OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 3 June 3, 2010 6:45 PM I Peter Strawson famously wrote more than thirty years ago that "a philosopher's views on [perception] are a key to his theory of knowledge and to his metaphysics" (1979, 41). At that time, this statement probably would have been quite provocative inasmuch as it made perception sound more important than it was assumed to be. Now, thirty years later, Strawson's claim sounds too weak. A philosopher's views on perception are as important as her theory of knowledge or her metaphysics. Some may even be tempted to say that a philosopher's views on epistemology or metaphysics are a key to her theory of perception. Perception is no longer seen as an inferior subfi eld of philosophy that may or may not help us to understand the philosophical questions that are supposedly more fundamental. Perception, at present, is as central a philosophical subfi eld as it gets. This change is not only a merely quantitative one. It is true that more philosophers are working on perception and that their output is more sophisticated and nuanced than ever before, but this is not the whole story. What is more relevant, and more interesting from a philosophical point of view, is that the nature of the questions that are being asked about perception has also changed. The aim of this volume is to give a representative sample of this new wave of philosophy of perception. And the aim of this introduction is to outline the questions contemporary philosophers of perception are concerned with and how they differ from the "old" philosophical questions about perception. II One salient fact about the questions contemporary philosophers of perception are concerned with is that they have intricate links to other subfi elds 1 Philosophy of Perception The New Wave Bence Nanay 4 Perceiving the World OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 4 June 3, 2010 6:45 PM of philosophy: epistemology, philosophy of language, metaphysics, aesthetics, even value theory. To put it somewhat provocatively, philosophy of perception no longer seems to be merely a subfi eld of philosophy of mind. Many of the chapters in this volume, for example, rely more heavily on the conceptual apparatus of other subfi elds of philosophy than that of general philosophy of mind. Some of the most infl uential philosophical questions about perception are located fi rmly within philosophy of mind: What is the difference between perception and belief? What is the difference between perception and sensation? What is the relation between perception and action? When is perception successful? What is the difference between perception and mental imagery? What are the differences among the different sense modalities? Answering these questions has been possible, indeed desirable, within the boundaries of philosophy of mind. These questions are, of course, still with us. But there are many more, ones that could not even be raised without relying on the conceptual apparatus of subdisciplines other than philosophy of mind. Many of the questions the chapters of this volume ask are of this kind. One such question is whether and in what sense perception is normative. Two of the chapters in this volume argue for the seemingly surprising claim that the concept of normativity plays a crucial role in understanding perception. Sean Kelly uses phenomenological considerations about shape and size constancy to argue that perception is essentially normative. Mohan Matthen's starting point is also perceptual constancy, and he also pays attention to visual phenomenology, but his concern is mainly the question of how constancy can be explained with the help of the simple fact that different properties are attributed to different parts of the visual scene while preserving the normative character of perceptual content. The claim that there is something normative about perception is not new (see Koffka 1935 ; Gibson 1979 , 138–140; see especially the summary in Hatfi eld 1990 ), but it has largely been a neglected view in the last couple of decades. Kelly's and Matthen's chapters, taken in tandem, may put the concept of normativity back into mainstream philosophical analyses of perception. Andy Egan argues for a version of projectivism, according to which at least some properties that we perceive objects as having are our projections. This general idea is a very old one that goes back at least to David Hume, but Egan's way of arguing for a particular version of projectivism uses a general framework of self-locating/ de se propositions (Quine 1969 ; Lewis 1979 ; Chisholm 1982 ), which he fi rst used in the context of philosophy of language and epistemology (Egan 2006 ). Egan's conclusion about the projectivist character of some of the properties we perceive objects as having shares a number of features with claims he makes elsewhere about seemingly distant philosophical subfi elds, such as aesthetics (Egan forthcoming). Jonathan Cohen defends a somewhat similar claim, that colors are constituted in terms of relations between subjects and objects, and his Philosophy of Perception: The New Wave 5 OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 5 June 3, 2010 6:45 PM argument turns on a sophisticated metaphysical analysis of the nature of properties and dispositions (see also Cohen 2009 ). Epistemology has always had special ties to philosophy of perception, traditionally because of the role perception is supposed to play in justifi cation. This link between perception and knowledge is at least partly due to the works of Fred Dretske over the decades (starting with Dretske 1969 ). Dretske's contribution to this volume, however, turns the established connection between perception and knowledge on its head. He is interested in what we perceive, and some of the considerations he uses in order to answer this question are about what we know (see also Dretske 2006 , 2007 ). This turn demonstrates neatly the change of emphasis in recent philosophical studies of perception. Perception is no longer interesting inasmuch as it can tell us something about knowledge (like the Strawson quote above seems to suggest). Quite the contrary: We can use epistemological considerations to answer intrinsically interesting questions about perception. III But why is it that, of all the subdisciplines of philosophy of mind, philosophy of perception receives all this special attention? What makes perception special? Three potential distinctive features come to mind. First, perception can be analyzed without talking about language or other higher cognitive apparatus, maybe even without talking about beliefs; hence, one possible strategy for understanding the mind would be to explain the relatively simple perceptual processes that human and nonhuman animals share and then move on to complex, exclusively human mental phenomena, such as language or higher order beliefs (this strategy is not so new; see Quine 1974 ). Second, we have more empirical data on perception than on any other aspects of how the mind works. But the third potential distinctive feature seems to be the most infl uential: Perception is our window to the world-it is the mental faculty that puts us into direct contact with the world. Much of recent philosophy of perception aims to do justice to this special role that perception plays in our mental life. And this brings us to a central, arguably the most central, question in contemporary philosophy of perception: whether, and in what sense, perceptual states could be considered to be representations. Philosophers and psychologists often talk about perceptual states as representations. Traditionally, one of the most important problems in philosophy of perception has been to explain in what way perceptual states represent the world. This seems to be a very natural framework to use if we want to talk about perception. Some of our mental states are representational. Most of our emotions are about something: We are afraid of a lion, for example. The same goes for beliefs, desires, and imaginings. It seems natural, then, 6 Perceiving the World OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 6 June 3, 2010 6:45 PM to suppose that perceptual states are also representations: When you see a cat, your perceptual state is about this cat-it refers to this cat. To understand perception is to understand in what way perception represents the world. Note that this framework emphasizes the continuity between philosophy of perception and other subdisciplines of philosophy of mind. There is a problem many (maybe even most) branches of philosophy of mind have in common: explaining how mental states represent the world. Philosophy of perception is not an exception: Its concern is to explain how perceptual states represent the world. And many (indeed, most) classic debates in philosophy of perception emerge naturally if we accept this conceptual framework. Furthermore, many classic debates in philosophy of perception have presupposed this conceptual framework, as I try to demonstrate briefl y here. If we reject the assumption that perceptual states are representations, these debates will look very different. Talking about perceptual representations has some important explanatory advantages. Two of the most important (and oldest) philosophical questions about perception have been (a) what is the difference between perception and sensation, and (b) what is the difference between perception and belief. According to the standard picture of perceptual processing, mere sensation, that is, the stimulation of our sensory organs, at some point in the processing gives rise to perception, and perception then (sometimes) gives rise to beliefs. In order to know what perception is, we need to have a way of delineating it from sensation, on one hand, and belief, on the other. If we think of perceptual states as representations, then there is a (relatively) simple way of drawing these lines. Perception is representational, but sensation is (arguably) not. The stimulation of our sensory organs (of the retina, e.g.) does not have content: It does not represent anything (although it may be a reliable indicator, like the number of tree rings is a reliable indicator of the tree's age). But our perceptual states represent the perceived object as having certain properties. So a clear division could be drawn between sensation, on the one hand, which does not have content, and perception and belief, on the other, which do. And as perception and belief supposedly represent the world differently, this representational difference between the two kinds of mental states may be used to draw the line between perception and belief. There are a number of proposals about the differences between the way beliefs and perceptual states represent the world, and these proposals, taken together, cover a large proportion of the traditional longstanding debates of philosophy of perception. One popular suggestion is that while perception represents the world in a very fi ne-grained manner, beliefs do so in a rather coarse-grained fashion-an image is worth a thousand words, as they say. This suggestion was criticized because the content of beliefs can be very fi ne-grained, and the content of some of our perceptual states is very coarse-grained indeed (see Dennett 1996 ). Philosophy of Perception: The New Wave 7 OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 7 June 3, 2010 6:45 PM Another interesting potential difference concerns the indexicality of these representations. Some of our beliefs have indexical content , which means that the correctness of the belief depends on the context of the tokening of this belief. My belief that today is Sunday or that I am now in Vancouver has indexical content because the correctness of these beliefs depends on when (and where) I have these beliefs. Some other beliefs have nonindexical contents: The belief that Paris is the capital of France does not have indexical content; the correctness of this belief does not depend on when or where you have this belief or even who has this belief. Thus, some but not all beliefs have indexical content. But one could argue that the content of perceptual states is always indexical. If you see a cat, you always see it as being in front of you or on your left or on your right- as being localized in your egocentric space. If Bill is sitting across the room from you, he may also see the same cat, but if you see the cat as being on your right, he sees it as being on his left. Thus, although Bill and you see the same cat, the content of his perceptual state is different from that of yours. The content of one's perceptual state, the argument goes, is always indexed to the person who has this perceptual state (see Peacocke 1986 , 1989 , 1992a ; see also Evans 1982 ; Noë 2004 ; Matthen 2005 on the concept of egocentric space). A third potential difference between perceptual content and belief content is that while the content of one's beliefs is conceptual, that is, could not have the content it has if one did not master certain concepts, the same may not be true of perceptual states. You could not have a belief that Paris is the capital of France if you did not master the concept of capital. But, arguably, you could perceive a cat without mastering any concept at all, including that of cat. You may not see the cat as a cat (which may require some conceptual apparatus), but you see the cat nonetheless (see, e.g., in favor: Evans 1982 ; Crane 1992 ; Bermúdez 1995 , 2007 ; Peacocke 1992b , 2001 ; Cussins 1993 ; Heck 2000 ; against: McDowell 1994 ; Noë 2004 ; for a good summary, see Byrne 2005 ). A fourth proposal is the following. The content of your belief that Paris is the capital of France is sensitive to the content of your other beliefs. In fact, you would not be able to have this belief unless you had some other beliefs, such as the one that Paris is a city. The same is not true of perceptual states. Our perceptual states can be very insensitive to our beliefs. We know that the two lines in the Müller-Lyer illusion fi gure are of the same length, but we can't help perceiving them as having different lengths. Finally, a potential difference between the contents of beliefs and of perceptual states is the nature of represented properties. Beliefs can represent their objects as having pretty much any property. Perceptual states, in contrast, represent their objects as having a limited set of properties, as having a certain shape, size, color, and spatial location. The list may be extended, but it is unlikely to encompass all properties. You do not perceptually represent the object in front of you as a laptop made in 2006 in 8 Perceiving the World OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 8 June 3, 2010 6:45 PM Malaysia. The question, then, is which properties are represented in perception and which ones are not (Siegel 2006 ). An important candidate for a perceptually represented property is the property of affording a certain action. It has been argued that we perceive objects as affording a certain action: We do not just infer that they do; we literally perceive this property (Nanay forthcoming, see also Gibson 1966 , 1979 ). These various ways of differentiating between perceptual and nonperceptual representations and their philosophical consequences cover most of the terrain of "traditional" philosophy of perception. In fact, most of the central debates of "traditional" philosophy of perception can be rephrased as debates about the nature of perceptual representation. But what happens if we question the assumption that perceptual states are representations? Although considering perceptual states to be representations may be a natural way of describing our perceptual system, and this assumption dominated both the philosophical and the psychological research on perception, some have recently questioned this entire framework. The proposal is that perceptual states are not representations: Perception is a genuine relation between the perceiver and the perceived object (and not between the agent and some abstract entity called "perceptual content"). This recent antirepresentationalist view of perception is often called the "relational view of perception" (the terminology comes from Campbell 2002 ). It is important to note that if we reject the representational view of perception, the classic debates of philosophy of perception does not go away. Many of these debates can be easily rephrased in nonrepresentational language (e.g., the question about what properties we perceive objects as having; see Siegel 2006 ). But some other debates seem more diffi cult to transplant into the relationalist framework. The representational versus relational debate is one of the most important and infl uential debates in philosophy of perception today (on the relational side, see Snowdon 1990 ; Martin 2004 , 2006 , forthcoming; Travis 2004 ; Brewer 2006 , forthcoming; Fish 2009 ; Hellie 2007 ; on the representational side, see Chalmers 2004 ; Byrne 2001 ; Byrne and Logue 2008 ; Siegel 2010 ; Pautz forthcoming; Tye 2007 ; see also Crane 2006 for a good summary). Unsurprisingly, no less than four chapters in this volume aim to contribute to this debate, mainly by clarifying its dialectics. Susanna Siegel's chapter gives a clear account of the basic commitments of the representational view and argues that, to genuinely depart from it, the relational view has to take on a radical and implausible form. Standard versions of the relational view, she argues, are hard-pressed to deny that experiences have contents. Adam Pautz gives a thorough analysis of various possible arguments in the representational–relational debate, for and against (see also Pautz forthcoming). He concludes that none of the alleged knockdown arguments are conclusive, but we have some (although maybe not fully decisive) reason to prefer the representational Philosophy of Perception: The New Wave 9 OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 9 June 3, 2010 6:45 PM alternative. Together, these two chapters form a very good introduction to debates concerning the status of perceptual states as representations. Benj Hellie's chapter does not argue for the relational view (he does so in Hellie 2007 ) but rather examines how we can analyze our inner experiences if we reject representationalism. Mike Martin explores various ways of talking about how things look without endorsing the representational view. They both attempt to carve out a way of examining some of the old problems of philosophy of perception while discarding the supposition that perceptual states are representations. These two chapters indicate an important possible direction for philosophy of perception: If we reject the idea that perceptual states are representations, this does not solve all the problems of perception, nor does it make them become irrelevant. One big challenge for the antirepresentationalist camp is to create a conceptual apparatus for raising some of the old questions about perception while doing justice to the intuition that perception provides our direct contact with the world. Hellie's and Martin's chapters in this volume take some steps to this direction. IV So far, I have focused on how the questions philosophers ask about perception have changed. But it is important to note that the way these questions are addressed has also changed considerably. An important feature of the new way of arguing about philosophical questions concerning perception is that paying close attention to empirical fi ndings about perception seems to be the norm, rather than the exception. What this means is not that philosophy of perception has became theoretical vision science. Rather, the philosophical arguments about perception are constrained by, and sometimes supported by, empirical evidence. Even in the case of some of the most genuinely philosophical debates, such as the representationalism versus relationalism debate, many of the arguments use empirical fi ndings as premises. The empirical fi ndings used by the authors of this volume are very diverse. Jérôme Dokic uses mainly cognitive neuropsychological evidence about patients with Capgras's and Fregoli's syndromes in his treatment of the questions of whether and in what sense the recognition of people is perceptual and in his argument for his positive claim that the recognition of people involves a nonsensory component: the feeling of presence. Jesse Prinz, in contrast, uses pretty much all subfi elds of psychology and neuroscience to decide the age-old question about what makes perception conscious. His answer is: attention. One important feature of Prinz's contribution is that, based on neuroimaging and behavioral evidence, he sketches an empirically plausible philosophical account of attention. Given that the concept of attention seems to play an increasingly important role in philosophy of perception, Prinz's theory provides a valuable 10 Perceiving the World OUP UNCORRECTED PROOF NANAY-Chapter 1-Page Proof 10 June 3, 2010 6:45 PM contribution to the growing body of research on the relation between attention and consciousness (see also Huang and Pashler 2007 ; Koch and Tsuchiya 2007 ; Nanay 2010 ; Mole forthcoming; Prinz forthcoming). It is not at all surprising that philosophy of perception is the fi eld where empirical considerations are used most widely in philosophical arguments. Vision science is in many ways the most advanced branch of cognitive science, and as a result, it seems easier to bring empirical considerations into philosophical arguments about perception than into arguments about beliefs or desires. 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