Introduction

With Consciousness: the Science of Subjectivity Antti Revonsuo has written a wonderfully clear, very well-organized and insightful introduction to the philosophical and empirical study of consciousness.

As the book cover introduces him, Revonsuo is a Professor of Cognitive Neuroscience at the University of Skövde (Sweden), as well as Professor of Psychology at the University of Turku (Finland), and he has been directing an undergraduate degree program on conscious studies since 1997. These are telling biographical details, for Revonsuo’s concern with his students is tangible throughout this work. He takes his time to introduce the subject, barely presuppose any knowledge about it — although one chart of the brain with the name of its different parts and respective main functions could have been helpful. He employs a crystal clear language and organizes his paragraphs and introduction of very diverse philosophical and empirical theories in an explanatory order. The shortness of the paragraphs makes it easy to digest new information. This is further aided by the short summaries and enumeration of discussion questions at the end of each chapter and the glossary at the end of the book. All of this makes this an excellent introduction in the study of subjectivity for the beginning student, but equally so for the conference participants in the big interdisciplinary conferences on consciousness in Tucson, Arizona and of the ASSC to which Revonsuo alludes: Revonsuo’s work introduces them to the keynote speakers and to the basic aim and method of those fields of research which they are not so familiar with.

 

Summary

Revonsuo starts off with determining how we should actually conceive of consciousness: i.e. as subjectivity. A conscious subject is a subject who has experiences. It is a subject for whom it is like something to be. He also makes the reader feel why consciousness is mysterious, what it makes one wonder about. Although we can scan the brain and see specific neurons firings at the occurrence of a certain conscious state — say an emotion or a dream –, the brain scan will neither show us the content of this subject’s consciousness, nor how this experience feels like for the subject. We also seem not to manage to objectively describe this subject’s experience in such a way that when someone were to hear this description, he would have access to this subject’s conscious state: we only arrive at imagining how this experience would be for us, from our point of view, and thus not at how this experience is actually for this subject. Further, philosophers and scientists alike have failed to explain how something as physical as neurons gives rise to something as meaningful as thoughts. And when they would finally be able to do so, they would come across another problem. Philosophers struggle with constructing a model in which something mental can have causal efficacy. Say, how my feeling of thirst could make me lift the glass of water. Given our current scientific view of the world every physical effect must have a physical cause. Following the same scientific view every effect can also only have one sufficient cause. So if the effect of me lifting the water must be sufficiently and physically caused by neuron firing and muscle contractions, then there does not seem to be any causal role left for my feeling of thirst in the coming about of this effect.

With this subject and some of the main questions which it evokes clearly in view, Revonsuo continues to introduce the different studies of consciousness.

The first part of the book outlines the background of the science of consciousness. Revonsuo runs through the different dualistic and monistic theories of consciousness (i.e. through the theories which either claim that consciousness is constituted by both physical and spiritual matter, or by only one of these), to then explain why neither Cartesian dualism, epiphenomenalism, idealism, nor eliminative, reductive and emergent materialism dissolve the just mentioned big mysteries about consciousness.  [See glossary below.]

He then sketches the historical foundations of consciousness science. Revonsuo explains why phrenology does not yet count as a scientific study of consciousness, but has the merit of drawing attention to consciousness as a potential subject for scientific research. In phrenology predictions about someone’s future are made on the basis of the size and shape of his skull. Phrenology cannot be called a science because it is not based on empirical research. Yet it has had its relevance for the science of consciousness because it defines consciousness as a biological phenomenon and it launches the idea that the brain can be subdivided into different parts which’s respective activity gives rise to different states of consciousness. This fair and illuminating dissection of the flaws and benefits of a particular theory characterizes Revonsuo’s approach throughout.

Revonsuo consequently elaborates upon the work of three of the founders of scientific psychology: Wundt, Titchner and William James. In spite of their internal disagreements about the particularities of the method of studying consciousness and about the conclusions about its nature and function, they each push introspectionism forward as a reliable method to study consciousness. Their claim is that we can draw scientific conclusions from the analysis of a subject’s verbal reports of his subjective experience.

This idea was soon to lose its resonance and Revonsuo subsequently reconstructs the expulsion of consciousness as a subject in scientific psychology. He explains how behaviorists claim that consciousness cannot be the object of scientific consciousness because it is not publicly observable; how Freud draws our attention to the games that the unconscious plays with the conscious; and how functionalism conceives of the mind as an information processing machine which delivers a certain output for every input in accordance with a set of rules of which it does not have to be conscious and, thus, studies the mind but not consciousness.

This trend too will shift and Revonsuo concludes the first part of his work with a sketch of the phoenix rising of the modern science of consciousness and its conceptual foundations.

As a logical and chronological follow-up on this Revonsuo introduces the reader in the second part of his work to the current science of consciousness. He casts light upon the neuropsychological science of consciousness. In this section, especially his take on what happens with the self-consciousness of split-brain patients is revealing. Split-brain patients are patients for whom the connections between the left and right hemisphere are severed in such a way that what the subject perceives with each hemisphere can only be reported by this hemisphere and not by the other. Philosophers have wondered whether we would in such a case have to speak of two subjects instead of one. Revonsuo suggest that this is not necessary since the coherent narrative that we tell about ourselves is produced by the left hemisphere and this stays intact in split-brain patients.

In a next section Revonsuo enumerates the current philosophical and empirical theories of consciousness and fruitfully correlates each with the corresponding theory in the other field of research.

Revonsuo concludes this part with a fascinating sketch of the scientific study of altered states of consciousness in which he deals with dreams, hypnosis, out-of-body experiences and near-death experiences (which natural explanations would not entirely be able to account for).

 

Evaluation

Revonsuo generally allows different theories to come to the fore and gives arguments for their pros and cons while being a critical but not too partial observer. When all theories fail to account for a certain phenomena, Revonsuo refrains from suggesting a way out. This could be an interesting addition in a second edition of this book. When it would prove impossible to come up with the perfect theory, or even to converge the best of the existing theories, new thinking could perhaps be furthered by pointing to the common flaw in the existing theories. When they appear to all share a view on reality, we could start questioning a view that we have always taken as the only possible or valid option.

 Still, Revonsuo leaves us with something. His honest and rather impartial assessment of different theories of consciousness — seen in his attempt to point to the merits of the most dubious, and the flaws in the most promising theories — does not prevent him from ultimately taking a stance and be open about the theory of consciousness that he wishes to defend: i.e. an emergent materialism that would allow us to at some day explain the emergence of consciousness out of physical matter, just like one has succeeded in explaining the emergence of life out of non-lively matter. This openness about his own position is a necessary move and does not make this work more biased. On the contrary, it gives the reader the necessary background information to be motivated to scrutinize Revonsuo’s claims and take in an own position in the ongoing debate about consciousness.

Here are some question marks that one could put next to Revonsuo’s text.

Revonsuo mentions how “[u]p until roughly the 1850s, human consciousness was conceived of as a Cartesian soul: nonphysical by nature, without spatial extension or location in physical space and intrinsically unified or undividable. The soul, by its very nature, was taken to be beyond scientific observation or measurement. Therefore, there could be no such thing as a science of consciousness.” (48) This statement may be too bold for two reasons. Firstly, the fact that one — as testified in literature —  was even before this time well aware that certain drinks could make someone go crazy seems to contradict that one saw the soul as something nonphysical. Secondly, one can only wonder why Revonsuo does not mention Kant. There may be reasons to refrain from calling his Critique of Pure Reason a scientific study of consciousness and determine it as a philosophical study of consciousness, but it is certainly a systematic study of consciousness. And if one determines consciousness as Kant does, then perhaps this systematic philosophical analysis of consciousness is the only way to gain knowledge about conscious, and, thus, in a way the only scientific approach to it.

In a similar way it is surprising to discover that Revonsuo does not mention the philosopher Edmund Husserl when he depicts the emergence of consciousness studies. This is especially striking because Husserl developed a whole new way to study consciousness in a reaction against the method according to which psychologists study consciousness for the first time. Revonsuo elaborates upon this latter method. If he would mention Husserl as well, his sketch of the first psychological theories of consciousness would explain to philosophers what Husserl reacted against, and the exposition of Husserl’s reaction could in its turn help one understand what goes wrong in these psychological theories.

But, to come back to Kant, if Revonsuo would have included him, he may also have paid more attention to the fact that our conscious experiences do not only have a subjective feel to them, but that they also have a specific meaning for us. When Revonsuo for example says “Perhaps we will learn that the visual experience of seeing blue is really ‘40 Hz neuroelectrical oscillations in cortical visual area V4′, we can wonder whether we would under this kind of description only have an intuition of something and no concept of it, and how this would work. Would we see a colour without realizing that it is a colour, and would this then really be the same experience as the experience that we typically call the experience of seeing a colour?

It is quite striking that Revonsuo does not emphasize this meaning component of experience more, since it could support his defense of emergent materialism as a model to understand consciousness. For if a conscious experience would have a meaning, this meaning could be determined by our specific acquaintance with (history of experience with) the world, and this could be a reason why a conscious experience may emerge out of a neurophysiological process, but (once this has occurred) never again be reduced to it.

This line of reasoning could also defend the conceivability of neurological zombies which Revonsuo denies (p. 92). A neurological zombie is supposed to be a creature which may exhibit the same behaviour as we do when similar neurons would fire in its brain, but would unlike us not have a conscious experience at a neuron firing that causes us to have such an experience. Perhaps if a neurologist made a neuron fire in this zombie which typically induces a certain experience, this neuron firing would not cause this experience in this case, because usually this neuron fires in recognition of something in the world, whereas now, by lack of experience, there cannot be this recognition.

The main complaint about this work of Revonsuo’s could be that he occasionally fails to make distinctions or argue for a certain position.

A major distinction which the reader may be left unaware of springs from Revonsuo’s praiseworthy success in letting empirical findings function as a curtailment for philosophical theories about consciousness. It could make one forget that there is a distinction between the epistemological and metaphysical question about consciousness: the conditions which should be fulfilled for us to know that we or someone is conscious could differ from the conditions that should be fulfilled for us or someone to be conscious. That this distinction may be forgotten becomes tangible in a statement like this: “If consciousness is nothing over and above (a high degree of) integrated information, then it becomes possible in principle to separate phenomenal conscious experience from higher level cognitive functions such as language, self-awareness and verbal reports. If it were possible to measure the degree of information integration in infants or animals, we would be able to infer whether they are phenomenally conscious or not.” (212)

Other than this, it is the briefness of Revonsuo’s paragraphs that makes him not always make a distinction or provide an argument for a statement. Some examples are the following:

At one point Revonsuo declares “Amnesic patients who cannot form new memories are doomed to live in a permanent present moment. They have lost the awareness of self as a temporally continuous being who has travelled a long road from the past to the here and now, to this very moment of present conscious experience, and who will be heading towards the future.” (137) Perhaps Revonsuo could have made more distinctions here. It seems like while amnesia patients may fail to remember what they did in the past, as well as fail to execute certain of their intentions, a lot of them may still have an idea that they have a past (and for example be frustrated about not remembering it) and work with some kind of idea of a future (an amnesia patient may express the wish to start driving again or to die soon; she may also wish a granddaughter well on her travels — even if she forgets soon after this that her granddaughter is traveling at all). If a distinction is made between these amnesia patients and the patients who also lose this minimal sense of having a past and a future, it becomes even more interesting to find out the details of what the experience, behaviour and sayings of these latter patients are like. Apart from memories and executed intentions, what else is lacking in their lives?

Another striking lack of distinction on Revonsuo’s part is to be found in an either/or choice which he confronts the reader with. He asks “How could the qualia I see now here on Earth, when I look at the star be really located on a faraway star that no longer even exists?” (191), so as to demonstrate that qualia (i.e. the phenomenal content of experiences) are not in the objects which we perceive, but in our brain. It may however not be entirely fair to suppose that qualia must be either in external objects or in the brain. Why could they not be in the different realm of the mind? Revonsuo takes it for granted that the contents of conscious experiences must have a designated place in the physical world, but does not deliver any arguments to support this assumption. Without these further arguments Revonsuo’s statement that representationalism “by treating phenomenality as identical to representational content…ends up throwing the contents of phenomenal consciousness out from the mind of the subject, into the external physical world”(191) can be contested. The representational content may be part of the mind (we do not necessarily know whether we truly see something, we could also just be hallucinating something), but this does not mean that it is part of the brain (say the firing of a neuron). It is also worth noting that Revonsuo’s statements are paradoxical. He blames the representationalists for throwing the contents of phenomenal consciousness out from the mind of the subject, into the external physical world, but does exactly the same by presupposing that if the contents of phenomenal consciousness are not in the external world, they must be in the brain. For my brain is part of the external world. It is physical and external to my consciousness: my brain and its functioning are not typically given in my experience of the world. This is problematic because it is unclear why or how what is in consciousness should also be given outside of consciousness.

Related to this it could have been revealing if Revonsuo had introduced the quite actual debate in philosophy of mind about the distinction between a hallucination and a real perception. For if this distinction is real, then this seems to be one reason not to reduce consciousness to the inside of the brain (or even of the mind).

A third statement of Revonsuo’s that could use some unpacking is the following: “the experiences I go through are mine; there is an I who goes through the experiences; thus, the experiences necessarily refer to a person, a self, me — the experiences are self-referential; and the self they refer to is an embodied self.” (193) This may ultimately be true, but for this to be established it would be necessary to justify, as philosophers have in fact attempted, that when experiences appear to have an I as a subject, this I is also to be conceived of as a particular person, and, subsequently, that this person is an embodied self. For one could object that the I to which experiences refer is just some kind of grammatical necessity and/or that it does not necessarily refer to a person who stays the same through time. Or one could doubt that persons have to be embodied and not see why they could not in principle be purely spiritual.

It is unfortunate that Revonsuo also concludes his otherwise quite poised work with an unsubstantiated statement when he says that “we humans alone on this planet possess the capacity for a Theory of Mind, the capacity to imagine or simulate how other conscious subjects feel about their subjective lives…”. This claim is in fact not as well established as Revonsuo takes it to be. Biologists have attributed a theory of mind to birds which only re-hide their food in a different and deliberately confusing way when they know that another bird has been watching them hide their food for the first time. These birds can be said to have a theory of mind since they make an assumption about where the other bird will go and look for the food.

Although these remarks are not few and more could be made, it is worth emphasizing that they do not take anything away from the many points of view and arguments which Revonsuo does introduce, as well as that these questions are only a response to Revonsuo’s invite — extended by the set-up of the book, his clear language and his honesty about his own position —  to critically further his thinking.

 

Glossary

Dualism is the view that there are both mental events and physical matter in this world.

Epiphenomenalism is the view that there are mental phenomena but that they do not cause anything; everything in this world is caused by a physical process.

Idealism is the view that there are only mental phenomena in this world and that there is no physical matter.

Eliminative, reductive and emergent materialism are respectively the view that consciousness should not even be explained and that we can tell the entire story about the world by looking at physical and chemical stories only; consciousness is a real phenomenon but that everything that it does can be explained by referring to its physical and chemical correlates; consciousness arises out of complex physical structures and processes, but becomes then something radically different than these.

 

 

© 2010 Fauve Lybaert

 

Fauve Lybaert is a PhD-student in philosophy (2008-2012) at the University of Leuven. She works on personal identity and self-consciousness and writes a dissertation with as title ‘Personal Identity and the Formal Self. She is funded by the Flanders Research Foundation.