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Consciousness – The Science of Subjectivity

Antii Revonsuo, University of Skövde & University of Turku

Psychology Press (Taylor & Francis Group)

INTRODUCTION: This book is useful in providing clear expositions and criticisms of the numerous versions of mainstream consciousness theory. Revonsuo emphasises the distinction between theories of consciousness that concentrate on subjective experience and qualia, and theories that view consciousness as related to information processing. He is particularly critical of theories that explain only information processing in the brain, and deny or avoid subjective experience and qualia. He is not afraid to criticise leading consciousness study figures such as Dennett. Unfortunately, in his very brief mention of quantum theories of consciousness, he entirely misses the point that quantum theorists regard consciousness as a fundamental aspect of the universe that cannot be explained in terms of classical science.

Epiphenomenalism: The idea of epiphenomenalism, where consciousness is regarded as a functionless by-product of brain activity, is regarded as a trap by the author. He sees it as something that mainstream theorists resort to when they have explained information processing in the brain, but are left with subjective experience unaccounted for. In fact, the author classes epiphenomenalism as the same sort of thing as dualism, which is the concept of a spiritual substance separate from the physical world. He argues that for something to be real or to exist in scientific terms, it must be capable of being detected, and to be detected it must have some causal power to act on instruments or observers. But epiphenomenalism posits a mental realm that has no causal powers, therefore cannot be detected, and is thus outside the physical universe, a concept which is not part of science.

Eliminative materialism: This theory gets around the difficulty of explaining consciousness in terms of the physical world, by denying the existence of consciousness. Consciousness is compared to phlogiston, a substance that was supposed to be released when substances burnt. The need for the concept of phlogiston ceased with the discovery of oxygen, which explained the nature of burning. The author argues that this and similar examples are false analogies. Consciousness is not in the position of phlogiston, but in the position of the actual burning. Eliminative materialism is not getting rid of phlogiston, but instead denying the existence of the burning substance, the very data which it has been called on to explain.

Reductive materialism: This type of theory accepts the existence of consciousness, but argues that it is identical with particular forms of neural activity. The author views this as a similar assumption to that seen in eliminative materialism, to the effect that the whole concept of consciousness will be made redundant by the advance of science, which will replace it with a theory of neural activity. For the author, the problem with reductive materialism is that it is not clear why neural processes, which appear well suited to information processing should also be able to produce the qualia of colour sensation, pain or emotional responses. Of course, this could be clarified by the advance of science, but the drift of reductive materialist thinking is very much that subjective experience can be produced by existing text book neuroscience descriptions, with perhaps a bit more of the same.

New mysterians: Revonsuo discusses the 'mysterian' or 'new mysterian' view of consciousness. In this, consciousness is deemed to be a physical property, but one that cannot be understood by humans, either because they lack the right type of intelligence, or because consciousness gives us contact with parts of the universe that science will not be able to describe. The author for his part is hopeful that science will be able to get beyond the barriers suggested by the mysterians. At the present time, the mysterians might seem unduly pessimistic, given the to date success of the human mind in understanding the nature of the universe.

Cognitive science: Revonsuo attacks cognitive science as a science of the mind that is devoid of consciousness. Cognitive science's idea of the mind was based on the computer, and as such was not a science of consciousness, but was merely a theory of information processing going from input to output. Cognitive science leant itself to the theory of functionalism, and neuroscience was regarded as largely irrelevant, because the mind did not necessarily have to be based on organic matter. In the last part of the twentieth century the increase in brain scanning made it possible to relate mental experience to brain activity as revealed by neuroscience, and this gave rise to cognitive neuroscience, which attempted to describe previously excluded features such as the emotions and consciousness.

Functionalism: For functionalism, which is closely related to cognitive science, consciousness is a set of relationships. This set of relationships happens to arise in the brain, but consciousness could be generated by anything, such as a silicon computer, that had the same set of relationships. The author points out that one of the theory's advantages is that it does not identify consciousness with physical matter, and therefore obviates the problem of working out how consciousness could arise from physical matter. Originally, it was also seen as a strength of functionalism that it explained the mindlike qualities of computers. However, the author says that this is really a weakness because the theory gives no account of qualia/subjectivity, and to an extent it cannot, because there is no clear role for qualia in the input to output information process that computers comprise.

Attention and awareness: The author discusses the difference between consciousness and attention. Some researchers have suggested that consciousness is the same thing as attention. The author defines attention as the selection of some information for more detailed processing. The signals to be attended may be amplified, while other signals are filtered out. Attention often involves consciousness, but the two things can be dissociated from each other. It is known that attentional amplification or filtering of information can take place in non-conscious areas of the brain. Thus, a word that is shown for too short a time to enter consciousness can nevertheless draw attention and produce a response in the brain. Conversely, we are subjectively conscious of things outside of the focus of attention. As an example, in looking for a familiar face in a crowd, we focus attention on individual faces serially, while being subjectively aware of the surrounding crowd. This implies that there is some subjective experience outside of the focus of attention.

The author disagrees with arguments that attempt to suggest there is no consciousness outside the focus of attention. These claims are based on two types of study. First 'change blindness', where subjects fail to notice an obvious change in a picture, such as whether or not an aircraft has an engine, and secondly, 'inattentional blindness', which is not noticing something happening in the current environment. The author argues that change blindness is merely a failure to remember all the details in the previous picture. The proponents of inattentional blindness think that attention only briefly visits the peripheral areas of vision and that the information here gets out of date. The author however argues that the peripheral areas still have the ability to get into consciousness. If they did not, the fate of the peripheral areas would be more like a condition known as simultanagnosia, where the subjective awareness of the background is lost, and the patient is only aware of one object at a time. The patient does not know where the object is, and as a result, the object appears to hang in a void.

Introspection: Revonsuo examines the criticisms that introspection into what is going on in the mind is unreliable, because of potential for confabulation or misremembering. He argues that this problem can be offset, if there are similar reports for large numbers of subjects and/or from subjects in different groups. One might add that that evolution is likely to have selected for access consciousness and memory that is reliable most of the time, because of its obvious survival advantages. There is a sense that unreliability of introspection is over played in much of the literature, with examples of confabulation in particular often deriving from artificial and unusual situations.

Representation: Revonsuo discusses the subject of representation. Consciousness is sometimes defined as the ability to represent information from the external world within the brain. The brain has an internal representation of an external object, if activity in a part of the brain fluctuates in line with the presence or absence of the object. However, the author argues that neural activity that covaries with an object has no necessary connection with subjective experience. Many external stimuli registered by the brain are in fact not associated with any subjective experience. Similarly, other experiences, such as dreams are not related to a direct stimulus from an external object. It is thus argued that representation, while an important part of the brains information processing, is not directly related to consciousness. The author has a similar approach to the use of awareness as a substitute for consciousness. This tends to refer to consciousness of the representation of an external object as in 'aware of a dog', but this, as argued above, does not comprise a complete picture of consciousness.

Dennett: The philosopher, Daniel Dennett, was a supporter of functionalism, and has been possibly the most influential figure in consciousness studies. Revonsuo, however, is inclined to regard his ideas as having been superseded by new trends in mainstream consciousness thinking over the last decade. Dennett starts from axiom of only looking at third-person material, and regarding any form of introspection, or first-person point of view, as being invalid. Consciousness, in Dennett's view, is simply some special form of information processing that gives subjects the false impression of a centre of consciousness in the brain that Dennett calls the Cartesian theatre. This is also claimed to be the source of the false impression of the existence of a self. Dennett says that all these subjective impressions are false. He claims that the idea of a central place in the brain carries with it the idea of an internal observer, but if that were so the internal observer would have a consciousness inside it, and we would enter an infinite regress. Instead, Dennett proposes that there are a lot of information streams in the brain competing to become part of its output, and the successful information streams are the conscious ones.

The author's main criticism of Dennett's theory is that it does nothing to explain consciousness. Dennett dismisses qualia and subjectivity as illusions, and has it that consciousness is merely a feature of successful information streams. The trouble is that many people who actually have subjective consciousness feel that they have been left without an explanation of what they experience. Dennett's information based theory appears to leave out exactly the things that many people want to have explained about consciousness, and is thus a denial of the data that the theory is called on to explain.

Blindsight: Although there have been ingenious attempts to mitigate the damage, the reductionist position has never really recovered from the discovery of blindsight, which showed that the same cognitive function could be either conscious or non-conscious. This struck at the belief that consciousness is identical to neural processing. P Blindsight is a form of brain damage, often resulting from stroke, where there is blindness in part of the visual field. The physical substructure of blindsight is that there is a ventral visual stream that is conscious, but a dorsal visual stream that is non-conscious. When asked to guess the location of objects, blindsight patients guess correctly much above chance. Nevertheless, they continued to miss most of the meaning of an object, such as whether it was animate or inanimate. Further, the patients continue to have no conscious knowledge of the objects about which they are correctly guessing.

For reductionism, the destructive aspect of blindsight is that the dorsal stream can do the whole function of guiding us towards objects, but does this without having the property of consciousness, which in reductive theories adds nothing to neural activity. Blindsight is suggested to resemble the guidance system of creatures such as frogs, which respond to prey such as flies as moving objects, but could starve to death in a tank full of dead flies that do not have the trigger property of movement. Thus there appears to be something in the ventral stream that is not in the dorsal stream, and also not in conventional neuroscience text books.

Embodied consciousness: The last decade has seen the rise of the idea of embodied consciousness, with the body and its action in the environment being involved at the basic level of consciousness, rather than the mind and consciousness being only related to brain activity. The author criticises the embodiment approach for being vague as to where in the brain/body/environment consciousness is actually located, and how it functions there.

The 'reflexive monism' of Velmans also puzzles the author. This proposes that while qualia arise in the brain, they are projected back into the physical world, and that subjective consciousness is outside of rather than inside of the brain. This should not be understood as some physical mechanism projecting the qualia, but a psychological process, although, confusingly this may in part be a physical process. The author criticises the theory for not really providing a physical location for consciousness.

David Chalmers: This philosopher is best known for defining consciousness as the 'hard problem' and arguing that the problem cannot be resolved by reductive explanations, and that qualia should be accepted as fundamental features of the physical universe. The more detailed levels of his ideas seem more problematic to the author. Cognitive processing is here the physical counterpart of the subjective, but the subjective itself is not really physical, thus moving towards a dualistic view. There is also a panpsychist angle, in which all information, even the most basic, is coupled with consciousness. The author criticises the theory as untestable, and as proposing a non-physical subjective element that cannot act causally in the universe.

Higher order theories (HOTs): These theories have been fashionable in consciousness studies in recent years. In these, consciousness is proposed to arise from the relationship between different non-conscious representations. The author takes the view that these theorists are really talking about the relationship between reflective consciousness and representations in the brain. These have to become the object of top-down activity by reflective consciousness, before they become subjectively conscious. What is not clear is how reflective consciousness becomes consciousness, or how or why consciousness arises in the relationship between reflection and representation. It is also suggested that the theory might be hard to test.

Baar's global workspace theory: This theory is based on the cognitive science view of the mind, and proposes that the mind is composed of distinct modules analysing sensory input, and competing for access to a more unified central system or workspace. The central system is conscious, as distinct from the non-conscious modules. The exact location of the workspace is vague, and again there is no real explanation of why or how consciousness arises at that particular stage.

Crick and Koch: The work of Crick and Koch has been prominent from the beginning of modern consciousness studies. In this book, the author really seems to be referring to their position in the last decade. When Crick first outlined his views on consciousness, there was a confident note, with respect to reaching a reductive explanation of consciousness based on something close to text book neuroscience. His frequently quoted phrase at the time was 'you're nothing but a pack of neurons', and this in a context in which the neurons were regarded as computer switches.

In the last decade, Crick and Koch essentially backed off from the challenge of explaining consciousness or qualia and decided to concentrate on identifying the correlates of consciousness, which meant the set of neural activity relating to particular conscious experiences. It is admitted that something being correlated with consciousness is not the same thing as it being conscious. However, I think that an element of fudge can sometimes creep into the modern view of neural correlates, in the sense that an element of certainty is allowed to appear relative to the hope that the correlates would give access to an actual explanation of consciousness. The more rigorous view that there is no identity or necessary downward causal connection between correlated occurrences tends to be downplayed.

Emergent property theories: The classic example of an emergent property is the liquidity of water, which emerges from the electric forces between the constituent molecules. Consciousness is suggested to be another such emergent property, in this case, a property emerging from the biochemical complexity of the brain. Revonsuo in fact favours a theory of this kind, but is nevertheless concerned that emergent property theories can easily resolve into yet another reductive explanation that does not actually explain why being conscious is like what it is. In this section, I feel that it might have been more useful to discuss whether there is much prospect of discovering a chain of macroscopic physical causation, by which consciousness could emerge. Where we do see emergent properties in nature, we can also determine their origins back to the quantum level as in the example of the liquidity of water. The problem here is that science now has a very good understanding of the forces involved in the type of matter than makes up the brain, and there is nothing in these forces that looks like combining to produce the property of consciousness.

Edelman/Llinas: Gerald Edelman has advanced the theory of selected groups of neurons that strongly interact with one another in the cortex and thalamus forming reciprocal connections and being spatially coordinated. This is called the dynamic core, and different groups of neurons at different times are capable of participating in the dynamic core. Edelman thinks that it is the integration of this activity rather than individual neurons or other units that create consciousness. Revonsuo criticises this approach for identifying consciousness with information, without really providing any evidence for why this should be the case. Rodolfo Llinas puts forward a similar view to Edelman/Tononi. He concentrates on the reciprocal connections between the thalamus and the cortex, and suggests that cells in the reticular thalamic nucleus could be responsible for the gamma synchrony. The thalamocortical information loop along with the gamma synchrony binds the unity of consciousness, and as in Edelman/Tononi, consciousness arises from integrated information.

Quantum consciousness: When it comes to quantum theories of consciousness, Revonsuo essentially misses the point of why they have been proposed. Revonsuo seems to be concerned that what we consciously perceive is nothing like the quantum world. However, the reasons for the resort to quantum theory are in fact writ large in Revonsuo's own book, where one after the other he comes up with forceful arguments against mainstream classical theories. The basic argument for looking at the quantum world is that there is nothing in classical physics that explains consciousness, a point which is time and again implicit in Revonsuo's own discussion. We can see that as we move into the second decade of the 21^st century, the strategy of the mainstream towards quantum theory seems to be to ignore it, rather than discuss it in a logical or evidence based manner, in the assumption or hope that it will simply go away.