Mental images, imagining, and the 'Multiple Use Thesis' Kathleen Stock, University of Sussex k.m.stock@sussex.ac.uk Abstract My topic is a certain view about mental images: namely, the 'Multiple Use Thesis'. On this view, at least some mental image-types, individuated in terms of the sum total of their representational content, are potentially multifunctional: a given mental image-type, individuated as indicated, can serve in a variety of imaginative-event-types. As such, the presence of an image is insufficient to individuate the content of those imagination-events in which it may feature. This picture is argued for, or (more usually) just assumed to be true, by Christopher Peacocke, Michael Martin, Paul Noordhof, Bernard Williams, Alan White, and Tyler Burge. It is also presupposed by more recent authors on imagination such as Amy Kind, Peter Kung and Neil Van Leeuwen. I reject various arguments for the Multiple Use Thesis, and conclude that instead we should endorse SINGLE: a single image-type, individuated in terms of the sum total of its intrinsic representational content, can serve in only one imagination eventtype, whose content coincides exactly with its own, and is wholly determined by it. Plausibility aside, the interest of this thesis is also in its iconoclasm, as well as the challenge it poses for the diverse theories that rest on the truth of the Multiple Use Thesis. Keywords: Imagination; mental images; Christopher Peacocke. 2 Mental images, imagining, and the 'Multiple Use Thesis' 1. The 'Multiple Use Thesis' I'm about to examine a widely held and usually unexamined view about the nature of mental images. Following Paul Noordhof (2002: 428-9), let's call my target 'the Multiple Use Thesis' or 'MULTIPLE' for short. Because most cases taken to demonstrate the truth of MULTIPLE involve images of what things look like, I'll mostly talk of those in what follows, but the claim is, I assume, a more general one, potentially extended to images of what things sound like or feel like too. MULTIPLE is found in Christopher Peacocke (1985) and the assertion that, for instance, a single mental image can serve in the projects of, on one hand, imagining a suitcase, and, on the other, imagining a suitcase with a cat totally obscured behind it. Equally, he writes, a single image can serve in the projects of imagining 'being at the helm of a yacht; imagining from the inside an experience as of being at the helm of yacht; and imagining from the inside what it would be like if a brain surgeon were causing you to have an experience as of being at the helm of a yacht'(1985: 19). Michael Martin (2002) endorses a similar point: 'The same imagery can be put to different imaginative purposes: one might imagine red apples, perfect wax replicas of apples, the skins of such apples with the cores hollowed out or a cunning illusion of the presence of apples, while visualising in the same way' (2002: 403). MULTIPLE is also present in Alan White's claim that: '.. To have an image of red grass is not necessarily to imagine grass being red or that grass is red. The imagery of a sailor scrambling ashore could be exactly the same as that of his twin brother crawling backwards into the sea, yet to imagine one of these is quite different from imagining the other (1990: 92)1.' Other authors who accept MULTIPLE include Noordhof (2002: 428-9), Tyler Burge (2005: 66), Amy Kind (200: 101) and in more recent writing, Peter Kung (2010: Section 1; see also forthcoming) and Neil Van Leeuwen (forthcoming)2. As I write, I know of no-one who has explicitly argued in published work against it. 1 This instance of MULTIPLE also seems to assume that mental image-types may not represent movement properties, but must be static. 2 Confirmed through private correspondence. 3 Less obviously detectable endorsement of MULTIPLE IS found, for instance, in David Chalmers' claim that: 'one can imagine pairs of situations that are perceptually indistinguishable: for example.. the existence of a conscious being and its zombie twin..In these cases, [where S is one of those situations] we don't form a perceptual image that represents S' (2002: 151). An unusual version of MULTIPLE is also implicit, I'll suggest, in Bernard Williams (1976). So what exactly is the claim I have in mind? MULTIPLE is rarely argued for explicitly, and usually casually assumed on the way to some bigger argumentative target. However, with a bit of spadework its implicit commitments can be unearthed, via the things its proponents tend to say. We first need to distinguish MULTIPLE from close and less problematic relatives. At a first pass, MULTIPLE says that the same mental image-type can serve in variety of imagination-events (or imagination-event-types)3, where the latter differ from one another in their representational contents overall. Perhaps obviously, this is not the claim that the same mental image-type (e.g. of a brunette woman in a red dress) might be used to imagine a) a woman b) a woman in a red dress c) a brunette woman in a red dress. This would not be a case where a single image-type served in a variety of imagination-events with different representational contents overall: in each case, it seems more natural and less theoreticallyladen to say, we would have the same imagination-event, variously described. But to say only that the same mental image-type can serve in a variety of imagination-events, which differ from one another in terms of overall representational content, makes MULTIPLE look rather bland. For there are many ways to type-individuate mental images, some more coarse-grained than others, and it seems clear that at least under some description, the same type of mental image might feature in two different imagination-events. (e.g. the type of mental image had by this particular thinker). To better home in on our target, we need to designate the respect in which the image is being type-individuated. We can distinguish at this early stage between two different versions of MULTIPLE, each of which type-individuates mental images according to different criteria: (1) The 'phenomenal' version: for any single mental image-type M (type-individuated in terms of phenomenological feel from the inside), M can appear in a variety of imaginationevents, each of which differ from one another in terms of representational contents overall. (2) The 'content' version: for any single mental image-type M (type-individuated in terms of its intrinsic representational content), M can appear in a variety of imagination-events, each of which differ from one another in terms of representational contents overall. 3 Why I use the relatively clunky 'imagination-event' will be elucidated shortly. 4 I'll assume, for reasons to become clearer later4, that someone who endorses (2) is likely to appeal to (1). In any case I'll be casting doubt upon both (1) and (2). For the most part, though, I'll focus on (2): focus, that is, on the 'content' version of MULTIPLE. Let us assume that mental images have representational content, unproblematically. The 'intrinsic content' of an image, as I'll use it, is the content it would have no matter what imagination-event it featured in. Many particular articulations of this view have a further commitment. They say that the imagination-events in which M can appear are constrained thus: they are those that represent scenarios that might be visually indiscernible from one another in actuality. So, for instance, we are told by Martin, a single mental image-type might appear in i) an imagination-event which represents apples; ii) an imagination-event which represents apple-simulacra; iii) an imagination-event which represents apple-hallucinations. The reason why these imaginationevents were chosen and not others is presumably because they represent scenarios each of which might be visually indiscernible from one another. Equally, in one of Peacocke's examples, a single mental image-type might appear in i) an imagination-event that represents a suitcase and ii) an imagination-event that represents a suitcase with a cat thoroughly hidden behind it. Again, what is represented in the first case is something potentially visually indiscernible from what is represented in the second. At this point we must add a further commitment of all versions of MULTIPLE, pushed to the fore by noting this tendency to discuss the representation of visually indiscernible situations. As already indicated, there are many ways to type-individuate mental images: one way would be to designate as belonging to type T, all those mental images which shared some particular representational properties, irrespective of the further representational properties in which they differed. For instance, we might designate as a type of mental image, all those mental images that represent events involving red appearances (whatever else they represent, at a more finegrained level of description). It seems true that potentially, members of this course-grained type might be involved in say, an imagination-event which represented a red apple, an imaginationevent which represented a red apple-simulacrum, and an imagination-event which represented a red apple-hallucination. But this looks innocuously true and unsurprising, as well as relatively complicated to deny. So I take it that a substantive version of the content version of MULTIPLE must be committed to c): a) M is type-individuated in terms of the sum total of its representational properties. With this clarified: for the most part, the view I'll be scrutinising is that the very same imagetype, individuated as such, fine-grainedly, in terms of total representational content, could be 4 Namely, the temptation to arrive at something like (2) on the basis of a 'highest common factor' strategy, as discussed in section 5. 5 used to represent various imagination-event-types, each with different overall contents, but each of which represent situations which would be visually indiscernible if actualised. Though it is rarely spelled out, this is the claim that I take it, most proponents of the 'content' version are committed to. (An exception is Willams, whose relatively unusual view I'll consider in the next section). A question remains about the scope of this claim. Most advocates of MULTIPLE explicitly say only that some images are multifunctional. To my eye, however, MULTIPLE looks potentially universal in scope. Effectively MULTIPLE says that wherever a mental image-type M, individuated in terms of the sum total of its representational properties, contributes to an imagination-event-type which represents scenario S, M might equally have contributed to an imagination-event-type T, as long as T might be visually indiscernible from S in actuality. I also assume that for any scenario S there might be a further one T visually indiscernible from it. The conjunction of these assumptions seems to make MULTIPLE universal. However, I'll proceed cautiously and discuss a version more limited in scope. A final preliminary: one might wonder why so far, I have used the relatively clunky term 'imagination-event' rather than the more natural looking 'imaginative episode' (or 'imaginative project'). It seems that an imaginative episode might naturally be thought of as extended over time, and perhaps include mental imagery as a part of it, in which case there will be a sense in which the same image-type might serve in a variety of imaginative episodes; but MULTIPLE entails something stronger. That is, there is a further distinction to be drawn, between the following cases: a) A mental image M, experienced by a thinker as enduring for a given period of time p, serves in a narratively structured imaginative episode EP which endures for a longer time period than p, and where EP's representational content overall is different to that of M. b) A mental image M, experienced by a thinker as lasting for a given period of time p, serves in an imagination-event E whose temporal duration is also p, and where E's representational content overall is different to that of M. The 'content' version of MULTIPLE says that b) is true for many cases. As an alternative to MULTIPLE, we should adopt SINGLE. SINGLE says that a single imagetype, individuated in terms of the sum total of its intrinsic representational content, can serve in only one imagination event-type, whose content coincides exactly with its own, and is wholly determined by it. Even where scenario S might be visually indistinguishable from scenario T in actuality, there is no need to say, of a mental image involved in representing S, and a mental image involved in representing T, that they are of the same type, except in the innocuous sense previously detailed, in which both images might fall count as tokens of a course-grained type, among other types. In what follows, I'll suggest that we have no good reason to endorse MULTIPLE over SINGLE, despite most philosophers' relatively quick assumptions to the 6 contrary. Should the arguments be persuasive, my thesis has value in its relative iconoclasm, as well as the challenge it poses for the many theories that rest on the truth of the Multiple Use Thesis. 2. 'Adding' or 'de-emphasising'? As yet, I've said nothing about what representational properties an image might intrinsically possess according to MULTIPLE. It seems that there are two paths one might take here. According to the first and more popular strategy, the sort of entities a mental image may represent is restricted to only those entities that might be represented in every one of the imagination-events in which the image-type in question is said to possibly appear. Meanwhile, some additional mental act or item (though not necessarily one is conscious of) 5 is simultaneously present to 'add' in further non-intrinsic content, so as to differentiate the imagination-events from one another overall. So, for instance, where one holds that a single image-type might represent (for instance) either an apple, or an apple-replica, or an apple-hallucination, this strategy would urge that the image-type in question can't represent apples: for apples are, precisely, not present in the second or third scenario listed here. Effectively, assuming that a mental image-type M may serve in imagination-events which represent scenario S, T, and U respectively, then this strategy says that those properties M may intrinsically represent are restricted to only those entities which might be represented throughout visual experience of S, T and U. As we'll see, this assumption looks present in Peacocke; it is also explicit in Kung (2010: 623) who characterizes the 'basic qualitative content' of an image as comprising colored, shaped objects at very basic levels of description. On this strategy, what one allows as possibly intrinsically represented by a mental image-type will be determined by the range of imagination-events in which, it is judged, the mental imagetype may potentially play a role. So, if one's only example as an instance of MULTIPLE was Peacocke's suitcase example, one might allow that an image intrinsically representing a suitcase is present in both imagining a suitcase, and imagining a suitcase with a cat hidden behind it, but deny that this image could serve to represent a suitcase-hallucination. But if one allowed that this same image-type might equally appear in an imagination-event representing a suitcase-hallucination, then it looks like suitcases would be ruled out as potentially intrinsically represented by the relevant image-type. Since most advocates of MULTIPLE do allow that the same image-type might serve in a representation of a medium-sized object O and an Ohallucination, I'll focus on this version for most of what follows. But whichever: on this sort of 5 See Kung (forthcoming). Kung also denies that he is granting that two distinct psychological processes are involved. However, if we're to take seriously the idea that images have two different kinds of content, it is hard not to think that that content must have been produced via ultimately different routes. Many of my complaints against MULTIPLE don't depend on this point, however. 7 strategy, we can usefully distinguish between i) the intrinsic representational content of imagetype M and ii) that 'extra' representational and non-imagistic content which is contingently added in each case, in order to arrive at the content of the imagination-event overall.6 This 'additive' strategy is explicit in Peacocke, who designates the mental act that adds content 'Simagining' (1985, p. 25). Kung, meanwhile, distinguishes between 'basic qualitative content' and 'assigned content' (p.623); Martin talks about the 'sensory core' of an image, and the way that that core is 'labeled'. There is, however, another view of what a mental image-type may potentially intrinsically represent, which I'll now take a moment to consider. This is the view expressed in Williams (1976). As above, on this view mental images have intrinsic content, in virtue of which they are type-individuated; and an accompanying non-imagistic mental act interacts in some way with that intrinsic content. But this time, the effect of this act is to place certain emphasis on only some of the intrinsic content of the image, ignoring other parts of that content as negligible. So on this version it is not so much that non-intrinsic content is contingently added to an image, but that some aspects of intrinsic content are contingently de-emphasized such that the overall content of the imagination-event differs from that of the image on its own. Williams claims there is a potential difference between what is 'visualized' (i.e. what is the intrinsic content of a mental image) and what is imagined (i.e. what is the overall content of the imagination-event). He argues that a thinker may imagine a bath, but not a woman in a bath, by way of having an image of a woman in a bath: 'even when we imagine by way of visualising, we can properly be said to imagine something lacking an element which is present in what we visualise' (1976: 33). So we see that on this version of MULTIPLE, somewhat unusually in comparison to its other advocates, Williams is not obviously concerned to invoke the view for cases where, supposedly, a single mental image-type can be used to represent various visually indiscernible scenarios, in the context of different imagination-events. For there seems to be an obvious visible difference between the scenario in which there is (only) a bath, and the scenario in which there is a woman in a bath. What, according to Williams, is the nature of the non-imagistic accompanying mental act which interacts with the intrinsic content of a mental image? It is the thinker's intention to imagine something (or at least, 'the story a man would ideally tell if telling what he imagined': 30) that emphasizes some aspects of an image's intrinsic content whilst de-emphasizing others. 6 When I talk about content 'contingently' present, I mean content which does not belong intrinsically to the image-type, strictly speaking, but only to the imagination-event as a whole; but which may sometimes colloquially be described as belonging to a mental image, when we are talking loosely. 8 Might all this be used to support MULTIPLE? Amongst its supporters, at least one person thinks so: Noordhof cites Williams on this matter approvingly (2002: 427). But the strategy now being considered stands or falls by the plausibility of the claim that intention can 'deemphasize' certain aspects of one's image so they don't transfer to the content of the imagination-event overall. Unfortunately for MULTIPLE, plausibility looks lacking. Consider two possible cases, between which Williams tends to waver (33-34). In the first, Jane intends to imagine a bath; in response, she has an image that intrinsically represents a woman in a bath. There is no reason here to deny that Jane imagines a woman, even if the woman is strictly speaking irrelevant to her project. The things that one intends to imagine have to be imagined some way or other: equally, one might intend to imagine a lion, and in response have the image of a lion yawning. Yet there would be no temptation here to say that overall one imagined only a lion, but not one yawning. That one might not mention or focus upon the yawning when asked doesn't show it wasn't present in the first place. A different case is where Jane intends to imagine an empty bath; in response, she has an image that intrinsically represents a woman in a bath. Here I see no reason to deny Jane has an imagination-event that represents a woman in a bath, even though she intended to do otherwise. It is possible to fail in one's intention to imagine something, as this example shows; and in such cases, there is no sense in which mere presence of the original intention get to determine by fiat what actually occurs. Williams offers a further example that turns out to be structurally similar to the case of Jane, and to share its problems. He contrasts the cases of two people who imagine the assassination of the Prime Minister by way of an image of Lord Salisbury: the first (let's call her Jess) erroneously believes that Lord Salisbury is the Prime Minister, and intends to imagine the Prime Minister, whoever he is, as being assassinated; and the second (Ralph) knows that Salisbury is not the Prime Minister, but imagines (and intends to imagine) him as such (30-31). Williams suggests that, at least in some sense, only Ralph imagines Lord Salisbury as the Prime Minister being assassinated, on the grounds that it is inessential to Jess's project to imagine something about Salisbury, or at least, it would be, were he in full knowledge of the fact that Salisbury was not actually Prime Minister. Again, this seems to mix up two different considerations. The first is whether, when one's intention is to imagine S by way of an image, the way in which S is concretely represented in one's image (e.g. as having property P) transfers to the overall account of what one imagines. As with the case of the yawning lion image, there is no reason to deny this. The other question is whether, when an intention to imagine something is unsuccessful in some way as is Jess's intention to imagine whoever the Prime Minister actually is we should analyse what the thinker actually imagines overall in terms of what she is trying to do, rather than what she does. Again, there seems no reason to concede this. Imagining is standardly classed as an action, albeit a mental one, and the concept of unintended action is a familiar enough one. 9 I conclude that despite Williams' efforts, it remains obscure how an accompanying mental act such as an intention might de-emphasize some aspect of the intrinsic content of a mental image, so that the resultant imagination-event differed in total content from its component image. This obscurity is highly detrimental to the chances of the 'de-emphasis' version of MULTIPLE. For the rest of the paper, I'll focus on the 'additive' version as an apparently more plausible alternative– the view, already described in detail, according to which a single mentalimage type, individuated in terms of its total content, may serve in a variety of imaginationevents, each of which represent scenarios which would be visually indiscernible from one another if actualized. The image-type in question has content more restricted (not less, as the de-emphasis version would have it for some cases) than any of the imagination-events in which it may feature, and so requires some accompanying mental item to 'add' contingent content to the image-type somehow, to arrive at its content of the imagination-event overall7. When I talk of MULTIPLE in what follows, it is this version I have in mind. 3. 'Quick' routes to MULTIPLE barred There are a few quick routes by which one might think to reach MULTIPLE. Since ground for MULTIPLE aren't usually offered, it's reasonable to try to anticipate the hidden and relatively unreflective motivations for it. This will make room later for discussion of more involved and perhaps more persuasive considerations in MULTIPLE's favor. One might, for instance, start with the thought that i) Mental images can intrinsically represent only what might be visible. Does this lead to MULTIPLE? Only if we insert a second premise citing an implausibly strict necessary condition on what it is for something to be visible, according to which ii) If x might be visible then vision must be able to detect some evidence for x's presence rather than the presence of an exact doppelganger. ii) allows as visible, perhaps, colors, shapes, twin-Romulus-or-Remus appearances; appleappearances. But it disallows that twin Romulus in particular, rather than identical twin Remus, might be visible; or that an apple as opposed to an identical apple-simulacra, or an applehallucination, is visible, strictly speaking. Given i) and ii) we would get: iii) Mental images can intrinsically represent only those entities such that vision might detect some evidence for their presence, rather than the presence of an exact doppelganger. 7 Readers should also bear in mind that I am focusing on the 'content' version of MULTIPLE. The 'phenomenal' version will be considered along the way. 10 In other words, just as what is visible is restricted as described, so too is the intrinsic representational content of mental imagery. But ii) is surely too strong. In ordinary discussion we allow that apples are visible, even despite the fact we may not be able to distinguish them from apple-simulacra or apple-hallucinations. Equally, at least in some circumstances, applereplicas indiscernible from apples are visible – e.g. in a world in which they predominate. The same point would apply to apple-hallucinations in certain contexts. If it is insisted, however, that ii) is right, my response, via the objections which follow, will be that it turns out that the natural thought that mental images can represent only what is visible is false, strictly speaking. A different 'quick' route to MULTIPLE might deny that mental image-types can represent only what is visible, given an alternative necessary condition on visibility, which the things represented by images fail to meet: for x to be visible to me, then I must be in direct causalperceptual contact with x. For instance, say that I see (under a relatively coarse-grained description) a glass of clear liquid in front of me. Part of what makes it the case that I see water as opposed to indiscernible flat lemonade is determined by my direct causal-perceptual relation to water in the glass. The next move here would be to ask what makes it the case that, where I have a mental image of water in a glass, I have an image of water as opposed to an image of indiscernible flat lemonade, given that no such causal-perceptual links determine the nature of my thought (at least, directly)? At which point, MULTIPLE might seem to beckon: in the absence of any causal-perceptual relation to water, the best explanation of fact my image is of a glass of water rather than, say, a glass of flat lemonade, is that such content is stipulatively 'assigned' separately and non-imagistically. But this can't be right. The general question of what makes thoughts about A rather than B, in the absence of any direct causal-perceptual links to A, is surely puzzling but it extends further than the question as it pertains to imagery. But this shows that the proposed solution won't work. The present suggestion is that in the case of imagery, whether an image-type ultimately represents water or flat lemonade is a matter of stipulation via some further non-imagistic mental content. But if the claim is that, in the case of imagery, what makes my image of water rather than flat lemonade is further content which non-imagistically represents water, as opposed to flat lemonade, one might equally ask: what makes that content about water, rather than flat lemonade, given that there is no water which causes it directly? A regress clearly threatens. Whatever the story about how our images can represent things to which we are not obviously directly causally corrected, it can't be this. A third 'quick' route might be presented as follows, this time in the form of intuition-pump. Say that I tend to get Jess and Bess confused, and I have a mental image of one of them, which I know is a memory image deriving from a party I was at where they were present. I 'scrutinise' the image to work out which it is of, and work out that it is of Jess. Isn't this a case where a single mental image-type has persisted throughout two different interpretations of it, and so two different imagination-events? I see no reason to accept the intuition pump, as long as I can construe the example plausibly in a way consistent with SINGLE. In that case I can dismiss the intuitions of those who construe it 11 as supporting MULTIPLE as already in MULTIPLE's grip, so that the case is inconclusive. And I can so construe it. Before one realized that one's image was of Jess, one had an image which intrinsically represented only someone of a Jess-or-Bess-appearance; after one's realization one had a different mental image-type, representing not only someone of a Jess-or-Bessappearance but also where that someone was represented as Jess not Bess. These are different types of image respectively. Moreover, we needn't analyse what occurs here as a matter of 'scrutinising' an image to see what it is of; we can simply say that we are thinking again about what we saw, which seems much less metaphysically prejudiced. I conclude that none of these 'quick' routes to MULTIPLE convincingly motivate it. I'll now consider a potential route to MULTIPLE which is rather more complicated, and which derives from examination of the context in which Peacocke presents MULTIPLE. 4. Peacocke and MULTIPLE Peacocke is rare amongst supporters of MULTIPLE in embedding it in an argumentative context that might be interpreted as providing support for it. In addition to MULTIPLE, Peacocke endorses the 'Experiential Hypothesis', according to which having a mental image of an object O necessarily involves, at least, imagining a perceptual (usually visual) experience as of O. Putting MULTIPLE with the Experiential Hypothesis, we get: a mental image-type, intrinsically representing a visual experience as of O, might be had in the context of imagining an O, an O-replica or an O-hallucination. As already indicated, Peacocke introduces 'S-imagining' as the mental act responsible for introducing the additional content that differentiates the overall contents of each imaginationevent from one another. For instance, in the case of the yacht-based imagination-events, 'In one case it is [S-]imagined that the experience is perceptual; in the second it is left open; in the third, it is imagined that it is produce by an intervening brain surgeon' (1985, p.25). Against this background, Peacocke relies upon MULTIPLE to support the Experiential Hypothesis as follows: the Experiential Hypothesis helps explain how MULTIPLE (assumed as correct, without argument) is possible: 'When the same image can serve two different imaginative projects, that is because the imagined experience fulfilling each project can be the same. An experience of a suitcase and an experience of a suitcase with a cat wholly obscured behind it may be of the same type: the same applies to the imagined experiences in the yacht example' (p.24). Now, on the face of it, this might seem puzzling: how could the very same image-type which represented a visual experience as of a yacht contribute to the imaginative representation of a yacht -hallucination? I take it that in addition to MULTIPLE, there is a further implicit 12 commitment in the background here: representationalism about perceptual experience. That is the view that a visual experience of an yacht, and of a yacht-replica, and of an yachthallucination, are all potentially type-identical in a way fundamental to their identity, in that they potentially share the same total set of representational (and sensational) properties. At this point it is worth a quick digression to explain one of the surface attractions of representationalism, which will become relevant again later. Following Haddock and Macpherson (2008) let's call this a 'highest common factor' argument. It notes that there is, potentially, a relatively homogenous phenomenology – a 'highest common factor' amongst various visual experiences of different causal provenance e.g. (to return to Martin's example) apple experiences, apple-simulacrum experiences, apple-hallucinations. In each case, it is for the perceiver as if there is a apple, presented in a certain way, so that this appearance would have authority over her beliefs, in the absence of countervailing evidence she was aware of. It is assumed that this shared phenomenology should inform the type-individuation of experiences: same phenomenology, same experience-type, irrespective of the variety of objects or other causes exposure to which might have eventuated in that experience-type. The representationalist then seeks to explain this 'highest common factor' in terms of some further shared feature between all the experiences in question: namely, shared representational content (plus, perhaps also, sensational properties8). So for the representationalist, a visual experience 'of' medium-sized object O need not be factive: need not be veridical, nor Oinvolving. Another way of putting this it is that in a certain sense, representationalism is a 'multiple use' theory of visual experience: the very same visual experience-type, individuated in terms of its total set of representational and/or sensational properties, might have appeared in a context where the visual experience was caused by a different object or experience. (This is not exactly analogous to MULTIPLE, however, because the specification of the variety of contexts in which a visual experience-type might have appeared, according to representationalism – i.e. where the visual experience might have been caused by various objects differs from the specification, according to MULTIPLE, of the variety of contexts in which an image-type might have appeared – i.e. where the image might have been accompanied by a mental act responsible for interfering with the content of the image in various ways.) Let's return now to Peacocke's implicit argumentative strategy. Though he doesn't say so in the paper, I speculate that he thinks that the truth of the 'content' version of MULTIPLE is explained by representationalism plus the Experiential Hypothesis. This is what makes sense of his claim that 'When the same image can serve two different imaginative projects, that is because the imagined experience fulfilling each project can be the same' (p.24). But if this were right, it might seem that support for MULTIPLE might be provided, providing independent arguments could be provided for representationalism and the Experiential Hypothesis, 8 Peacocke allows that visual experiences have sensational properties as well as representational content (1984). 13 respectively. I'll argue, however, that the promise is illusory: even if representationalism and the Experiential Hypothesis were right, MULTIPLE still wouldn't follow. Following the lead of Martin (2002) let's stipulate that a representation counts as phenomenologically committed with respect to there being an O, if it is for the thinker who has it, as if there were an O that was thus-and-so, in a way which has authority over her beliefs, other things being equal, in the sense in which she would believe there was an O in front of her unless she had prior reason to doubt it. Otherwise it is phenomenologically neutral. Then the commitments of the views we are considering as potentially supportive of MULTIPLE, can be spelt out as follows: Where O is a medium-sized object (i.e. not an appearance, or a colour or shape) (1) Representationalism: A visual experience 'of' O/ of an identical O-replica/ 'of' an Ohallucination (or better, 'as of' O, etc.) is a) phenomenologically committed to there being an O; b) represents an O; but c) is not factive with respect to an O. (2) Experiential Hypothesis: A mental image colloquially 'of' O (or colloquially of an identical O-replica, or 'of' an O-hallucination) intrinsically represents (at least) a visual experience as of O. (1) and (2) are supposed to support: (3) Peacocke's version of MULTIPLE, interpreted for the moment as entailing that the intrinsic content of a mental image colloquially 'of' O (or colloquially of an identical Oreplica ,or 'of' an O-hallucination), in virtue of which that image is type-individuated, does not represent an O in the imagined scene. From this we get the intermediate premise: (1+2). A mental image colloquially 'of' O (or colloquially of an identical O-replica ,or 'of' an Ohallucination), represents (at least) [a visual experience as of O, which is a) phenomenologically committed to there being an O; b) represents an O; but c) is not factive with respect to an O]9. Would this support MULTIPLE? That is, would either (ex hypothesis) the facts either that a visual experience VE was phenomenologically committed to there being an O, or that it represented an O, or that it was non-factive with respect to O, either: i) transfer to a mental image-type M which (ex hypothesis) represented VE, either straightforwardly, or as an imagined property of that visual experience; and 14 ii) somehow motivate the claim that M does not intrinsically represent O? In a word, no. But let's take each in turn. First, even if representationalism plus the Experiential Hypothesis were true, the phenomenological commitment of a visual experience VE with respect to there being an O, would not seem to plausibly transfer straightforwardly on any account to an image M which represented VE, since clearly, images are not phenomenally committed in this way on any account: when one has an image of O, it is not for the thinker as if there is an O, in a way which would have authority over her beliefs other things being equal. Instead, it might be claimed by the exponent of the Experiential Hypothesis that the phenomenal commitment of VE transfers to M as an imagined property of VE (in having image M, one imagines a visual experience VE which is phenomenally committed to there being an O). This seems like it might be right, but in any case, it offers no obvious support for the claim, which for the moment we are considering as central to MULTIPLE, that M doesn't represent an O: the two points look unconnected. What about the fact that VE represents an O? If representationalism plus the Experiential Hypothesis were right, the property of representing O presumably would straightforwardly transfer to the image M which represented VE. For if an image M itself represented a [visual experience VE which represented an O], then it seems to follow that M would then in turn represent an O. However this is precisely the wrong result, since, at the moment at least, we are trying to establish that M would not represent O! Finally, even if representationalism plus the Experiential Hypothesis were true, the nonfactiveness of a visual experience VE with respect to O would not seem to plausibly transfer straightforwardly to the image M which represented VE on any account, since whether or not M veridically represents O or not doesn't seem to have anything to do with its type-individuation – mental images are hardly ever veridical, after all. Meanwhile, were representationalism and the Experiential Hypothesis true, the non-factiveness of VE would not seem to transfer to M as an imagined property of VE either. That is, even if the content of a mental image colloquially 'of' O actually intrinsically represented only a visual experience as of O, and even if visual experiences were type-individuated in the way that representationalism suggests, it would surely not be the case that in having an image M which represented visual experience VE, one would therefore imagine that VE was non-factive with respect to an O. That is, it is unreasonable to think the imaginer must take some stance, even implicitly, on whether representationalism is true or not. (Additionally, even if non-factiveness did transfer in this way as an imagined property of VE as represented by M, it is unclear exactly how this would support the claim that M does not represent O). Spelt out in detail, then, representationalism plus the Experiential Hypothesis would not seem in any way to support MULTIPLE. One might object here that the combination of representationalism with the Experiential Hypothesis is not the only candidate approach in this area. At least one supporter of MULTIPLE, Martin, looks committed to a) the Experiential Hypothesis b) disjunctivism, according to which the most explanatorily important way to type-individuate visual experiences is not in terms of their total representational content, as representationalism would have it, but 15 rather in terms of what objects they manifest direct awareness of and have as constituents (2002). On this basis, he seems to take it that a mental image which (ex hypothesis) represents a visual experience of O, also represents an O. In fact, it is not clear how this is supposed to work: for just as before, it is not clear how a fact, if it is one, about whether or not a visual experience is factive – that is, whether the experience needs to be veridical to count as the type of experience it is (disjunctivism says yes) – could standardly transfer to the content of an image which represented that visual experience, either straightforwardly (clearly it doesn't) or as an imagined property of the image. But leaving this aside, in any case, it seems clear that for Martin, an image that represents a visual experience of O, represents an O too. And as we have just seen, that a mental image represents an O would seem to follow from the fact, ex hypothesis, that a mental image represented [a visual experience which represented an O]; so this looks promising. But then the question arises: How might this new possibility be compatible with the claim that same image-type, which represents an O as well as a visual experience as of O, might also have been involved in an imagination-event which represented, not just an O, but also an 0replica, or an O-hallucination? In other words, it looks like we are now considering a version of the 'de-emphasis' strategy discussed in the context of Williams earlier. Yet I take it that with our prior rejection of 'de-emphasis' as a possibility, there is no explanation remaining of how the intrinsic content of a mental image-type present throughout imagination-events representing an O, an O-replica and an O-hallucination, could intrinsically represent an O. So, despite appearances, MULTIPLE can find no actual support here. This throws us back once again to the 'additive' strategy. We have found no support for this view in Peacocke, even allowing representationalism and the Experiential Hypothesis for the sake of argument. In the next section, I'll seek to further undermine the view, by considering what must seem to many one of its more powerful attractions. 5. Highest common factor again I anticipate a reader asking why I am bothering with the relatively byzantine reconstruction of possible routes to MULTIPLE via Peacocke's use of it, when there is a much more straightforward strategy obviously available. Earlier I described a means of apparent support for representationalism, via the 'highest common factor' strategy, which notes that the very same stable phenomenology might accompany several visual-experience tokens, each with distinct sensory sources as their causes; and infers this is a reason to think they are of the same type. Analogously, it might be argued, the very same stable phenomenology might accompany several mental-image tokens, each with distinct sensory sources as their imagined causes; this is a reason to think they are of the same type. There is a problem here however: namely that, once we leave aside any prejudice that this claim must be true, and simply examine them on their own terms, we find that we don't easily find anything analogously stable that would count as the 'same phenomenology', shared between relevant images. Images are fleeting, changeable, and what it is like to experience 16 them seems to be thoroughly infused with understanding of what they represent. In imagining apple-replicas by way of an image, or apple-hallucinations by way of an image, it is very hard to establish with security that there is something phenomenologically stable here, which might equally well have represented apples in another imagination-event. This is an empirical hypothesis about the pre-theoretical phenomenology of people's mental imagery, and as such is obviously vulnerable. But it can be supported by noting a further difference between mental images and visual experiences. In visual experience but not mental imagery we can easily make a coherent distinction between: i) the phenomenology of an experience (what it seems to the thinker to be of) and ii) the thinker's simultaneous beliefs about what is really the case in the perceived scene. The two might come apart (for instance, where one's experience is phenomenologically committed to there being an O, but one has independent reason to believe there is no, e.g. because one is in a world where there are many fake O's, or because one thinks one is on hallucinatory drugs). It is surely this fact about visual experience – that one can disbelieve the appearances of one's visual experience that importantly motivates the thought of a stable phenomenological aspect shared by visual experiences and hallucinations, and even provides some evidence for it, perhaps. Yet no analogous facts are true of mental images, in a way that might similarly ground thought of a 'highest common factor' phenomenologically: there is apparently no analogous gap between, as one might put it, the surface appearances of the image – what it seems to the thinker to be of – and what, she has reason to believe, it is really of. That is, there is apparently no possibility that one's current 'image-array', as it were, is simultaneously caused by some unexpected object or other entity. The only way in which one can be wrong about the content of one's mental imagery is where unbeknownst to one, one misapplies a concept10. But this is a different case; in the case of it seeming in visual experience as if there is a barn, on the basis of being in relation to a fake barn, there is no conceptual confusion. It is this case with which there is no apparent analogy in imagery. Hence Sartre's remarks that 'the material of the mental image is.. already constituted as an object for consciousness' (Sartre 1972, p.68). Whereas perception implies 'the necessity of making a tour of objects', the case is contrasted with having an image, where 'we no longer need to make a tour of it: the imaged cube is given immediately for what it is' (1972). So a major source of support for the idea of a 'highest common factor' shared between visual experience and hallucination is not available to support any analogous move with respect to images. This throws us back to our own self-reports; a source of evidence, I suggest, not 10 In a Monty Python sketch, Mr Anchovy wants to tame lions, but has confused lions with anteaters, stating that he has seen lions at the zoo and that they are 'brown furry things with short stumpy legs and great long noses'. Were Mr Anchovy to try to have a mental image of a lion advancing upon him, the image he would produce would be causally related to an experience of, or beliefs about, an anteater, not a lion. Hence, though it seemed to him at the time of imagining that his mental image was of a lion, in fact it would not be. 17 secure enough to do the work a defender of MULTIPLE might need. I take it then that the foregoing point effectively undermines the security of the 'phenonemal' version of MULTIPLE described towards the beginning of the paper; and insofar as the 'content' version rests on the prejudice that some shared phenomenology between the cases must be present, it undermines that too. 6. What is the nature of the 'added ingredient'? A final significant problem for the 'content' version of MULTIPLE is as follows. Recall that, following the dismissal of the 'de-emphasis' strategy, the only remaining tenable version of the 'content' version of MULTIPLE said that the intrinsic content of a mental image is relatively restricted to elements shared with every scenario represented (e.g. for Peacocke: a visual experience as of O; for Kung: basic colours and shapes). This implies that some non-imagistic mental item accompanies a mental image and contingently supplements its intrinsic content, to produce the overall content of the imagination-event as a whole. That an act is supposed to be involved indicated by Peacocke in his talk of S-imagining; and by Noordhof when he says that: 'the Multiple Use Thesis demonstrates that the content of our imaginings is not settled by the nature of the mental image in play. Instead, it is partly determined by the intention or supposition behind the use of the image.' (2002, p.429). Burge similarly talks of an 'act of imagination' which accompanies imagery and determines how it is 'used'. (2005, p.66) Others are more ambivalent: Kung, for instance, talks simultaneously of images being 'prelabelled' (2010, p.624) so that there is 'no extra activity' on the thinker's part, but at the same time apparently allows that what counts as 'assigned content' is under voluntary control. Kind does not commit herself, saying only that 'the image is not sufficient for making the image the type it is' (2001, p.102). One might ask whether there isn't room here for a much more modest version of MULTIPLE which says, not that an act adds non-intrinsic content to the image in order to arrive at the overall content of an imagination-event; but that there are simply two distinct kinds of content present in an imagination-event: imagistic and descriptive? I take it that, with the highest common factor strategy dismissed, we have lost one major attraction for even this view, for we have lost any obvious reason to think there is such a thing as 'imagistic' content distinct from 'descriptive' content, at least accessible at the personal level. It is true that there is a separate claim often made, taking place against the background of a computationalist theory of mind, that mental images to some extent have a 'propositional component': indeed Kosslyn claims that this is 'widely agreed'( 1994, p.6). Kosslyn and his opponents are arguing over whether the image content of imagining is, at root, propositional. Whatever answer transpires, it won't help establish, or demolish, a distinction between image content and something else. 18 In any case, I'll focus now on those views that clearly do endorse the idea of an accompanying mental act, adding content, since clearly some do. What is the nature of that act supposed to be? There seems to be three main candidates. The first is intending, one of the options suggested by Noordhof (albeit that Noordhof seems to endorse an 'additive' strategy for some cases, and a 'de-emphasis' strategy for others; since I have dismissed the 'de-emphasis' version already, I'll consider the options he offers with respect to the 'additive' strategy only). One might be tempted here by an analogy with the relation between a painter and her picture: the painter produces certain colours and shapes on the canvas, imbuing them with meaning via an intention that they represent a certain state of affairs, rather than a visually indiscernible alternative11. Whether or not this is a good account of painting, it seems hopeless as an account of the relation of a thinker to her mental images. She does not either construct or even just discover an entity with certain very restricted content, and then intend of that entity that it furthermore represent more complex scenarios. There is no separate entity with basic content that she has any prior awareness of. As already emphasised, her images come to consciousness already thoroughly interpreted in a particular direction. Of course, this is not to deny the obvious truth that we can intend to have certain mental images (and succeed or fail). It is to deny that we intend of pre-existing images, that they have further content not already 'contained' in them. The next candidate is supposition (or non-imagistic imagining; or make-believe – I'll consider these all equivalent here). Here a tempting analogy might be with the spectator of a painting who comes across a canvas which she takes to represent a medium-sized object O, and then, perhaps for fun, supposes or imagines of that canvas that it represents an O-replica, or an Ohallucination, or some other indiscernible scenario. Again though, this seems to violate the requirement upon supposition-of (also pertaining to intending-of) that there is an identifiable entity whose existence precedes the act of supposition, and which can function appropriately as the object of the thought. As before, the thinker's mental image does not exist in her consciousness as an object she is aware of prior to any putative act of supposition directed towards it. A slightly different approach would be to talk as if supposition were directed, not towards the image itself, but towards features represented by the image: e.g. that one supposes of the colours and shapes 'in' the image that they represent an apple. But this would be ambiguous between two readings. The first is that one is supposing certain things of coloured parts of the image, as one might of coloured parts of a canvas; this suffers from the same objection as before. The other is that one is somehow supposing something of some colours and shapes themselves – not coloured parts of the image, but the colours and shapes represented by the image, intrinsically. Here too, it seems that one has no prior awareness of any such basic 11 Indeed, Noordhof makes an analogy between mental images and works of art (2002, p.431) though he denies that works of art get their content wholly through authorial intention. 19 entities; in addition, the objection looms that there are no actual colours and shapes one is currently aware of, to act as the appropriate objects of de re supposition. Alternatively, if the claim is, as for Peacocke, that the image intrinsically represents only a visual experience as of an O; and the suggestion is that one additionally supposes of that visual experience that it has some particular cause; then the objection is that there is no such visual experience to count as an object of the supposition. To this, in each case, I suppose it might be replied that the relevant act of supposition, is directed, not towards a token but towards a type – e.g. a type of colour, or a type of visual experience. If this suggestion is to be taken seriously, we first need to hear more about how supposition-of, which prima facie looks to require a concrete, spatio-temporally located object, could be directed towards abstract objects such as types (for related discussion see Sawyer (2002)). This form of objection applies, mutatis mutandis, to any construal of the possible content of an image-type, restricted to some relatively basic elements. There is no prior consciousness of any such elements; and nor do any such elements, construed as tokens, exist at all; meanwhile, construed as types, it needs to be established how supposition de re might occur with respect to them. I don't deny, of course, that one might have a mental image of O and in doing so, focus in thought upon, for instance, O's colour, or some other element of it. But in doing so, it seems to me, one is thinking of the colour of O; not of some colour-token, or colourtype, independent of any context, upon which one then performs some suppositional act to transform it into 'the colour of O'. A final possibility would be to say that the mental act which 'adds' content to a mental image is sui generis. One might add: since it is sui generis, there is no need to think that the constraints we have just examined with respect to intention-of and supposition-of need transfer to this sort of act. Peacocke comes close to suggesting this option when he says that S-imagining, though a form of imagining, is not supposition (p.25); since it is not imagery either, this makes it relatively unfamiliar. Whether or not he means this seriously, let's consider whether we can reasonably posit a sui generis mental act in this role, and stick with S-imagining as our name for it. The terms of the discussion will need to be altered depending on what is counted as the basic content of an image; I'll use Peacocke's view for the sake of simplicity. So: we are considering the claim that the following are two distinct co-occurring mental events that jointly compose the act of imagining-via-imagery: A) I have an image of a visual experience as of O B) I S-imagine of that visual experience that it is caused by ...12 12 The details of the interaction between S-imagining and A) are obscure here, just as they were in the last two cases, and presumably will encounter similar problems. 20 Presumably, to take seriously the claim that these are distinct events, we need to find contexts in which one occurs without the other. Now, at least with supposition-of and intention-of, there are clear contexts, irrelevant to imagery, in which it is wholly appropriate to posit their respective existences. But not so with S-imagining, which is being considered as sui generis and whose only posited role is given in the context of a version of MULTIPLE. Equally, though, there seems very few contexts in which it would be useful to posit the existence of A): that is, of an image whose content is restricted to the point where it does not intrinsically represent medium-size objects. Nearly all of the contexts in which we usefully use mental imageryto remember things, to work out what would happen if certain other things happened (Williamson 2007), to fantasise about things for the purposes of gratification – precisely concern things, not visual experiences as of things, or appearances, or colours or shapes. Empirical research seems to back this up: there is evidence that skilled chess players can remember and reproduce mental images of chessboards laid out in recognizable chess positions, but not laid out randomly (Saariluoma and Kalakovski 1998). In brief: we have found no compelling reason to analyse mental images as involving a mental act of transformation upon some distinct entity with restricted content. And in fact, I have sought to argue throughout, there is no compelling reason to countenance the existence of any such distinct entity with restricted content either. Therefore we should at most be agnostic about MULTIPLE's superiority over SINGLE; or even downright sceptical, given the obscurity that surrounds its putative mental mechanics. In turn, I suggest, we should look again closely at the relatively many arguments that depend upon MULTIPLE's truth. Bibliography Burge, Tyler (2005) 'Naive realism and perceptual psychology' Philosophical Topics 33 (1):178. Chalmers, David (2002) 'Conceivability and possibility', eds. Tamar Gendler and John Hawthorne, Oxford University Press, pp.145-200. Haddock, Adrian and Macpherson, Fiona (2008) 'Introduction' in Naive realism: Perception, Action and Knowledge, eds. A. Haddock and F. Macpherson, Oxford University Press. Jeshion, Robin (2010) 'Introduction to new essays in singular thought' ed. Jesion New Essays in Singular Thought, Oxford University Press. Kind, Amy 'Putting the image back in imagination', Philosophy and Phenomenological Research 62 (1): 85-110. Kung, Peter (2010) 'Imagination as a guide to possibility' Philosophy and Phenomenological Research Vol. LXXXI No. 3. 21 Kung, Peter (forthcoming) 'Thought Experiments in Ethics' in Amy Kind and Peter Kung (eds). Knowledge Through Imagination, Oxford University Press. Martin, Michael (2002) "The transparency of experience", Mind and Language, 17:4; pp. 376425. Noordhof, Paul (2002) 'Imagining objects and imagining experiences' Mind and Language 17: 4: 426-455. Peacocke, Christopher (1985) "Imagination, experience and possibility", in: J. Foster & H. Robinson (eds.) (1985) Essays on Berkeley. Oxford: Clarendon Press. Peacocke, Christopher (1984) Sense and Content, Oxford University Press. Saariluoma, Pertti and Kalakoski, Virpi (1998)'Apperception and imagery in blindfold chess' Memory 6:1. Sartre, J.P. (1972) The Psychology of the Imagination, London: Methuen. Van Leeuwen, Neil (forthcoming) 'The Imaginative Agent' in Amy Kind and Peter Kung (eds). Knowledge Through Imagination, Oxford University Press. White, Alan (1990) The Language of the Imagination Sawyer, Sarah (2002) 'Abstract artifacts in pretense' Philosophical Papers 31(2): 183-198. Williams, Bernard (1976) 'Imagination and the self' in Problems of the Self, Cambridge. Williamson, Timothy (2007) The Philosophy of Philosophy Oxford: Blackwell.