Imagination and Possibility

© 2007 The Philosophical Forum, Inc.

IMAGINATION AND POSSIBILITY1 REBECCA HANRAHAN

Something has gone missing in the current debate over modal epistemology. In the rush to find a means of justifying those modal beliefs that would tell us something about consciousness, philosophers have missed the bigger picture. Without a doubt, zombies and the systematically color deprived are central to the philosophy of mind. But our almost exclusive focus on such characters has obstructed both the general project of arriving at a modal epistemology and, in particular, the role the imagination can play in such an epistemology. Both David Chalmers and Ernest Sosa, for example, consider our ability to imagine as one of the methods by which we can conceive of a proposition.2 But both philosophers quickly dismiss the imagination as providing us with a guide to possibility by noting that this method is limited. There are propositions, they argue, whose modal status is in question but whose truth cannot be imagined. But this dismissal is too hasty. Consider its implications. To reject the imagination because it is limited is to concede that this method provides us with a guide to some possibilities, specifically, those possibilities that concern states of affairs that can be perceived. Sosa even admits this, claiming that the imagination may “perhaps provide a distinctive source of justification,” though he does not explain how it might do so.3 But if this method of conceiving can potentially provide us with a guide to even some possibilities, isn’t it worth figuring out if and how it 1

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I would like to think the referees at this journal, as well as Keith Simmons, William Lycan, and Samuel Mitchell for their invaluable comments on earlier drafts of this article. I would especially like to thank a man known only as “ThunderStick.” See E. Sosa, “Modal and Other A Priori Epistemology: How Can We Know What Is Possible and What’s Impossible?” The Southern Journal of Philosophy XXXVIII (Suppl.) (2000): 1–16, at 2; and D. Chalmers, “Does Conceivability Entail Possibility?” Conceivability and Possibility, ed. T. Gendler and J. Hawthorne (Oxford: Clarendon Press, 2002) 145–200, at 150–51. Sosa (2000): 2.

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does this? Beyond the fact that these questions are interesting in their own right, answering them will let us see what is involved in employing any method of conceiving as a guide to possibility. In addition, by answering these questions, we will discover the extent to which the imagination is limited as a guide to possibility. Can it tell us about the modal status of all those propositions that concern states of affairs that can be perceived, or just some subset of this larger set? Clearly, it will serve us well to define this limit. For in the best case scenario, where other methods of conceiving do in fact provide us with a guide to possibility, defining this limit will tell us how much more work remains for these other methods. In the worst case scenario, where it turns out that our only guide to possibility is our imagination, we will have arrived at the boundary of our modal knowledge.4 Finally, it at least seems as if in some everyday situations the imagination is relevant when it comes to deciding what is possible.5 For example, when trying to discover whether it is metaphysically (not merely epistemically) possible for there to be a bear in my backyard, one of the things I in fact do is imagine a bear there. Given this, it is worth considering whether we can make sense of this justificatory practice. Thus, in what follows, I want to develop the beginnings of a modal epistemology that depends in part on our imagination.6 I shall argue that via our imagination, we will be able to justify a certain set of our modal beliefs. Nevertheless, this still might not seem like a worthwhile project. I want to develop a modal epistemology which will enable me to justifiably claim that it is possible for a bear to be in my backyard. Don’t I already know that this is possible? Do I really need an epistemology to tell me that? Aren’t I working very hard to prove very little? 4

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Even in this worst case scenario, the actual will also be a guide to the possible. But such a guide is not informative. It does not tell us anything more about the world than what we learned when we determined that the relevant proposition was true. For this reason, I leave off discussion of this method of justifying our modal beliefs. Even Tidman, who seemingly rejects conceivability as providing us with any kind of possibility, admits this point. “Typically, it must be granted, when we consider whether a state of affairs is possible, we do attempt to imagine what it would be like for that state of affairs to obtain. And for some impossible states of affairs, such as round squares, or objects that are both red and green all over, we find ourselves unable to imagine them. If these things were possible it seems we should be able to conceive of them and our inability to do so provides us with evidence that they are not possible.” See P. Tidman, “Conceivability as a Test for Possibility,” American Philosophical Quarterly 31 (1994): 297–309, at 307. As I said above, it seems as if we do at times employ our sensory imagination as a guide to possibility. And this is reason enough to consider whether this method of conceiving can justify some of our modal beliefs. That said, I am not offering up here a bit of modal psychology. I am not trying to describe how we actually go about justifying our modal beliefs. Instead, I am presenting an argument that shows how the images we call forth could play a part in justifying such beliefs.

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Even if I concede that I have knowledge of this possibility, I do not yet know how I came to have this knowledge. I do not know how my belief in this possibility is justified. Given the lengths to which epistemologists have gone to show that we are justified in believing other claims we all take for granted, it would be absurd to insist that our modal beliefs, or any subset of them, are so secure as to need no justification.7 At this point, though, I must offer two caveats. First, the modal epistemology that I will be arguing for here will not provide us with proof of possibility. It will only allow us to justify some of our modal beliefs. Note that as it is commonly understood, justification is defeasible—it does not entail the truth of the proposition justified. Second, while my modal epistemology will depend on the imagination, the images I call forth will not alone provide the necessary justification. As we shall see, the method of conceiving that will provide us with a guide to possibility will be composed of both sensory and conceptual elements.8 In order to present my epistemology, I will explore an analogy. Some philosophers (e.g., S. Yablo and W. D. Hart) have claimed that the imagination is to the possible as perception is to the actual.9 Specifically, they claim that just as what we perceive tells us about what is actual, what we imagine tells us about what is possible. It is commonly thought that our perceptions tell us about what is actual because the actual world causes these perceptions in us. But if our imagination tells us about what is possible, it cannot be because there are some possibilia out there causing us to imagine what we do. For even if we adopt Lewis’s view and take possible worlds to be concrete entities, we do not interact with such worlds. Lewis’s worlds are in their own space and time and hence are causally inaccessible

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Consider, for example, Chisholm’s attempt to establish that the proposition “I seem to have a headache” can be directly evident to him. Or consider G. E. Moore who famously proved that he has two hands. See R. Chisholm, “The Directly Evident,” Justification and Knowledge, ed. G. Pappas (Dordrecht: Reidel, 1979) 115–27, and G. E. Moore, “Proof of an External World,” Philosophical Papers (London: Allen and Unwin, 1959) 127–50. Cf. Colin McGinn’s notion of “cognitive imagining,” that is, imagining that a given proposition obtains. Such imagining “may or may not be accompanied by imagery proper; in any case, it is a conceptual act, with all the marks thereof ” (128). The method I have in mind is thus, in McGinn’s terms, cognitive imagining accompanied by sensory images. As will become clear, my treatment of the imagination is consistent with McGinn’s. See Colin McGinn, Mindsight (Cambridge, MA: Harvard UP, 2004). See W. D. Hart, Engines of the Soul (Cambridge: Cambridge UP, 1988) 10, and S. Yablo, “Is Conceivability a Guide to Possibility?” Philosophy and Phenomenological Research 53 (1993): 1–42, at 7. In addition, Peacocke seems to be alluding to this analogy when he claims that our inference from what is imaginable to what is possible is based on two claims. “What can be experienced is possible and [. . .] experiences that can be imagined are possible.” See C. Peacocke, “Imagination, Experience, and Possibility: A Berkeleian View Defended,” Essays on Berkeley, ed. J. Foster and H. Robinson (Oxford: Oxford UP, 1985) 19–35, at 31.

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to us.10 Thus, a metaphysical/causal interpretation of this analogy does not work. Given this, when drawing out this analogy, we need not bother considering the conditions under which a perception is veridical. Instead, we would do better to consider the conditions under which we are justified in accepting a perception as veridical. We need, in other words, to give an epistemological rather than a metaphysical interpretation of this analogy. Such an interpretation will allow us to see how our imagination can in some cases play a role in justifying our belief that a proposition is possibly true. The plan for this article is as follows. To begin, I shall describe a way in which we can conceive of a proposition (p) that combines two methods of conceiving: imagining that p and telling a story about p. Next, I will discuss one theory as to how our perceptual beliefs are justified: explanationism. In this discussion, I will highlight the role storytelling has in justifying even these beliefs. Then, by employing what we have learned about justification from this discussion, I will demonstrate with the aid of an extended example how conceivability can in some cases provide us with a guide to possibility. To close, I will discuss the strengths and limitations of my modal epistemology in its current form. I. THE COMBINED APPROACH In what follows I will argue that a particular method of conceiving, one that combines imagining with storytelling, provides us with a guide to some possibilities.11 To imagine that p is to call forth a mental image of a state of affairs in which p is true. These images can capture how something looks as well as how it feels, smells, tastes, and sounds. To imagine, for example, that my computer has crashed via this method, I might call forth both the visual image of a computer screen on which no words appear and the sensation of my fingers vigorously striking the keyboard. I intend there to be no ontological force behind my describing the imagination in terms of our calling forth mental images. For my purposes here, it needs to be acknowledged that these images are mental states of some sort which are somewhat under our control, if not in their origins, then in their course, content, and duration. It also needs to be acknowledged that these states are sensorial in nature and hence from a first-person perspective somewhat like veridical perceptions.

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See D. Lewis, On the Plurality of Worlds (Oxford: Basil Blackwell, 1986). Other philosophers who have considered the relationship between conceivability and possibility have employed this same sort of method. See Peacocke (1985); S. Reynolds, “Imagining Oneself to be Another,” Nous 23 (1989): 615–33; and B. Williams, “Imagination and the Self,” Problems of the Self (Cambridge: Cambridge UP, 1973) 26–45.

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But neither of these claims is all that controversial. As even Colin McGinn points out, there is one “non-negotiable fact about images: [. . .] they bear a phenomenological resemblance to percepts.”12 And he argues as well that among the distinguishing features of imagined images is that “they can be willed but percepts cannot.”13 That said, there are controversies surrounding the ontological status of these images. But my argument does not depend on how these various controversies are resolved.14 (I will refer to this method of conceiving as “imagining.”) To conceive that p via a story is to describe or narrate the conditions associated with p’s truth.15 So, for example, to conceive of a situation in which I supplement my income by working nights as a sushi chef, I might tell a story either about how I came to have such a job, what it is like to tend a sushi bar, or how working with raw fish has affected my personal and professional life. (I will refer to this method of conceiving as “storytelling” or “narration.”) Finally, to conceive that p via “the combined approach” is to merge these two methods together. So, for example, to conceive of a situation in which I am playing a game of fetch with my dog, I might begin by describing how excited he gets when he sees me grab a tennis ball while I also call forth images of him jumping into the air. Next I might call forth the sounds of his raucous barking as he chases the ball. Then, I might again switch methods of conceiving to storytelling to explain my dog’s refusal to retrieve the ball after I accidentally throw it into the bushes. Note that the temporal sequence associated with my employing these two methods together is irrelevant. To conceive of this game of fetch, I first employed these methods in combination and then I employed each separately, but I could have done otherwise, if doing so would have captured something important. In this way, the combined approach is a process which unites images together with stories in ways that can be both complementary and mutually reinforcing.

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McGinn (2004): 41. Ibid: 12. For the details of this debate, see A. Kind, “Putting the Image Back in the Imagination,” Philosophy and Phenomenological Research LXII, 1 (2001): 111–28; S. Kosslyn, Ghosts in the Machine: Creating and Using Images in the Brain (New York: W. W. Norton and Company, 1980); Z. Pylyshyn, “The Imagery Debate: Analog Media versus Tacit Knowledge,” Imagery, ed. N. Block (Cambridge: MIT Press, 1981) 151–206; G. Ryle, “Imagination,” Essays in Philosophical Psychology, ed. D. F. Gustafson (Garden City: Double Day, 1964) 117–53; A. R. White, The Language of Imagination (Cambridge: Basil Blackwell, 1990); and Z. Vendler, “Vicarious Experiences,” The Matter of Minds (Oxford: Clarendon Press, 1984) 43–65. For more on this method of imagining, see I. Dilman, “Imagination,” The Proceedings of the Aristotelian Society Suppl. 4 (1967): 19–36; and J. F. M. Hunter, “Imagining,” Essays after Wittgenstein (Toronto: U of Toronto P, 1973) 43–66.

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II. STORYTELLING AND THE JUSTIFICATION OF PERCEPTUAL BELIEFS As I said above, we can establish a justificatory connection between conceivability and some of our modal beliefs by examining an analogy with the way in which our perceptual beliefs can be justified. In this section, I wish to sketch what I take to be a plausible position on the justification of such perceptual beliefs. Explanationism identifies inference to the best explanation as a source of justification. Briefly, this theory holds that each of us has an explanation of how the world works. Compared with the other explanations we could have employed, this explanation is the best explanation insofar as it possesses more of the epistemic virtues and it possesses them to a greater degree than the other explanations we could have employed. The epistemic virtues include such qualities as coherence, simplicity, and fruitfulness.16 Now, it is via this explanation that we can determine (among other things) whether we are to take a particular mental state to be a veridical perception, a product of our imagination, or an optical illusion. For example, according to explanationism, we are justified in taking a mental state to be a veridical perception if that state and the account we give of that state via our best explanation satisfies certain requirements. These are: 1.

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The account of that state as a veridical perception must possess all of the epistemic virtues to a greater degree than any of the other accounts we could have given of that state and it must also increase or at least preserve the epistemic virtues of our best explanation over the long run. The account of that state as a veridical perception must, of course, include or imply that the state is a product of the normal workings of our senses which accurately reflects the way the world is. The state must be sensorial in nature and it must usually (though not always) be highly forceful, vivacious, and determinate.17,18

For a fuller presentation of this theory, see G. Harman, “The Inference to the Best Explanation,” Philosophical Review 74 (1965): 88–95; W. Lycan, “Epistemic Value,” Judgment and Justification (Cambridge: Cambridge UP, 1988) 112–27; W. Lycan, “Occam’s Razor,”Judgment and Justification (Cambridge: Cambridge UP, 1988) 128–56; and P. Thagard, “The Best Explanation: Criteria for Theory Choice,” The Journal of Philosophy 75 (1978): 76–92. Sensorial mental states (regardless of their origins) are said to have qualities that vary in degree. What qualities these are and how they are best described is not important to my theory. I chose above to talk of force, vivacity, and determination for the sake of both tradition and convenience. Nothing turns on my choice of these qualities. In most cases, we are justified in taking a particular mental state to be an optical illusion when: (1a) the account we give of that state as an optical illusion possesses more of our epistemic virtues than

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Note that the mental states at issue here are those that are ( from a first-person perspective) associated both with our having imagined something and with our having either veridically or non-veridically perceived something.19 As a consequence, for any such mental state we can ask of it whether it is a veridical perception, a product of our imagination, or an optical illusion. Because we can ask this question, these mental states should be considered (again, from a firstperson perspective) ontologically neutral with respect to their origins. (From here on, I will use “image” and “sensory mental states” interchangeably. Given the above, I do not intend the use of these words to mark any ontological distinction.) Note as well that these three criteria are purely epistemic. They are what license us in concluding that the mental state in question is a veridical perception. These criteria do not necessarily pick out those metaphysical features that distinguish every veridical perception from all other kinds of mental states. If these criteria were taken to serve such a function, they would run afoul of the obvious counterexamples—my imagination can and has produced for me forceful, vivid, and determinate images of Shaun Cassidy while my senses have at times only produced for me weak and indeterminate images of the moon. As McGinn notes, “[m]aybe images are typically more indeterminate than percepts, but both seem to admit of some indeterminacy; if so, there is no ground for a sharp distinction here.”20 This will become important below. An example might help here. When I was little, my family drove across a desert. As we were driving, it seemed as if in the distance there was water covering the road. The best account I could give of this experience at that time was that I was seeing water which had spilled out onto the road after a water main had burst. This account possessed and preserved the epistemic virtues of my best explanation. Moreover, it implied that the mental states at issue were products of my senses which accurately

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the other accounts we could have given, (2a) this account implies that this state came to us through our senses in a non-standard way and hence does not accurately reflect how the world is, (3a) the state itself, typically, lacks some degree of force and vivacity and is indeterminate to some extent. Finally, we are in most cases justified in taking a particular mental state to be a product of our sensory imagination, when condition 3a (immediately above) has been met and when the account we give of this state as a product of our imagination preserves our epistemic virtues and implies that this state did not directly come to us through our senses but instead came to us via the workings of our own mind (and/or brain). It might be the case that there is a particular kind of mental entity associated with each mental function. For example, it might be the case that percepts are different in kind from mental images and that percepts are associated only with perception and mental images are associated only with the imagination. But even if there are such entities and associations, this is something we cannot discover from a first-person perspective. If we could, then we would not confuse (as we do at times) veridical perceptions with either optical illusions or those mental images produced through the imagination. McGinn (2004): 25.

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reflected how the world actual was. Finally, these states were themselves sufficiently determinate and they possessed high degrees of force and vivacity. Consequently, I justifiably took these states to be veridical perceptions of water. As we drove closer to this water, I noted that this puddle was quickly shrinking. In fact, by the time we reached the place this puddle was supposed to be it had disappeared. Given my best explanation, I knew that the rapid disappearance of this puddle could not be explained by evaporation. Thus, I could no longer account for these states as veridical perceptions of water. Consequently, I had to come up with a different explanation. Initially, the only explanation I could come up with led me to the conclusion that these states were products of my imagination. But then it happened again— and again. In the distance it appeared to me as if there was water covering the road but as we approached this water it quickly disappeared. This repetition forced me to abandon my belief that I was imagining. I then spoke with my older brother about my experiences. From him, I learned that hot air rising from the heated pavement refracts light in a way similar to the way in which water refracts light and as a consequence, when looking toward that air, it appears as if there is water where there is not. Thus, upon changing my best explanation to incorporate this new information, I then was justified in taking these states to be optical illusions. This example is a good illustration of an important tenet of explanationism. It is our account of a mental state that at least in part licenses how we are to take that state. As I had these various “experiences of water” and as my best explanation evolved, I was justified in taking the associated mental states first to be veridical perceptions, then products of my imagination, and finally optical illusions. At each step, what provided the justification was my changing ability to account for these states. Importantly, what did not provide the justification and, in fact, what did not change, were the qualities associated with these states. Each was as forceful, vivacious, and determinate as the last, yet my account of and hence beliefs about these states changed.21 This example also illustrates a connection that exists between one method of conceiving, viz., storytelling, and justification in non-modal contexts. From my perspective now, the initial account I gave of my experiences did not capture the causal mechanisms which were responsible for it appearing to me as if there was water on the road. As far as I know now, there was no water, let alone a water main.

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Of course, I am not suggesting here that we actually concoct such explanations in every case of justified perceptual belief. It is usually only when the veridicality of a particular mental state is called into question that we take the trouble to explicitly put forth a justification at all. In fact, typically, we make explicit this explanation to either defend that belief or, when that fails, to understand how we came to be wrong. But even though we usually do not offer up such explanations, according to explanationism it is our ability to do so that does the justifying.

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In fact, this account in the end seems to be just a bit of fiction, a story I concocted about the origins of my mental states. Nevertheless, because this story satisfied the necessary requirements (requirements 1 and 2 above) and because these states possessed the requisite degrees of force, vivacity, and determination (requirement 3), I was justified in taking these states to be veridical perceptions. Thus, from an explanationist’s perspective, truth and justification pull apart. Assume that I have an experience and an account of that experience which, together, satisfy the three requirements listed above. In such a situation, I will be justified in taking the associated mental states to be veridical perceptions regardless of the truth of my account. Thus, truth is not a requirement for these accounts or for justification. But, if this is the case, then these accounts should not be considered descriptions of the events that in fact brought about these states. Instead, just as in the above example of the “water,” it seems reasonable to think of these accounts as stories told within the confines of our best explanation about some aspect of our mental lives. Thus, we see here how storytelling has a role in the justification of our veridical perceptions: It is in virtue of our ability to tell a particular kind of story about a mental state (i.e., a story that satisfies requirements 1 and 2 above) that justifies us in taking that state to be a veridical perception.22 How is all this relevant when it comes to establishing that our imagination provides us with a guide to possibility? My contention is that the same basic strategy the explanationist uses to justify our taking a particular mental state to be a veridical perception and hence a guide to the actual can be used to justify our taking an image we have called forth to be a guide to the possible. Given that this is my strategy, it is clear that the viability of my argument rests on the viability of explanationism. Unfortunately, there is not sufficient space here to mount a full defense of explanationism. But it is worth noting that the reader can accept my argument without endorsing explanationism as the sole account of justification; it is enough if she accepts it as one way, among others, by which our beliefs can be justified. And, of course, there is good reason to accept inferences to the best explanation as a source of justification, for such inferences are just part and parcel of what it means to be rational.23 Moreover, explanationism is best characterized as a coherentist theory of epistemology. If our beliefs about possibility are justifiable, this justification will have to come by way of this sort of epistemology, for modal claims cannot be justified via a foundationalist theory. Foundationalists maintain that there are noninferentially justified propositions from which we can infer the truth of other 22

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By the same token, stories also have a role in the process by which we justify our taking a mental state to be either an optical illusion or a product of our imagination. “To infer to the best explanation is part of what it is to be rational. If that is not rational, what is?” See D. M. Armstrong, What Is a Law of Nature? (Cambridge: Cambridge UP, 1983) 59.

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propositions. Admittedly, foundationalists give many different accounts of this non-inferential justification. But, even so, most associate these foundational propositions with either perception or introspection. Given this, the only kinds of propositions that could be inferred from these foundations are those that concern the actual world. Propositions which concerned non-actualized possible worlds could not be inferred from these foundations. Thus, even a foundationalist will have to adopt a coherentist theory of some sort when seeking to justify claims about these worlds.24 So, my working with explanationism here is in keeping with what is required when seeking to justify our modal claims, regardless of whether coherentism or foundationalism holds true in a more general sense. And, again, while I cannot here fully defend explanationism (or coherentism, for that matter), from the above we can see some of the appeal of these related theories, especially for those who think that our modal claims can be justified. Specifically, coherentists, unlike foundationalists, can offer a unified epistemological theory that encompasses both the actual world and the non-actualized possible worlds. That said, let us continue with my argument by considering another example. III. IMAGINATION AND THE JUSTIFICATION OF MODAL BELIEFS Bears are quite common in my part of the country. Because of this fact, I have been doing some research on bear behavior. I have learned that bears primarily subsist on nuts, berries, and small mammals. I have also learned that they are creatures of habit who tend to return to any food source they discover. My neighbors are nature lovers who keep many bird feeders fully stocked with seed. They told me that while they have never seen any bears in our neighborhood, a nearby college issued a Bear-Alert after a bear had been spotted on someone’s porch. All this got me wondering whether there could ever be a bear in my backyard. So, as I was sitting at my desk, staring out my back window, I intended to imagine a bear in my backyard and images (i.e., sensorial mental states) came before my mind’s eye that were to some degree special. These images were of a bear lumbering across my yard and they were for the imagination quite forceful, vivacious, and determinate. In what follows, I shall argue that my ability to call forth these images in combination with my ability to tell a certain kind of story about them will justify my belief that the following proposition, (B) A bear is in my backyard, is possibly true.25

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The only exception here might be some form of modal intuitionism. I argue against this view below. It should be clear that the indexical in B, like the other indexicals used in my examples, is innocuous and should be read as shorthand for a complete description of the relevant indices.

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To see this, begin by assuming that there is a possible world which is populated by our epistemic twins up to the point at which I intended to imagine this bear. Our epistemic twins are those individuals that exist in some possible world who have the same mental lives as we have in the actual world. That is, from a first-person perspective, our twins have experienced the same mental states we have, be they sensorial or conceptual in nature, and they have also adopted the same beliefs and justificatory practices. Now, the fact that our mental lives and our twins’ mental lives are the same from this first-person perspective does not imply anything about how similar these two worlds are beyond these mental states, nor does it imply anything about the causal processes that produced these mental states. Rather, as I explained above, these mental states are necessarily the same only from the subjects’ point of view.26 Thus, in this sense, the same sensorial mental state could, for example, come before my mind and my twin’s mind, though mine could be veridical and hers could be non-veridical. This is the notion of “same” that I will be employing here.27

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I do not mean to suggest anything here, one way or the other, with regard to the debate over externalism about mental content. On these views, the content of a subject’s mental states is determined, at least in part, by how things are “outside the head.” All I require is that there be a common, introspectively available element in the subjects’ mental lives, regardless of how the world is. Whether this element is what determines the referents of those mental states is neither here nor there. Many externalists allow a realm of “narrow” content, which is precisely that which is available from the first-person perspective, in addition to the “broad content” that is fixed by facts about the world. Even those externalists, like John McDowell, who reject this “portmanteau” conception of content acquiesce in the common sense claim that two subjects embedded in different environments can share, in a quite obvious sense, a common mental life. We can see this if we look briefly at McDowell’s response to Blackburn. Roughly, McDowell argues that the fact that there is a common element shared by the two subjects says nothing about whether the environment makes a contribution to the representational powers of their mental states. McDowell writes, “[t]he uncontentiously legitimate category of things that are the same across the different cases is the category of how things seem to the subject.” And the legitimacy of this category “is consistent with an essentially disjunctive conception of the state of seemingly entertaining a singular thought, and is hence powerless to recommend the conclusion that thoughts are only extrinsically connected with objects” (248). In other words, the unobjectionable claim that different environments can present subjects with states that are indistinguishable from their first-person perspectives is simply irrelevant to the question of externalism. Thus, even the most convinced externalist should not have a problem with my notion of epistemic twins. See J. McDowell, “Singular Thought and the Extent of Inner Space,” Meaning, Knowledge, and Reality (Cambridge, MA: Harvard UP, 1998) 228–59. Epistemic twins should not be confused either with the Kripkean notion of an epistemic counterpart or with Putnam’s twins located on Earth and Twin Earth. Epistemic twins, like Kripkean counterparts and Putnam’s twins, share each other’s first-person epistemic properties. But they need not share any other properties as they would if they were Kripkean counterparts of each other. And they need not be “molecule for molecule identical” as they would if they were a pair of Putnam twins. See H. Putnam, Reason, Truth and History (Cambridge: Cambridge UP, 1981) 18.

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Now, as I have said above, though my twin and I have experienced the same mental lives, let us assume that at the point at which I intended to imagine this bear, a difference emerges. In the actual world, I consciously willed myself to have these images of this bear come to me. Let us assume that in this possible world, my twin, a.k.a. Rebecca, had the very same sensory mental states come to her but unlike me, she did not consciously will herself to have these images.28 Instead they came to her unbidden. Insofar as Rebecca did not consciously will herself to have these images, technically speaking, she is no longer my epistemic twin. Thus, why think there could be such a Rebecca? More specifically, why think that there is a possible world in which Rebecca has had images of a bear come to her without her conscious will being involved? In answer to this question, note that any image we conjure up via our imagination is an image that could have come to us via an alternative pathway. That is, I have just willed myself to have images come to me which possess (from a first-person perspective) a specific qualitative content. Given this, I also know that mental states with this same content could have come to me either via my veridically or non-veridically perceiving the world or via my synapses being in some way stimulated in the appropriate manner. This claim might seem controversial. But those who think that the images we call forth via the imagination are composed of aspects of what we have at some point perceived should not object to it. And those who think that the imagination and perception are not so tightly linked should still accept this claim. For this claim is at the foundation of external world skepticism. To reject it is to dismiss out of hand the question as to whether or not we are brains in a vat and this is something that philosophers should be loath to do. Thus, the fact that I just imagined this bear means that these same mental states could have come to me via one of these alternative routes. But to say this, is just to say that there is a possible world in which these images did come to my counterpart via one of these routes. Be careful. Nothing has been said here that enables us to determine how these images have in fact come to my counterpart. At this point none of these alternative routes has been foreclosed or presupposed. If one had—if, for example, it could be inferred that these images came to my counterpart via her veridically perceiving the world—I could be charged with begging the question. 28

Typically, when it is claimed that a person did not consciously will herself to have a particular image come to her, the conventional implication is that this person did will it, though she was not aware of herself as having done so. I am not here employing this implication. Thus, when I assume that Rebecca did not consciously will herself to have these images of this lumbering bear, I am not implying that she unconsciously willed them.

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But even though nothing here allows us to determine how exactly these images came to my counterpart, if these images were produced via one of these alternative pathways, then they are not a product of her conscious will. Thus, because I have imagined this bear, we know that there is a possible world in which my counterpart, a.k.a. Rebecca, has had images of this bear come to her without her conscious will being involved. What then follows from all this? I will argue that in this possible world Rebecca is justified in believing that B is true and I will also argue that her being so justified provides me with the necessary justification for believing that B is possibly true. As I explained, at the point at which these images came to Rebecca and me, we ceased to be epistemic twins. But even so, in most every respect we should still be considered so related. For at this point, epistemically, Rebecca and I barely differ from each other. In every way but one, Rebecca’s internal experiences of these images were just like mine. Rebecca’s images had the same content and they were as forceful and vivacious as my own. Internally, our images only differed from each other with respect to the fact that I consciously willed these images while Rebecca did not. Moreover, the fact that these images came to Rebecca unwilled would not have caused her to modify either her best explanation or how she employed her best explanation.29 Thus, at this point Rebecca employs her (and hence my) best explanation just as I would employ it. Finally, to an overwhelming extent, we two still share the same set of beliefs and these beliefs are organized and combined in the same way. For these reasons, Rebecca should for all intents and purposes be considered my epistemic twin. Given that Rebecca and I should be considered epistemic twins, the conditions under which she is justified in taking an image to be a veridical perception are the same for her as for me. For me to be so justified, again, I must be able to offer an account of that image that both preserves my best explanation and implies that this image came to me through my senses in the standard way (requirements 1 and 2 above). In addition, this image must itself be sufficiently determinate, forceful, and vivacious to be considered veridical (requirement 3). Now because Rebecca possesses nearly all the beliefs I possess, all the information I have recently gathered about bears is available to her. Thus, I know that the story she can tell about these images that best preserves the epistemic virtues of her best explanation is one that deems them to be veridical perceptions. In this story, this bear had in the past found a mound of birdseed to dine on in Rebecca’s 29

I know this because prior to these images coming to either of us, Rebecca and I did share the same best explanation. Part of one’s best explanation includes the conditions under which that explanation is to be modified. Well, for myself and hence Rebecca, these conditions are not satisfied by the mere fact that these images of this bear came to Rebecca without her conscious will being involved. Thus, I am safe in my conclusion that Rebecca has not modified her best explanation.

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neighbor’s backyard. And this bear (being a creature of habit) returned to these bird feeders (via Rebecca’s yard) to see if there was more that very morning as Rebecca was looking out her back window. Thus, requirements 1 and 2 above have been satisfied. But what about requirement 3? Are these images sufficiently forceful and vivacious so that Rebecca can deem them to be veridical? It is with respect to this requirement that some might raise an objection. Some might argue that Rebecca would never take these images to be veridical perceptions unless in the actual world I had suffered a hallucination that produced these images. But because I intentionally brought forth these images, they could not satisfy this requirement. To explain, Rebecca’s internal experiences of these images differ from mine in only one respect: They were not accompanied by an intention to imagine. In every other respect, her internal experiences here were just like mine. Thus, Rebecca’s images possess the same qualities and same content as my images possess. Well, my images were produced by my intentionally imagining them. Consequently, they possess qualities associated with this sort of process. Specifically, while they are quite forceful, vivacious, and determinate for images produced by the imagination, they lack high degrees of these very qualities. But, the objection runs, it is only those images that possess high degrees of these qualities that are considered veridical. So, the argument concludes, Rebecca will not ever take these images to be veridical perceptions. But consider that many philosophers both underestimate the imagination and overestimate perception. As Oliver Sacks has demonstrated, some people’s imaginations are astoundingly vivid and forceful.30 Admittedly, the average person’s imagination might in general lack force and vivacity. But, even so, most people have been surprised at the power of their own imagination. Most everybody has been jolted out of a daydream that seemed overwhelmingly real. Thus, the claim that the mental images we consciously call forth do not possess high degrees of force and vivacity is debatable. In fact, while quite forceful and vivacious images are usually associated with perception, the standard empiricist line (present within my and hence Rebecca’s best explanation) is that the images that come to us via other routes can at times be as forceful and vivacious as a perception. Moreover, sometimes the images that come to us via our senses can lack force and vivacity. We have all made judgments at night or in the fog or as we turn our heads, and the images on which we base these everyday judgments have as a consequence lacked to some degree force, vivacity, and determination. But we do not therefore declare our judgments to be unjustified. Given this, the question becomes, do Rebecca’s images of this bear have the same degrees of force, vivacity, and determination as these kinds of images, that is, images that are 30

Most recently, see Oliver Sacks, “The Mind’s Eye: How the Blind Imagine Vision,” The New Yorker LXXIX (July 28, 2003): 48–59.

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considered to be veridical even though they lacked high degrees of the requisite qualities? My answer here is that they did. They were as forceful, vivacious, and determinate as these images.31 Thus, I have reason to think that Rebecca’s images of this bear were sufficiently forceful, vivacious, and determinate to be considered veridical. This, of course, means that requirements 1, 2, and 3 above have been satisfied. Hence, Rebecca is justified in taking these images to be veridical perceptions and consequently she is justified in believing that there is a bear in her backyard. So, there is a possible world in which Rebecca is justified in believing that proposition B is true. Keep in mind that my goal here is to establish that I am justified in believing that B is possibly true. Unfortunately, the fact that Rebecca is justified in believing that B is true does not by itself justify my belief that B is possibly true. In order to be so justified, I must next find some reason to base my beliefs about B’s possibility on Rebecca’s beliefs. One way I can provide myself with such a reason is by establishing that Rebecca is a reliable witness with respect to what did or did not happen in her backyard. This might seem especially difficult given that Rebecca is in a possible world and not in the actual world. But in many ways the position I am in with respect to Rebecca is similar to the position we are often in when we try to justify claims about past events. Past events are in many ways as inaccessible as possible worlds. We can no more jump in a time machine to establish what has happened in the past than we can hop in a spaceship and travel to possible worlds. How then do we justify our claims about the past? One prominent way is by basing our beliefs on those of a person whom we have deemed to be a reliable witness with respect to the events in question. So, let us examine the conditions that must be met for a person to be deemed a reliable witness and then see if Rebecca can meet these conditions. First we must determine that the person has reasoned well. Specifically, she must have reasoned to the right conclusion given her best explanation and given her situation as she perceives it. Insofar as a person’s reasoning process is being evaluated here, this condition can be thought of as the internal condition. The second condition is the external condition. Here we need to establish that the witness was not impaired either physically, mentally, or intellectually at the time in question. Now the question is, can Rebecca meet both of these conditions?

31

Of course, some might not trust my self-report in this instance, for it all too conveniently supports my theory. Here again I think it is worth considering those mental states that come to us when we let ourselves get caught up in a particularly good daydream. The fact that we can call forth such compelling and realistic visions is proof in principle that Rebecca’s images of this bear could have possessed a sufficient degree of the requisite qualities to be considered veridical. And this proof in principle is adequate for my purposes here.

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I have already established that Rebecca is justified in her belief that B is true. Now, prior to this lumbering bear episode, Rebecca was my epistemic twin. Moreover, as I have argued, post this episode, Rebecca should still be considered my epistemic twin. She still employs the same best explanation that I employ in the same way that I employ it. And, in all respects but one, she has had the same internal experiences as I have had. Given all this, it is thus safe to conclude that if I were in Rebecca’s situation, I would have drawn the same conclusion that she drew about seeing this bear. Hence, I cannot find fault with Rebecca’s reasoning.32 Consider now the second, external condition. Do I have any reason to believe that Rebecca is or was epistemically impaired? Again, up to the point at which I intended to imagine this bear, Rebecca was my epistemic twin. Thus, I have no more reason to think that she was taking drugs that day than I have reason to think that I was. I also have no reason to think that her vision was obscured or impaired or that there was a holograph in her backyard. But might she have imagined this bear? I imagined this bear. Don’t I, therefore, have reason to believe that unbeknownst to Rebecca she imagined this bear as well? While Rebecca and I should still to be considered epistemic twins in most respects, in those respects in which our differences are relevant, those differences should not be ignored. Rebecca’s images, unlike mine, came to her unwilled. The default within our best explanation is not to consider such unwilled mental states products of our imagination. It is instead to consider them precepts (be they veridical or non-veridical).33,34 Thus, I have reason to think that Rebecca has perceived this bear and no reason to think that she has imagined this bear. Given all this, I must then conclude that in this situation Rebecca has satisfied the two conditions associated with being considered a reliable witness. I have every reason to believe that she has reasoned well and no reason to think that she is or was epistemically impaired. Because Rebecca is in my estimation a reliable 32

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Though I cannot find fault with Rebecca’s reasoning, she might have reasoned poorly here. But, if she had, I would be blind to her errors because I am her epistemic twin. Thus, I might deem her conclusion to be reasonable, when it was not. Similarly, I might not be aware of all the ways a person can be impaired. Hence, I might judge that Rebecca was in the right frame of mind when she drew her conclusion, when she was not. Thus, reliability is not relative to the individual. But if I do all that I can to insure that my standards cohere with the best standards available to me given my community and if I do my best to appropriately apply these standards, then even if I am wrong in my judgment about the reliability of a particular witness, my conclusion that she is reliable will be justified. Again, as McGinn has argued, percepts cannot be willed (see McGinn [2004]: 12). Might I instead have reason to think that Rebecca is suffering from a hallucination, an unwilled image produced through her imagination? Again, our best explanation leads us a way from this conclusion. The default assumption is that an individual’s unwilled sensory states are perceptions (either veridical or non-veridical) and we only question that assumption when we have reason to think that that individual is epistemically impaired. As I have explained, I have no such reason in regards to Rebecca. Hence, I have no reason to think that she is hallucinating.

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witness, I am justified in basing my beliefs on her beliefs. Thus, the fact that Rebecca is justified in believing that a bear has lumbered across her yard justifies my belief that it is possible for B to be true. Now, to be justified in believing that a proposition is true in some possible world is to be justified in believing that that proposition is possibly true.35 Hence, I am justified in believing that it is possible that there is a bear in my backyard. Here then is an instance of my justifying my belief in a possibility via employing both storytelling and the imagination.36 This is a good place to stop and consider a broad objection to my argumentative strategy. I want to justify my belief that B is possibly true. In order to provide myself with this justification, I have made an assumption that I have tried to defend. But in this defense, I have employed some of my beliefs about what is possible. For example, my above argument depends on the claim that the images we produce via our imagination could have come to us via an alternative pathway. So, I am seemingly trapped in a circle. This method of justification does in fact depend on some of my beliefs as to what is possible. But, even so, I am not trapped in a vicious circle. For the beliefs I have employed here do not in any way imply that there could be a bear in my backyard. When we seek to establish that a proposition is possibly true, we need not start from scratch, throwing out all of our modal beliefs. We only need to avoid

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Consider the principle just stated: (C) To be justified in believing that a proposition is true in some possible world is to be justified in believing that that proposition is possibly true. On the one hand, if you subscribe to S5, you will accept C as a general principle that applies to all modal claims. For on S5 all possible worlds are equally accessible to each other such that if it is proven that p is possible from one world, then p is possible from all worlds. On the other hand, if you subscribe to S4, you will reject C as a general principle insofar as on S4 all worlds are not equally accessible to each other. But you will accept C insofar as it pertains to first order modal claims, that is, those claims in which no modal operator is contained within the scope of another modal operator. For on S4, all first order possible worlds are accessible from this world. Given this, subscribers to S4 and subscribers to S5 should both find C acceptable within the confines of this argument. Above I have shown how images and stories can together justify the belief that a proposition is possible. Taking a line from Sellars, someone might argue that mental imagery, being nonconceptual, cannot enter into inferential relations. Hence, such mental states cannot have any role in justification. But while a Sellarsian does not accord non-conceptual mental states a direct role within the process of justification, s/he acknowledges that we can have higher order beliefs about these states. I can, for example, believe that an image of a bear has come before my mind’s eye. And s/he thinks that such higher order beliefs can have a role in justification. But in conceding this, the Sellarsian is allowing non-conceptual mental states to sneak back into the process of justification. That is, whether or not my higher order belief can justify any other beliefs I hold will depend on whether or not this mental image of a bear did in fact come to me. I contend that the images we call forth can have a role in justifying my modal beliefs. But whether these images, themselves, play a direct role in justification or whether they indirectly play a role through their association with higher order beliefs is irrelevant to my theory. Thus, this Sellarsian objection finds no purchase. (I thank a referee for bringing this line of thought to my attention.)

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assuming the possibility of the proposition whose modal status is in question. This I have done. Let us now review my argument. I want to know whether it is possible for there to be a bear in my backyard. So, I imagine a bear there. I then assume that there is a possible world which is populated by our epistemic twins up until the point at which I intended to imagine this bear. At this point, I assume that Rebecca’s images of this bear, unlike mine, came to her without her conscious will being involved. I defend this assumption by noting that the mental images that come to us via our imagination could have come to us via an alternative route not associated with the workings of our conscious wills. Thus, the fact that I have imagined this bear gives me reason to think that these same mental images came to Rebecca unbidden. I have begged no questions in making or defending this assumption. For nothing here necessitates that there is in fact a bear in Rebecca’s backyard. Now in this possible world, Rebecca would be justified in taking these images of this bear to be veridical. For on her best explanation, mental states of this kind are considered veridical, especially when a person can tell a story that accounts for them as veridical perceptions. And Rebecca can tell just such a story. She can tell a story about how this bear came through her backyard looking to lunch on her neighbor’s birdseed. And, of course, because Rebecca is justified in taking these images to be veridical, she is also justified in believing that there is a bear in her backyard. Again, Rebecca is my epistemic twin up to the point at which I intended to imagine this bear. After this point, she ceases to be my twin because she formed no such intention. But, at least initially, she only differs slightly from me. We two still share the same best explanation, justificatory practices, and the same epistemic virtues and vices. In addition, for the most part, we still share the same belief set. As a consequence of all this, I cannot help but think of her as a reliable witness to all that happens around her. As I have just established, Rebecca is justified in believing that there is a bear in her backyard. Now because she is in my estimation a reliable witness, I can rightly base my beliefs on her beliefs. Thus, I am justified in believing that there is a bear in her backyard as well, which means I am justified in believing that there is a possible world in which there is a bear in my backyard. IV. STRENGTHS AND LIMITATIONS Many of our beliefs about what is possible can be justified via an argument of this sort. While looking out my window into my backyard, I can imagine a red fox burrowing a den, a bald eagle at the bird feeder, and a horse chewing on some grass. And via an argument similar to the one presented above, I will be able to justifiably say that what I have imagined in these instances is possible. Thus, this argument goes some way toward justifying a certain set of our modal beliefs. 142

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But, admittedly, this set is small. At most, it contains only those propositions that refer to variations in our immediate surroundings. And, yet, even in regard to this set of propositions, care must be taken. Surely there are possibilities within this limited set that cannot be accounted for given my best explanation. And if I happen to call forth images of one of these possibilities and then attempt to account for them as veridical perceptions, I will fail. Take, for example, the proposition that Martians have landed on my side lawn. I can seemingly call forth images of such an occurrence, but given my best explanation I cannot account for these images as veridical perceptions. Thus, I will not be justified in concluding that a Martian landing is possible and I will be tempted to conclude that such an occurrence is impossible. But my best explanation might be flawed or incomplete in some relevant way (though I truly doubt that this is the case here). Moreover, my best explanation was constructed with the actual world in mind. By design, it is ill-equipped to deal with possible worlds that are radically different from this one. Thus, p may be possible but my modal epistemology will give me no evidence as to p’s modal status, if p is the kind of proposition that is true only in these radically different worlds. For this reason, if I fail to justify the possibility of a particular proposition via my modal epistemology, I cannot then conclude that that proposition is impossible. It may be that there is some possible world in which that proposition is true but yet I cannot access information about that world via my epistemology. Thus, this modal epistemology as it stands now is limited. But the mere fact of its limitation is not reason to dismiss it. While there are ways this epistemology can be extended, let us assume the worst. Let us assume that my epistemology can justify only those possibilities that refer to certain variations in our immediate surroundings. If this is the case, the limitations of this epistemology, arguably, support a limited skepticism about possibility. For the two most prominent alternative modal epistemologies face seemingly insurmountable problems, problems from which my theory does not suffer. Consider first a method of justifying our modal beliefs that is clearly related to storytelling, which I will refer to as set-constructionism. Possible worlds are often conceived of as being either composed of or described by a maximally consistent set of propositions. Given this, the best and simplest strategy for justifying the belief that p is possible would be to construct a maximally consistent set that includes p. Unfortunately, we could not ever construct such a set, for these sets are infinitely large. Even so, some might argue that we would only need to construct an infinitely large set if we wanted to prove that p is possible. If instead we only wanted to justify this belief, it would be sufficient to construct a mere subset of this larger set. The problem with this alternative strategy is that the vast majority of propositions that describe a world will be left out of any such subset, no matter how 143

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large it is. This fact prohibits our using these subsets as means for justifying our modal beliefs, for we could never adequately dismiss the possibility that one of the many propositions left out of such a subset contradicts one of the propositions included within it. To avoid this sort of problem (often referred to as the problem of incompleteness), I turned to explanationism. The story I told above about bears and bird feeders justifies my belief that B is possible, but not because this story is composed of a subset of a larger set of propositions which (I assume) describes a possible world. If it did, questions would arise in regards to my assumption here that this subset is consistent with what is left out of it. Rather, this story justifies my belief that B is possible because it provides Rebecca with the necessary justification to take the images before her mind’s eye to be veridical perception of B. To review, my ability to offer this story about bears and bird feeders is what justifies my belief that Rebecca has such an explanation at her disposal. Now, because she has this explanation at her disposal, she is justified in believing that the images before her mind’s eye are veridical perceptions. And, of course, the fact that she is so justified provides me with the necessary justification for my belief that B is possibly true. When I (like everyone else) employ my best explanations to account for those beliefs I have about the actual world, no one demands that these accounts constitute a complete description of this world. Incompleteness is allowed for here. Moreover, everyone recognizes that the incompleteness of these accounts and even the incompleteness of my best explanation might hide an unsolvable problem. But, despite all this, inferences to the best explanation are still taken to justify those beliefs we base on our perceptions. Given that this is the case, it seems only fitting that we ignore similar problems when we employ conceivability as a guide to possibility.37 Thus, we see how the problem of incompleteness which plagues set-constructionism can be avoided on my theory. Consider now the second most prominent mode of justifying our modal beliefs: modal intuitionism.38

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Some might think that on my theory, the images we call forth are mere prompts that compel us to tell a story and that it is this story that alone justifies our modal beliefs. But these images are not mere prompts. Again, I am justified in believing that B is possibly true because Rebecca is justified in believing that B is true. But what justifies Rebecca here? It is both the images she calls forth and the stories she tells about them that does the justifying. Specifically, Rebecca is justified in believing that B because images are before her mind’s eye which she is justified in taking to be veridical perceptions of B and she is so justified because she can tell a particular kind of story about these images. For a full presentation of this theory, see G. Bealer, “Modal Epistemology and the Rationalist Renaissance,” Conceivability and Possibility, ed. T. Gendler and J. Hawthorne (Oxford: Clarendon Press, 2002) 71–126; and J. van Cleve, “Conceivability and the Cartesian Argument for Dualism,” Pacific Philosophical Quarterly 64 (1983): 35–45.

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Modal intuitionism holds that when we consider a proposition we often intuit that that proposition describes a possibility or, short of that, that that proposition does not describe an impossibility. Any form of intuitionism, however, suffers from the problem of adjudication. Chalmers, for example, claims that it is possible for there to be a world that is like ours in every way, except that our counterparts in this world do not experience qualia. Thus, there is sugar in this world, but Zombie-Rebecca never experiences its sweetness. Chalmers’s belief in the possibility of Zombie World rests for the most part on his “brute intuition.”39 But I do not share this intuition. It is just not intuitively obvious to me that there is a possible world that is subject to our laws of nature and is composed of the same physical stuff as ours but yet its inhabitants lack phenomenal experience. How are we to adjudicate this dispute? It might be the case that what I am referring to as an intuition is not what Chalmers is referring to. How are we to decide who is operating on the right kind of intuition and who is not? Alternatively, we might both have the right kind of intuition here, but one of our intuitors might be broken, making it prone to false positives. But how are we to tell whose is broken? Here then is the problem of adjudication. Because the intuitions that supposedly ground our modal beliefs are mysterious in their nature and their origin, it seems impossible to adjudicate disputes. But within my modal epistemology there is some room for adjudication. If two people disagree as to the modal status of a proposition, they can evaluate each other’s best explanation and the account they give of the images each has called forth. They can determine which is most fruitful, coherent, and simple. But what if the problem between the two is located in the fact that one can call forth images associated with the proposition in question, while the other cannot? Obviously, two people cannot share and evaluate each other’s imagined experiences. But if we allow that there is some relationship between what we imagine and what we perceive, one person can provide some guidance to another. Consider here how you might get someone who did not know what a chimera was to imagine one. You would ask them to imagine a lion, a goat, and a serpent, then you would tell them how to combine the three. In this way, some kind of conversation can be had about what is or could be imagined. Thus, adjudication is at least possible on my modal epistemology; it is not in modal intuitionism.40 If the problems associated with either modal intuitionism or setconstructionism could be addressed, then we would have a modal epistemology that would enable us to justify more of our modal beliefs than mine can as it stands. But I see no way for these problems to be addressed. Thus, if the scope of 39 40

D. Chalmers, The Conscious Mind (Oxford: Oxford UP, 1996) 96. Chalmers’s modal rationalism combines modal intuitionism with set-constructionism. Hence, it suffers from both the problem of incompleteness and the problem of adjudication.

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my modal epistemology cannot be extended, then the limits of my epistemology might just be the limits of our modal knowledge. For this reason alone, my epistemology should not be dismissed. It might tell us all we can know about what is possible.41 V. CONCLUSION Consider again the claim that the imagination is to the possible as perception is to the actual. Those who offer this analogy are claiming that our imagination tells us about what is possible in the same way as our perceptions tell us about what is actual. Well, a perception provides us with a guide to the actual only when we take the associated images to be veridical. These images must themselves be sufficiently forceful, vivacious, and determinate and we must have within the confines of our best explanation an account of these images which justifies us in taking them to be veridical perceptions. Working with this analogy, I have argued that the images we call forth provide us with a guide to the possible if there is a possible world in which we would be justified in taking these same images to be veridical perceptions. If we can establish that there is such a world via an argument similar to the one presented above, then we are justified in basing our beliefs in what is possible on these images. Whitman College, Walla Walla, WA

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We should be careful not to exaggerate the limitations of my modal epistemology. This epistemology as it stands now can provide us with some insights into current philosophical worries. For example, in “Consciousness and Modal Empiricism” (under review), I apply my epistemology to Chalmers’s zombie world.

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