In this dissertation, I evaluate whether conceivability can be regarded as an epistemic guide to possibility.

Wie ist es wohl, eine Fledermaus zu sein? Wäre ein rein physikalisches Duplikat von mir nur ein empfindungsloser Zombie? Muss man sich seinem Schicksal ergeben, wenn man sich unfreiwillig als lebensnotwendige Blutwaschanlage eines weltberühmten Violinisten wieder findet? Kann man sich wünschen, der König von China zu sein? Bin ich vielleicht nur ein Gehirn in einem Tank mit Nährflüssigkeit, das die Welt von einer Computersimulation vorgegaukelt bekommt? Worauf beziehen sich die Menschen auf der Zwillingserde mit ihrem Wort 'Wasser', wenn es bei (...) ihnen gar kein H2O gibt? -/- Diese und weitere seltsame Fragen sind das tägliche Brot vieler professioneller Philosophen. Die abstrusen Umstände, die dabei geschildert werden, nennt man "Gedankenexperimente". -/- Was soll die Erörterung dieser Szenarien, die sich so weit von unserem alltäglichen Leben, z.T. außerhalb der Grenzen unserer Wirklichkeit abspielen? Welche Rolle spielen diese "Gedankenexperimente" in der philosophischen Methodologie? Ist diese Rolle überhaupt berechtigt? -/- Das vorliegende Buch gibt Antworten auf diese Fragen. Es stellt sich heraus, dass diese seltsamen Gedankenexperimente nicht nur berechtigte, sondern überaus wichtige Instrumente philosophischen Forschens darstellen. (shrink)

I lay out the framework for my theory of sensory imagination in “Imagining as a guide to possibility.” Sensory imagining involves mental imagery , and crucially, in describing the content of imagining, I distinguish between qualitative content and assigned content. Qualitative content derives from the mental image itself; for visual imaginings, it is what is “pictured.” For example, visually imagine the Philadelphia Eagles defeating the Pittsburgh Steelers to win their first Super Bowl. You picture the greenness of the field and (...) the football’s brown oblong shape. Some of what you imagine isn’t explicitly pictured, however. That it is Sunday, that it is the Super Bowl: these facts are assigned. (shrink)

I focus on a key argument for global external world scepticism resting on the underdetermination thesis: the argument according to which we cannot know any proposition about our physical environment because sense evidence for it equally justifies some sceptical alternative (e.g. the Cartesian demon conjecture). I contend that the underdetermination argument can go through only if the controversial thesis that conceivability is per se a source of evidence for metaphysical possibility is true. I also suggest a reason to doubt that (...) conceivability is per se a source of evidence for metaphysical possibility, and thus to doubt the underdetermination argument. (shrink)

: It is generally accepted that skeptical scenarios must be possible to raise legitimate skeptical doubt. I argue that if the possibility in question is supposed to be genuine metaphysical possibility, the skeptic's reasoning does not straightforwardly succeed. I first motivate the metaphysical possibility requirement on skeptical scenarios : it's a plausible position that several authors accept and that a family of prominent views—sensitivity, safety, relevant alternatives—are committed to. I argue that plausible constraints in modal epistemology show that justification for (...) believing that certain global skeptical scenarios are metaphysically possible rests on some justified beliefs about the external world, and that this undermines the skeptical argument. While there may still be local skeptical challenges, skeptics cannot appeal to the metaphysical possibility of skeptical scenarios to generate global external world skepticism. (shrink)

Some hold that if we can imagine God creating a world in which a particular proposition (p) is true, then we can conclude that p is possible. I argue that such appeals to God can’t provide us with a guide to possibility. For either God’s powers aren’t co-extensive with the possible or they are. And if they are, these appeals either beg the question or court a version of Euthyphro’s Dilemma. Some may argue that such appeals were only intended to (...) prompt us to think broadly about the modal claim at issue. I argue instead that these appeals must be understood as more than mere prompts. For it is these appeals that would, if successful, render the conceivability principle viable. (shrink)

David Chalmers supports his contention that there is a possible world populated by our zombie twins by arguing for the assumption that conceivability entails possibility. But, I argue, the modal epistemology he sets forth, ‘modal rationalism,’ ignores the problem of incompleteness and relies on an idealized notion of conceivability. As a consequence, this epistemology can’t justify our quotidian judgments of possibility, let alone those judgments that concern the mind/body connection. Working from the analogy that the imagination is to the possible (...) as perception is to the actual, I set forth a competing epistemology, ‘modal empiricism.’ This epistemology survives the incompleteness objection and allows some of our everyday modal judgments to be justified. But this epistemology can’t justify the claim that Zombie World is possible, which leaves Chalmers’s property dualism without the support it needs. (shrink)

Kripkean examples of necessary a posteriori truths clearly provide a challenge to attempts to connect facts about possibility to facts about what people can conceive. The paper argues for a general principle connecting imaginability under certain special circumstances to possibility; it also discusses some of the issues raised by the resulting position.

The counterintuitive implications of law necessitarianism pose a far more serious threat than its proponents recognize. Law necessitarians are committed to scientific essentialism, the thesis that there are metaphysically necessary truths which can be known only a posteriori. The most frequently cited arguments for this position rely on modal intuitions. Rejection of intuition thus threatens to undermine it. I consider ways in which law necessitarians might try to defend scientific essentialism without invoking intuition. I then consider ways in which law (...) necessitarians who accept the general reliability of intuition might try to explain away the intuitions which conflict with their theory. (shrink)

Traditionally, imagination has been considered to be a primitive mental state type (or group of types), irreducible to other mental state types. In particular, it has been thought to be distinct from other mental states such as belief, perception, and memory, among others. Recently, however, the category of imagination has come under attack, with challenges emerging from a multitude of different directions. Some philosophers have argued that we should not recognize belief and imagination as distinct states but rather on a (...) continuum, whereas other philosophers have argued something similar with respect to belief and memory. And some philosophers have suggested that we can reduce imagination to other mental states, whether mental imagery, belief, supposition, or some combination. In this paper, I address some of these challenges in an attempt to show we need to maintain imagination as a distinct – and indeed, robust – category in our taxonomy of mind. (shrink)

Gettier cases are used to show that having a justified true belief is not sufficient for knowledge. They are cases in which an epistemic agent has a belief that is both justified and true, but intuitively cannot be taken to count as knowledge. Modal epistemology is the field of philosophy that tackles questions regarding the sources of our knowledge of modalities (possibility and necessity) and what offers justification for beliefs about what is possible or necessary. Part of the tradition in (...) modal epistemology is to consider conceivability as a guide to metaphysical possibility. As such, if an agent can conceive that P, then the agent is justified to believe that P is metaphysically possible. In this paper I will discuss the possibility of constructing Gettier cases for a tripartite, conceivability-based, definition of modal knowledge. (shrink)

In this paper, I will make the case that an associative account of predication in Hume seems to allow for impossible predicative conceptions—that is, the conceiving of impossible states of affairs involving subjects instantiating properties or qualities—which violate his Conceivability Principle. The natural response is to argue that such conceptions are not clear and distinct, but substantive worries are raised about a number of attempted solutions along these lines. This poses a predicament for Hume scholars: either we must modify or (...) abandon the Conceivability Principle, or reject an associative account of predication, or concede that Hume faces a difficulty he cannot solve. (shrink)

It has long been recognized that we have a great deal of freedom to imagine what we choose. This paper explores a thesis—what we call “intentionalism (about the imagination)”—that provides a way of making this evident (if vague) truism precise. According to intentionalism, the contents of your imaginings are simply determined by whatever contents you intend to imagine. Thus, for example, when you visualize a building and intend it to be of King’s College rather than a replica of the college (...) you have imagined the former rather than the latter because you intended to imagine King’s College. This is so even if the visual image you conjure up equally resembles either. This paper proposes two kinds of counterexamples to intentionalism and discusses their significance. In particular, it sketches a positive account of how many sensory imaginings get to be about what they are about, which explains how the causal history of our mental imagery can prevent us from succeeding in imagining what we intended. (shrink)

This paper investigates a capacity I call actuality-oriented imagining, by which we use sensory imagination in a way that's directed at representing the actual world. I argue that this kind of imagining is distinct from other, similar mental states in virtue of its distinctive content determination and success conditions. Actuality-oriented imagining is thus a distinctive cognitive capacity in its own right. Thinking about this capacity reveals that we should resist an intuitive tendency to think of the imagination’s primary function or (...) default mode as representing the non-actual or the fictional. Instead, the imagination is a cognitive faculty that often puts us in touch with the way things are in reality. (shrink)

Some people might be tempted by modal ontological arguments from the possibility that God exists to the conclusion that God in fact exists. They might also be tempted to support the claim that possibly God exists by appealing to the conceivability of God’s existence. In this chapter, I introduce three constraints on an adequate theory of philosophical conceivability. I then consider and develop both imagination-based accounts of conceivability and conceptual coherence-based accounts of conceivability. Finally, I return to the modal ontological (...) argument and consider whether the premise that possibly God exists can be supported by some conceiving. (shrink)

Philosophers have always taken an interest not only in what is actually the case, but in what is necessarily the case and what could possibly be the case. These are questions of modality. Epistemologists of modality enquire into how we can know what is necessary and what is possible. This dissertation concerns the meta-epistemology of modality. It engages with the rules that govern construction and evaluation of theories in the epistemology of modality, by using modal empiricism – a form of (...) modal epistemology – as a running example. In particular, I investigate the assumption that it is important to be able to meet the integration challenge. Meeting the integration challenge is a source of serious difficulty for many approaches, but modal empiricism is supposed to do well in this respect. But I argue that once we have a better grasp of what the integration challenge is, it is not obvious that it presents no problem for modal empiricism. Moreover, even if modal empiricism could be said to be in a relatively good position with respect to integration, it comes at the cost of a forced choice between far-reaching partial modal scepticism and non-uniformism about the epistemology of modality. Non-uniformism is the view that more than one modal epistemology will be correct. While non-uniformism might not in itself be unpalatable, it must be defined and defended in a way which squares with the modal empiricist’s other commitment. I explore two ways of doing so, both involving a revised idea of the integration challenge and its role for the epistemology of modality. One involves a bifurcation of the integration challenge, and the other a restriction of the integration challenge’s relevance. Both ways are interesting, but neither is, as it turns out, a walk in the park. (shrink)

We often ascribe possibility to the scenes that are displayed by mental or nonmental sensory images. The paper presents a novel argument for thinking that we are prima facie justified in ascribing metaphysical possibility to what is displayed by suitable visual images, and it argues that many of our imagery‐based ascriptions of metaphysical possibility are therefore prima facie justified. Some potential objections to the arguments are discussed, and some potential extensions of them, to cover nonvisual forms of imagery and nonmetaphysical (...) forms of possibility, are endorsed. (shrink)

The dissertation is in the format of a collection of several academic texts, composed of a two-part presentation and three papers on the topic of conceivability and the epistemology of modality. The presentation is composed of, first, a general introduction to conceivability theses and objections and, second, a discussion of two cases. Following the presentation, Asger provides three papers. The first paper, Pretense and Conceivability: A reply to Roca-Royes, presents a problem and a dilemma for Roca-Royes’ Non-Standard Dilemma for conceivability-based (...) epistemologies of de re modality in which she concludes that conceivability cannot be the whole story of our de re modal knowledge. The second paper, Conceivability Externalized, proposes an externalist conceivability-based epistemology of possibility inspired by Stalnaker. The third paper, Inconceivability as a Guide to Impossibility, considers inconceivability as an epistemic guide to impossibility, aiming to explore and add support to the underexplored thesis that one can justify beliefs about the impossibility of P on the basis of the inconceivability of P. (shrink)

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. One purpose of this paper is to argue that the notion is not fruitfully explicated in terms of the imagination. The most natural way of presenting a notion of conceivability qua imaginability is open to cogent criticism. In order to avoid such criticism, an advocate of the modal insightfulness of the imagination (...) must broaden the idea of what it is to be imaginable. I argue that this required broadening renders the imagination idle . Consequently, I distinguish two different accounts of the evidential basis of modal knowledge and present a more general argument that concludes that the very notion of conceivability should be eschewed in modal epistemology. (shrink)

According to what Hume termed an ‘establish’d maxim’, nothing absolutely impossible is imaginable. It has recently been claimed against this that given the ubiquity of stipulative imagination, where one imagines a proposition simply by adding it as a stipulation about the imagined situation, it seems that we can imagine any impossibility whatsoever, even plain contradictions: all we need to do is add them as stipulations. The aim of this article is both to defend Hume’s maxim against this objection and – (...) hopefully interestingly – to do so while granting the assumption that adding something as a stipulation is a valid way of imagining something. To this end, appeal is made to a particular development of a second Humeanism, according to which necessary truths are analytic in the sense that their truth follows from their meaning. Their analyticity, it is then argued, secures that they are true in all imagined situations. Therefore, even if it is right that a valid way of imagining something is to add it as a stipulation, attempting to stipulate that, say, some imaginary bachelor is also married is bound to fail: you can’t stipulate it to be the case because it really isn’t the case. (shrink)

Many philosophers since Hume have accepted that imagining/conceiving a scenario is our prime guide to knowing its possibility. Stephen Yablo provided a more systematic criterion: one is justified in judging that p is possible if one can imagine a world which one takes to verify p. I defend a version of Yablo’s criterion against van Inwagen’s moderate modal scepticism. Van Inwagen’s key argument is that we cannot satisfy Yablo’s criterion because we are not in a position to spell out far-fetched (...) possible scenarios in relevant detail. Van Inwagen’s argument can be applied to the use of conceivability for everyday possibility claims, leaving us with the spectre of pervasive modal scepticism. In order to answer the sceptical threat, I combine van Inwagen’s main example with general considerations about the nature of metaphysical modality to motivate a version of Yablo’s criterion and show that it does not lead to scepticism. One structural condition of p being metaphysically possible is that it coheres with a complete reality. This condition gives rise to Yablo’s criterion. However, for the criterion to be of any avail, we have to disregard details we are not in a position to specify. To account for our practice of doing so, I use Yablo’s distinction between imagining a world as determinate and imagining it determinately. I present a condition when we may simply disregard details as determinate. The condition results from integrating analogical reasoning into the conceivability test. (shrink)

I compare two prominent approaches to knowledge of metaphysical modality, the more traditional approach via conceiving viz. imagining a scenario and a more recent approach via counterfactual reasoning. In particular, Timothy Williamson has claimed that the proper context for a modal exercise of imagination is a counterfactual supposition. I critically assess this claim, arguing that a purely conceivability/imaginability-based approach has a key advantage compared to a counterfactual-based one. It can take on board Williamson’s insights about the structure of modal imagination (...) while avoiding aspects of counterfactual reasoning which are orthogonal to figuring out metaphysical modality. In assessing whether A is possible, we creatively devise test scenarios, psychologically and metaphysically apt A-scenarios, which manifest the relevant metaphysical requirements and test them for their compatibility with A. In this exercise, imagination is subject to implicit constraints as Williamson has it, but it is not bound to drawing consequences from minimally altering actuality such as to make room for A. (shrink)

Dogmatists often exploit the skeptical argument based on the brains-in-a-vat scenario as a test case for their epistemological enterprises. I argue that this ‘argument’ does not deserve our attention, so it should not be used as a test case. I first show that the possibilities of empirical knowledge and of skeptical scenarios are inconsistent. If so, the BIV-skeptic must make the case for preferring such scenarios over the possibility of empirical knowledge. The central argument of my paper is that the (...) BIV-skeptic can neither rely on any selection principle for this purpose, nor can she claim that she needs no such principle. Then I will show that we can even dispense with the Inconsistency Thesis: if the skeptic wishes, she may allow for the possibility of empirical knowledge. The essay concludes with considering the morals of the above argument for the dogmatist endeavor. (shrink)

The notion of conceivability has traditionally been regarded as crucial to an account of modal knowledge. Despite its importance to modal epistemology, there is no received explication of conceivability. In recent discussions, some have attempted to explicate the notion in terms of epistemic possibility. There are, however, two notions of epistemic possibility, a more familiar one and a novel one. I argue that these two notions are independent of one another. Both are irrelevant to an account of modal knowledge on (...) the predominant view of modal reality. Only the novel notion is relevant and apt on the competing view of modal reality; but this latter view is problematic in light of compelling counterexamples. Insufficient care regarding the independent notions of epistemic possibility can lead to two problems: a gross problem of conflation and a more subtle problem of obscuring a crucial fact of modal epistemology. Either problem needlessly hampers efforts to develop an adequate account of modal knowledge. I conclude that the familiar notion of epistemic possibility should be eschewed in the context of modal epistemology. (shrink)

Moral properties would supervene upon non-moral properties and be conceptually autonomous. That, according to Simon Blackburn, would make them if not impossible at least mysterious, and evidence for them best explained by theorists who say they are not real. In fact moral properties would not challenge in ways Blackburn has contended. There is, however, something new that can be gathered from his arguments. What would the supervenience of moral properties and their conceptual autonomy from at least total non-moral properties entail (...) not only for Intuitionists, who ‘knew this all along,’ but for all moral realists, that there are synthetic necessary moral principles? There is for all moral realists the problem of explaining ‘what in the world’ makes possible these necessities. (shrink)

In part because “imagination” is a slippery notion, its exact role in the production of scientific knowledge remains unclear. There is, however, one often explicit and deliberate use of imagination by scientists that can be (and has been) studied intensively by epistemologists and historians of science: thought experiments. The main goal of this article is to document the varieties of thought experimentation, not so much in terms of the different sciences in which they occur but rather in terms of the (...) different functions they fulfil. I argue that thought experimentation (and hence imagination) plays a role not only in theory choice but in singular causal analysis and scientific discovery as well. I pinpoint, moreover, some of the rules governing the use of thought experiments in theory choice and in singular causal analysis, that is, some of the criteria they should meet in order to fulfil those functions successfully. (shrink)

ABSTRACT: Recently the discussion surrounding the conceivability thesis has been less about the link between conceivability and possibility per se and more about the requirements of a successful physicalist program. But before entering this debate it is necessary to consider whether conceivability provides us with even prima facie justification for our modal beliefs. I argue that two methods of conceiving—imagining that p and telling a story about p—can provide us with such justification, but only if certain requirements are met. To (...) make these arguments, I consider those of Paul Tidman, whose position I use as a foil.RÉSUMÉ: Dernièrement, le débat sur la thèse de la concevabilité a peu porté sur le lien entre la concevabilité et la possibilité per se et s’est plutôt intéressé aux conditions requises pour la réalisation du programme physicaliste. Toutefois, avant d’entrer dans ce débat, il est nécessaire de se demander si la concevabilité offre une justification même élémentaire des croyances modales. Je soutiens que deux méthodesde concevoir — imaginer que p et raconter une histoire à propos de p — sont susceptibles de nous fournir cette justification, mais seulement dans la limite de certaines conditions. À l’appui de mon propos, j’envisage la position de Paul Tidman, qui me sert de repoussoir. (shrink)

Islamic theological contradictions are metaphysical contradictions as opposed to logical and semantic ones. I shall demonstrate that if these theological contradictions are tolerable on the theoretical account of metaphysical dialetheism, then logical space, despite being the space of all possibilities, does not accommodate them in virtue of Chalmers’s ‘deep epistemic possibility’. To resolve this issue, I offer a recalibration of the modal concept of possibility. Doing so would redraw a demarcation between what is possible and what is not. Consequently, we (...) can expand logical space, so it is properly inclusive of all possibilities, including metaphysical dialetheism. Expanding logical space in this way would repudiate Chalmers’s ‘deep epistemic possibility’ and make room for Islamic theological contradictions. (shrink)

A particular family of imagination-based epistemologies of possibility promises to provide an account that overcomes problems raised by Kripkean a posteriori impossibilities. That is, they maintain that imagination plays a significant role in the epistemology of possibility. They claim that imagination consists of both linguistic and qualitative content, where the linguistic content is independently verified not to give rise to any impossibilities in the epistemically significant uses of imagination. However, I will argue that these accounts fail to provide a satisfactory (...) basis for an epistemology of possibility as they fall victim to, what I call, the problem of modally bad company. In particular, I will argue that there is a deep methodological problem that these accounts face: to deliver the significant epistemology of possibility that they promise, they have to rely on problematic prior knowledge of necessities. (shrink)

I outline Hume’s views about conceivability evidence. Then I critically scrutinise two threats to conceivability-based modal epistemology. Both arise from Hume’s criticism of claims to knowing necessary causal relationships: Firstly, a sceptical stance towards causal necessity may carry over to necessity claims in general. Secondly, since – according to a sceptical realist reading – Hume grants the eventuality of causal powers grounded in essential features of objects, conceivability-based claims to comprehensive metaphysical possibilities seem endangered. I argue that although normal conceivability-based (...) claims are defeasible, they are prima facie vindicated. Humes Ansichten über Vorstellbarkeit als Indikator für Möglichkeit werden zusammengefasst. Dann werden zwei Schwierigkeiten für eine auf Vorstellbarkeit basierende modale Erkenntnistheorie aufgeworfen. Beide entstehen aus Humes Kritik an Ansprüchen aufWissen notwendiger kausaler Beziehungen. Erstens könnte sich eine skeptische Haltung gegenüber kausaler Notwendigkeit auf Ansprüche, notwendige Zusammenhänge zu kennen, im allgemeinen auswirken. Zweitens gesteht Hume gemäß einem skeptischen Realismus die Eventualität kausaler Kräfte zu, die in wesentlichen Eigenschaften der Dinge gründen. Dies scheint unvereinbar mit der auf Vorstellbarkeit gestützten Behauptung umfassender metaphysischer Möglichkeiten. Dagegen soll gezeigt werden, dass auf Vorstellbarkeit gestützte modale Wissensansprüche zwar widerlegbar, aber prima facie gerechtfertigt sind. (shrink)