidence both for a theory of fiction and for theories of meaning, mind and epistemology. This article focuses on what we can learn about fiction from reflecting on impossible fictions. First, different kinds of impossible fiction are considered, and the question of how much fiction is impossible is addressed. What impossible fiction contributes to our understanding of "truth in fiction" and the logic of fiction will be examined. Finally, our understanding of unreliable narrators and unreliable narration (...) in fiction needs to accommodate stories that, on the face of it, cannot possibly be true. (shrink)

David Lewis’s arguments against magical ersatzism are notoriously puzzling. Untangling different strands in those arguments is useful for bringing out what he thought was wrong with not just one style of theory about possible worlds, but with much of the contemporary metaphysics of abstract objects. After setting out what I take Lewis’s arguments to be and how best to resist them, I consider the application of those arguments to general theories of properties and relations. The constraints Lewis motivates turn out (...) to yield an argument for concretism about possible individuals that is quite different from the better-known Lewisian arguments for that position. The discussion also touches on the puzzling question of whether things are the way they are because of the properties they have, or are the properties and relations the way they are because of the things that have them. (shrink)

Abstract There are at least eight good reasons practicing historians should concern themselves with counterfactual claims. Furthermore, four of these reasons do not even require that we are able to tell which historical counterfactuals are true and which are false. This paper defends the claim that these reasons to be concerned with counterfactuals are good ones, and discusses how each can contribute to the practice of history. Content Type Journal Article Pages 1-19 DOI 10.1007/s11098-011-9817-z Authors Daniel Nolan, School (...) of Philosophy, Australian National University, 0200 Canberra, Australia Journal Philosophical Studies Online ISSN 1573-0883 Print ISSN 0031-8116. (shrink)

A lot of good philosophy is done in the armchair, but is nevertheless a posteriori. This paper clarifies and then defends that claim. Among the a posteriori activities done in the armchair are assembling and evaluating commonplaces; formulating theoretical alternatives; and integrating well-known past a posteriori discoveries. The activity that receives the most discussion, however, is the application of theoretical virtues to choose philosophical theories: the paper argues that much of this is properly seen as a posteriori.

This paper discusses the principle of recombination for possible worlds. It argues that arguments against unrestricted recombination offered by Forrest and Armstrong and by David Lewis fail, but a related argument is a challenge, and recommends that we accept an unrestricted principle of recombination and the conclusion that possible worlds form a proper class.

One very popular kind of semantics for subjunctive conditionals is aclosest-worlds account along the lines of theories given by David Lewisand Robert Stalnaker. If we could give the same sort of semantics forindicative conditionals, we would have a more unified account of themeaning of ``if ... then ...'' statements, one with manyadvantages for explaining the behaviour of conditional sentences. Such atreatment of indicative conditionals, however, has faced a battery ofobjections. This paper outlines a closest-worlds account of indicativeconditionals that does better (...) than some of its cousins in explaining thebehaviour of such conditionals. The paper then discusses objectionsoffered by Dorothy Edgington and Frank Jackson to closest-worldsaccounts of indicative conditionals, and shows that these objections canbe met by the account outlined. (shrink)

The philosophy of necessity and possibility has flourished in the last half-century, but much less attention has been paid to the question of how we know what can be the case and what must be the case. Many friends of modal metaphysics and many enemies of modal metaphysics have agreed that while empirical discoveries can tell us what is the case, they cannot shed much light on what must be the case or on what non-actual possibilities there are. In this (...) paper, in contrast, I discuss and defend naturalistic approaches to discovering the facts about necessity and possibility. After some remarks about what methodological naturalism in philosophy might amount to, I argue that naturalistic method in modal investigations may not need to be particularly revisionary of much of what is currently being done in modal investigation. I then discuss a number of respects in which a naturalistic orientation in modal investigation may improve on our current epistemic situation. (shrink)

Curry's paradox for "if.. then.." concerns the paradoxical features of sentences of the form "If this very sentence is true, then 2+2=5". Standard inference principles lead us to the conclusion that such conditionals have true consequents: so, for example, 2+2=5 after all. There has been a lot of technical work done on formal options for blocking Curry paradoxes while only compromising a little on the various central principles of logic and meaning that are under threat. -/- Once we have a (...) sense of the technical options, though, a philosophical choice remains. When dealing with puzzles in the logic of conditionals, a natural place to turn is independently motivated semantic theories of the behaviour of "if... then...". This paper argues that the closest-worlds approach outlined in Nolan 1997 offers a philosophically satisfying reason to deny conditional proof and so block the paradoxical Curry reasoning, and can give the verdict that standard Curry conditionals are false, along with related "contraction conditionals". (shrink)

One increasingly popular technique in philosophy might be called the "platitudes analysis": a set of widely accepted claims about a given subject matter are collected, adjustments are made to the body of claims, and this is taken to specify a “role” for the phenomenon in question. (Perhaps the best-known example is analytic functionalism about mental states, where platitudes about belief, desire, intention etc. are together taken to give us a "role" for states to fill if they are to count as (...) mental states.) We then look to our best theory of the world to see where this role is satisfied, if at all. Unfortunately, the platitudes analysis, so characterised, does not seem to help when we are doing fundamental metaphysics—when we want to know what, at base, our world is like (and not merely where things like e.g. the mental would be found in an already-specified ontology). Nevertheless, I will argue that the platitudes analysis, properly understood, does have the materials to help us answer questions in fundamental metaphysics as well. I will explore three different ways it can do so. (shrink)

Creationism about fictional entities requires a principle connecting what fictions say exist with which fictional entities really exist. The most natural way of spelling out such a principle yields inconsistent verdicts about how many fictional entities are generated by certain inconsistent fictions. Avoiding inconsistency without compromising the attractions of creationism will not be easy.

What is the connection between valid inference and true conditionals? Many conditional logics require that when A is a logical consequence of B, "if B then A" is true. Taking counterlogical conditionals seriously leads to systems that permit counterexamples to that general rule. However, this leaves those of us who endorse non-trivial accounts of counterpossible conditionals to explain what the connection between conditionals and consequence is. The explanation of the connection also answers a common line of objection to non-trivial counterpossibles, (...) which is based on a transition from valid arguments to the corresponding conditionals. It also contributes to the wider project of illuminating the connections between contexts of utterance, on the one hand, and the truth-conditions of conditionals uttered in those contexts, on the other. (shrink)

There’s an argument around from so-called “linguistic theories of vagueness”, plus some relatively uncontroversial considerations, to powerful metaphysical conclusions. David Lewis employs this argument to support the mereological principle of unrestricted composition, and Theodore Sider employs a similar argument not just for unrestricted composition but also for the doctrine of temporal parts. This sort of argument could be generalised, to produce a lot of other less palatable metaphysical conclusions. However, arguments to Lewis’s and Sider’s conclusions on the basis of considerations (...) about vagueness are uncompelling, even if we accept the crucial premises about vagueness. And a good thing too, since the generalised form of the argument would prove far too much. (shrink)

Questions about necessity (or what has to be, or what cannot be otherwise) and possibility (or what can be, or what could be otherwise) are questions about modality. Fictionalism is an approach to theoretical matters in a given area which treats the claims in that area as being in some sense analogous to fictional claims: claims we do not literally accept at face value, but which we nevertheless think serve some useful function. However, despite its name, “Modal Fictionalism” in its (...) usual manifestations is not primarily fictionalism about claims of necessity and possibility, but rather a fictionalist approach to claims about possible worlds. (For instance, modal fictionalism is not normally fictionalist about the claim that “it is possible that there be a species of tail-less kangaroo”, but rather about the claim that “there is a possible world in which there is a species of tail-less kangaroo”.) The practice of taking possible worlds to be merely convenient fictions, or of treating talk about possible worlds as being useful without being literally correct, is quite common in philosophical circles. It is only recently, however, that philosophers have seriously examined the implications of taking possible worlds to be merely fictional objects, like Sherlock Holmes or a frictionless surface. (shrink)

Williamson proposes that a "suppositional procedure" is a central heuristic we use to evaluate the truth of conditionals, though he also argues that this method often leads us astray. An alternative approach to the link between supposition and conditionals is to claim that we are guided by our antecedent conditional judgements in our supposing, and in particular in our determining which things follow from an initial supposition. This alternative explanation of the close link between conditionals and supposition is developed and (...) compared to Williamson's proposal. (shrink)

The surviving sources on the Stoic theory of division reveal that the Stoics, particularly Chrysippus, believed that bodies, places and times were such that all of their parts themselves had proper parts. That is, bodies, places and times were composed of gunk. This realisation helps solve some long-standing puzzles about the Stoic theory of mixture and the Stoic attitude to the present.

A standing challenge in the theory of counterfactuals is to solve the “deviation problem”. Consider ordinary counterfactuals involving an antecedent concerning a difference from the actual course of events at a particular time, and a consequent concerning, at least in part, what happens at a later time. In the possible worlds framework, the problem is often put in terms of which are the relevant antecedent worlds. Desiderata for the solution include that the relevant antecedent worlds be governed by the actual (...) laws of nature with no miracles; that the past in those worlds before the antecedent time matches the actual past; that the account is compatible with determinism, and that many of our ordinary counterfactual judgments are correct, and would be correct even given determinism. Many theorists have compromised on one or more of these desiderata, but this paper presents an account employing impossible worlds that satisfies them all. (shrink)

Are there dispositions which not only do not manifest, but which could not manifest? We argue that there are dispositions to Ф in circumstances C where C is impossible, and some where Ф is impossible. Furthermore, postulating these dispositions does useful theoretical work. This paper describes a number of cases of dispositions had by objects even though those dispositions are not possibly manifest, and argues for the importance of these dispositions.

Modal Fictionalism, the theory that possible worlds do not literally exist but that our talk about them should be understood in the same way that we understand talk about fictional entities, is an increasingly popular approach to possible worlds. This paper will distinguish three versions of Modal Fictionalism, and will show that the third, a version endorsed by some of the most prominent Modal Fictionalists, faces at least three serious objections: that it makes modality too artificial, the modal fiction does (...) not have the representative resources it needs, and the approach has trouble accounting for propositions. (shrink)

Unified theories of de se attitudes and de dicto attitudes, along the lines of David Lewis’s proposal, face a problem. Whether or not they are adequate for representing beliefs, they can misrepresent the content of many of our desires, which rank possible outcomes in which the agent with the desire does not exist. These desires are shown to play a role in the rational explanation of action, and recognising them is important in our understanding of ourselves. Lewis’s account of attitudes (...) de dicto and de se is shown to be unsatisfactory, and the lessons learned are applied more broadly. (shrink)

This paper describes a plausible view of the nature of physical objects, their mereological connections to each other, and their relation to spacetime. As well as being parsimonious, the view provides a plausible context for denying all of the following: (1) A theory that objects endure through time (and do not have temporal parts, as normally conceived) cannot claim that material objects are identical to space-time regions they occupy. (2) At least one of the family of mereological connections (part-whole, overlap (...) etc.) is to be taken as primitive. (3) Claims entirely in the language of quantifiers and identity and mereology are not semantically vague. It is thus an example showing that the there are more options for the metaphysics of objects, spacetime and mereology than many metaphysicians ordinarily assume. (shrink)

I argue that Graham Priest's story 'Sylvan's Box' has an attractive consistent reading. Priest's hope that this story can be used as an example of a non-trivial 'essentially inconsistent' story is thus threatened. I then make some observations about the role 'Sylvan's Box' might play in a theory of unreliable narrators.

This paper argues that all of the standard theories about the divisions of space and time can benefit from, and may need to rely on, parsimony considerations. More specifically, whether spacetime is discrete, gunky or pointy, there are wildly unparsimonious rivals to standard accounts that need to be resisted by proponents of those accounts, and only parsimony considerations offer a natural way of doing that resisting. Furthermore, quantitative parsimony considerations appear to be needed in many of these cases.

The question of what truths are necessary in the broadest possible sense is a difficult one to answer, as is the question of what the limits are to what is possible. (Most people would see these two questions as different sides of the same coin, of course, since many think the question of what is possible is just the question of what is not necessarily ruled out). We have three general sorts of strategies for determining whether something is necessary (or (...) possible). We can identify it in a class that we were previously sure was a class of things that are necessary – we might show it is a theorem of a logical system that we have confidence in, or that the sentence appears to be true simply in virtue of the meanings of the words, or that it is a true statement involving names or about natural kinds of the “necessary a posteriori” sort discussed by Kripke and Putnam, and there are perhaps other classes of claims which we are prepared to accept are necessary if true.1 Likewise, we might establish the possibility of something occurring by reference to a class of well-established or uncontroversial possibilities: e.g. we are inclined to think that it is possible (in the broadest sense) for an event to occur in the future if one of the same kind has occurred in the past. (shrink)

Lewis is famous as a contemporary philosophical system-builder. The most obvious way his philosophy exhibited a system was in its content: Lewis’s metaphysics, for example, provided answers to many metaphysical puzzles in an integrated way, and there are illuminating connections to be drawn between his general metaphysical views and, for example, his various views about the mind and its place in nature.

the virtues which are desirable for scientific theories to possess. In this paper I discuss the several species of theoretical virtues called 'fertility', and argue in each case that the desirability of 'fertility' can be explicated in terms of other, more fundamental theoretical virtues.