Customer Reviews

Consciousness: A User's Guide

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An articulate, liberally educated neurologist at the University of Edinburgh, Adam Zeman has written columns for The Times of London and is an occasional commentator for the BBC and the co-author of a book on ethical problems in neurology. His new book covers many aspects of consciousness for general readers. His treatment of the disorders of knowledge is superb. If you were intrigued with ''The Man Who Mistook His Wife for a Hat,'' you'll appreciate the buildup to what Oliver Sacks described in that work. Zeman's much more subtle examples give you some appreciation for how seeing and describing can become disconnected from recognition and other forms of knowledge.

There have been a number of fine books on consciousness in the last dozen years, starting with Daniel Dennett's ''Consciousness Explained,'' which was written from the standpoint of a philosopher well versed in cognitive sciences and evolution. I am also fond of ''The Feeling of What Happens,'' by Antonio Damasio. Like Zeman, Damasio is a neurologist steeped in both literature and philosophy. But Zeman's ''Consciousness'' is the broader book, the one that could be used in an undergraduate humanities or psychology course to fill in the neuroscience background for readers coming to it for the first time. Indeed, Zeman first introduces his subject and then spends a hundred pages on neurobiology and human evolution before returning to consciousness. Readers impatient for consciousness per se can skim these chapters without losing the thread, though they are relatively painless introductions to what consciousness is built atop of.

p.24(28 September 2003).

THis is a quite nice book, an introductory book, quite up to date and very refreshingly clinically oriented. Zeeman is a neurologist and he mostly stays in clear waters. His introduction is a quite interesting analysis of the definitions and concepts of consicousness, he traces uses and origins of the words themselves: consicousness, awareness, self-consicousness etc., are all discussed. THis is new, as only some philosophers had concerned themselves with these issues. Then comes the review of litterature, the core of the book. This is the most valuable part not because of its originality but because of the information within it. Zeeman explains the neural systems of wakefulness and alertness, that is, the acending reticular activating system, as well as the neuroelectrophysiology of the thalamocortical system. Zeeman gives historical points and is quite thurough. Right next he examines brain disturbances that alter this system: coma, seizures, vegetative states, etc..topping with what these contribute to the search for the former. He does the same with the neural system of vision, from retina to v1 and extrastriate cortices. He also examines disturbances of vision, achromatognosia, prosopagnosia, agnosia, blindness, blinsight. This method, of investigating the science of the phenomenon, and then the brain damage that alters it, gives a fuller view of the phenomenon and its neural basis, and Zeeman does a good job.

Up untill now everything is good and ready, only with the probable objection that consicousness is not ust wakefulness with sensory content, as Zeeman seems to mantain. But Zeeman also writes chapters on the evolution of consicousness, and seems to give a rather naive argument for why it must be casual. To be sure, if it evolves, it must not be epiphenomenal, but not much follows from this. He also fails to give an adequate story of how consicousness gradually appeared, but only claims it must have. His views on animal consicousness are sensical enough. His chapter on scientific theories of consicousness is quite weak, both becuase he only passingly explains the theories and because he seems to misundertstand some and give some poor objections. He discusess Edelman, Crick, Seki, Baars,Damasio,E.r jOhn, Llinas among a few others, and could have given much more detail. He readily falls to explanatory gap concerns, and cannott do a good critical or explanatory job. He does see through some basic agreements, like the idea of distribuited but integrated neural assemblies in the thalamocortical system.

His chapter on philosophy, freewill, and AI is also quite bad. He fails to really analyse the thought experiments, of colorblind mary, zombies, absent andf inverted qualia. Zeeman cannot see how Mary by gaining physical knowledge can come to have experience, because he seems not to be aware of the litterature that argues for such physical knowledge, like Van Gulicks or John Perrys work. HIs critiques of Dennett or Searle are not profound, but on the right track. He does however explain clearly (but not adequately) the views out there, like physicalism, functionalism, dualism, property dualism, etc. Zeeman is no philosopher and it shows. He ha slittle to say on machinec consicousness, only that its possible, and on free will, suprisingly ignores LIbets work, probably most relevant, and is quite straightforward. Although in principle actions are predictable because they are physical and caused, this does not at all mean we are not free. I think this is largely right, because even if in the same conditions we could not have acted differently, there is no reason why not in the same moment the conditions could have changed by virtue of our actions. This is a weak kind of freedom, but it is naturalistic and unproblematic.

Besides my negative comments, this book is in a short list of comprehensible and scientifically oriented introductions to consicousness, and is highly recomended for newcomers to the field. Zeeman does make some good points, but remains uncontroversial enough. Good book.

Consciousness is an incredibly complex concept, if not the most complex concept in the universe. This book does a good job in distilling a lot of this complexity into layman's terms. Overall, I had mixed feelings about the book. Sometimes the material was engaging and readable and at other times, it was dry and I had to force myself to trudge through it. The more nuanced studies described in the book were presented in more of a textbook like fashion which may require multiple read throughs to understand, especially if it's the first time you've been introduced to it.

Some of the most important topics of consciousness are covered. The author starts off with a brief history of the study of consciousness and the definition of consciousness followed by some of the background neuroscience that will be necessarily to understand some of the material from the later chapters, like various brain scans and pathologies of the brain. He also dedicates a couple chapters on vision which is a big chunk of what makes up our consciousness. The chapters on vision are rather comprehensive from the basics of light to perception. He also talks about some of the ways vision can go wrong. The chapter after vision goes into the origin of the universe and life and finally ends with man and consciousness. It was a bit out of place in the middle of the book but nonetheless relevant. The next chapter goes into some of the current theories of consciousness from a cognitive science perspective. The final chapter goes into how consciousness current cannot be studied, like the possibility of machine consciousness and what alien consciousness would be like.

There were a couple of chapters that I was particularly interested in. In chapter 3, he goes into detail about some of the anatomical basis of consciousness. Starting off with EEG and brain waves (alpha, beta, theta, delta) is nice because many people may have heard about these either through popular reading or the news. He then mentioned some of the mainstream thoughts and studies related to that from which I learned a good deal that I didn't know before. He also includes some diagrams and they generally are simple to read and understand. Some diagrams, however, look like they were taken directly from a journal article and if you are not familiar with reading scientific graphs, they could be a bit confusing. For example, many EEG graphs in neuroscience have the y-axis reversed with negative pointing up and positive pointing down. These graphs are reproduced faithfully (with the reversed axis) in the book but needlessly. The chapter ends by talking about sleep. On why we sleep: "A child aged three: 'Because it's night.' Her sister, aged six: 'If we didn't we'd get really tired and stuff, and we wouldn't be able to do anything.'" Those were the responses given by the author's daughters and it pretty much sums up what we know about sleep. He covers some of the major topics in sleep but does miss some important studies that I read elsewhere such as some of the "sleep bunker" studies. In the end, the book concluded like every other book on sleep: no one knows why we need to sleep.

Chapter 4 was about some of the pathologies of the brain and on some of the disorders of consciousness. This was also the reason why I choose this book on consciousness over some of the other ones. It was a enjoyable chapter as it was engaging to read. Then again, the nature of the subject is a bit more exciting to read because it usually involves blood, trauma, or drug abuse. There is one section about different kinds of comas which I was particularly interested in but it did leave a bit more to be desired. Only about 4 pages were dedicated to talk about different comas such as persistive vegetative state and locked in syndrome. I think the author could have been expanded a bit in comparison to the other pathologies like faints, seizures, or drug use which all got more page volume attention.

The final chapter brings up some really interesting philosophies and unanswered questions about consciousness. He covers dualism and physicalism which are mainstream ideas that try to get at the mind-body problem. Some of these questions of consciousness are question that have I have asked myself, such as, what is the consciousness of another animal like? Right now, the only way we can get at this is by studying animal brains, but their brains are very different from ours so comparing consciousness in that way would be very difficult. I agree with the author that looking at the evolutionary continuity of us and other animals may bring more insight to this question. Another interesting question that the author asks is whether machines can have consciousness or not. "Computers in research laboratories around the world are gradually acquiring artificial senses and artificial limbs - governed by artificial brain." That quote by the author give good reason to consider the possibility of an artificial consciousnesses. He goes into many arguments for and against it, including the famous Turing test. Right now, the answer to that question is possibly, and I wholly agree. Consciousness even extends out into the universe and I'm kinda surprised that this book covers even that debate. Alien minds is really hard to talk about because you don't even know what alien life would be like. However, I don't believe any real coherent argument can be made, and the author made some similar comments. I also agree that there is a huge knowledge gap between our conscious experience and the brain anatomy behind it.

In summary, I think this book provides a great summary of some of the research into consciousness. It provides good background information and covers a wide breadth of topics. He starts with the basic definition of consciousness and some of the neuroanatomy behind it. He then goes into some disorders of consciousness as well as vision, which is a big part of our consciousness. He then covers some cognitive psychology approaches to consciousness and finally ends with some philosophical discussions as well as questions to be answered in the future. You will definitely learn something new if you are new to the subject and probably learn something new even if you are an expert. Being published in 2002 does make the book a bit out of date in terms of recent research as neuroscience is a quickly evolving field. Sometimes the book is engaging but other times the material can be a bit dry. I expected a bit more readability from a casual book like this one.

3 1/2 Stars. Dr. Zeman's book on consciousness is splendidly and engagingly written. The first six chapters are well written/explained/supported. In chapter 1 he introduces his topic with context; Ch 2 is a great introduction to the nervous system; Ch 3 a structural basis for consciousness; Ch 4 the pathologies of consciousness (fainting/coma(s), etc) Ch 5 places a structural basis for consciousness within the framework of light (great explanation of our visual systems), and Ch 6 a discussion of blindsight.

The second part of the book seems disconnected from the first, even though the good doctor makes attempts to tie the whole thing together and does a reasonable job in the epilogue, however the intervening three chapters are catalogues of the philosophy surrounding consciousness, standing up one philosopher's straw-man only to have another dispute.

In my reading, Dr. Zeman offers one sentence which is more telling than all the theories and illustrative of "what we don't know" and how much we take on faith: page 285: "But no scientific theory is worthy of the name unless it makes some tangible predictions that can be tested."

Earlier on page 236 the author makes another prescient and telling point when explaining what it would be

"like to be a bat? Once again it looks as though there is a dimension of knowledge the objective observer is denied. Scientific explanation fails to encompass the 'view from within' which consciousness confers on its possessor."

While the author provides ample context, I gathered from these comments what I guessed before I commenced this study (two books down, three or four to go)---given our uniqueness and the subtleties of our thought processes, I suspect there will be much time to speculate, for the size of a model and dimensions of a suitable test could not be constructed which would pass scientific examination (at least not today).

Dr. Zeman has made a commendable and accessible contribution to the discourse and his book comes with my recommendation. Well done.