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Mainstream 13Seeing Red A Study in Consciousness Nicholas Humphrey INTRODUCTION: This book seeks to show that the process of qualia/sensation arising in the brain is a separate system from the functioning of information/perception. The arguments for separate systems are discussed below in detail, but do not appear to be strong. The qualia/sensations are further argued to create the illusion of the conscious self. However, no mechanism is put forward for how sensations could be experienced in the first place, without an experiencer of some description, or how the experiences, if somehow they did arise by themselves, could physically work to create the further sensation of a self. Although this book appears to favour the mainstream scientific view of the mind, it is in common with quite a number of such books, surprisingly light in terms of explanation or even hypothesis concerning detailed physical processes in the brain. The book gets properly underway in chapter two, where Humphrey considers the subjective experience of looking at a red screen. The screen is described as reflecting red light at a wavelength of 760 nanometres. This is an objective fact that could be measured by a photometer. Such a measurement does not depend on any subjective experience of redness, and the measurement would be the same if there was no one in the room. However, a subjective observer of the red screen will have a subjective experience of redness, but this subjective experience also has an objective aspect, because, at least in principle, a brain scan might detect visual cortex activity signifying red. Humphrey splits this subjective experience of red into a propositional component and a phenomenal component. The propositional component involves the acquisition of ideas, beliefs and feelings about something. With the propositional experience, the subject is just an observer. However, in the phenomenal component, the subject generates qualia, which are not external or observed, but part of him, and can be viewed as being brought into being by him. Qualia are something that do not exist until the subject looks at the screen, and ceases to exist, when he moves away from it, and thinks about, or observes something else. The qualia are different from beliefs about external objects. The conscious sensation or qualia is essentially different from the image on the retina. While the red qualia is a private sensation, it is also perceived as an objective fact about a red surface in the external world. The fact of subjective experience is seen by the author, as being linked to the idea of a subject or something which has experience. Humphrey builds from this to an argument that the experience of sensation creates the self. Maybe, this is plausible, if we think of the self as the easily deconstructed combination of narrative history and the distinction or boundary between the body and the rest of the world. However, it does nothing to explain how sensation/qualia, as distinct from mere information processing, arises in the first place in order to create the self. The essential first building block is missing. The more traditional suggestion here is that the external object is initially involved in transmitting a stimulus to the brain, and the subjective sensation in the brain can be read off to give information about the nature of the external object. In the analysis that the author produces here, the subjective sensation and the information about the external object are deemed to be separate systems. Feeling and perceiving are thus seen as separate functions in Humphrey's analysis. MAIN ARGUMENTS: Humphrey's purpose is to argue that sensation and perception operate on different paths in the brain, and that sensation, which also produces the self, exists in a kind of passive bubble, separate from the active business of the brain. He argues firstly from the evidence of blindsight. In its normal form, blindsight is related to blindness, in just a part of the visual field, resulting from illness such as stroke. Patients have no awareness of vision in this part of the visual field, but when urged by researchers to guess, what there is in the blind part of their visual field, they score significantly above chance. The most common view has been that there is a dorsal and non-conscious tract to the visual field as distinct from the ventral route. What is certainly not true, but sometimes seems to be implied in this book, is that blindsight is functionally the same thing as ordinary sight. Patients are usually unaware that they have blindsight, and can actually object to the apparent futility of guessing, when they can see nothing. This would suggest that in the conditions we evolved for, which did not include many neuroscientific researchers, the characteristic would not have been particularly useful. Furthermore, even when it does start to function it is only better than guess work, rather than giving the reliability of normal vision, and patients do not seem confident to make much use of it, even when they become aware of its existence. In relation to this, the author also discusses a case that is clinically different, but functionally much the same. Here a patient had had an operation for cataracts present since childhood, but the visual cortex is unable to process the new data. It turns out that this patient has, when urged by Humphreys, a sort of blindsight ability to identify the position of objects. However, quite apart from there being no conscious experience, the ability to identify some objects was in practise not even functionally useful, and after a period of personal work with Humphrey in trying to utilise her blind sight, the patient went back to using dark glasses and a white stick, in preference to trying to build on the blind sight function. Humphrey's also refers to a condition called metamorphopsia, resulting from damage to parietal cortex, in which the visual fields are in flux, swelling, contracting and changing colour, in an Alice in Wonderland manner. He remarks that these patients are able to negotiate the world. However, this seems merely to say that the brain is quite good at adjusting to conditions, as in studies where subjects can get used to glasses that invert the world, and actually take some time to adjust back to normal vision. It would be adaptive to have the ability to adjust to defects in sensory inputs in a single pathway, and it does not require us to evoke the existence of a second and speculative pathway. There seems no call on the basis of this condition, to say that sensations are not functional, and that there is something else doing perception behind the scenes. Humphrey's third attempt at evidence refers to altered states of consciousness resulting from drugs such as mescaline and LSD. He tries to say that the experience of transfigured or heightened perception is a separate pathway from normal information/perception. However, there is no real evidence for this in the operation of the brain under these conditions. The brain is nowadays normally conceived as creating an adaptive model of the external world that is nothing at all like the actual external reality, which physics describes as merely bits of energy fluctuating a a vacuum. Drugs binding to particular receptors can to a greater or lesser degree amend this model. but there is no reason to believe that they are operating on a different pathway from the normal information/perception. In fact, in this case the authors idea appears to contradict the conventional idea of the action of drugs, by calling for them to act over another pathway from the normal receptor route, or possibly to act on a complex double set of receptors. A further attempt to establish the author's point of view is a discussion of sensory substitution, which attempts to help blind patients, by transducing visual information picked up by a camera, into either auditory or tactile information. The results seem rather similar to synaesthesia with, for instance, a man 'seeing' his wife as a 'squishy type of sound.' One subject did say that he seemed to experience two types of consciousness, which is seized on as evidence that there are separate pathways. However, when using the auditory system to generate symbols for visual objects, it is not really surprising that such a mixed sensation should arise. As described, the mixture would appear to be between sight and sound as different types of qualia/sensation, rather than qualia/sensation and information/perception as different things. What the patient did not say was that they experienced sensations of whatever kind as one thing and information as another. Finally, in an apparent attempt to bolster his theory, Humphrey uses a tactic frequently seen in experimental psychology, of an experiment relating to an experience unlike anything that could be expected to have occurred in the hunter-gatherer world, for which we evolved. In this case, there is an experiment, where the subject's hand is hidden underneath a table, while an artificial hand is visible on top of the table. The subject can be persuaded that a series of taps on the real hand is being experienced by the artificial hand. As it would be difficult to imagine such a problem arising in the hunter-gatherer world, it would seem to be adaptive for the brain to model the situation, on the basis that the tapping must be happening to the visible hand. There seems no requirement for the speculative proposal of a second pathway carrying the sensation/qualia, as distinct from the information/perception. Towards the end of this book, Humphrey does eventually attempt to explain how sensation arises, and here he resorts to what I call the 'old video camera trick.' Primitive organisms monitor the environment, and also start to monitor their own bodies, and qualia or conscious sensations are in this model proposed to arise from this interaction. The problem with this is that items of non-conscious machinery routinely monitor one another, and there is no evidence for conscious sensation arising from these activities. Nor do 'video' theories, such as this one, ever contain any proposal as to what physically happens when the monitoring takes place that is different from what occurs in the rest of the universe, and could thus give rise to the distinct property of consciousness. Elsewhere in the book, there is an attempt to effectively re-run the video, idea as the concept of a loop within the brain, but again there is no indication of a point in the loop, at which a new physical mechanism or property such as consciousness could arise. It is also argued that creating a sensation in the brain is akin to bodily action or expression, in line with the current trend to emphasise the embodied, as distinct from isolated brain, nature of the mind and consciousness. However, bodily actions as such are not conscious, and are not by themselves, in the absence of some additional action in the brain, likely to produce consciousness. This idea, although having relevance to consciousness does not seem to be developed into a coherent model. At another point, the ability to create an experience is linked to the 'thickness of time' or the 'thickness of now'. The idea is that the present moment is not a temporal singularity, but contains a lingering element of the immediate past, and a tiny anticipation of the immediate future. I think this idea is quite insightful, but it is not clear how, time, which in rigorous terms, is part of the spacetime of the universe, can act to produce sensation. These things do not look akin to one another, except in a fundamentalist model, as with Penrose, or arguably Bohm, where there is an attempt to link spacetime and consciousness at a fundamental level. However, this is almost certainly not what Humphrey has in mind. Humphrey does try to answer the problem that arises with regard to evolutionary theory, which is why evolution should select for qualia/sensation, if it has no function. In Humphrey's model consciousness is portrayed as an illusion that fills us with grandiose and illusory ideas about ourselves, and this in turn motivates us to be outperformers, defending families and building civilisations. It is not clear why an information/perception non-conscious mechanism could not have been fine-tuned by evolution to provide just as good survival procedures, and that without the disadvantage of maladaptive conscious desires. Other issues are raised by this model. Although the self is described as being an illusion, it nonetheless appears to be attributed causal efficacy in defending families and building civilisations, with, by implication, some element of freewill, something that does not normally figure in this type of model of the mind. The model does at the very least seem to propose the existence of an efficacious illusion. The implications of this model in terms of efficacy and freewill are not in fact worked out in this book. |
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