Most Helpful Customer Reviews
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56 of 62 people found the following review helpful:
5.0 out of 5 stars
Neural Darwinism reaching out to the mind., September 5, 2000
This new volume provides a biologically-based perspective on consciousness. Although Edelman & Tononi may often appear to lead the reader into believing that a `selector' is needed in order for one to choose between the many alternative possible behaviours that one might act out, there is no room for a Humunculus (the little man inside the man `seeing' solutions) of any sort here. For those unfamiliar with Edelman's previous writings (all of which I would recommend) there are plenty quotes from his earlier self, the principle idea here being a logical extension of his thesis developed over the last 20 yrs. Coming clean right from the start, the data acquired from introspection is rejected as a technique to be subjected to any robust empirical analysis, but consciousness is here identified not solely with brain states/activity (there is a clear need for interactions with others and the world `out there') - the authors putting forward a model of consciousness as being a `particular kind of brain process'; unified/integrated, yet complex/differentiated.The early parts of the book discuss the `impasse' reached by many philosophers in their attempts to explain the `mind-body' problem whilst rejecting both strong dualist and reductionist positions: "..consciousness requires the activity of specific neuronal substrates .......... but is itself a process, not an object". There is a clear appeal to holistic thinking here (`the whole is greater than the sum of its parts') - but the message is more subtle. What Edelman & Tononi are pointing out is that, still in need of explanation is the fact that although the contents of consciousness change continually, its possessor remains continuous. The problem of how one discriminates between our vast repertoire of conscious states (and how one is `selected' for experience in real time from this pool) is the main evolutionary question being addressed. Assumptions are not ignored (reflexes are allowed to operate in certain circumstances), but emphasis is placed upon the integration function of the human brain, rather than the clearly identified anatomical segregations long known to exist. For example, there have been at least 36 different visual areas reported in primate brain, each linked by more than 300 connection/projection pathways, 80% of which have recurrent-colateral or re-entrant connections. These latter findings are the focus of Edelman's developing theory of consciousness. For a long time now, many researchers have come to believe that distinct, distributed patterns of neuronal firing give rise to the integration of perceptual and motor processes - but how such patterns are strengthened to provide routinised behaviour and expertise remains unclear. The data presented with respect to the detailed nerve receptor-level changes re growth and the known pharmacological effects of certain natural transmitter substances and drugs are welcome and well written for the lay person to follow (often lacking in the specialist journals of the field!). However this debate may resolve, Edelman & Tononi are here suggesting that in like process, co-ordinated behaviour (including consciousness) derive from the detailed brain connectivities together with their variability and plasticity over time - especially in relation to the (highly flexible?) dynamics of reentrant connections. How such distributed neuronal firing patterns are `selected' for as `the brain interacts with the body' requires better evidence, but with our current state of knowledge, this is definitely a step in the right direction. From an evolutionary perspective, this is Neural Darwinism writ large, proposing a research agenda entirely consistent with that thesis. For those in the know, there are also (uncited) tributes to Waddington (as in `Epigenetic Landscapes') and support for those working on behavioural robotics and the emergent properties of dynamic systems. The details of the text I will leave to the reader to enjoy - clinical data, normal and abnormal brain architecture, even systems theory - all accessible and clearly phrased for the non-expert reader. As with his previous writings in evolutionary neuroscience his work `feels right' and if successful (and hope that they are) Edelman could follow in the footsteps of Marie Curie in claiming a second Nobel Prize.
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54 of 62 people found the following review helpful:
3.0 out of 5 stars
Extremely interesting data, dubious conclusions, June 20, 2000
This book is worthwhile mostly for the wealth of experimental data provided. Unfortunately, I think the authors often jump to conclusions that their evidence neither precludes nor proves. The most pervasive example of faulty logic is the central theme of the book. The authors provide evidence that consciousness is *associated* with vast, interconnected regions of the brain. When a person is aware of a stimulus, more neural areas are active than when he/she is not. From this, they conclude that consciousness *arises* from diverse neural areas in the brain. This is the key fault of the book--the authors do not differentiate between *association* and *origin*. Perhaps conscious activity that occurs in a small area of the brain promotes extracurricular activities elsewhere. Just because two events occur simultaneously does not mean one caused the other!The authors describe their work as a "theory of consciousness"--completely misleading in another sense. Even if we were able to precisely understand what neural processes lead to consciousness, which neurons were involved, etc., the consciousness mystery still would not be solved. The most fascinating and mysterious question is "HOW do the neural processes lead to consciousness?" Uncovering the neural processes associated with consciousness is a great way to begin, perhaps the only way. However, to call the authors' work a "theory of consciousness" is absurd. Imagine a 18th century person able to view the modern automobile through timetravel. Suppose here were able to deduce that turning a key started the automobile, pushing the right pedal made it accelerate, etc. before he was forced to return to his time. Would his knowledge be a "theory of the automobile"? Only in an extremely superficial sense. He would know how the automobile worked, but would have no idea as to the physical mechanisms (e.g. electromagnetism) at play. I DO recommend this book but I strongly suggest that you pay close attention to the *data* and consider it yourself.
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22 of 25 people found the following review helpful:
5.0 out of 5 stars
A scientific explanation of consciousness and its properties, May 12, 2003
This is a very important book. Although the authors recognize that there is still awfully much tot do, their analyses and hypotheses are a big step forward in our understanding of consciousness.
It is certainly not an easy book. One should have a basic knowledge of the constitution and the working of the brain.
I, personally, would have liked more concrete examples, like those for instance in the book of C.J. Lumsden and E.O. Wilson 'Promethean Fire'.This book doesn't explain how consciousness arises, but what it is (properties) and how it works.
Consciousness is not a thing or a property, but a process (of neural interactions).
One of the reviewers here compares consciousness to a car. But a car is a thing, not a process.
Consciousness is a private, integrated, coherent, differentiated, informative, continually changing process.
The authors make also the opportune distinction between primary (animal, unconscious) and higher-order consciousness (the ability to be conscious of being conscious). Crucial for the authors are re-entrant interactions, degeneracy (recategorical memory), and a part of the brain 'the dynamic core' (a subset of neuronal groups responsible for consciousness).
The dynamic core provides then a rationale for distinguishing conscious processes from unconscious ones (e.g. the circuits that regulate blood pressure). This book shows clearly that the brain is not a computer and that it doesn't work as a computer program or algorithm.
It has also very important philisophical consequences, which the authors summarize as follows: being is prior to describing, selection is prior to logic and doing is prior to understanding. I also fully agree with the authors that Darwin's theory is the most ideologically significant scientific theory ever written. Although this book is rather technical, it should not be missed by those interested in the real nature of the conscious process. I should also recommend the work of V. Ramachandran 'Ghosts in the Brain', for its multiple examples of (un)conscious behaviour and its philosphical implications (the body/mind problem).
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