Rating: 
Summary: Absolute Zero
Review: From "Cold Numbers Unmake the Quantum Mind," as reported by Charles Seife in SCIENCE for February 4, 2000, Volume 287, on page 791. "The idea [of a brain as a quantum computer] attracted a few physicists, some consciousness researchers, and a large number of mystics. Quantum physicists, however, largely ignored it as too speculative to be worth testing with numerical calculations. Now [Max] Tegmark, a physicist at the University of Pennsylvainia, has done the numbers. In the February issue of Physical Review E, Tegmark presents calculations showing just what a terrible environment the brain is for quantum computation.""...the problem is that the matter inside our skulls is warm and ever-changing on an atomic scale, an environment that dooms any nascent quantum computation before it can affect our thought patterns. For quantum effects to become important, the brain would have to be a tiny fraction of a degree above absolute zero." So quantum consciousness may finally, after an eleven year bestselling run, hit the junkheap of large offbrand ideas about how the brain works. Another system of unaccepted ideas will come along to replace it soon enough. It seems there is always, in every decade, a shadow science of ideas about how the brain works. One question for the "real" science of the brain must be: Why do these shadow sciences thrive so wonderfully? The answer is that the real science of the brain is not believable. There exists no reasonable explanation of how the brain actually works. Something is wrong. Some fundamental and incorrect and huge going-in assumption about the brain must be blindsiding us. The rise and fall of cult books like this one, and the murky brain sciences they urge, should be understood as one signal that the established science of the brain is a failure.
Rating:
Summary: A VERY BORING BOOK
Review: its a very very boring wrting style and has no material except of science history, if any body is looking for a hisory book.. then he will not find a better one, if there were less than a star for rating i would give it to this book, i recommend hyper space for kaku for any body looking for a nice science book.
Rating:
Summary: Fascinating work with a fatal flaw
Review: Roger Penrose sets out to refute the claims of those researchers in artificial intelligence and cognitive neuroscience who claim that the mind is a product of algorithmic processes. Penrose uses ideas from the theory of computation, and Godel's incompleteness theorem to attempt to show that algorithmic processes cannot be used to explain the diversity of human consciousness. Fine so far. But the book has a fatal flaw and it is this: it is rubbish (and speculative rubbish at that) from top to bottom. The incompleteness theorem has NOTHING WHATEVER to say about human consciousness. For an excellent discussion of the incompleteness theorem, see Barrow's 'Impossibility'. I would also recommend Daniel Dennett's 'Darwin's Dangerous Idea' for a further refutation of Penrose's position, and Steven Pinker's 'How the Mind Works' for an exposition of the algorithmic theory of mind. Penrose sets up a straw man and then knocks it down. To come up with a spurious claim about the capabilities of the human mind and then set out a completely new (and frankly untestable) theory about how mystical quantum-mechanical effects give rise to entirely new problem solving techniques is not even science. It's the worst sort of 'Just-So Story' that those attacking algorithmic theories of consciousness are always accusing AI researchers et al. of peddling. Penrose has done himself a grave disservice with this nonsense. Recent work has all but ruled out his ideas about micro-tubules (and even if there was something fishy going on there, the self-same microtubules exist in the brains of cockroaches). The fact that incompleteness is only of significance in an algorithmic system that is incapable of error seems to have passed him by. In short: not even close - definitely no cigar.
Rating:
Summary: Not enough concrete stuff. Too speculative.
Review: Couldn't finish the book. It was too whimsical to take seriously. Generally, it simply skipped all the fantastic reality there is to modern physics, and substituted speculation.
Rating: 
Summary: Unfounded and irrational speculation
Review: While parts of this book devoted to the popular description of concepts of modern physics and mathematics hold a pedagogical value for a lay reader, the rest of the book is really poor. The author makes an extremely loose connections between completely unconnected problems, and with surprising immodesty puts forward an extremely contrived theory of mind without providing any semblance of logic, let alone proof. For any scientist familiar with both quantum mechanics and some basic knowledge of biology of the CNS, the main thesis of the book that consciousness is somehow connected to the quantum mechanics of the brain function should certainly look ridiculous; it's a completely arbitrary connection, and no proof is even suggested. The author in effect attempts to employ a very cheap trick to solve two of the greatest problems of modern science and philosophy, the problem of consciousness and the problem of (apparent) ambiguities in the formulation of quantum physics, by deciding to cancel them against each other, linking them with an arbitrary mental construction. How convenient! The suggestion that Godel's theorem proves that human thought is non-algorithmic is laughable; while the theorem is one of the greatest achievements of modern logic, it is only relevant for symbol-based computation, and our brain certainly isn't a purely symbol-manipulating machine: most neural-network computations are not based on applying symbolic rules, although they can be implicitly algorithmic. Besides, to suggest that humans can never encounter a statement that can be neither proved nor disproved is almost humorous in its arrogance: the problem of consciousness alone holds lots of such examples; problems of ethics is another great example. Penrose's argument will only be applicable when we discover a theory of everything and there will be no philosophical questions left to be solved for humanity; only in that case one could say that there are no contradictory statements for a human mind. ...I could go on and on, but this is too long already. I personally find it fascinating that an undoubtedly talented scientist like Penrose, one of the greatest mathematicians of our times, can come up with something as absurd. I guess this can teach the rest of us something about how the human brain works, after all...
Rating: 
Summary: superb math, physics and computation theory, poor biology
Review: Penrose's text should be seen as a two fold effort: the first is pedagogical: it exposes with superb insight the theories of mathematical physics, the physical basis of computation theory (he draws on an analogy with geometry), as well as, a Platonic philosophy of mathematics (the present reviewer believes in a naturalistic approach, but that is hardly the matter here!). IF this was all in the book one could hardly give it less than five stars. However, Penrose goes further and discusses the biology of cognition; in my opinion at this point he is a bit out of his personal scientific experience and contributions, and his thoughts are speculative; the further involment of cosmology in the work makes the whole project a bit incoherent. Overall Penrose connects cosmology with biology of cognition through the key theory of quantum gravity which he speculates ties them together!; well for those who like to study science and not mere speculations these mean that they shall not enjoy some parts of the book! The other central theme, that quantum gravity is nonalgorithmic, and thus since (as he speculates) cognition is a quantum-gravitational phenomenon it should be also nonalgorithmic, it is of course a consistent conception, but again science requires more than that, it requires ways to test ideas and in my opinion Penrose offers none! But after all perhaps he did not intented to write down a science book.
Rating: 
Summary: Penrose Knows.
Review: Penrose is DEAD RIGHT. Strong AI is a nonsense. The irrational, subjective, mishmash of the childish and the spiritual; the experience of sudden inspiration, the emotionally biased reasoning to get the result we WANT as opposed to the result dictated by pure logic; these will NEVER be replicated by computers. The fact that anyone would even support this idea is proof of the unstable way in which we reason - why passionately support something which will never work? (How can you smugly announce that a machine can have the same definition of Intelligent as a human when the study of the mind and its workings are at an infantile stage of early development. Such arrogance! You cannot argue by saying that a selected number of outcomes are the same. If I wear my hair the same way as Pavarotti and put on 120 pounds does that mean I am a great singer? DUH!!). Because you are subjective and emotional you are attached to strong AI in the way a child is attached to a comfort blanket. You have committed so much time and vocal support to your backing of the idea that you CANNOT let go of it without losing face. It is a beautiful example of Dr. Robert Cialdini's description in "Influence: The Psychology of Persuasion" of the fatal human propensity to consistency. (And there's another quality you will not find in a strong AI machine!). Strong AI is strictly for Trekkies - "strong AI machines are better than humans; strong AI machines do not have to deal with human emotions (nasty unquantifiable things!!); therefore as a supporter of Strong AI machines I do not have to deal with my emotions. Viola! It is all right for me not to be able to cope with life ... because it's LIFE that's wrong, not me!." If anyone can put the irrationality WHICH IS PART OF THE DFINITION OF BEING HUMAN on a glass slide, they will be in Penrose country. Handle it.
Rating:
Summary: Superb
Review: There are two central themes to this book - first, a rejection of strong AI as a theory of consciousness, and second, the conjecture that the failure is related to the philosophical problems of quantum theory. The first is very lucidly argued and does NOT, in the words of one frustrated (but clearly lazy) reviewer rely on some wishy-washy claim that the real world is too complicated for a computer to "understand". Nor has it anything to do with an appreciation of beauty. Instead, it relies of Godel's theorem, which states that propositions can be true but non-algorithmic (non-provable by algorithm). Penrose claims that these same truths can nonetheless be grasped (and understood to be true) by human minds. The second theme - the relationship of the failure of AI to quantum theory - is conjectural but fascinating. I urge people to make the effort to read this book, by one of the great mathematical physicists of the post-war era.
Rating: 
Summary: No royal road,
Review: Rather too rigourous and pedantic for the tastes of the fringe dabbler in popular science, it is all too easy to dismiss this book as tedious. The fact is, Penrose has been careful not to oversimplify a controversial and poorly understood subject. The crucial weakness of more readable books like Godel Escher Bach is that, in the interests of clarity, no attempt is made to present opinions on the controversial aspects and to elaborate a lot on the better understood aspects. Not a good book to start with - GEB is a better introduction, but ultimately a more satisfying read simply because there is more depth here. I would label this book as halfway between being true 'popular' science a la GEB, Metamagical Themas and a textbook. Not an easy read, approach with care! And if you want even more detailed speculation look at Shadows of Mind which gets even closer to being a textbook.
Rating:
Summary: Penrose is heading in the right direction
Review: This is a book of insights. Penrose is touching the edge of the truth about the human mind but just missed it. I am now reading another book that has a section called "Emperor Penrose's Mind". In my opinion, that book is truly revolutionary in helping us understand the nature of reality and of the human mind. The author suggests that the square root of -1 is the psy-factor in laws of quantum mechanics and theories of relativity. He also shows why John Searle, Douglas Hofstdater and Denial Dennett all committed the Fallacy of Unity Projection. the author agrees with Penrose that quantum mechanics is a possible key to the mystery of the mind, and the mind is more fundamental than material. The most fascinating part is that all these ideas are demonstrated in sci-fi like adventure stories (thought experiments) in virtual reality. The title of the book is, Get Real: A Philosophical Adventure in Virtual Reality, by Philip Zhai.
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