Previous research has suggested that an effective strategy for debiasing judgments is to have participants "consider the opposite." The present research proposes that considering any plausible alternative outcome for an event, not just the opposite outcome, leads participants to simulate multiple alternatives, resulting in debiased judgments. Three experiments tested this hypothesis using an explanation task paradigm. Participants in all studies were asked to explain either 1 hypothetical outcome (single explanation conditions) or 2 hypothetical outcomes (multiple explanation conditions) to an event; (...) after the explanation task, participants made likelihood judgments. The results of Studies 1 and 2 indicated that debiasing occurred in all multiple explanation conditions, including those that did not involve the opposite outcome. Furthermore, the findings indicated that debiased judgments resulted from participants' spontaneous consideration of additional alternatives in making their likelihood judgments. The results of Study 3 also identified the perceived plausibility of the explained alternative as an important moderating variable in debiasing. (shrink)

The standard by which we apply decision-making for those unable to do so for themselves is an important practical ethical issue with substantial implications for the treatment and welfare of such individuals. The approach to proxy or surrogate decision-making based upon substituted judgement is often seen as the ideal standard to aim for but suffers from a need to provide a clear account of how to determine the validity of the proxy's judgements. Proponents have responded to this demand by providing (...) the truth-conditions for the substituted judgement in terms of counterfactual reasoning using a possible worlds semantics. In this paper, I show how these underpinnings fail to support the substituted judgement approach as a reasonable standard for decision-making. Firstly, I show how this counterfactual element has been poorly interpreted. I then explain how various accounts have failed to reflect problems and limitations associated with providing an interpretation of their truth-conditions using counterfactuals. Finally, I argue that, even when we attend to the initial problems of providing a counterfactual analysis, it still deeply problematic as a means of determining the validity of substituted judgements for two main reasons. Firstly, making determinate judgements as to the truth-value of these judgements will often not be possible and, secondly, there is a strong requirement when interpreting many counterfactual claims to charitably accede to their being true. I conclude that substituted judgements, as interpreted through counterfactual reasoning and possible worlds semantics, do not therefore provide an adequate standard for surrogate decision-making. (shrink)

Incompetent patients need to have someone else make decisions on their behalf. According to the Substituted Judgment Standard the surrogate decision maker ought to make the decision that the patient would have made, had he or she been competent. Objections have been raised against this traditional construal of the standard on the grounds that it involves flawed counterfactual reasoning, and amendments have been suggested within the framework of possible worlds semantics. The paper shows that while this approach may (...) circumvent the alleged problem, the way it has so far been elaborated reflects insufficient understanding of the moral underpinnings of the idea of substituted judgment. Proper recognition of these moral underpinnings has potentially far-reaching implications for our normative assumptions about accuracy and objectivity in surrogate decision making. (shrink)

Possibilities haunt history. The force of our explanations of events turns on the alternative possibilities these explanations suggest. It is these possible worlds which give us our understanding; and in human affairs we decide them by practical rather than theoretical judgement. In his widely acclaimed account of the role of counterfactuals in explanation, Geoffrey Hawthorn deploys extended examples from history and modern times to defend his argument. His conclusions cast doubt on existing assumptions about the nature and place of (...) theory, and indeed of the possibility of knowledge itself, in the human sciences. (shrink)

The numerous difficulties facing the traditional Humean regularity approach to the problem of causation have been discussed in the literature at great length. In view of the current interest in possible worlds semantics, it is not surprising that the only serious alternative treatment of causation presently available, the counterfactual approach, has been explored recently as a means of circumventing the apparently unresolvable difficulties facing regularity causal theories. It is the purpose of this paper to suggest that such a strategy (...) holds little promise. Specifically, I will argue that, in addition to giving rise to problems directly analogous to those facing regularity accounts, the counterfactual approach fails in principle to reflect important properties of causal relations as we understand them intuitively. David Lewis's possible worlds account, the most comprehensive counterfactual theory to date, is further criticized for implicit problems with natural lawhood even more serious than those typically raised for regularity accounts, for additional inadequacies in its analysis of causal relations, and for its failure to satisfy basic empiricist epistemological standards. (shrink)

The standard semantics for counterfactuals ensures that any counterfactual with a true antecedent and true consequent is itself true. There have been many recent attempts to amend the standard semantics to avoid this result. I show that these proposals invalidate a number of further principles of the standard logic of counterfactuals. The case against the automatic truth of counterfactuals with true components does not extend to these further principles, however, so it is not clear that rejecting the latter should be (...) a consequence of rejecting the former. Instead I consider how one might defuse putative counterexamples to the truth of true-true counterfactuals. (shrink)

Conditional structures lie at the heart of the sciences, humanities, and everyday reasoning. It is hence not surprising that conditional logics – logics specifically designed to account for natural language conditionals – are an active and interdisciplinary area. The present book gives a formal and a philosophical account of indicative and counterfactual conditionals in terms of Chellas-Segerberg semantics. For that purpose a range of topics are discussed such as Bennett’s arguments against truth value based semantics for indicative conditionals.

In this paper I argue that there is a difficulty for Fine's exact semantics for counterfactuals. The difficulty undermines Fine's reasons for preferring exact semantics to possible worlds semantics.

The basic idea of counterfactual theories of causation is that the meaning of causal claims can be explained in terms of counterfactual conditionals of the form “If A had not occurred, C would not have occurred”. While counterfactual analyses have been given of type-causal concepts, most counterfactual analyses have focused on singular causal or token-causal claims of the form “event c caused event e”. Analyses of token-causation have become popular in the last thirty years, especially since the development in the (...) 1970's of possible world semantics for counterfactuals. The best known counterfactual analysis of causation is David Lewis's (1973b) theory. However, intense discussion over thirty years has cast doubt on the adequacy of any simple analysis of singular causation in terms of counterfactuals. Recent years have seen a proliferation of different refinements of the basic idea to achieve a closer match with commonsense judgements about causation. (shrink)

This article links recent work on assimilative and contrastive counterfactual thinking with research on the impact of accountability on judgment and choice. Relative to participants who felt accountable solely for bottom-line performance outcomes, participants who were accountable for their decision-making process (a) had more pronounced differential reactions to clearly winning versus (winning but) nearly losing and to clearly losing versus (losing but) nearly winning; (b) were less satisfied with the quality of their decisions when they nearly lost and more (...) satisfied with the quality of their decisions when they nearly won; and (c) invested less money into investments that nearly failed and more money into investments that nearly succeeded. This pattern is consistent with the hypothesis that process accountability amplified assimilative counterfactual thinking, whereas outcome accountability attenuated it. The evidence underscores the power of contextual features of the decision-making environment to shape key cognitive and affective consequences of upward and downward counterfactual comparisons. (shrink)

I present a puzzle concerning counterfactual reasoning and argue that it should be solved by giving up the principle of substitution for logical equivalents.

The epistemology of modality is gradually coming to play a central role in general discussions about modality. This paper is a contribution in this direction, in particular I draw a comparison between Lewis’s Modal realism and Timothy Williamson’s recent account of modality in terms of counterfactual thinking. In order to have criteria of evaluation, I also formulate four requirements which are supposed to be met by any theory of modality to be epistemologically adequate.

People frequently entertain counterfactual thoughts, or mental simulations about alternative ways the world could have been. But the perceived plausibility of those counterfactual thoughts varies widely. The current article interfaces research in the philosophy and semantics of counterfactual statements with the psychology of mental simulations, and it explores the role of perceived similarity in judgments of counterfactual plausibility. We report results from seven studies (N = 6405) jointly supporting three interconnected claims. First, the perceived plausibility of a counterfactual event is (...) predicted by the perceived similarity between the possible world in which the imagined situation is thought to occur and the actual world. Second, when people attend to differences between imagined possible worlds and the actual world, they think of the imagined possible worlds as less similar to the actual world and tend to judge counterfactuals in such worlds as less plausible. Lastly, when people attend to what is identical between imagined possible worlds and the actual world, they think of the imagined possible worlds as more similar to the actual world and tend to judge counterfactuals in such worlds as more plausible. We discuss these results in light of philosophical, semantic, and psychological theories of counterfactual thinking. (shrink)

Encouraging people to consider multiple alternatives appears to be a useful debiasing technique for reducing many biases (explanation, hindsight, and overconfidence), if the generation of alternatives is experienced as easy. The present research tests whether these alternative generation procedures induce a mental simulation mind-set (cf. Galinsky & Moskowitz, 2000), such that debiasing in one domain transfers to debias judgments in unrelated domains. The results indeed demonstrated that easy alternative generation tasks not only debiased judgments in the same domain but also (...) generalized to debias judgments in unrelated domains, provided that participants were low in the need for structure. The alternative generation tasks (even when they were easy to perform) showed no evidence of activating a mental simulation mind-set in individuals high in need for structure, as these individuals displayed no transfer effects. Implications of the results for understanding the role of the need for structure, ease of generation, and mental simulation mind-set activation for debiasing are discussed. (shrink)

The epistemology of modality is gradually coming to play a central role in general discussions about modality. This paper is a contribution in this direction, in particular I draw a comparison between Lewis’s Modal realism and Timothy Williamson’s recent account of modality in terms of counterfactual thinking. In order to have criteria of evaluation, I also formulate four requirements which are supposed to be met by any theory of modality to be epistemologically adequate.

This article is a selective review of David Lewis's Counterfactuals, a challenging, provocative, absorbingly interesting attempt to analyze statements of the form “If it were the case that P, then it would be the case that Q.” I shall follow Lewis in calling these “counterfactuals,” and shall nearly follow him in abbreviating them to the form P→Q.Chapter 1, which is nearly a third of the whole, gives the analysis and proves that it endows counterfactuals with some properties which they evidently (...) do have. Chapter 2 presents some “alternative formulations” of the analysis—a logical jeu d'esprit which I shall not discuss except for the section about “cotenability.”. (shrink)

This book uses the formal semantics of counterfactual conditionals to analyze the problem of non-locality in quantum mechanics. Counterfactual conditionals enter the analysis of quantum entangled systems in that they enable us to precisely formulate the locality condition that purports to exclude the existence of causal interactions between spatially separated parts of a system. They also make it possible to speak consistently about alternative measuring settings, and to explicate what is meant by quantum property attributions. The book develops the (...) possible-world semantics of quantum counterfactuals using David Lewis's famous approach as a starting point but modifying it significantly in order to achieve compatibility with the demands of the special theory of relativity as well as quantum mechanics. There have been several attempts to use counterfactuals semantics to strengthen Bell's theorem and its cognates such as the GHZ and Hardy theorems. These are critically evaluated in the book. Finally, a counterfactual reconstruction of the EPR argument and Bell's theorem is proposed that sheds a new light on their philosophical consequences regarding the relations between realism and local causation. (shrink)

Stephen Barker argues that a possible worlds semantics for the counterfactual conditional of the sort proposed by Stalnaker and Lewis cannot accommodate certain examples in which determinism is true and a counterfactual Q > R is false, but where, for some P, the compound counterfactual P > (Q > R) is true. I argue that the completeness theorem for Lewis’s system VC of counterfactual logic shows that Stalnaker–Lewis semantics does accommodate Barker’s example, and I argue that its doing so (...) should be understood as showing that the example is an exception to Lewis’s Time’s Arrow requirements. (shrink)

Philosophers have long analyzed the truth-condition of counterfactual conditionals in terms of the possible-worlds semantics advanced by Lewis [13] and Stalnaker [23]. In this paper, I argue that, from the perspective of philosophical semantics, the causal modeling semantics proposed by Pearl [17] and others (e.g., Briggs [3]) is more plausible than the Lewis-Stalnaker possible-worlds semantics. I offer two reasons. First, the possible-worlds semantics has suffered from a specific type of counterexamples. While the causal modeling semantics can handle (...) such examples with ease, the only way for the possible-worlds semantics to do so seems to cost it its distinctive status as a philosophical semantics. Second, the causal modeling semantics, but not the possible-worlds semantics, has the resources enough for accounting for both forward-tracking and backtracking counterfactual conditionals. (shrink)

The standard view about counterfactuals is that a counterfactual (A > C) is true if and only if the A-worlds most similar to the actual world @ are C-worlds. I argue that the worlds conception of counterfactuals is wrong. I assume that counterfactuals have non-trivial truth-values under physical determinism. I show that the possible-worlds approach cannot explain many embeddings of the form (P > (Q > R)), which intuitively are perfectly assertable, and which must be true if the contingent (...) falsity of (Q > R) is to be explained. If (P > (Q > R)) has a backtracking reading then the contingent facts that (Q > R) needs to be true in the closest P-worlds are absent. If (P > (Q > R)) has a forwardtracking reading, then the laws required by (Q > R) to be true in the closest P-worlds will be absent, because they are violated in those worlds. Solutions like lossy laws or denial of embedding won't work. The only approach to counterfactuals that explains the embedding is a pragmatic metalinguistic approach in which the whole idea that counterfactuals are about a modal reality, be it abstract or concrete, is given up. (shrink)

McCall (1984) offered a semantics of counterfactual conditionals based on “real possible worlds” that avoids using the vague notion of similarity between possible worlds. I will propose an interpretation of McCall’s counterfactuals in a formal framework based on Baltag-Moss-Solecki events and protocols. Moreover, I will argue that using this interpretation one can avoid an objection raised by Otte (1987).

The canonical version of possible worlds semantics for story prefixes is due to David Lewis. This paper reassesses Lewis's theory and draws attention to some novel problems for his account.

As the opening line of Dickens' classic novel suggests, it is very often the case that people can imagine both better and worse alternatives to their present reality. Although Dickens was writing about events that occurred over two centuries ago, it remains just as true today that we clearly live in neither the best nor the worst of possible worlds. For instance, we can wish for the amelioration of present difficulties in the Middle East yet still take comfort in (...) the fact that the threat of nuclear war has been greatly reduced since the end of the Cold War. On a more mundane level, it is easy for us to imagine how various aspects of our lives, such as our jobs, marriages, or physical fitness, could be both better and worse. Undoubtedly due to the pervasiveness and intrinsically fascinating qualities of this phenomenon of imagining alternatives to reality, there has been a veritable explosion of research in recent years on what have been termed mental simulation and counterfactual thinking processes. This chapter speculates upon and provides evidence for the antecedents and consequences of two types of counterfactuals: upward (it could have been better) and downward (it could have been worse). The importance of studying the antecedents and consequences of counterfactual direction lie in the differential structures, emotions, intentions, inferences, and behavioral consequences of upward versus downward counterfactual thinking. (shrink)

Possible world semantics considers not only what an expression actually refers to but also what it might have referred to in counterfactual circumstances. This has proven exceptionally useful both inside and outside philosophy. The way this is achieved is by using intensions. An intension of an expression is a function that assigns to each possible world the reference of the expression in that world. However, the specific intension of terms has been subject to frequent disputes. How is one (...) to determine the intension of a term? Carnap has shown how the intension of a term depends on the type of that term. Two-dimensional semantics has shown how intensions also depend on the actual state of affairs. I will show how, in addition, intensions are no less dependent on metaphysical criteria of identity. Furthermore, I will reveal how these three factors interact to fix the exact intension of a term. In other words, I propose an outline of the overall mechanism by which intensions are being fixed. (shrink)

Among philosophers working on modality, there is a common assumption that there is a strong connection between temporal possibility and counterfactual possibility. For example, Sydney Shoemaker 1998, 69 70) writes: It seems to me a general feature of our thought about possibility that how we think that something could have differed from how it in fact is [is] closely related to how we think that the way something is at one time could differ from the way that same thing is (...) at a different time. In possible worlds jargon, the ways one and the same thing of a given sort can differ across worlds correspond to the ways one and the same thing of that sort can differ at different times in the same world. Could I have been a plumber or an accountant instead of a philosopher? The answer seems to be yes -- and this goes with the fact that we acknowledge the possibility of a scenario in which someone who was exactly as I was at some point in my life undergoes a series of changes resulting in his eventually being a plumber or an accountant. In a footnote, he acknowledges that this connection between counterfactual and temporal possibility needs to be qualified in response to an objection by Randy Clarke: «The property of being the child of someone who has visited Paris is not one that one can have and then lose; but it is one that one can have in the actual world and not have in some other possible world.» (1998, 75n.9) Therefore, he restricts the inference from temporal to counterfactual possibility and vice versa to «non historical properties.». (shrink)

Counterfactuals have become an important area of interdisciplinary interest, especially in logic, philosophy of language, epistemology, metaphysics, psychology, decision theory, and even artificial intelligence. In this study, we propose a new form of analysis for counterfactuals: analysis by algorithmic complexity. Inspired by Lewis-Stalnaker's Possible Worlds Semantics, the proposed method allows for a new interpretation of the debate between David Lewis and Robert Stalnaker regarding the Limit and Singularity assumptions. Besides other results, we offer a new way to answer the (...) problems raised by Goodman and Quine regarding vagueness, context-dependence, and the non- monotonicity of counterfactuals. Engaging in a dialogue with literature, this study will seek to bring new insights and tools to this debate. We hope our method of analysis can make counterfactuals more understandable in an intuitively plausible way, and a philosophically justifiable manner, aligned with the way we usually think about counterfactual propositions and our imaginative reasoning. (shrink)

Saul Kripke did more than anyone else to bring possible worlds into the contemporary philosophical discourse, first with his more formal work on the model theory for modal logic in the 1960s, and then with his more philosophical lectures on reference and modality, delivered in January 1970, that used the possible worlds apparatus informally to clarify the relations between semantic issues about names and metaphysical issues about individuals and kinds. Possible worlds semantics have been widely applied since (...) then, both in philosophy and in other fields such as linguistic semantics and pragmatics, theoretical computer science, and game theory. Kripke’s work, along with that of David Lewis, stimulated an ongoing debate about the nature and metaphysical status of possible worlds. Kripke himself has had little to say about the issues raised in this debate, in print, beyond what he said in Naming and Necessity and in brief remarks in a preface to a later edition of the lectures, published in 1980. But there is a clear view of the nature of possible worlds, and of the status of an explanation of modality in terms of possible worlds, implicit in the lectures and the preface. -/- The central focus of the post–Naming and Necessity debate about possible worlds has been a contrast between David Lewis’s modal realism and various versions of actualism. On this general issue, it is clear enough where Kripke stands: His criticisms of what he describes as the “other countries” picture of possible worlds are an explicit rejection of Lewis’s realism about possible worlds. But the rejection of modal realism raises a range of further questions: What exactly are possible worlds (or possible states of the world, which Kripke suggests would be less misleading terminology)? What contribution do they make to the explanation of modal discourse, and of the distinctive facts that modal discourse is used to state? Does the slogan “necessity is truth in all possible worlds” provide, or point to, a reductive analysis of necessity? Are possible worlds, in some sense, prior to modal operators and modal auxiliaries? If not, in what sense are they explanatory? How are possible worlds, or counterfactual situations, specified? How do they contribute to our understanding of specific meta- physical questions about the relations between particular individuals and their qualitative characteristics, the kinds to which they belong, and the matter of which they are constituted? How are we to understand the possible existence of individuals that do not actually exist? What is the status of the domains of individuals in merely possible worlds? -/- My aim in this chapter is to spell out the views about some of these foundational questions that are expressed or at least implicit in Kripke’s lectures. In Section 2, I discuss the general contrast between modal realism and actualism and questions about the kind of explanation that possible worlds provide for modal discourse and modal facts. In Section 3, I look at Kripke’s views about how possible worlds are specified, in particular at the role of individuals in specifying possible worlds. In Section 4, I consider the problems about merely possible individuals. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Journal of the History of Philosophy 38.4 (2000) 479-502 [Access article in PDF] Possible Worlds in the Tahâfut al-Falâsifa Al-Ghazâlî on Creation and Contingency Taneli Kukkonen University of Helsinki 1. This article is the second half in an inquiry into the debate between al-Ghazâlî (1058-1111) and Averroes (1126-1198) on the metaphysical basis of modalities. The first article focused on Averroes' exposition of the Arabic Aristotelian position on the (...) eternity of the world and the modalities, as found in the Tahâfut al-tahâfut, the "Incoherence of the Incoherence [of the Philosophers]" from ca. 1180.1 In this paper I propose to sketch the outlines to a very different conception suggested by al-Ghazâlî in the Tahâfut al-falâsifa (1095) and quoted verbatim and commented upon by Averroes in the Tahâfut al-tahâfut.2 In contrast to the naturalistic model of modalities propounded by [End Page 479] Averroes, al-Ghazâlî develops an interpretation of possibility in which conceivability and co-assertability are central. In several key respects al-Ghazâlî's approach mirrors that of John Duns Scotus in the fourteenth century: it makes possible, for instance, a distinction between conceptual and natural possibilities in a manner reminiscent of later Latin medieval theory, and, reflecting this, a distinction between the (non-temporal) moments of conception and causation in the divine mind. The parallels between al-Ghazâlî's and Augustine's basic conceptions, meanwhile, highlight the theological motives lying at the heart of the new thinking.As in the previous article, the dialectical form of Averroes' later Tahâfut al-tahâfut is used for critical insight. Averroes' criticism of al-Ghazâlî's modal theoretical innovations gives rise to an important question about the lengths to which al-Ghazâlî's proposals could be taken. The issue is to an extent unresolveable; one would do well to note why. Whereas Averroes' formulations in the Tahâfut al-tahâfut are made readily understandable against the backdrop of his Aristotelian commentaries and wider systematic teaching, it is less easy to determine how far al-Ghazâlî is willing to develop his own ideas. The materials given in the Tahâfut al-falâsifa leave the impression of being inconclusive and open-ended—perhaps deliberately so—and the ambiguities are mirrored in al-Ghazâlî's other texts.3Taken as they stand, al-Ghazâlî's formulations retain a substantial Avicennian residue, for better or for worse. This makes for a curious mixture of old and new in his overall scheme, a feature which Averroes can exploit by criticizing al-Ghazâlî from a strict Aristotelian viewpoint (just as he criticized Avicenna), while all the time maintaining that his adversary's proposals do not add up to a coherent and full-bodied alternative to that venerable tradition. But Averroes' criticisms do not touch on the way al-Ghazâlî's suggestions, vague as they may be, do represent a genuine breakthrough. Al-Ghazâlî's interpretation of the modal terms bypasses the connection traditionally made between true possibility and temporal instantiation. This allows for a freer handling of counterfactual possibilities, an important feature in any refiguring of the limits of possibility. 2. Al-Ghazâlî's innovations have their root in the idea of God freely choosing (arbitrating) between alternatives equal to him. This simple kernel of an idea, seated in the kalâm conception of possibility, allows for a recognition of the genuineness of synchronic alternatives: a seemingly small shift, but all-important [End Page 480] to the ensuing debate. Al-Ghazâlî has defended the notion of God's genuine choice earlier,4 but in refuting "the third proof of the philosophers for the world's eternity," he begins to make systematic use of the notion of possibility. A brief recapitulation of the philosophers' argument will serve to recall the reasoning from which al-Ghazâlî takes his cue. The philosophers, in al-Ghazâlî's words, had... (shrink)

_ Source: _Page Count 19 The theory of possible worlds has been minimally employed in the field of theory and philosophy of history, even though it has found a place as a tool in other areas of philosophy. Discussion has mostly focused on arguments concerning counterfactual history’s status as either useful or harmful. The theory of possible worlds can, however be used also to analyze historical writing. The concept of textual possible worlds offers an interesting framework to (...) work with for analyzing a historical text’s characteristics and features. However, one of the challenges is that the literary theory’s notion of possible worlds is that they are metaphorical in nature. This in itself is not problematic but while discussing about history, which arguably deals with the real world, the terminology can become muddled. The latest attempt to combine the literary and philosophical notions of possible worlds and apply it to historiography came from Lubomír Doležel in his _Possible Worlds of Fiction and History: The Postmodern Stage_. I offer some criticism to his usage of possible worlds to separate history and fiction, and argue that when historiography is under discussion a more philosophical notion of possible worlds should be prioritized over the metaphorical interpretation of possible worlds. (shrink)

As part of an ongoing study of causal models in the history of science, a counterfactual scenario in the history of modern astronomy is explored with the aid of computer simulations. After the definition of “linking advance”, a possible world involving technological antecedence is described, branching out in 1510, in which the telescope is invented 70 years before its actual construction, at the time in which Fracastoro actually built the first prototelescope. By using the principle of the closest (...) class='Hi'>possible world, we estimate that in this scenario the discovery of the elliptical orbit of Mars would by anticipated by only 28 years. The second part of the paper involves an estimate of the probability of the previous scenario, guided by the principle that the actual world is the mean and using computer simulations to create possible worlds in which the time spans between advances is varied according to a gamma distribution function. Taking into account the importance of the use of the diaphragm for the invention of the telescope, the probability that the telescope were built by 1538 for a branching time at 1510 is found to be smaller than 1%. The work shows that one of the important features of computational simulations in philosophy of science is to serve as a consistency check for the intuitions and speculations of the philosopher. (shrink)

Ever since Saul Kripke and others developed a semantic interpretation for modal logic, 'possible worlds' has been a much debated issue in contemporary metaphysics. To propose the idea of a possible world that differs in some way from our actual world - for example a world where the grass is red or where no people exist - can help us to analyse and understand a wide range of philosophical concepts, such as counterfactuals, properties, modality, and of course, the (...) notions of possibility and necessity. This book examines the ways in which possible worlds have been used as a framework for considering problems in logic and argument analysis. The book begins with a non-technical introduction to the basic ideas of modal logic in terms of Kripke's possible worlds and then moves on to a discussion of 'possible for' and 'possible that'. The central chapters examine questions of meaning, epistemic possibility, temporal logic, metaphysics, and impossibility. Girle also investigates how the idea of a possible world can be put to use in different areas of philosophy, the problems it may raise, and the benefits that can be gained. (shrink)

Ever since Saul Kripke and others developed a semantic interpretation for modal logic, 'possible worlds' has been a much debated issue in contemporary metaphysics. To propose the idea of a possible world that differs in some way from our actual world - for example a world where the grass is red or where no people exist - can help us to analyse and understand a wide range of philosophical concepts, such as counterfactuals, properties, modality, and of course, the (...) notions of possibility and necessity. This book examines the ways in which possible worlds have been used as a framework for considering problems in logic and argument analysis. The book begins with a non-technical introduction to the basic ideas of modal logic in terms of Kripke's possible worlds and then moves on to a discussion of 'possible for' and 'possible that'. The central chapters examine questions of meaning, epistemic possibility, temporal logic, metaphysics, and impossibility. Girle also investigates how the idea of a possible world can be put to use in different areas of philosophy, the problems it may raise, and the benefits that can be gained. (shrink)

[Robert Stalnaker] Saul Kripke made a convincing case that there are necessary truths that are knowable only a posteriori as well as contingent truths that are knowable a priori. A number of philosophers have used a two-dimensional model semantic apparatus to represent and clarify the phenomena that Kripke pointed to. According to this analysis, statements have truth-conditions in two different ways depending on whether one considers a possible world 'as actual' or 'as counterfactual' in determining the truth-value of the (...) statement relative to that possible world. There are no necessary a posteriori or contingent a priori propositions: rather, contingent a priori and necessary a posteriori statements are statements that are necessary when evaluated one way, and contingent when evaluated the other way. This paper distinguishes two ways that the two-dimensional framework can be interpreted, and argues that one of them gives the better account of what it means to 'consider a world as actual', but that it provides no support for any notion of purely conceptual a priori truth. /// [Thomas Baldwin] Two-dimensional possible world semantic theory suggests that Kripke's examples of the necessary a posteriori and contingent a priori should be handled by interpreting names as implicitly indexical. Like Stalnaker, I reject this account of names and accept that Kripke's examples have to be accommodated within a metasemantic theory. But whereas Stalnaker maintains that a metasemantic approach undermines the conception of a priori truth, I argue that it offers the opportunity to develop a conception of the a priori aspect of stipulations, conceived as linguistic performances. The resulting position accommodates Kripke's examples in a way which is both intrinsically plausible and fits with Kripke's actual discussion of them. (shrink)

This paper is predicated on the idea that some modal operators are better understood as quantificational expressions over worlds that determine not only first-order facts but modal facts also. In what follows, we will present a framework in which these two types of facts are brought closer together. Structural features will be located in the worlds themselves. This result will be achieved by decomposing worlds into parts, where some of these parts will have “modal import” in the sense that they (...) will determine structure on other worldly parts. The main upshot of this will be a clearer grasp of the interaction between modal notions. (shrink)

A prominent contemporary anti-skeptical strategy, most famously articulated by Keith DeRose, aims to cage the skeptic′s doubts by contextualizing subjunctive conditional accounts of knowledge through a conversational rule of sensitivity. This strategy, I argue, courts charges of circularity by selectively invoking heavy counterfactual machinery. The reason: such invocation threatens to utilize a metric for modal comparison that is implicitly informed by judgments of epistemic sameness. This gives us reason to fear that said modal metric is selectively cherry-picked in advance to (...) support the very anti-skeptical conclusion for which the contextualist longs. (shrink)

Why do humans imagine alternatives to reality? The experiments conducted by Byrne explain the mental mechanisms we use when we do just this – that is, imagine one, or more, alternative reality. But why do we do this? The general reason is to give ourselves an explanation of the world, to tell stories; at times to console ourselves, and at times to despair. A good story is not only based on a description of what happened, but also hints at, or (...) explains, what might have happened. Depending on our aim, we construct different kinds of counterfactuals. In all cases, however, we are faced with constraints. These constraints are specific to a given domain of beliefs and use of counterfactuals. (shrink)

[Robert Stalnaker] Saul Kripke made a convincing case that there are necessary truths that are knowable only a posteriori as well as contingent truths that are knowable a priori. A number of philosophers have used a two-dimensional model semantic apparatus to represent and clarify the phenomena that Kripke pointed to. According to this analysis, statements have truth-conditions in two different ways depending on whether one considers a possible world 'as actual' or 'as counterfactual' in determining the truth-value of the (...) statement relative to that possible world. There are no necessary a posteriori or contingent a priori propositions: rather, contingent a priori and necessary a posteriori statements are statements that are necessary when evaluated one way, and contingent when evaluated the other way. This paper distinguishes two ways that the two-dimensional framework can be interpreted, and argues that one of them gives the better account of what it means to 'consider a world as actual', but that it provides no support for any notion of purely conceptual a priori truth. /// [Thomas Baldwin] Two-dimensional possible world semantic theory suggests that Kripke's examples of the necessary a posteriori and contingent a priori should be handled by interpreting names as implicitly indexical. Like Stalnaker, I reject this account of names and accept that Kripke's examples have to be accommodated within a metasemantic theory. But whereas Stalnaker maintains that a metasemantic approach undermines the conception of a priori truth, I argue that it offers the opportunity to develop a conception of the a priori aspect of stipulations, conceived as linguistic performances. The resulting position accommodates Kripke's examples in a way which is both intrinsically plausible and fits with Kripke's actual discussion of them. (shrink)

This entry provides a brief exposition and formal reconstruction of the argument for possible worlds in David Lewis's _Counterfactuals_.