Rating: 
Summary: Spaguetti writting, weak arguments, mostly physics.
Review: This book was recomended to me and some colleagues when I was in college. I read it after college, tho, and I think it's probably the worse science-divulgation book I've ever read. The writting is messy ("check page xxx back there", or "will be further discussed in chapter yyy"), the AI arguments he presents are weak and were long refuted (just search the net), and his "insinuation" that there are quantic processes involved in out mind is totally without fundament/proof - pure speculation. The book is mostly about physics (with some depth to it), and hard to understand.
Rating: 
Summary: Very thought provoking but logically flawed
Review: I found the book to actually be more interesting in its discussion of physics and quantum mechanics than when I got to his thesis on mind and the computational impossibility of reproducing it in a computer. Although most of this is lucidly written and meticulous in its attention to detail, Penrose's final conclusion that the mind must have a quantum-mechanical aspect is unsupported by any evidence and seems to come from nowhere but his own deep desire to be more than chemicals. For me, the weakest part of the argument (in fact the only "evidence" he gives for his conclusion, really!) is the discussion of how long it takes a computer algorithm to solve a particular type of problem vs. how long it takes a person. It seems plausible, but ignores the fact that in this world, thousands of people work in parallel and cooperatively over many years to solve difficult problems and build on previous successes and failures. It ignores the roles of specialized education, folk knowledge, anecdotal evidence and how all of these result in common-sense elimination of fruitless pathways and recognition of fruitful pathways in human problem-solving. Nevertheless, I found his physics primer (the first several chapters) to be better than many I have read, and the whole book gave me many nights of weird dreams. At the end, though, I wound up disappointed and feeling like I had been hoodwinked into someone's attempt to logically deduce his own personal faith.
Rating:
Summary: A poor man's Godel Escher Bach
Review: Readers must wade through a several-hundred page exhaustive, sometimes interesting, always tedious, usually irrelevant review of modern physics before the author even begins to address the supposed main subject of the book -- will a computer ever be able to do everything a human mind can do? The final conclusion is this: Scientists don't understand consciousness; another area of poorly-understood scientific inquiry is quantum gravity...therefore, the two must be related somehow. As an intellectual exercise this book is extremely disappointing, and I urge readers with even a remote interest in the subject matter to immediately purchase Douglas R. Hofstadter's Godel, Escher, Bach instead
Rating: 
Summary: Thoroughly enjoyable and mind stretching!
Review: This book, together with its companion Shadows of the Mind, is the
result of many years thought by one of Britain's most original scientific
thinkers. It contains a fantastic sweep through classical and quantum
physics as well as Godel's theorem, Turing machines, and the like. His conclusion - the mind is not governed purely by algorithmic processes - is highly unpopular with many philosophers and the AI community. However it
is very carefully argued and apart from anything else makes a significant
contribution by laying out in a very clear way the logical options
available in understanding aspects of how the mind might compute.
Many of those working on understanding the mind do not want to be told they will have to get deeply involved in quantum mechanical issues before they will get anywhere near their goal. However Penrose makes
a profound argument that this is in fact the case
Rating: 
Summary: A good, readable, and enjoyable book
Review: Roger Penrose's book is more a journey into all of today's
physics than simply an attempt to explain the human mind.
The trip with Penrose is very readable (although he puts in
formulas and equations). His points of view regarding the
strong AI approach may need more punch to it, and the field
is still an enfant one to easily decide. That said, the book
presents a strong point of view, and Penrose has been right
too many times to easily dismiss his theories.
Rating:
Summary: Penrose attempts to debunk the computational approach to AI.
Review: In his book, "The Emperor's New Mind", Roger Penrose
attempts to show that the computational approach to
artificial intelligence, is, as he puts it, untenable.
Also referred to as functionalism, or "strong AI",
computational AI is based on the notion that thought is a
computational process which need not be bound to a
particular type of computer. In other words, a sufficiently
complex computer should be able to run the same "programs"
as those the human brain utilizes. Penrose takes exception
to this is a major way. His arguments are based partly on
his assertion that the conscious mind simply cannot work
like a computer, and partly on his own definition of what
the term "computation" means. As such, the book is an
attempt at a poke in the nose for the supporters of strong
AI, but it misses the mark. Pro-computational AI works such
as Douglas Hofstadter's "Godel, Escher, Bach: An Eternal
Golden Braid" have a sense of weight and depth which
Penrose's book lacks. Penrose sometimes sounds more like a
person who simply wants a reason, any reason, to believe,
like Decartes, that there is an extra ingredient to the mix
that makes up mind. Unlike Descartes, Penrose isn't willing
to come right out and claim the existence of a "soul" or
some other immaterial "stuff", but he does hold that there
is more to emotional response, appreciation of beauty, and
feelings of love than can be captured in a computational
algorithm. In the book "Daydreaming in Humans and Machines",
Erik Mueller has shown that it is indeed possible to encode
emotional drives into a computer program, and it actually
isn't all that hard to do. "The Emperor's New Mind" is well
written, although a bit convoluted in places, but it just
doesn't have the punch it needs to really take a firm
stance against the computational approach to artificial
intelligence. Nonetheless, for all its faults it should be on the reading
list of anyone seriously interested in artificial intelligence
or cognitive philosophy, if for no other reason than to show
how not to argue against a well-entrenched paradigm.
Rating:
Summary: Don't be fooled by kitsch materialists
Review: First, what this book is not: It is not "creation science"...it doesn't address evolution...or the existence of God...or existence of the human soul. In other words, it is NOT special pleading against modern science by someone with a religious agenda. What it IS rather, is a solid study of cognition, theories of artificial intelligence, and the enduring problem of the nature of human consciousness by one of the world's top physicists (a professed materialist by the way, not a religious believer), who together with Stephen Hawking developed the astrophysics of "black holes" in the '60's. What Penrose suggests here (a theory he expands on in his subsequent "Shadows of the Mind"), is that science, and specifically physics, is inadequate now, and more importantly will always be inadequate, to describe the nature of human intelligence, cognition, and consciousness--a thesis similar to the showing of Godel's 1931 Theorem that certain fundamental axioms of mathematics were incapable of proof within any mathematical system. In other words, Penrose suggests that there are elemental restrictions within science itself limiting our understanding of our own mental processes, which concomitantly limit the possibilities for development of artificial intelligence. And that obviously doesn't sit well with those for whom naturalistic science is itself a kind of "religion," as some of the dismissive reviews on this page show. My advice: just ignore them and read this book, and well as its successor, "Shadows of the Mind." It's a challenging read and not for intellectual lightweights, but it will richly reward those with the patience to make it through.
Rating: 
Summary: The argument is 25 years old and invalid.
Review: Ok so here is Penrose's argument:1: Acourding to Gödels theorem no system is 100% consistent and complete
2:An algorithm is a system
3:Therefore the human mind is not representable by an algorithm. There you have it folks! Its the book in a nutshell. Penrose simply ignores the fact that the exact same argument can be used to show that a human mind cannot be 100% consistent and complete. He also ignores the fact that humans make mistakes, and so the entire argument in the book falls. A more detailed explanation why this argument is invalid is to be found in Hofstadter's excelent book "Gödel Escher Bash an Eternal Golden Braid" which was first published in 1979. As when it comes to Penrose's idea that Quantum Mechanics plays a part in the human mind, he has no proof or justification whatsoever. It sounds cool and Quantum Mechanics is a hot topic right now, but with the level of justification that Penrose has put forward he could just as well have claimed that one can determine someones personality from the dents in the persons skull.
Rating:
Summary: A voyage to the limits of human knowledge
Review: This book is a voyage to the ragged edges of physics, logic and mathematics, in search of cracks in the naïve materialism that seems to be (again!) the orthodox philosophy (or religion?) of the scientifically educated. Many pearls are collected during this voyage. One just has to look at Figure 4.3 (hardback edition), showing the space of propositions in a formal system. The fractal geometry of the set of provable propositions (which is not recursive) is shown. Also shown is the even stranger set of the true propositions, which is not even recursively enumerable. I can't avoid thinking that this figure illustrates the logic of the future: much less formal and essentially geometric in nature. Also great is the discussion of Quantum Mechanics (QM). Penrose makes the correct point that nothing in the world we live in can be explained without QM. QM is not a theory of the behavior of matter in strange conditions, but an explanation of why the world is made of solid objects, like cats, viruses or chairs. Classical Mechanics does not even explain why you don't just fall through the floor. Usually the indetermistic nature of QM is stressed in popular expositions: its stabilizing properties are not mentioned. Because QM is so important in practice (nothing, from Chemistry to Genetics works without it), its philosophical problem are of great importance.
The main issue in this book is the problem of consciousness. Consciousness is too important a problem to be left to brain scientists or even to biologists: it is still a philosophical (and theological) question. Then, how successful is the book in its main aim? Does it disprove the strong AI assumption? I think very much so, since strong AI is an extraordinary assertion that lacks even weak evidence, much less the extraordinary evidence it actually needs. It is not necessary to disprove it: like the emperor's new coat, it just needs to be questioned to collapse. Only a strange conjunction of religious materialism and computer worship keeps strong AI alive in the minds of its supporters. Then, from my point of view, this book is not so much a refutation of strong AI, but an attempt to find a replacement, while avoiding total irrationality. I am not so sure of the relevance of Godel theorem to the consciousness problem, but the people that think that the Quantum Mechanical argument is nonsense should remember that the orthodox (Copenhagen) interpretation of QM used to involve self-consciousness in an essential way. Only in the post-Copenhagen era has the consciousness link to QM been dropped, but the substitutes have been even more incredible. One only has to think of the many-worlds interpretations. I think, deep down, this book is motivated by the belief that self-consciousness is an essential part of our experience of the universe and of ourselves, one that naively materialistic philosophy cannot account for.
Rating:
Summary: As if by magic!
Review: Daniel Dennett's excellent book Consciousness Explained extracts a very funny cartoon from Scientific American, in which two professors stare at a blackboard showing a formula full of complex algebra. In the middle of the formula appears the sentence, "THEN A MIRACLE OCCURS". One professor points to the statement and says to the other, "I think you should be more explicit here in step two."
Roger Penrose isn't just any old boffin: he is the Emeritus Rouse Ball Professor of Mathematics at Oxford University and has been knighted for his services to Science. The Emperor's New Mind is his attempt to crack that perennial philosophical chestnut, the Consciousness/Artificial Intelligence problem. Penrose's view is that Strong AI is simply wrong and that a computer could never replicate (functionally or actually) what we know as "consciousness".
Right. Take a deep breath here. For it's a scary thing for a mere mortal (with a decidedly ordinary bachelor's degree in the humanities) to say something like this about the one of the cleverest men on the planet, but I can't see any way around it: In this book Roger Penrose completely, totally, misses the point. Insofar as it's considered an entry on the Consciousness/AI debate, The Emperor's New Mind - all 583 pages of it - is all but worthless.
There. I said it.
Then again, nearly 500 of those pages don't even purport to be about consciousness, so perhaps all is not lost. Instead, they contain an extremely dense, at times fascinating, but uniformly (and I use the word deliberately) dazzling overview of the more esoteric parts of modern mathematics, physics and cosmology. While Penrose thinks it is necessary background, it isn't - it amounts to an extremely long winded appeal to authority:
One is left with the firm impression that the Rouse Ball Professor of Mathematics at Oxford University is a very, very smart chap, and that one really ought to see that what ever he says goes. This is no small irony, given the title of his book. For if anyone is holding himself out as being a tailor purveying a cloth that only the cleverest people can see, it's Roger Penrose.
Here's where I think he goes wrong. Firstly, his attempt to undermine the AI position is founded on purely mathematical reasoning. Pure mathematics is a closed logical system. Its truths aren't falsifiable, so by themselves have no explanatory force. Mathematical statements (such as "1+1=2") are necessarily true for all time and all universes so, ipso facto, they can't - by themselves - tell us anything about any particular universe. Yet that is just what Penrose asks them to do. He invokes Gödel's theorem of undecidability, perhaps to counter the argument I have just made, but it isn't convincing - being logically unable to prove all truths in a particular set (even though you know they are true) is very different from being able to falsify them. Without that power, you have no explanatory traction in the outside world. Penrose's entire attack on Strong AI is based on an unfalsifiable, and therefore non-content carrying, argument.
Another error is to assume an algorithm must have been designed for the purpose for which it is used, and must work perfectly to be of any use. Natural selection illustrates that this is simply not the case. An algorithm may have a number of useful unintended by-products, and an algorithm can be extremely useful even when we know it to be completely misconceived at every level: take Newtonian mechanics as a good example. We've known for a century it isn't correct but in most practical circumstances it works fine.
Which brings me to my next point: for all the learning Penrose includes on Mandelbrot sets, phase space, entropy and Hawking Radiation, The Emperor's New Mind is conspicuous for what it leaves out: The bibliography contains no reference to Karl Popper nor the general philosophy of science - which might have helped him on the issue of falsifiability - nor crucially to a number of writers who have been very influential on the modern mind/AI question: Daniel Dennett is barely mentioned (Dennett's writing probably represents the "forefront" of the consciousness debate), nor is Richard Dawkins well-referenced, despite having written compellingly (and, being a zoologist, with a great deal more expertise) on the question of algorithms in natural selection. Indeed, Penrose doesn't clearly present the arguments of any particular supporter of strong AI, but rather chooses to generalise loosely as if he is convinced his mathematical deductions can carry the day, and that AI doesn't present a significant challenge. Douglas Hofstadter is given a little space, and John Searle and his largely discredited Chinese Room Experiment a fair space, but other than that the only philosopher Penrose seems to be aware of is Plato.
Another thinker Penrose doesn't seem familiar with is William of Occam. Instead of doing some background reading (and applying a little common sense), Penrose has launched a theory which (as he proudly proclaims) takes us to the ends of time and the universe and back to the smallest subatomic particles to explain (in ways he freely admits he doesn't understand) an everyday, prosaic (but still extremely hard to grasp) phenomenon. In its interstellar journey Penrose's theory drifts very close to dualism, and close (but not quite so close, perhaps) to positing (or needing) some sort of God to work. That will give succour in some quarters, but not the ones Penrose has in mind, I suspect.
Occam's Razor would require that such untestable and speculative suppositions be rejected unless no other explanation is available. Penrose would protest there are none; Dennett, Dawkins, Hofstadter and their colleagues and adherents (including me) would beg to differ, and point to a lot of literature that Penrose hasn't read. In any case one would think that Penrose's own intuition (which he claims helps him to see truth despite Gödel undecidability!) ought to help him see his theory is, as Jeremy Bentham would say, "nonsense on stilts".
Ultimately, when Penrose says "quantum theory explains consciousness" he is really saying no more than "something magic happens!" or even "THEN A MIRACLE OCCURS".
Mr Penrose, I think you should be more explicit here in step two.
Olly Buxton
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