The Emperor's New Phenomenology? The Empirical Case for Conscious Experiences without First-Order Representations Hakwan Lau1, 2 & Richard Brown3 1-Department of Psychology, Columbia University 2-Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen 3Philosophy Program, LaGuardia Community College, CUNY Correspondence: Hakwan Lau – hakwan@gmail.com Richard Brown – onemorebrown@gmail.com 2 Abstract We discuss cases where subjects seem to enjoy conscious experience when the relevant firstorder perceptual representations are either missing or too weak to account for the experience. Though these cases are originally considered to be theoretical possibilities that may be problematical for the higher-order view of consciousness, careful considerations of actual empirical examples suggest that this strategy may backfire; these cases may cause more trouble for first-order theories instead. Specifically, these cases suggest that (I) recurrent feedback loops to V1 are most likely not the neural correlate of first-order representations for conscious experience, (II) first-order views seem to have a problem accounting for the phenomenology in these cases, and either (III) a version of the ambitious higher-order approach is superior in that it is the simplest theory that can account for all results at face value, or (IV) a view where phenomenology is jointly determined by both first-order and higher-order states. In our view (III) and (IV) are both live options and the decision between them may ultimately be an empirical question that cannot yet be decided. 3 Introduction One major divide in philosophical theories of phenomenal consciousness is that between higherorder and first-order approaches. First-order states are those states that represent objects or properties in the world and higher-order states are those that represent other (first-order) mental states1. So the divide between first-order theories and higher-order theories corresponds roughly to whether one accepts what David Rosenthal calls the Transitivity Principle, which states that a perceptual state's being phenomenally conscious consists in one being aware of oneself as being in that state (in some suitable way), and, conversely, that a perceptual state of which I am in no way aware of being in cannot be phenomenally conscious2. For instance, on a specific version of the higher-order view known as the higher-order thought theory (Rosenthal 2005), in order to make a first-order perceptual state conscious, one needs to have a thought-like mental representation to the effect that one is in that particular perceptual state. This is because to be aware of oneself as being in some state or other requires that one represent oneself as being in that state and one plausible way of doing that is to deploy an intentional thought-like representation to the effect that one is in some first-order state or other. There are different ways of implementing the Transitivity Principle but most, if not all, versions of the higher-order approach adopt this principle. In contrast, first-order theories reject this principle, and hold that merely having the right kind of first-order states is necessary and sufficient for phenomenal consciousness. Because the higher-order approach involves two levels of representations, critics have long challenged the view by considering hypothetical cases where the content of the first-order and higher-order representations mismatch (Neander 1998, Balog 2000, Levine 2001). If one is aware of oneself as seeing blue when one really has a first-order representation of redness, what is it like for the subject? If one consciously experiences redness in such cases, then in a sense we have rejected the higher-order approach; the conscious experience follows the first-order content and this seems to render the higher-order representation irrelevant. But if one consciously experiences blueness then the first-order states seem to play no role in consciousness. In response to this Rosenthal and others have argued that it is the higher-order representation that determines the character of the conscious experience (Rosenthal 2005 p. 186, 187, 203; Weisberg 2008). Though the first-order representations play a relatively indirect role with respect to consciousness, it has been independently argued they should nonetheless be 1 The phrase 'mental representation' is used interchangeably with 'mental state' or sometimes just 'representation' or 'state'. Also, unless otherwise specified, we always use the term 'conscious experience' to refer to phenomenally conscious experience. Other similar and related terms are 'conscious phenomenology', 'conscious perception', ''what-it's-likeness', and 'phenomenally conscious state'. 2 When we talk about the 'higher-order approach to consciousness' or 'higher-order view' we always mean what Block calls the ambitious version of the theory as opposed to the modest version of the theory (Block 2011). That is, in this chapter we always take it to be a theory of phenomenal consciousness as opposed to merely a theory of state consciousness. Because of this some theorists may reject the way that we have formulated the transitivity principle (see, for example, Rosenthal 2011 page 435). 4 considered to be qualitative mental states (Rosenthal 2005 p 38-39).3 Thus, because it is the higher-order representations that really determines the character of conscious experience –that is, determines what it is like for one to have the experience- even when the first-order representation is missing one's conscious experience should not be altered.4 As a result of this many higher-order theorists thought that nothing more needed to be said about this problem. Misrepresentation may seem intuitively odd but it is nothing that the higher-order theory can't handle. Block has recently put a novel twist on this traditional worry (Block 2011). He argues that if we claim that we are just as conscious in the empty higher-order case as in the normal case, this seems to violate the Transitivity Principle. If conscious perception happens in the empty higherorder case, it would no longer be because a first-order perceptual state becomes conscious as we become aware of being in it. There is no such first-order state to begin with, and a non-existent state cannot become conscious. So what is conscious seems to be the higher-order state, not the first-order state. Thus the Transitivity Principle, which states that a first-order state becomes conscious when we are aware of being in it, seems to be wrong. Though proponents of the higher-order view have resisted this argument (Rosenthal 2011; Weisberg 2011), Block takes it that considerations of empty higher-order states motivate rejecting the higher-order view, and in turn to support his own view which is a variant of a firstorder view5. Our goal in this paper is to bring a new perspective to this debate by employing a strategy for which Block himself is well known: We will be considering empirical cases that bear on the philosophical issues. We argue that there are plausible cases where subjects seem to enjoy conscious experience, and yet the relevant first-order states are either missing or insufficient to explain the reported phenomenology. These may be considered to be empirically plausible empty higher-order state cases. The fact that empirical results suggest that such cases actually exist means that these cases are not just meant to be a hypothetical conceptual problem for a particular theory. Any successful theory will have to be able to interpret these cases. The upshot of the paper is that it turns out this strategy backfires, as they may actually be more troublesome for a first-order view rather than a higher-order view. In brief, the first-order view has difficulty accounting for these cases. In addition, we argue that the higher-order view can account for them 3 In brief the argument for this is that the first-order states do have a large functional-role to play and they do account for most of our performance. It is just with respect to conscious experience that they have an indirect role. 4 Technically Rosenthal holds that there are two aspects to a typical conscious experience. On the one hand you have the higher-order state, which accounts for what it is like for one to have the experience. And on the other hand one has the first-order qualitative state that accounts for the functioning and perceptual role. So in the empty case we do have something odd going on but there is no difference in conscious phenomenology (though there will be a difference in performance). 5 On our interpretation, we can call him a first-order vehicle theorist, who holds that having the right kind of biological substrate for the first-order representation partly is necessary for consciousness. 5 under certain interpretations of the Transitivity Principle, without giving up the core ingredients of the higher-order approach. Plausible Empirical Cases of "Empty Higher-Order Representations" with Phenomenally Conscious Experience In this section we will discuss three empirical cases that we take to be plausible candidates for 'empty' higher-order representations. These three cases are Rare Charles Bonnet Syndrome, Inattentional Inflation, and Periphovael Vision (together we call these the Emprical Cases). Our aim in this section is to simply present these cases without arguing for any interpretation of them. In the subsequent section we will examine various interpretations of the Empirical Cases. In order to relate the philosophical issues to empirical data we first need to consider plausible neuroanatomical interpretations of the substrates of first-order and higher-order representations. Fortunately, the general picture is not controversial. Authors, including Block himself, typically find it plausible that first-order representations are reflected by activity in early sensory regions, and that higher-order representations are reflected by activity in the prefrontal cortex (and possibly the parietal areas too) (Lau and Rosenthal 2011). This lines up nicely with what is traditionally meant by these terms. First-order states are those that represent the world outside, so to speak and those representations are likely found in the early sensory areas. Likewise, higherorder states represent other mental states, and those representations are found in the higher-areas of the brain. We hereby adopt this interpretation for the purposes of this paper, such that when we say 'first-order representations', we simply mean early sensory activity that represents the contents of perception.6 In this sense, when the relevant early sensory activity is missing, the 'first-order representation' is missing, even though one may somehow be able to represent the perceptual content (e.g. at some higher level of processing).7 Though there is general agreement about activity in early sensory regions being involved, there is some debate as to what the exact neural correlates of first-order representations really are. One view suggests that awareness critically depends on activity in the feedback projection of extrastriate activity back to the primary visual cortex (V1) (Lamme 2006). For instance, for conscious perception of motion, cortical activity typically first arises at V1, and then it travels through feed forward connections to motion sensitive area MT/V5. Conscious experience seems 6 We also assume an identity between neural activity in early sensory areas and representations of, say red. Thus we can switch between talking about neural activity, spiking, etc. and representations of red, blue, pain, etc. 7 Unfortunately the term "early sensory regions" is often not technically delineated, even in the neuroscience literature. Here, concerning the visual modality, we use it to refer to primary visual cortex (i.e. striate cortex, also known as V1), extrastriate areas including V2, V3, V4, MT, as well as other areas in the occipital and temporal lobes that are known to contain high number of neurons explicitly coding for visual objects (e.g. fusiform face area). All other areas are considered "higher-order", but we typically consider such higher-order areas to be in the lateral prefrontal cortex and areas around the intraparietal areas. 6 to critically depend on projection of activity from MT/V5 back to V1. Though popular, this view has its critics (e.g. Silvanto 2011). However, Block endorses, or at least favors, this view (2005, 2007), and therefore we will consider feedback to V1 as the primary candidate for the correlate of first-order representations. In suitable places we will consider the alternatives and consequences if Block is to give up this specific view. Assuming that first-order representations are supported by feedback to V1, cases where subjects report conscious visual experience following damage to V1 can be considered potential cases of conscious awareness with "Empty Higher-Order Representations". This occurs in a rare form of Charles Bonnet syndrome. In typical cases of Charles Bonnet syndrome (Ffytche 2005), which in general can result from a variety of brain damages, patients report that they experience vivid hallucinations of objects such as faces, familiar persons or objects, and complex geometrical designs.8 However, the patients are otherwise cognitively intact. Unlike in schizophrenia or other psychotic experiences, sufferers of Charles Bonnet syndrome typically show no sign of irrational fear regarding the hallucinations, and often can lucidly describe the content of the hallucination and accept that it is a visual deficit. Therefore, there are good reasons to believe that they actually go through these visual experiences, rather than merely thinking that they do. Here we are concerned with a rare form of Charles Bonnet syndrome (we call these Rare Charles Bonnet Cases), which results from damage to the occipital areas including the primary visual cortex (Duggan and Pierri 2002, Ashwin and Saloumas 2007, Contardi et al 2007). Since these patients lacked an intact primary visual cortex, on which first-order representations presumably critically depend, it seems plausible that some higher mechanisms are driving such hallucinations.9 Such cases are dramatic, but rare. In the laboratory, we can demonstrate a related but less dramatic phenomenon. Whereas we cannot deliberately lesion visual cortex of human subjects to completely abolish the first-order representations (!), we can find cases where the first-order representations seem "too weak" to generate the reported conscious experience. The "strength" of a first-order representation can be estimated in terms of signal-to-noise ratio, which can be indirectly assessed through behavior (Green & Swets 1966), or by brain imaging measurements. We can try to find cases where there is activation of the relevant early sensory brain areas but 8 In the philosophy literature, sometimes the word "hallucination" is used to refer to cases where a first-order representation refers to a non-existent object. Here we are not restricted by this usage. By hallucination we simply mean non-veridical conscious experiences, regardless of whether it is driven by a first-order or higher-order representation. 9 Also relevant are cases in which, through intracranial magnetic brain stimulation, one can induce conscious motion percept in a patient where the spatially relevant part of the primary visual cortex is damaged (Silvanto et al 2007). We not consider this case in more details here because it has been discussed at length elsewhere (Silvanto & Rees 2011). But we note that it corroborates with the conclusion from the Rare Charles Bonnet Cases here that conscious visual experience can occur in the absence of the primary visual cortex. 7 this activation is not robust enough to account for the level of phenomenology reported by subjects. For instance, we can have two cases where the levels of activation in the visual cortex are the same, and yet in one case the level of phenomenology is reported to be richer or more vivid. This would constitute a case where the putative higher-order representations are not exactly "empty", because there is actually a relevant first-order representation. However, this is similar in spirit to the "empty higher-order" cases because the first-order representation is not strong enough to account for the conscious experience, and thus there is still some degree of "emptiness" that needs to be explained. All that we mean by this is that there is more to the experience phenomenologically than can be accounted for by the first-order representations (as reflected by activity in early sensory areas). For example Rahnev et al (2011) presented grating patterns of strong luminance contrast to the unattended locations of the visual field, and grating patterns of weak luminance contrast to the attended locations, such that the forced-choice task performance was matched between the attended and unattended. Specifically, the authors used signal detection theoretic analysis to estimate the signal-to-noise ratio of visual processing – a measure known as d' (pronounced dprime). Under matched d' conditions, subjects produced more hits and false alarms for detection of gratings in the unattended locations, i.e. subjects reported they see the grating target more frequently in the unattended location, even though the strength or capacity of signal processing in that location is no higher than in the attended location In another condition, the task was to discriminate the orientation of the grating (left tilted versus right titled), rather than to detect a target. In this case, subjects gave higher visibility ratings for stimuli presented in the unattended locations, even though they were no better at discriminating them (d' was again matched between unattended and attended). The signal-to-noise ratio measure, d', is estimated from behavioral data. To directly assess the level of neural activity in the brain, one can use functional magnetic resonance imaging (fMRI). So in a follow up study (Rahnev in review), these authors used fMRI to track the spontaneous fluctuation of brain activity in brain areas that are known to be critical for spatial attention (in the intraparietal region and frontal eye fields). When such activity was low, which presumably reflected a low state of attention, subjects gave higher confidence ratings in a discrimination task – again, even though their ability to discriminate the stimuli was not higher. Also, the average intensity of activity in the early visual areas was not higher in either the attended or unattended conditions. We can call this phenomenon 'Inattentional Inflation of Subjective Perception' ('Intentional Inflation' for short), which on the face of it contradicts the general notion that attention boosts visibility and the subjective appearance of objects (Carrasco et al 2004). The critical difference here is that in the experiments discussed here, the focus is on the changes in subjective ratings (confidence or visibility) or detection bias (propensity to give "yes" response in detection, 8 resulting in higher hit rate and false alarm rate), when the effects of signal processing capacity (as assessed by d', task performance, etc) was already controlled for. Previous studies have found that attention boosts visibility, and at the same time it positively changed the signal processing capacity itself, as well as boosted brain activity in the visual cortex (Carrasco 2011). On the other hand, the experiments described here (Rahnev et al. 2011, Rahnev et al in review) showed that independently from this positive impact on signal processing capacity and visual activity, there is also a negative impact on subjective reports of conscious experience. The results of Rahnev et al. (2011; in review) are based on precise laboratory measurements, but they are also somewhat technical and perhaps unintuitive. So finally we consider a case from everyday experience, which is the case of Peripheral Vision. Introspection suggests, to us at least, that peripheral vision is colorful and vivid. Perhaps it is subjectively less so than foveal vision, but one typically gets a sense that one can see a fair amount of color in the periphery, and that when we take a single quick glance at a unknown scene, the perception of detail is relatively uniform, i.e. the detail in the periphery is not entirely missing. However, it is not clear if the physiology of the retina and the wiring of its input to the primary visual cortex can afford such details of processing (Azzopardi & Cowey 1993, Newton & Eskew 2003). It seems likely, as in the case of Rahnev et al. (2011), that some similar subjective inflation is at work for peripheral vision. This last example of Peripheral Vision is perhaps the least decisive, because it relies on introspection and some may disagree about the exact phenomenology. However, the point is to complement the results of Rahnev et al (2011). To sum up, there are three kinds of Empirical Cases Rare Charles Bonnet Cases (i.e. Charles Bonnet cases that result specifically from damage to the primary visual cortex), Inattentional Inflation (i.e. the results of Rahnev et al, in press and in review) and Peripheral Vision (introspective evidence from everyday life). The three cases serve slightly different purposes. The Rare Charles Bonnet Cases highlight the possibility of vivid conscious experience in the absence of primary visual cortex. If we take the primary visual cortex as the neural structure necessary for first-order representations, this is a straightforward case of conscious experience without first-order representations. In Inattentional Inflation, the putative first-order representations are not missing under the lack of attention, but they are not strong enough to account for the "inflated" level of reported subjective perception, in that both behavioral estimates of the signal-to-noise ratio of processing and brain imaging data show that there was no difference in overall quality or capacity in the first-order perceptual signal, which does not concern only the primary visual cortex but also other relevant visual areas. Finally, Peripheral Vision gives introspective evidence that conscious experience may not faithfully reflect the level of details supported by first-order visual processing. Though this does not depend on precise 9 laboratory measures, it gives an intuitive argument that is not constrained by specific experimental details. We argue that these are plausible "empty higher-order" cases, in the sense that since the firstorder representations in question seem to be either missing or too weak to account for the conscious experience, it seems plausible that one may need to stipulate higher-order mechanisms to provide a coherent account. However, exactly how this argument goes, and what implications it has for the first-order and higher-order theories, depends on our interpretation of the phenomenology in these Empirical Cases. Authors like Block may not want to take the reported conscious experience in these cases at face value. In the following sections we will argue that the higher-order approach can account for these cases and that the first-order view has difficulty accounting for them. The No Conscious Experience Interpretation One possible interpretation of our putative cases of "empty higher-order representations" is to deny that there is actual conscious experience when the first-order representations are missing. That is, in our Rare Charles Bonnet Cases, perhaps the patients were only thinking that they have those phenomenal experiences without actually having them. Likewise, for the case of Inattentional Inflation, one can try to deny that there is actually a higher degree or intensity of conscious experience when the strength of the first-order representations remained similar between attended and unattended conditions. Subjects only reported it to be the case because of some cognitive or reporting bias, but such reports did not faithfully reflect the actual character of the relevant conscious experience. Similarly for Peripheral Vision, perhaps we do not actually experience vivid colorful details. We only think that we do. Denying the empirical plausibility of these cases will keep Block's philosophical position intact, i.e. if there is no conscious experience in the Empirical Cases, they are in general compatible with a first-order view. But we find such denial outlandish. Though other authors have in other cases denied reported conscious experience as real, such views have not been popular. For instance, there have been previous attempts to deny phenomenology in dreams (Dennett 1976), by arguing that one is actually not enjoying any conscious experiences while dreaming. It is only during wakeful recall that one recreates the conscious experience, and remembers the dreams as conscious. Though some authors hold this view, like many others we find this implausible. Importantly, in dreams one is rarely asked whether one is conscious during the moment of dreaming. But in the empirical cases we review here, one is not asked to remember if a certain experience was conscious. In many of these cases one can be asked the question at the moment of the conscious experience. If one says one is vividly experiencing something right now, who are we to deny such claims?10 10 This is of course not to say that our experience of the world is always right in being veridical. We may hallucinate. But the point is even in hallucinations, there is genuine conscious experience. We cannot argue against 10 Importantly, as explained above, in our Rare Charles Bonnet Cases the patients were cognitively largely intact. We have no more reason to doubt their introspective reports of hallucinations, than we do to doubt that ordinary subjects are truthful in claiming themselves to be conscious. It is perhaps hard to ascertain whether such hallucinations are phenomenologically identical to normal perception, but to deny that there is any conscious experience associated with the reported hallucinations seems extremely implausible. Denying that the subjective reports in the Inattentional Inflation experiments actually reflected conscious experience is also somewhat problematical. Recall that in those experiments, when task performance was matched between attended and unattended locations, subjects responded "yes" more frequently in a detection task (i.e. higher hit rates and false alarm rates), and they also gave higher subjective ratings of visibility in a discrimination task. Crucially, it is the combination of both results of detection bias and subjective ratings of visibility that makes it appealing that there was some genuine difference in phenomenology between the attended and unattended. If a combined increase in the frequency of saying "yes I see the target" and higher visibility ratings is not good enough evidence that phenomenology changed, what else can count as good evidence? To deny that is to deny the common standard of interpretation of experiments in this field. Also, these results are unlikely to be just a cognitive effect (i.e. one somehow tries to use different responding strategies for attended versus unattended), because in Rahnev et al (in press) there were also conditions under which subjects were encouraged not to be biased, given trial-by-trial feedback as to what was the correct answers, etc, and it was found that the differences between attended and unattended were resistant to these changes in experimental context, as if this is something that is automatic, over which subjects have little control. Also, there is the case of Peripheral Vision to consider. That did not depend on any particular procedure of a psychological experiment, but just that introspectively, it seems (to us at least) as though Peripheral Vision gives a higher degree and intensity of conscious experience than can be afforded by the underlying physiological mechanisms at the early visual processing level. To sum up, we think denying that our putative "empty higher-order" cases involve real conscious phenomenology is unattractive. One may try to resist one of these cases, but it is difficult to see how to have a unified interpretation that can resist all three at the same time. It is extremely implausible that there is no phenomenology at all for the hallucinations in the Rare Charles Bonnet Cases. One can argue that those cases only involved lesions including V1 but not the entire visual cortex, therefore maybe some weak first-order representations still exist. But that requires giving up the notion that feedback to V1 is critical for awareness, something that Block such conscious experience by the fact that the object of perception may not actually exists. Thus, from a third person's point of view it is hard to argue for or against the existence of a genuine conscious experience without some kind of appeal to the first-person reports. 11 may not want (more discussion below). For the cases of Inattentional Inflation and Peripheral Vision, it involves converging evidence from different kinds of reports that reflect conscious experience. To claim that in all three cases, all of reported phenomenology merely reflects some cognitive or reporting biases seems outlandish. The Full Conscious Experience Interpretation Since denying that there is any conscious experience in all three of the Empirical Cases seems like an unappealing option, one may choose to just accept that there is normal phenomenology in these cases. To do this would be to hold that in Rare Charles Bonnet Syndrome subjects actually consciously experience the things they say they do; in Inattentional Inflation subjects are actually consciously experiencing the unattended stimuli more strongly and richly than they do for the attended targets; and in Peripheral Vision we really do experience color and vivid details as introspection suggests. If we accept that there is full conscious experience in the Empirical Cases, it may be problematic for the first-order view. Because the first-order view holds that having first-order representations are necessary and sufficient for conscious experience. Here however, in Rare Charles Bonnet Cases the primary visual cortex is missing, and so if we accept that such patients enjoy normal conscious experience, it seems to violate the first-order view. At this point the first-order theorist may suggest that there are after all enough first-order representations to account for the phenomenology in the Empirical Cases. After all, in none of the Rare Charles Bonnet Cases described was the entire visual cortex damaged. Yet, because the damages seem to involve V1, this poses a challenge to the view that first-order representations critically depend on feedback to V1. Block is not necessarily committed to this empirical claim, and can alternatively identify first-order representations with extrastriate activity (i.e. visual areas outside of V1; cf Prinz 2005).11 The notion that awareness critically depends on feedback to V1 has been independently criticized on empirical grounds (Macknik & Martinez-Conde 2008, Silvanto & Rees 2011), and we think locating first-order representations in extrastriate cortex is superior to the feedback-to-V1 view. However, one reason why Block may prefer something like the feedback-to-V1 view is not unrelated to his philosophical position. For a standard first-order representational theorist, the content of awareness is driven by the content of the first-order representations. Whereas we do not have a complete understanding of the content reflected by activity in different visual areas, it is plausible that extrastriate areas can support the suitable contents for the hallucinations in the Rare Charles Bonnet Cases, which are mainly objects, geometric shapes, faces, etc. However, on Block's view, it is the biological substrate of the first-order representation that is critical for conscious phenomenology. Presumably, the feedback-to-V1 view is attractive to him because the 11 Indeed, Block himself acknowledges this in his 2007; see especially his footnote 10. 12 recurrent processing reflected by the feedforward and feedback waves of neural activity seems to give a flavor of a specialized biological phenomenon. If Block is to abandon this view, he would need to specify what is special about extrastriate activity that allows them to support conscious phenomenology. Is it not just normal neural coding, that sometimes can reflect unconscious processing too? And also, there are the cases of Peripheral Vision and Inattentional Inflation for the first-order theorist to worry about, if we accept the suggested conscious experience at face value. In Peripheral Vision, it is not clear how the relevant first-order representations can exist, because even at the retinal level, the relevant input is not rich enough. One can perhaps argue that the color sensation and vividness of details in the first-order representation is created from top-down mechanisms, but one needs to substantiate such empirical claims. In our own introspective experience, even if we open our eyes for a brief period to new scene, we get the phenomenological feeling that the periphery is not exactly monochrome and devoid of details. It seems, at least to us, as if there is a kind of phenomenological inflation there even though it is unlikely that we are filling in the periphery with memory (because the scene is novel to us). In the case of Inattentional Inflation, we also argue against similar top-down mechanisms. Not only is it odd to suppose there is extra top-down mechanisms at work when one is not paying enough attention (which is a top-down mechanism in itself), the fMRI results showed no difference in overall intensity of activity in the early visual areas between the conditions where spontaneous fluctuation of attention differed. And yet, subjects gave higher subjective ratings for their visual discrimination when attention was at a low state, even though they were no better at the discrimination. Importantly, Rahnev et al (2011) offer a computational account of this finding that is essentially compatible with a higher-order approach. The model assumes that attention reduces the variability of the (first-order) perceptual signal. Because of the higher variability of the perceptual signal in the unattended case, the quality or strength of the perceptual process is low under the lack of attention. However, as in standard models of perception (Green and Swets 1966), subjective perception happens when the signal crosses a threshold or criterion. Importantly, the model assumes that this criterion is set based on consideration of the statistical properties of both the internals signals for the attended and unattended stimuli. This makes the criterion setting essentially a higher-order mechanism in that representing the properties of the first-order states sets the criterion. Because human subjects can only use the same criterion for both the attended and unattended if they are presented simultaneously (a known psychophysical fact based on previous work, Gorea and Sagi. 2000), the higher variability of the internal signal under the lack of attention turns out to lead to more frequent crossing of the criterion, i.e. more frequent occurrence of subjective perception. This model provides a good fit to the experimental data, and accounts for why, under the lack of attention, one is more likely to report "yes" that they see the target, and to give higher confidence and visibility ratings in discrimination. 13 In other words, within the context of first-order versus higher-order mechanisms, attention does change the variability of the perceptual signal itself, which we can consider an influence on the first-order representation. However, even when we present a stronger stimulus to the unattended location such that the signal-to-noise ratio of the first-order representation would be matched between the attended and the unattended, there would still be a difference in subjective perception. This is because according to the model, subjective perception happens when the firstorder signal crosses a criterion. When the criterion is fixed, a more variable signal, albeit noisy, can cross the criterion frequently because of the higher fluctuation. We argue that this criterion is determined based on higher-order mechanisms, because to set the criterion one needs to take into account the statistical properties of internal signals, such as what is the baseline activity level when no target is presented. To represent things like baseline activity level and its variance is to have higher-order representations, because these are properties of first-order representations, rather than properties of objects in the world. Importantly, even if one insists that there may be other ways to determine the criterion, such mechanisms likely reside in the prefrontal cortex (Lau & Rosnethal 2011), which means that they count as higher-order for the purpose of the arguments in this chapter (as stipulated at the beginning of this section). So if there is indeed normal conscious experience in the three Empirical Cases, the first-order view may be in trouble. But why should we think that there is really normal conscious experience in these cases? We have in the last section given negative reasons to think why denying the reported experience is an unattractive option. But is there any positive reason to think that accepting such reports at face value is attractive? One argument why this may be positively attractive is that this allows for a parsimonious view of how different lines of evidence converge. This is similar in spirit to Block's very own "Mesh" argument (Block 2007, 2008). The Mesh argument has roughly the following form. We should adopt the theory of conscious experience that allows for the most parsimonious explanation of the relationship between data at the neuroscientific level and data at the psychological level. When evaluating theories we should take into account as wide a swath of evidence as possible and look for the theory that gives a unified simple explanation of the various empirical discoveries. Block has tried to use this argument to show that we should accept the claim that there are two separable systems of conscious: one supporting phenomenally conscious experiences and one supporting conscious access to those phenomenally conscious experiences. If we accept this, then we can parsimoniously interpret two results. The first is what he calls "phenomenological overflow", i.e. in many experiments such as change blindness and inattentional blindness, subjects can report the details of only a few objects but subjectively they seem to see the entire visual scene in front of them. The other result is the neurobiological finding that the posterior visual system in the occipital and temporal lobes seem to have a higher informational capacity and resolution than the prefrontal system. If we map phenomenally conscious experience to the posterior visual system, 14 and conscious access to the prefrontal system, then we can see why there is phenomenological overflow: because the former has higher informational capacity and resolution than the latter. Therefore, there is phenomenal conscious experience that we cannot report or access. If this conclusion is true, perhaps so much the worse for ambitious versions of the higher-order theory, which denies that there can be phenomenal conscious experience without a higher-order representation, the latter of which presumably resides in the prefrontal cortex. If phenomenally conscious experience can "overflow" the prefrontal system, it seems that the ambitious version of higher-order theory is wrong. However, in the light of our Empirical Cases, we suggest that the ambitious version of higher-order theory can actually account for the possibility of phenomenological overflow just as well (Brown 2012a). In fact, it provides a better mesh for all evidence – because it allows us to accept the reported conscious experiences in the Empirical Cases at face value. First, we note that the ambitious higher-order approach fits just as well to the neurobiological finding that there is a high-capacity early visual system and a low-capacity prefrontal system. Both the higher-order view and the first-order view (i.e. one favored by Block) assume that there are two stages of visual processing. What is at issue is whether the correlates of conscious awareness are supported by the late stage low capacity-system or the early stage high-capacity system. On the first-order model the correlates of conscious experience go with the high-capacity system. On the higher-order model the correlates of conscious experience go with the low capacity system. Both claims are compatible with the neurobiological finding. What differs between the two views is the way they account for phenomenological overflow. For the first-order view, because access is supported by the late stage system which has lower capacity than the early stage system that supports conscious experience, one naturally expects phenomenological overflow. On the other hand, the higher-order view may seem to have some difficulty in account for phenomenological overflow. If conscious phenomenology is associated with the late stage low capacity system, how can it seem richer than what is reflected by access or task performance? On the higher-order view, the capacity for task performance is reflected the capacity of first-order representations. If we associate the first-order representation with the early stage visual system which has high informational capacity and resolution, shouldn't we expect the opposite of phenomenological overflow, i.e. that conscious phenomenology is less detailed than what is reflected by performance? One natural solution for the higher-order theorist is to deny that the richness of conscious experiences is determined by the informational capacity of the relevant neural system. Equating the richness of conscious experiences with the informational capacity of the relevant neural system is only appealing if we assume that the conscious experience is veridical. In the cases of phenomenological overflow, when the subject apparently experiences vivid details of the entire 15 visual scene, and yet can only report the identity of a few objects, one interpretation is that the experience of richness is not veridical. This is not to deny that subject experience such vividness, but that in reality, they do not actually represent the visual scene in such a vivid and rich way. Using an example of the famous Sperling postcue experiments (1960) in which subjects may have the impression to see clearly the identities of 12 letters, despite only being able to report accurately the identity of about 4 of them at a time, one interpretation is that the higher-order mental state represents oneself as vividly seeing the identities of all 12 letters, without specifying what are they (Brown 2012a, 2014). Because the higher-order system does not actually represent the identities of the 12 letters, the representation that one is vividly seeing the identities of all letters is non-veridical. But because such higher-order representations do not carry the actual information regarding the identities of the letters, this does not require an actual information capacity for all 12 items. However, in the Sperling experiments, subjects could have reported any 4 of the letters, if they were being cued immediately after the letters disappeared. This suggests that subjects must have had some form representations of all 12 letters too. We do not deny these results, but such representations are traditionally considered a form of iconic memory, and it is unclear whether they are conscious representations. Block (2011c) has recently argued that there is a general lack of evidence for such unconscious memory (see Brown 2014 a response). We agree that if one is considering unconscious memory as in the experiments where the stimuli were masked and cannot be perceived at all in the first place, it is not clear if they could form memories with such high capacity. But we should not conflate whether the memory representations are conscious with whether the stimuli are presented consciously in the first place. What we suggest is that in Sperling experiments or its variants, when the stimuli were consciously presented, the iconic memory representations for the stimuli may nonetheless not be conscious throughout the delay period. This issue may need to be empirically resolved by future studies. But at least so far there is no empirical evidence directly against the possibility that subjects did not have conscious detailed representations of the letters throughout the delay. The subjective impression that such memory is phenomenally conscious may well be supported by non-veridical higher-order representations. But is this move of invoking non-veridical higher-order representations ad hoc? Certainly not, for this is exactly what we expect based on the Empirical Cases that motivate this paper. E.g. in the case of Inattentional Inflation, subjects claimed to see more clearly under lack of attention, despite that they were no better at performing the visual tasks. This is compatible with the interpretation that the higher-order system can over-estimate the richness of perception. Also, as with Inattentional Inflation, phenomenological overflow tends to happen when focused attention is lacking (e.g. in the Sperling experiment, or in inattentional and change blindness experiments). 16 Given that the higher-order view can account for phenomenological overflow just as well as the first-order view, we can say that the higher-order view is superior, because it allows us to accept the Empirical Cases at value face. That is, unlike the first-order view, it does not require us to make ad hoc claims that deny the phenomenology in the Empircal Cases. Thus, in the very same spirit of the Mesh argument itself, one should prefer the (ambitious) higher-order view. So, to sum up: there is good reason to believe that there is real phenomenology in our empirical cases and we argue that this is in favor of the higher-order view. Nevertherless, Block seems to think otherwise. If there are indeed full conscious experiences in the Empirical Cases, Block's challenge to the higher-order view is that it seems to violate the Transitivity Principle, which states that a first-order state is conscious if and only if one is conscious of onself as being in such a state. In the Empirical Cases, especially the Rare Charles Bonnet Cases, the putative first-order state does not exist. Certainly, a non-existent state cannot be conscious? How can the higher-order view meet this challenge? Rosenthal's reply (Rosenthal 2011) is to point out that even when the relevant first-order state is actually missing, the higher-order state nonetheless represents oneself as being in a certain firstorder state, which just happens to be non-existent. Therefore, according to the Transitivity Principle, the non-existent first-order state is phenomenally conscious; the relevant conscious experience is determined by the content of the higher-order state and that state represents one as being in a (non-existent) first-order state, so what it is like for the subject will be like being in the first-order state even when one is in fact not in said first-order state. This may sound odd, but is perhaps not so if we consider the fact that non-existent objects in general have all sorts of properties. A non-existent letter can have representational content: e.g. the complaint letter I thought you had written (even though you did not) was about a new university policy (because we talked about complaining about it but unbeknownst to me you actually never wrote that letter). So likewise, perhaps it is not problematical at all to speak of conscious experiences arising due to our being conscious of such non-existent first-order states. It becomes less problematical when we realize that all that is meant by saying that the non-existent state is conscious is that the state is described in the content of the higher-order state. We emphasize the "perhaps" in the last sentence because in our experience we find that some readers find it insurmountably odd and downright unacceptable to say that a (non-existent) firstorder state is phenomenally conscious. On the other hand, some readers find it perfectly sensible. Instead of becoming bogged down arguing over this we offer an alternative solution to accommodate the Empirical Cases within a higher-order framework, under the Full Conscious Experience Interpretation. Specifically, Brown (2012b, 2015) has argued that phenomenal consciousness consists in implementing the transitivity principle, which is to say that it consists 17 in the occurrence of the higher-order state itself. On this alternative phenomenal consciousness just is a higher-order representation. Thus, for a first-order state to be (state-) conscious, one does need to represent oneself as being in that first-order state and we can happily say that the (as it happens) non-existent first-order state is state conscious in this sense (which is just to say that it is the content of the higher-order state). If we think of phenomenal consciousness as the property of there being something that it is like for the subject of the experience then it is the higher-order state that has that property. It is that state which is like something for the subject to be in; without it there is nothing that it is like for the subject. This is equivalent to saying that the first-order state is never phenomenally conscious. Phenomenal consciousness just is having the appropriate higher-order state.12 This is not to give up the Transitivity Principle. The Transitivity Principle, as we construe it, says that phenomenal consciousness consists in one being aware of oneself as being in some firstorder state. It is sometimes thought that the Transitivity Principle relies on there being a relation between the first-order state and the higher-order state. We explore a relational version of the transitivity principle in the next section but it is not the case that one must interpret the transitivity principle as involving a relation between a first-order state and a higher-order state. On this alternative non-relational view of the transitivity principle it relies on the instantiation of a specific kind of awareness. On this construal phenomenal consciousness just is being aware of oneself as being in a first-order state. This is what the ambitious higher-order theory under the full-conscious experience interpretation should be interpreted as saying. This solves Block's puzzle. In the empty case there is phenomenology and it consists in having the appropriate higher-order state. We grant that it may seem counter-intuitive that the redness of my conscious experience is nothing more than the occurrence of an appropriate thought-like representation to the effect that I am seeing red. It certainly doesn't seem to be that way when one has the conscious experience! Bu introspection cannot be reliable here since it is the very nature of the higher-order representation to make it seem to us as though we are in fact in the first-order state. Thus we would naturally expect it to be the case that it doesn't seem to us as though we are having a thought. It will seem to us as though we are seeing red! In our view either of the responses is adequate as a response to the Empty Higher-Order problem and we do not need to endorse one over the other. Our aim, rather, is to show that despite 12 This may not be all that different from the way that Weisberg (2011) should be taken in his response to Block. He says, while talking about a thought experiment where future neuroscientists have stimulated just the higher-order regions and elicited a conscious experience of pain in the subject, but in this case, the lower order state does not exist. What is to be said? Perhaps, the thing to say is that the HO state itself is the conscious state. And there's a certain meaningful sense of 'conscious state' where that is correct – the HO state is the state responsible for there being something it's like for the subject. (p. 442) 18 Block's contention that the higher-order approach has a problem accounting for Empty HigherOrder Representations the reverse is true. The higher-order approach has ready responses; indeed there may be others that we have not yet encountered. In fact, as we have tried to show, it is the first-order view which really has trouble accounting for Empty Higher-Order cases. The "Partial" Conscious Experience Interpretation The previous two interpretations are both extremes. One possible intermediate position holds there is conscious experience in the Empirical Cases, but such conscious experience is not as full-fledged as it would have been had the first-order representations been intact. That is, there is some "reduced" form of conscious experience in the Empirical Cases that is qualitatively different from what one expects in normal cases. The higher-order view can certainly entertain this interpretation as much as it does for the Full Conscious Experience Interpretation. All it takes is to stipulate that in the Empirical Cases, due to the weak or missing first-order representation, the higher-order representation comes to contain less detailed perceptual information. On the other hand, the first-order view seems to face the same problem as in the Full Conscious Experience Interpretation. Even if there is just a spark of phenomenology that is not explainable in terms of the missing or too weak first-order representations, it violates the view. One can perhaps imagine a response from a first-order theorist based on the strategy of divide and conquer. For example one can deny the reported conscious experience in the Inattentional Inflation case, and then argue that in the case of Peripheral Vision first-order representations are created via top-down mechanisms, or found in extrastriate areas, despite the lack of sufficient retinal input.13 And finally for the Rare Charles Bonnet Cases, one can argue that although the primary visual cortex (V1) is missing, activity in the remaining visual cortex is nonetheless sufficient for some "partial" conscious experience. Though we suspect that this may well be the reply that Block may favor, we note that this strategy would involve a fair amount of "patchwork" – one needs to deny the reported conscious experience in Inattentional Inflation, i.e. essentially denying that a change in detection bias (subjects' saying "yes" more frequently to target detection) and an increase in visibility rating in a discrimination task together do not constitute a reliable reflection of a change in conscious experience. While denying this single case is probably not an unarguable position, this seems ad hoc, and goes against the spirit of finding a simple coherent interpretation for all available evidence (Block 2007). And for Peripheral Vision, one needs to substantiate or at least commit to predicting the existence of the putative top-down mechanisms for creating those detailed first-order representations. And 13 One could also take the view that the representations n Peripheral Vision are indeterminate. See for instance Block 2010 page 52-53 19 finally, one also needs to abandon the feedback-to-V1 view for first-order representations for conscious experience, in order to deal with the Charles Bonnet Cases. What we find relatively more intriguing is the possibility that, under this "Partial" Conscious Experience Interpretation, one can take an intermediate view that capture some of the favor of both the first-order and higher-order view. The basic idea behind this option is that conscious experience perhaps jointly depends on both higher-order as well as first-order representations. On this view, we cannot tell what it is like for a subject just by looking at the first-order representations, nor can we tell what it is like for the subject just by looking at the higher-order representations. It is the combination of them that jointly determines the qualitative character of conscious experiences. What does it mean to say that conscious experience jointly depends on both higher-order and first-order states? Note first, that we are not claiming that the first-order state plays some indirect causal role in determining the final conscious experience, because higher-order theories usually allow first-order states to be causally relevant in normal circumstances.14 Here we are discussing a different view, that the first-order state partially constitutes the conscious experience. A simple analogy might help. In classical Newtonian physics, an object's acceleration depends jointly on the force applied to it as well as its mass. One cannot calculate the rate of acceleration of an object if one knew only the force alone. So too what it is like for one to consciously see red may jointly depend on both higher-order and first-order states. This kind of joint determination relationship may be quite general in nature, and not necessarily ad hoc. But an analogy is not specific enough. Below we explore what exactly this view concerning the basis of conscious experience could be. Others have argued for such a view as well, including Uriah Kriegel (2003, 2004, 2006). However, here we focus on a version of this 'Joint-Determination' view that is an extension of Lau (2008). On this view, the higher-order representation refers to the relevant first-order representation for the specific content and together the two states determine the exact nature of what it is like for the subject. E.g. a higher-order state may represent something like: "I am vividly perceiving the content of first-order representation F", where the first-order representation F may have red* as its content. The intensity of the conscious experience is 14 On Rosenthal's account the first-order state is needed in order to acquire the concept that one uses in the higherorder state but once one has the concept it is the higher-order state which determines what the experience is like for one. So in a way the overall phenomenology does depend on the first-order state in that it is necessary to have the concept and so its distinctive characteristics will be captured in the concept one deploys to represent it. The overall phenomenology is thus jointly determined by the higher-order and the characteristics of the first-order though not the actual first-order state that may be targeted. However this is not the idea of joint determination that we have in mind. Rosenthal's account looks like no more than causal connection like the kind that holds between states of the retina of visual representations. 20 determined by the higher-order representation (i.e. vividly perceiving, as opposed to having some faint and uncertain impression), but ultimately, the detailed content (e.g. of color) is determined by the first-order states, by virtue of the fact that it is being referred to by the higherorder state. So, in the normal case of consciously seeing red, one will have a higher-order state to the effect that one is seeing some determinate shade of red as specified by some first-order state and the relevant first-order state represents the specific shade of red. When the relevant firstorder state is missing, the phenomenology would be different: subjects should still experience seeing color but without any specific color consciously experienced. I.e. the subjects are confident that they have perceived the color of the relevant object, except that in trying to name the exact color, they may fail, because the first-order representations are actually missing. In this case the subject will experience what we can call "fake phenomenology" –they will have a conscious experience of a determinate color without it being of any determinate color. This may seem odd at first, but we suspect every-day peripheral vision is very much often like this. Not only do we "think" we see color in the periphery, but there is a phenomenological experience of perceiving color. However, upon more careful introspection, or under rigorous laboratory testing, it seems that we do not actually experience any determine color in the periphery. Thus each state contributes something to the overall phenomenology of normal conscious experience The appeal of the Joint-Determination view is that it retains some of the main motivations for both the first-order and higher-order views. In a sense, this is essentially a higher-order approach, following the Transitivity Principle. I.e. the first-order representation F (as in the example above) only gets to contribute to the qualitative character of conscious experience because one represents oneself as being in F. F on its own does not give rise to conscious experience; it is only when F is targeted by an appropriate higher-order representation that there is any phenomenology at all. A mere change in higher-order representation, keeping F constant, can lead to a change in conscious experience. However, a critical difference here is that on this joint determination view, the perceptual content is not being duplicated in the higher-order system. Following the standard higher-order view, in a sense, the Joint-Determination view also holds that the qualitative character of conscious experience is determined by the content of the higherorder representation. However, it is determined not only by the 'narrow content' but also the 'broad content'.15 I.e. whether the higher-order content is veridical would matter; if F actually does not exist, rendering the higher-order state non-veridical, the qualitative experience would be different. Thus the details of the qualitative experience ultimately come from the content of the first-order states to which the relevant higher-order state refers. This way, one also preserves the empirical intuition that the qualitative details of conscious experience may be too fine-grained to be represented by the higher-order system. 15 We adopt the terms 'narrow content' and 'broad content' here merely for illustrating this point. We are not committed to theories regarding these. 21 The Joint-Determination view would allow us to say that in the Empirical Cases, there is some conscious experience (because of the presumed existence of the relevant higher-order states) but such experience is not full blown, i.e. it is qualitatively different from normal cases (because of the absence or the low representational quality of the first-order states). For instance, in the case of Inattentional Inflation, the first-order state may be constant between the attended and unattended case but the higher-order state under inattention may represent one as having a more reliable and intense perceptual experience than under attention. Note that unlike the standard higher-order view, the Joint-Determination view cannot allow full blown conscious experience to occur if there were no first-order representations at all. If the higher-order state represents oneself as vividly seeing an object with shape as specified by F1, with color as specified by F2, etc, and it should turn out that the relevant first-order states (F1, F2, etc) are actually completely missing, one should just experience a sense of seeing "something" without being able to say what that something is. To be more precise, it is not just that they are unable to say it; the conscious experience itself also lacks the specific content of what it is that one is experiencing. While this may seem odd, once again we note that perhaps this happens not infrequently in everyday peripheral vision. However, this is certainly different from what is reported in Rare Charles Bonnet Cases, in which the patients claim to see vivid objects and are able to name them precisely. Therefore, the interpretation based on this 'joint determination' view is that in Rare Charles Bonnet Cases there is some impoverished first-order representation, despite the primary visual cortex being damaged. This is possible because one can hold the 'joint determination' view without holding the view that first-order representations critically depend on (feedback to) the primary visual cortex. One can hold that the first-order representation in Rare Charles Bonnet Cases are perhaps impoverished, but not non-existent, thus the representations of the colors and shapes of the hallucinated objects may be less precise and distinct. However, the precision and distinctness of the percept may well be subjectively inflated due to the idiosyncratic nature of the higher-order representations in these cases. In other words, committing to this intermediate Joint-Determination view would also involve rejecting the feedback-to-V1 view for first-order representations. Regarding Block's 'Empty Higher-Order Representation' argument, when the first-order representations are completely missing (which is not necessarily the case in the Empirical Cases, as noted earlier), there is some conscious experience, albeit impoverished Thus there is an important role played by the higher-order representations. However, such conscious experience would lack specific content. Usually, when one consciously perceives an object (or any specific content), it is natural to speak of the first-order mental representation of the object as being conscious. However, here in true 'empty higher-order' cases, there is no specific content to speak of, and therefore, no first-order mental states are conscious. In this sense, prima facie, the Transitivity Principle – i.e. that a first-order state is conscious only when we are conscious of 22 having that state – is not violated. There is no such first-order state in this case, and the theory does not claim that such state is conscious. The Joint-Determination view is clearly different from the first-order view because on the former, conscious experience only arises when the relevant higher-order states exist. However, one may wonder whether it is it truly distinct from the higher-order view. As noted earlier, in a sense, the qualitative character of the conscious experience is determined entirely by the content of the higher-order state – if we consider the broad, externalist content, i.e. including what it refers to and whether it is veridical. In this case this broad content would be the relevant firstorder representation. One may also wonder, when the first-order state is completely missing, how come there is conscious experience (albeit non-specific)? Does one not need to assume then that phenomenal consciousness is a property of higher-order states? Is this then not the same reply as the one by Brown (2015) in defending the higher-order view (under the Full Conscious Experience Interpretation)? The answer is: true enough, in a limited sense, by taking this jointdetermination view, one is probably conceding that the 'conscious sense of perceiving something' is essentially driven by the higher-order but not the first-order state. But one important difference here is that one need not claim that first-order states are never phenomenally conscious. When a first-order perceptual state is conscious, it is phenomenally conscious. It is just that even when no first-order states are phenomenally conscious, one can still have non-specific conscious experiences due to the higher-order states. One disadvantage of the Joint-Determination view is that they give up the explanatory power that is one of the main motivations for accepting the more traditional version of the higher-order approach. Consider a normal case of consciously experiencing a pain. On the higher-order thought theory one is in a higher-order thought-like state that represents oneself as being in pain. This is why it is painful for you to be in this state, because the higher-order state deploys the intentional concept of pain and this is what accounts for it seeming, from your point of view, that you are in pain. On the Joint-Determination view, we seem to lose that explanation. It is not clear how a first-order state's being referred to can account for the conscious experience. What does this higher-order "referring" do? With only a mere reference to the first-order state, unlike the higher-order thought which contains the relevant intentional concept, it seems relatively difficult to construct the kind of naturalistic explanation of consciousness that some higher-order theorists aim for. Another criticism could be that, if, ultimately, it is the higher-order state (which represents oneself as being in a particular first-order state) that leads to the conscious experience, why does it have to indirectly refer to the content of the first-order state? Why cannot the higher-order state represent the color content itself? In other words, what is the motivation for holding this 'joint determination' view? If it follows from the transitivity principle, isn't the ambitious higher-order view described in the last section more straightforward? 23 However, we maintain that these potential drawbacks aside, we should not reject the JointDetermination view offhand, because despite the disadvantages there may be advantages that outweigh them. For instance, because on the Joint-Determination view, the higher-order state does not duplicate the perceptual content from the first-order state, it avoids the kind of possible outright mismatch in content, e.g. a higher-order state represents oneself as seeing red, but the first-order state represents green-ness. As noted in the introduction, it has been argued that the possibility of mismatch poses a challenge to the higher-order view. If so, the 'joint determination' view bypasses these problems. However, higher-order theorists have offered other replies to this challenge of mismatch, and we do not think that bypassing the mismatch problem alone makes the 'joint determination' view superior. We suspect that the strongest motivation for the Joint-Determination view may be empirical. Recall the neuroanatomical interpretation adopted throughout this article, i.e. higher-order representations depend on activity in the prefrontal and parietal cortices, and first-order representations depend on activity in the early visual areas. It may be most plausible that the qualitative character of a conscious experience cannot be determined fully by the activity in the prefrontal cortex alone, as representations in the prefrontal cortex may not have the fineness of grain to capture the richness of the perceptual content in conscious experience. This is an open empirical question and we believe that no a priori theorizing can settle the matter at this point.16 Having explanatory power is one kind of theoretical virtue, but so too is fitting the data. At the current time we are unable to settle this issue and are happy to leave disputes between JointDetermination and standard higher-order views at the mercy of these future empirical results. I.e. we do not argue strongly for the Joint-Determination view, and we note the potential disadvantages. We only describe it here as a possibility that future work may explore further. Resisting the tri-lemma? The foregoing discussion is presented as considering three different interpretations of the Empirical Cases. However, it can also be seen as an argument against the first-order view, and in support of the higher-order approach. The main crux of the argument roughly boils down to the following: (1) There is either conscious experience, or not (No Conscious Experience Interpretation), in the Empirical Cases. (2) It is extremely implausible to deny that there is conscious experience in the Empirical Cases. 16 We should note that there is another wrinkle here. Rosenthal argues (2005) that the content of the higher-order states is essentially comparative. Thus instead of needing to represent every specific color that we encounter in the world we need only represent their characteristic similarities and differences. If so then much less processing power would be required by the PFC. We cannot resolve this issue currently since we do not really understand how the brain encodes this information. 24 (3) If there is conscious experience in the Empirical Cases it is either like normal conscious experiences (Full Conscious Experience Interpretation) or it is less full fledged (i.e. impoverished and non-specific) (Partial Conscious Experience Interpretation) (4) If the conscious experience in the Empirical Cases is like normal conscious experience (Full Conscious Experience Interpretation), the higher-order theory is more plausible than the firstorder theory (5) If the conscious experience in the Empirical Cases is not like normal conscious experience, but is rather impoverished and non-specific (Partial Conscious Experience Interpretation), then either the higher-order theory is true, or conscious experience is jointly determined by first-order and higher-order states. We take it that 1-3 are not so controversial. Point 4 depends on some loose ends; namely, should the higher-order theorist accept that it is fine to speak of non-existent first-order states being conscious (Rosenthal 2011), or accept that first-order states are never phenomenally conscious (Brown 2015)? There may yet be other solutions. But what we maintain is under the Full Conscious Experience Interpretation, the first-order theory does seem to be in much more trouble than the higher-order theory. We suspect point 5 is probably the most controversial. As pointed out in the last section, it is not impossible that a first-order theorist may find ways to defend a modified first-order view by taking the "Partial" Conscious Experience Interpretation. We do not find such defense plausible, and note that at the very least, the first-order theorist would have to give up the feedback-to-V1 view that Block endorses. And likewise, if one accepts the Joint-Determination view, one also has to give up the feedback-to-V1 view for first-order representation. Concluding remarks Just as in Hans Christen Anderson's fable where the emperor's thinking that he has gotten new clothes does not actually give him real clothes, one may think that one's mere thinking of being in a conscious perceptual state shouldn't give one real conscious experience. However, taking this analogy literally would be to do a disservice to the higher-order thought theory, because one should not confuse normal conscious thinking (as in the case of the emperor) with the specific higher-order representations stipulated by higher-order approaches. According to the theory, such higher-order states, unlike normal conscious thoughts, do not have to be conscious themselves, unless they become the content of yet another higher-order representation. Opponents may argue that unconscious thought leading to conscious perception is odd. However being odd is not the same as being incorrect. As Block himself has suggested (2009), something counter intuitive may well be needed to account for the infamous explanatory gap (Levine 2001). We recognize the counter-intuitiveness of some interpretations of the standard higher-order approach, but if our best scientific theories point in that direction we should be prepared to accept the conclusion. To those who cannot take this oddness straight up, we are also offering the 25 Joint-Determination view as an alternative to help to preserve some of the intuition of the firstorder view. In the spirit of repetition for emphasis we offer the following four points as a summary of what we take the argument of the paper to suggest. (I) Recurrent feedback loops to V1 have been hypothesized to be the neural correlate of conscious visual experience, but the Empirical Cases we appeal to suggest that this is most likely not the case. This is true under the Full Conscious Experience Interpretation as well as the Partial Conscious Experience Interpretation. Thus to save the feedback-to-V1 view the only option is to take the No Conscious Experience Interpretation, which we argue to be so implausible to the point of being outlandish. (II) The first-order view faces serious challenges regarding these empirical cases. This is because it is very unappealing to take the No Conscious Experience Interpretation, which would have been compatible with the first-order view. It is unclear how the first-order view can cope with the Full Conscious Experience Interpretation. On the Partial Conscious Experience Interpretation, we argue that there may be some hope for defending some core elements of the first-order view, but the first-order theorist will also need to make some important adjustments and sacrifices. (III) In light of this we argue that a version of the standard higher-order approach should be considered less problematical than the first-order view. We do not argue that the higher-order approach faces no difficulty whatsoever. The challenge seems to be that, under the Full Conscious Experience Interpretation (or the Partial Conscious Experience Interpretation), one needs to decide how to preserve the Transitivity Principle. Such solutions are not straightforwardly intuitive to everybody, but we argue that they pale in comparison to the problems facing the first-order view. (IV) One new alternative we see is to adopt the Joint-Determination view about conscious experience, which holds that phenomenology is jointly determined by both first-order and higher-order states. This view may have its problems, but also potential merits, and may well be the happy medium where first-order theorists can preserve some core intuitions of their theory amid the present challenges. Amongst these points, we feel most strongly about point (I): the recurrent feedback loop view has other problems and, as we noted earlier, has been independently criticized (Macknik & Martinez-Conde 2008, Silvanto & Rees 2011). Block (2007, footnote 10) has also noted previously that his view is not committed to this empirical claim. Though point (II) seems to us hard to deny, we are somewhat less sure about (III) and (IV), in the sense that we feel somewhat 26 ambivalent as to whether the Joint-Determination view is truly a good alternative – and to arbitrate between them would be to go beyond the scope of this chapter. Ultimately, it may depend on future empirical evidence. However, in any case, although the Joint-Determination view has some flavor of preserving some important intuitions behind the first-order view, we note that to take this option is likely to involve giving in quite a bit to the higher-order approach. This is not just the modest version of the theory that aims to explain what makes a conscious mental state one that one is aware of. This is about of the very nature of phenomenal consciousness. The position holds that the higher-order state is an essential component of phenomenal conscious experience and that it partially determines the overall nature of what it is like to have a conscious experience. Taking this option is to concede a lot to the higher-order theorist. Thus, rather than being defunct (Block 2011a), the higher-order approach to consciousness is alive and well indeed.17 17 We would like to thank Rocco Gennaro, Pete Mandik, Adam Pautz, Ian Phillips, Adrianne Prettyman, Jesse Prinz, David Rosenthal, Daniel Stoljar, and Josh Weisberg for helpful comments on an earlier draft. An earlier version of this paper was presented at the New York Consciousness Project meetings and we are grateful for the enormously helpful discussion at that meeting. 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