A New York Times bestseller when it appeared in 1989, Roger Penrose's The Emperor's New Mind was universally hailed as a marvelous survey of modern physics as well as a brilliant reflection on the human mind, offering a new perspective on the scientific landscape and a visionary glimpse of the possible future of science. Now, in Shadows of the Mind, Penrose offers another A New York Times bestseller when it appeared in 1989, Roger Penrose's The Emperor's New Mind was universally hailed as a marvelous survey of modern physics as well as a brilliant reflection on the human mind, offering a new perspective on the scientific landscape and a visionary glimpse of the possible future of science. Now, in Shadows of the Mind, Penrose offers another exhilarating look at modern science as he mounts an even more powerful attack on artificial intelligence. But perhaps more important, in this volume he points the way to a new science, one that may eventually explain the physical basis of the human mind. Penrose contends that some aspects of the human mind lie beyond computation. This is not a religious argument (that the mind is something other than physical) nor is it based on the brain's vast complexity (the weather is immensely complex, says Penrose, but it is still a computable thing, at least in theory). Instead, he provides powerful arguments to support his conclusion that there is something in the conscious activity of the brain that transcends computation - and will find no explanation in terms of present-day science. To illuminate what he believes this "something" might be, and to suggest where a new physics must proceed so that we may understand it, Penrose cuts a wide swathe through modern science, providing penetrating looks at everything from Turing computability and Godel's incompleteness, via Schrodinger's Cat and the Elitzur-Vaidman bomb-testing problem, to detailed microbiology. Of particular interest is Penrose's extensive examination of quantum mechanics, which introduces some new ideas that differ markedly from those advanced in The Emperor's NewMind, especially concerning the mysterious interface where classical and quantum physics meet. But perhaps the most interesting wrinkle in Shadows of the Mind is Penrose's excursion into microbiology, where he examines cytoskeletons and microtubules, minute substructures lying dee

# Shadows of the Mind: A Search for the Missing Science of Consciousness

A New York Times bestseller when it appeared in 1989, Roger Penrose's The Emperor's New Mind was universally hailed as a marvelous survey of modern physics as well as a brilliant reflection on the human mind, offering a new perspective on the scientific landscape and a visionary glimpse of the possible future of science. Now, in Shadows of the Mind, Penrose offers another A New York Times bestseller when it appeared in 1989, Roger Penrose's The Emperor's New Mind was universally hailed as a marvelous survey of modern physics as well as a brilliant reflection on the human mind, offering a new perspective on the scientific landscape and a visionary glimpse of the possible future of science. Now, in Shadows of the Mind, Penrose offers another exhilarating look at modern science as he mounts an even more powerful attack on artificial intelligence. But perhaps more important, in this volume he points the way to a new science, one that may eventually explain the physical basis of the human mind. Penrose contends that some aspects of the human mind lie beyond computation. This is not a religious argument (that the mind is something other than physical) nor is it based on the brain's vast complexity (the weather is immensely complex, says Penrose, but it is still a computable thing, at least in theory). Instead, he provides powerful arguments to support his conclusion that there is something in the conscious activity of the brain that transcends computation - and will find no explanation in terms of present-day science. To illuminate what he believes this "something" might be, and to suggest where a new physics must proceed so that we may understand it, Penrose cuts a wide swathe through modern science, providing penetrating looks at everything from Turing computability and Godel's incompleteness, via Schrodinger's Cat and the Elitzur-Vaidman bomb-testing problem, to detailed microbiology. Of particular interest is Penrose's extensive examination of quantum mechanics, which introduces some new ideas that differ markedly from those advanced in The Emperor's NewMind, especially concerning the mysterious interface where classical and quantum physics meet. But perhaps the most interesting wrinkle in Shadows of the Mind is Penrose's excursion into microbiology, where he examines cytoskeletons and microtubules, minute substructures lying dee

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4out of 5Ahmad–The argument is simple. There are mathematical problems that can't be solved using algorithms - non-computable problems. If you device an algorithm to solve that kind of problems, and let a computer run the algorithm, it would never stop. Yet the human mathematician is able to solve that kind of problems. Computational neuroscience (and Artificial Intelligence) treats the brain as a computer: either there is a neuronal signal or not, very much similar to the 0 and 1 scheme. But that algorithmic The argument is simple. There are mathematical problems that can't be solved using algorithms - non-computable problems. If you device an algorithm to solve that kind of problems, and let a computer run the algorithm, it would never stop. Yet the human mathematician is able to solve that kind of problems. Computational neuroscience (and Artificial Intelligence) treats the brain as a computer: either there is a neuronal signal or not, very much similar to the 0 and 1 scheme. But that algorithmic representation can't be truly faithful to what's really going on in the mathematician's brain. There must be a non-computable ingredient. Penrose argues then, that there's a deeper level of information processing in the brain, deeper than neural networks. Microtubules is the best candidate for that. Think of a unicellular organism, like an amoeba. How does it know where to go and what to do? It has no nervous system, not even a single neuron. Yet it does what it does, by the means of these cellular automata. One more thing: it appears that things at that molecular level behave according to the strange laws of quantum mechanics, providing the non-computable ingredient. This is an extraordinary approach to the problem of consciousness, and Penrose is a humble man (although in one of his interviews he pointed out to the interviewer that he should be called "Sir" Roger Penrose!) who doesn't claim to have solved the mystery of consciousness. He clearly states that the argument is strong at least for the quality of understanding. And that other qualities of consciousness like feeling, attention, imagination can't be simply explained by algorithms (only), or be regarded as phenomena emerging out of complexity (the cerebellum is as complex as the cerebrum yet it's totally automated and unconscious). ًو كان الله غفوراً رحيما

5out of 5Kerem Cankocak–Penrose, Gödel teoerimi üzerinden yapay zekanın hesaplanabilir bir etkinlikle oluşturulamayacağını söylerken aslında yapay zeka mümkün değil demiyor. Penrose'un ne demek istediğini anlamak için bu kitabı çok dikkatli okumak gerekir. Felsefecilerin Penrose'un argümanını tam olarak kavrayamadıkları kanaatindeyim.

5out of 5Alex Zakharov–First and foremost Penrose presents the best argument against computer-simulated human intelligence I’ve heard to date. In fact it is the only argument that I know of that holds water (and I think by now I have heard them all – from Searle’s chinese room to the fundamental energy limitations of recursive simulation models). The mechanics and technical details of the argument get a little complex (Penrose approach is very systematic, often formal, and quite exhaustive - a large spectrum of mathem First and foremost Penrose presents the best argument against computer-simulated human intelligence I’ve heard to date. In fact it is the only argument that I know of that holds water (and I think by now I have heard them all – from Searle’s chinese room to the fundamental energy limitations of recursive simulation models). The mechanics and technical details of the argument get a little complex (Penrose approach is very systematic, often formal, and quite exhaustive - a large spectrum of mathematical, logical and philosophical corner cases are covered) but broad strokes are easy enough to follow. The argument runs as follows. Consider math, which in theory should be the simplest thing for computer to “understand” before we even get to more complicated subjective areas such as emotions, qualia, free will etc. Then use Godel’s incompleteness theorem to show that regardless of how you pick your initial set of axioms (to be fed into the computer) there will exist mathematical statements that will be true, given the axioms, but will not be computable (in the church-turing sense) from those axioms. The truthfulness of those mathematical statements can be ascertained by humans but not by universal turing machines (i.e. computers). In other words there is something to human understanding that allows it to determine truthfulness/falsehood of statements and transcend the axiomatic rules from which such statements were derived from. It is exactly that kind of understanding that computers lack. Now, of course, to get to this point Penrose had to quickly cover a lot of ground – Turing machines, Church-Turing thesis, computability, decidability, (non)determinism, chaos, halting problems, tiling problems, discrete vs continuous computation, Godel’s theorem etc. It is a great refresher for those familiar with the subject matter and a nice introduction to those who aren’t. The second half of the book looks for a non-computational yet scientific basis for human intelligence. Here Penrose moves into a brief overview of quantum mechanics (QM) which was quite fantastic actually (I dreamed of Schrodinger’s cat for a couple of nights), he also shows where QM breaks down and where its inconsistencies with general relativity get manifested. Absolutely fascinating overview of the field and its conundrums. No surprises here - we all know TOE is still work in progress and Penrose view is that it is QM that would need to be radically modified to be consistent with relativity, not the other way around. Anyway, QM itself is very well-defined, precise and unambiguous but it is in its transition to non-quantum reality via state vector reduction where quite a few difficulties arise. Or to put it simply QM is perfectly well-defined (i.e. quantum coherence is indeed coherent) till the moment an observer is introduced. But in the end the author brings us to Hameroff-Penrose theory of consciousness that is linked to OR (objective reduction) of a wave function. And in the brain this non-computational process takes place not among the neurons themselves but in cytoskeleton microtubules (within neurons). Voila – we arrive at scientific non-computational basis for human understanding/consciousness What can I say – recruiting Godel to drive a solid very scientific nail through the heart of hard AI (part one of the book) was very very nicely done and just for that the book gets five stars. A gallop through QM and its difficulties was a bit masochistic but I did enjoy it. As far as microtubules – clearly highly speculative but Penrose says so himself at the outset, so I suppose you can take it or leave it. Overall though this is one of the more rewarding books I’ve read in recent and not-so-recent memory; if you are even marginally interested in the subject matter reading this one should be a no-brainer.

4out of 5Rajith–Penrose's conclusions imply that there is a separate mental world, grounded in the physical world, and there is also another separate world, that of abstract ideas. The book is clearly divided in two parts, The first part is a proof that traditional Physics is not adequate to explain consciousness. The second part uses Quantum Theory to draft a theory of consciousness. Penrose starts his argument by stating that classical Physics is inadequate to explain consciousness. Somehow this relates to G Penrose's conclusions imply that there is a separate mental world, grounded in the physical world, and there is also another separate world, that of abstract ideas. The book is clearly divided in two parts, The first part is a proof that traditional Physics is not adequate to explain consciousness. The second part uses Quantum Theory to draft a theory of consciousness. Penrose starts his argument by stating that classical Physics is inadequate to explain consciousness. Somehow this relates to Goedel's theorem, which puts a limit to what a Turing machine can do, a limit that does not apply to the human mind; Consciousness must be a quantum phenomenon because neurons are too big to account for consciousness. Inside neurons there is a cytoskeleton, the structure that holds cells together, whose microtubules (hollow protein cylinders 25-nanometers in diameter) control the function of synapses. Penrose believes that consciousness is a manifestation of the quantum cytoskeletal state and its interplay between quantum and classical levels of activity. Subjective reduction is what happens when an observer measures a quantity in a quantum system: the system is not in any specific state ,the system is in a "superposition" of possible states. until it is observed, the observation causes the system to reduce (or "collapse") to a specific state. This is the only reduction known to traditional Quantum Theory. Objective reduction is a Penrose discovery, part of his attempt at unifying Relativity Theory and Quantum Theory. Super positioned states each have their own spacetime geometries. Under special circumstances, which microtubules are suitable for, the separation of spacetime geometry of the superpositioned states (i.e., the "warping" of these space-times) reaches a point (the quantum gravity threshold) where the system must choose one state. The system must then spontaneously and abruptly collapse to that one state. This "self-collapse" results in particular "conformational states" that regulate neural processes. These conformational states can interact with neighboring states to represent, propagate and process information. The proteins somehow "tune" the objective reduction which is thus self-organized, or "orchestrated". In general, the collapse of the wave function is what gives the laws of nature a non-algorithmic element. Otherwise we would simply be machines and we would have no consciousness. Therefore, "protoconscious" information is encoded in space-time geometry at the fundamental Planck scale and that a self-organizing Planck-scale process results in consciousness. Penrose is stronger in his own backyard, when he describes objective reduction and comments on what has been known as the "Von Neumann measurement problem" of Quantum Theory.

4out of 5C.T. Phipps–The origins of consciousness are either an elusive mystery or something as painfully obvious as gravity. For many years, I didn't really even know there was an issue of consciousness and just assumed it was a natural consequence of the brain (generator of the soul in my theistic view but still intrinsically linked). In fact, there's a huge feud going on among scientists and philosophers over why a bunch of electrical meat generates "you" and "me." There's a number of theories ranging from the in The origins of consciousness are either an elusive mystery or something as painfully obvious as gravity. For many years, I didn't really even know there was an issue of consciousness and just assumed it was a natural consequence of the brain (generator of the soul in my theistic view but still intrinsically linked). In fact, there's a huge feud going on among scientists and philosophers over why a bunch of electrical meat generates "you" and "me." There's a number of theories ranging from the insane ("panpsychism") to the boringly mundane ("neurons") to the also insane but materialist ("there's no such thing as consciousness"). Sir Roger Penrose, one of the smartest men alive, teams up with Doctor Stuart Hammeroff to offer their own version that consciousness is a product of quantum physics ("qubits" or quantum information) interacting with the microtubbles in the brain. If that sounds like Greek to you and you're not Greek, it basically means consciousness exists as a product of physics rather than biology. In more esoteric terms, it means consciousness is the result of quantum collapse between information states. Schrodinger's Cat of the cat being both dead and alive is the basis for consciousness as our thoughts are the physical representation of those things coalescing into "yes, the cat is frigging dead." This is a theory which absolutely INFURIATES all manner of neurologists and physicists who believe it is ludicrous. Given the sheer volume of "quantum woo" (a.k.a pseudoscience), this is a reasonable fear but for the fact Penrose is one of the smartest men on the planet and Stuart Hammeroff's claims have repeatedly ended up being validated. Unfortunately, Hammeroff's claims have been somewhat tainted by his association with a bunch of very questionable figures (*cough* Deepak Chopra *cough*). The biggest consequence of this theory is that it does have one big huge effect on the immediate future of technology: artificial intelligence. If Penrose's theory is correct, basically, computational A.I. is impossible for humans to create. It is a biological process which is related to the celestial geometry of the universe. No matter how we program our NPCs, they'll never be able to be conscious. That's another reason the theory really ticks a lot of people off. The other flaw is the fact this book isn't exactly written for laymen. I know a good deal of physics for an amateur and required a couple of other scientists to understand everything which was being said. Penrose basically assumes his readers are familiar with not only quantum physics, his previous work, computation, but also problems of free will. Personally, I'm inclined to believe Orch-Or theory is the source of human consciousness. In effect, "imagination" is the real multiverse since alternate realities last only as long as they're thought of. The biggest flaw of this book, though, is a lot of the collaborating evidence for its truth came out through studies conducted after it was written. Many people still dispute this theory but no one has been able to put up a better one, IMHO.

4out of 5Jimmy Ele–What can I say about a book which challenged my mathematical understanding and revealed the unseen aspects of my own brain's cytoskeletal structures? Was it the knowledge that there is a type of water in these structures which is considered a necessary element for cancelling the interference that would null the necessary conditions for quantum coherence to take effect? Or was it the mathematical proof showing that because there are mathematical statements of which we know to be absolutely true y What can I say about a book which challenged my mathematical understanding and revealed the unseen aspects of my own brain's cytoskeletal structures? Was it the knowledge that there is a type of water in these structures which is considered a necessary element for cancelling the interference that would null the necessary conditions for quantum coherence to take effect? Or was it the mathematical proof showing that because there are mathematical statements of which we know to be absolutely true yet cannot prove, then it follows for us to conclude that a computer could never achieve consciousness (at least with the 1994 mathematical understanding available)? Trust me, Roger Penrose does it in a supremely much more elegant fashion than I could ever do it justice with in a GoodReads summary. So why 4 stars? Well, I'm not an expert at Lambda Calculus or many of the subjects that Roger Penrose expertly weaves in and out of, so it became supremely hard to follow at times. However, I broke through this barrier and was able to glean from it the nuggets that I could understand. I recommend anyone interested in these subjects to do the same.

5out of 5Rian Nejar–The author's stand, that we need new physics to understand the science of consciousness, and that this new physics he believes required is quantum physics, seems more his personal intuition (read delusion if you like!) than rigorous scientific inference. Applying models of sub-atomic phenomena to comprehend biological or life processes separated by very many orders of magnitude is an unscientific stretch too far. Quantum uncertainty of sub-atomic particles or fields does not map, by any evidence The author's stand, that we need new physics to understand the science of consciousness, and that this new physics he believes required is quantum physics, seems more his personal intuition (read delusion if you like!) than rigorous scientific inference. Applying models of sub-atomic phenomena to comprehend biological or life processes separated by very many orders of magnitude is an unscientific stretch too far. Quantum uncertainty of sub-atomic particles or fields does not map, by any evidence or intuition, to decision uncertainty in organic neural networks. Likewise, wave-particle duality in sub-atomic entities can hardly be called equivalent to concepts relating to the mind and the brain.

5out of 5Yubal Masalker–This book is great feat of human logic. It gives in a logical analysis why the human brain can't be a mere computational machine like computers. The author, Sir Roger Penrose, who is an acclaimed mathematical physicist, asserts on the basis of Godel's incompleteness theorems, that our brain's perception is beyond the constraints dictated by these theorems (which are true for the mathematics and the algorithms operating in computers). We wouldn't be able to grasp the mathematical concepts and to This book is great feat of human logic. It gives in a logical analysis why the human brain can't be a mere computational machine like computers. The author, Sir Roger Penrose, who is an acclaimed mathematical physicist, asserts on the basis of Godel's incompleteness theorems, that our brain's perception is beyond the constraints dictated by these theorems (which are true for the mathematics and the algorithms operating in computers). We wouldn't be able to grasp the mathematical concepts and to formalize new concepts if our brains and consciousness would be confined by those theorems' constraints. The author asserts that our brains operate by rules which require consideration of new Physics, particularly the Quantum Physics, in order to explain the rise of consciousness out of the brain. He gives practical examples by using AI (Artificial Intelligence) to show why brains can't be just some extended AI. Then he gives other practical examples from brain cells' basic structures to show how brains might use the mysterious principles of Quantum Physics to function and to having the abilities which surpass immensely the most advanced digital AI and that any digital AI wouldn't ever possess them in principle. The drawback of this book is that it contains extensive mathematical-philosophy discussions centered around Godel's incompleteness theorems, using many symbols in those discussions. The author himself advises most of the readers to omit such sections. But even besides it, IMO, the author's language is not always so friendly for the average reader in his explanations and conclusions about those discussions above.

4out of 5Atila Togay–Roger Penrose her zamanki titizliği ile konuyu en temellerinden ele alıyor ve önemli çıkarımlarda bulunuyor. Penrose sadece başkalarının çalışmalarını derleyen bilim yazarlarından değil. Önemli ve orijinal araştırmaları var. Bu nedenle bir şey yazdığında okumadan geçmiyorum. Ne var ki dili problemli. Kimi zaman cümleleri bir paragraf uzunluğunda ve üç beş kere okuyunca ancak anlayabiliyorum. Yazdıklarını önemsediğim için dip notlara kadar okumaya kalkınca bir ayda ancak bitiyor kitap. İyi tarafı Roger Penrose her zamanki titizliği ile konuyu en temellerinden ele alıyor ve önemli çıkarımlarda bulunuyor. Penrose sadece başkalarının çalışmalarını derleyen bilim yazarlarından değil. Önemli ve orijinal araştırmaları var. Bu nedenle bir şey yazdığında okumadan geçmiyorum. Ne var ki dili problemli. Kimi zaman cümleleri bir paragraf uzunluğunda ve üç beş kere okuyunca ancak anlayabiliyorum. Yazdıklarını önemsediğim için dip notlara kadar okumaya kalkınca bir ayda ancak bitiyor kitap. İyi tarafı ise şu : bazı detaylara girmek istemeyenlere hangi bölümleri atlayarak gidebileceklerini söylüyor. Dolayısı ile ana fikri kaçırmadan ve bütünlüğü bozmadan okuyabilirsiniz. Özetle içindeki fikirler ve çıkarımlar çok önemli, kitaplıkta mutlaka bulunmalı ve başvuru kitabı olarak kullanılmalı.

5out of 5Mathijs Aasman–A difficult read, I skipped most of the middle section owing to my undergraduate being in physics, and the middle section presents an introduction to quantum mechanics. I read the initial chapters, which go over an argument for why consciousness is not mere computation. THe final section goes over the possibility for microtubules to be units of neuronal processing, instead of the basic unit being the neuron, this greatly expands the computational capacity of the mind. Overall a speculative book, A difficult read, I skipped most of the middle section owing to my undergraduate being in physics, and the middle section presents an introduction to quantum mechanics. I read the initial chapters, which go over an argument for why consciousness is not mere computation. THe final section goes over the possibility for microtubules to be units of neuronal processing, instead of the basic unit being the neuron, this greatly expands the computational capacity of the mind. Overall a speculative book, and I noticed Penrose worked out a lot of this on his own, as the references section is shorter than many books of this type. THis does present an interesting 'new' take on a topic which has been explored by others in such glancing depth.

4out of 5Tom Prosser–It’s a well written, easy to follow book on AI and the Godelian argument towards mechanism. Penrose ultimately concludes that consciousness cannot be algorithmic, that brains are not Turing machines, and must be on a quantum level. If you’re interested in AI it’s a good read, but the argument itself isn’t great, it’s got a lot of problems and the Godelian argument is widely viewed as unsatisfactory and invalid by the academic community so don’t take the book as accurate. If you want a good book o It’s a well written, easy to follow book on AI and the Godelian argument towards mechanism. Penrose ultimately concludes that consciousness cannot be algorithmic, that brains are not Turing machines, and must be on a quantum level. If you’re interested in AI it’s a good read, but the argument itself isn’t great, it’s got a lot of problems and the Godelian argument is widely viewed as unsatisfactory and invalid by the academic community so don’t take the book as accurate. If you want a good book on AI and similar arguments, just pick up Douglas Hofstadter’s Godel, Escher, Bach. 2 stars as an academic work, 3 as a pop science book

4out of 5Balkha–Since I run in the opposite direction when it comes to mathematics, this was a challenging read. I skipped over entire sections in the book. Despite this, there is some insight to be gained. The author is a physicist after all so the language is not always simplified but his ideas to a large extent come through. I probably didn't appreciate his arguments or the math he presents as well as someone with a stronger science background would but the book still makes a lot of interesting points to thi Since I run in the opposite direction when it comes to mathematics, this was a challenging read. I skipped over entire sections in the book. Despite this, there is some insight to be gained. The author is a physicist after all so the language is not always simplified but his ideas to a large extent come through. I probably didn't appreciate his arguments or the math he presents as well as someone with a stronger science background would but the book still makes a lot of interesting points to think about. It was a difficult and slow read but I don't regret picking it up.

4out of 5Jason Hoskins–This book was extremely dense, but well worth it for those that have an interest in physics, artificial intelligence, or the philosophy or science of the human mind. The overall idea is that Godel's Incompleteness Theorem (which states that it is impossible to have a known set of axioms/theorems/algorithms that is both complete and sound) precludes the possibility that the human mind functions solely computationally/algorithmically, and this is seen perhaps most convincingly in the ability of hu This book was extremely dense, but well worth it for those that have an interest in physics, artificial intelligence, or the philosophy or science of the human mind. The overall idea is that Godel's Incompleteness Theorem (which states that it is impossible to have a known set of axioms/theorems/algorithms that is both complete and sound) precludes the possibility that the human mind functions solely computationally/algorithmically, and this is seen perhaps most convincingly in the ability of human mathematicians to continually formulate creative proofs of complicated mathematical concepts. The logic behind this assertion is both subtle, complex and foundational to all of Penrose's theories on non-computational physics and the mind, which is why he spends nearly half of the book on this matter. It's also why I am not going to try to convince you of the argument's validity in this dinky little review. This first half of the book was definitely the hardest to get through, and most people would people would probably be better served to jump to a few key discussions in this first half of the book (Penrose makes suggestions along the way on which parts are the most important for people to get the gist). The second half of the book brings people up to speed on classical (general relativity) and quantum physics, and the issues that keep the two branches separate. I feel that Penrose was much better at explaining the crazy nuances of quantum physics than Hawking was in "A Brief History of Time" or "Universe in a Nutshell". I also can appreciate now why classical and quantum physics are so hard to unify. Penrose proposes that this putative non-computational quantum physics that he hold as necessary for explaining conciousness must be found in the theory that will ultimate unify physics. He makes a couple somewhat vague suggestions for what this physics might look like, which seem plausible, but ultimately need some experimental validation to be taken super seriously. He then goes on to describe where in the context of the human brain these sorts of quantum interactions might be occuring that allows our minds to work non-computaionally (spoiler alert: microtubules). Overall, I found his ideas fascinating, and I hope that the experimental evidence shows him to be right, at least on the foundational premises of his theories. Of coures this book was written over 15 years ago, so maybe the primary literature has more to say on the matter at this point. I'll have to check it out. In the meantime, I suggest you check this book out.

5out of 5A De Grandis–I had this on my 'must read' list when it was first published then due to events (those things that get in the way o all our plans) it slipped below the surface of conscious mind and I forgot about it. Hearing Penrose at Hay in 2010 resurfaced it only for it again nearly to succumb to the plate tectonics of my brain and slip under the continent of my consciousness due to another set of events (I began to think there might be a quantum superpostion followed by a collapse of possibilites each time I had this on my 'must read' list when it was first published then due to events (those things that get in the way o all our plans) it slipped below the surface of conscious mind and I forgot about it. Hearing Penrose at Hay in 2010 resurfaced it only for it again nearly to succumb to the plate tectonics of my brain and slip under the continent of my consciousness due to another set of events (I began to think there might be a quantum superpostion followed by a collapse of possibilites each time I encountered Professor Penrose since both times relocation to a different part of Britain followed shortly after) Anyway this time I bought the book knowing that if it was sitting on my shelves it would keep presenting itself to my notice until I read it. I have now done so and it was worth every page turn and brain stirring moment! As some one who managed to pass O level maths but was kindly advised not to make the universe or at least my maths teacher suffer by attempting A level I found some of the book quite daunting in prospect but not in actuality. Even non-mathmeticians can follow the arguments he makes and the philosophy is logical and straightforward. Whether you agree or disagree with his premise that in terms of conscious thinking and computation there is something going on in the mind that cannot be explained in terms of current scientific knowledge will be for you to decide. Although the science of quantum physics has moved on in the last twenty years nothing invalidates the arguments he sets out. He takes the viewpoint that appropriate physical action of the brain evokes awareness, but this physical action cannot even be properly simulated computationally. The book is an exploration of this as contrasted with three other viewpoints that range from 'all thinking is computational and awarenes is evoked by this process' to the opposite which is 'awarenes scannot be explained by physical, computational or any other scientific terms'. Not the easiest of reads but incredibly rewarding and for anyone interested in what makes us human, self aware, conscious entities then I would thoroughly recommend it whether in the end you do or don't agree with his proposition the exploratory journey is worth your time and effort.

5out of 5Ben Phillips–The main argument that this book presents is incredibly weak. I obviously can't do it justice in a short review but the basic line seems to be (1) "Human mathematicians are not using a knowably sound algorithm in order to ascertain mathematical truth." (p.76) (2) Human mathematicians are sound theorem provers (3) Therefore computers cannot model the human thought process (since computers run algorithms and there is no knowably sound algorithm to ascertain mathematical truth). Penrose establishes The main argument that this book presents is incredibly weak. I obviously can't do it justice in a short review but the basic line seems to be (1) "Human mathematicians are not using a knowably sound algorithm in order to ascertain mathematical truth." (p.76) (2) Human mathematicians are sound theorem provers (3) Therefore computers cannot model the human thought process (since computers run algorithms and there is no knowably sound algorithm to ascertain mathematical truth). Penrose establishes (1) using Godel's Incompleteness theorem and I doubt many people would take issue with it (it seems intuitively obvious as well). (2) is where Penrose's argument falls to pieces and his various justifications for it are incredibly weak. I won't attempt to debunk it here but suffice to say that Penrose stumbles around even the most obvious objections (ex: that human mathematicians make mistakes all the time). His entire argument is not presented in the 3 steps I listed above (specifically, step 2 is broken down into many sub-arguments) but I think the 3 steps provide a fair overview. After the argument above he discusses how quantum mechanics might provide a basis for human consciousness. The ideas he presents are interesting but baseless. The only real redeeming quality of this book is that it presents some interesting proofs regarding turing machines and problems that they can't solve.

5out of 5Todd Stockslager–Penrose, while more famous, does not do as well at popularizing the heady physics and mathemathics in this area as Barrow and Tipler (which see elsewhere in this list). His reasoning is too tortured and formula-heavy for me, whom I consider an advanced popular reader. However, he does reach the deep conclusion that "whatever brain activity is responsible for consciousness . . . It must depend upon a physics that lies beyond computational simulation (p. 411)." Instead of resorting to the mind as m Penrose, while more famous, does not do as well at popularizing the heady physics and mathemathics in this area as Barrow and Tipler (which see elsewhere in this list). His reasoning is too tortured and formula-heavy for me, whom I consider an advanced popular reader. However, he does reach the deep conclusion that "whatever brain activity is responsible for consciousness . . . It must depend upon a physics that lies beyond computational simulation (p. 411)." Instead of resorting to the mind as mystical or mysterious, Penrose postulates that consciousness, while uncalculable, is still physical, perhaps in an interaction in the brain between classical physics and quantum physics not yet discovered or understood. Penrose points to the possibility of "microtubules" (part of the cytoskeleton that exist even in single-cell paramecium--and seem to give that cell some level of understanding!) that form nuerons at the quantum level being the answer to this current quandary: "Accordingly, the neuron level of description that provides the currently fashionable picture of the brain and mind is a mere shadow of the deeper level of cytoskeletal action--and it is at this deeper level where we must seek the physical basis of mind!" That Penrose only gets to this statement on p. 376 of this heavy tome is part of the problem with this book.

4out of 5Ronen–Consciousness seems to be one of the deepest and intriguing mysteries on the frontier of science today, and there isn't much more than speculation on the subject. Penrose offers an original and exciting (I found it to be :) ) approach. I've recently started an undergrad engineering degree, and a good deal of this book is way over my head. But I do feel that Penrose has done a good job in conveying the gist of things, and can be sensitive to readers' different backgrounds (sometimes suggesting an Consciousness seems to be one of the deepest and intriguing mysteries on the frontier of science today, and there isn't much more than speculation on the subject. Penrose offers an original and exciting (I found it to be :) ) approach. I've recently started an undergrad engineering degree, and a good deal of this book is way over my head. But I do feel that Penrose has done a good job in conveying the gist of things, and can be sensitive to readers' different backgrounds (sometimes suggesting an uninitiated reader to skim a certain part). I would say that prerequisite knowledge for the book would be prior familiarity with at least concepts of quantum physics ,computation, and Godel's theorem. That aside, I find the subject fascinating, and could very well identify with the "mysteries" Penrose details in the final chapters. Relating to consciousness as just another soon to be mastered field (as treated by the so-called "strong AI" proponents) seems presumptuous to me, and I find myself more identifiying with Penrose, who treats the subject with a lot more gravity. I'm no authority, but I would definitely recommend taking in other views though, from the strong AI perspective (Kurzweil maybe) and Godel, Escher Bach by Hofstadter.

4out of 5Andreas K.–In this book Roger Penrose uses the Gödel's incompleteness theorem (Gödel-Turing argument) to prove that human brains use non-computational processes in order to ascertain the truth of unprovable Gödel statements. He concludes that mathematical understanding, and consciousness in general, is not computational. One possible candidate for non-computational physics is quantum gravity. As long as a quantum system is effectively isolated from its environment and remains coherent, a process called “gr In this book Roger Penrose uses the Gödel's incompleteness theorem (Gödel-Turing argument) to prove that human brains use non-computational processes in order to ascertain the truth of unprovable Gödel statements. He concludes that mathematical understanding, and consciousness in general, is not computational. One possible candidate for non-computational physics is quantum gravity. As long as a quantum system is effectively isolated from its environment and remains coherent, a process called “gravitationally induced objective state reduction” (OR) can occur. This OR is claimed to be non-random and non-computational. Penrose's highly speculative idea is that cytoskeletal microtubules maintain large-scale quantum coherence through portions of brain, and when a critical threshold is reached the OR takes place. Such processes give rise to the non-computational behavior of the brain.

5out of 5Don Rea–The central argument is not as airtight as it should be, being written for a general readership and not for mathematicians, but I'm just in love with the idea of a mathematical proof that the human mind can't be algorithmic. I wonder if Penrose has published a proper version of the proof? The second half of the book, in which he speculates on what kinds of computation or processes might be the underpinnings of the working of the mind is also fascinating though, again, I don't find his arguments n The central argument is not as airtight as it should be, being written for a general readership and not for mathematicians, but I'm just in love with the idea of a mathematical proof that the human mind can't be algorithmic. I wonder if Penrose has published a proper version of the proof? The second half of the book, in which he speculates on what kinds of computation or processes might be the underpinnings of the working of the mind is also fascinating though, again, I don't find his arguments necessarily persuasive. (For instance, he basically waves away the "many worlds" interpretation of quantum uncertainty because he simply doesn't like it.) He's not quite as good a writer for the non-specialist as Sagan or Feynman, but he's a bona fide genius and his speculations are well worth the trouble to read and understand.

4out of 5Ravi Warrier–This is the first book that I have read that attempts to determine the existence of the mind mathematically (scientifically) and it is interesting how Penrose, argues for both and against various points, maps out logic mathematically and links quantum mechanics to the working of the brain, thus generating the phenomenon of the 'mind'. The book is heavy on maths and if you are like me, most of it will just go over the head, despite Penrose's claim that it's just basic maths. Ignoring the maths is This is the first book that I have read that attempts to determine the existence of the mind mathematically (scientifically) and it is interesting how Penrose, argues for both and against various points, maps out logic mathematically and links quantum mechanics to the working of the brain, thus generating the phenomenon of the 'mind'. The book is heavy on maths and if you are like me, most of it will just go over the head, despite Penrose's claim that it's just basic maths. Ignoring the maths is possible at times, but in certain cases you have to wade through. The only motivation to do so, is to see the light at the end of the figurative tunnel - to know what Penrose's conclusions are. It is a page-turner (though I mostly, skipped the maths) and for the person with a serious drive to understand consciousness and the mind, this would be one of your text books.

5out of 5George Hohbach–Inspiring sequel to the Emperor’s New Mind: The three key insights I took away were: 1. The mathematical, timeless Platonic world contains all of math 2. The connection between superpositions (when, e.g., a quantum propagates forward in a mysterious configuration of existing at different places at the same time), the quantum mechanical probability of finding a quantum at a certain location and the random appearance of a quantum at one location caused by a large scale measurement. 3. The question: Ho Inspiring sequel to the Emperor’s New Mind: The three key insights I took away were: 1. The mathematical, timeless Platonic world contains all of math 2. The connection between superpositions (when, e.g., a quantum propagates forward in a mysterious configuration of existing at different places at the same time), the quantum mechanical probability of finding a quantum at a certain location and the random appearance of a quantum at one location caused by a large scale measurement. 3. The question: How can there be both deterministic processes and processes that appear to be happening randomly? What is the deeper connection so that these opposite processes can occur in one and the same universe?

5out of 5Enrique Oviedo–Para un público muy limitado. Para empezar, no recomendaría leer este libro a nadie que no haya leído previamente "La nueva mente del emperador". Aquel libro finalizaba con una serie de conjeturas sobre el posible modo en que funciona el pensamiento. En este "Las sombras de la mente" se sigue prácticamente con un punto y seguido a aquellas especulaciones. Se intenta apoyan con más evidencias las líneas de pensamiento allí esbozadas y refutar los argumentos contrarios que le han ido planteando a P Para un público muy limitado. Para empezar, no recomendaría leer este libro a nadie que no haya leído previamente "La nueva mente del emperador". Aquel libro finalizaba con una serie de conjeturas sobre el posible modo en que funciona el pensamiento. En este "Las sombras de la mente" se sigue prácticamente con un punto y seguido a aquellas especulaciones. Se intenta apoyan con más evidencias las líneas de pensamiento allí esbozadas y refutar los argumentos contrarios que le han ido planteando a Penrose. Acompañar al autor en este viaje es una gimnasia mental sugerente y estimulante. Sin embargo, requiere un esfuerzo muy elevado para seguir unas líneas de pensamiento que no dejan de ser meras intuiciones.

4out of 5Rob Springer–In this book, Penrose narrows the thesis he set out in The Emperor’s New Mind, that the human mind cannot be emulated in a computer. He gives the barest outlines of a new approach to physics he thinks is necessary to bring Mind under the prevue of science. I found, however, that I skipped over the maths even more than I did in The Emperor's New Mind.

5out of 5Ronny–This book's value is in exploring the question of the nature of consciousness and in dismissing the easy answers. Unfortunately, its ending is very weak as the author poses some kind of biological structure as the reason for consciousness. I found this ultimately unsatisfying, although I wonder if it's just me...

5out of 5Unni Krishnan–This was my introductory book to Roger Penrose. But the book was very intimidating, even for a computer science graduate. Only consolation was that exploration of the high level concepts of Turing machine was not the only theme of the book. Which pop-science enthusiast would understand both Goedell theorems (and their proofs !) completely? So, I can justify myself.

5out of 5Jon–Spoiler alert: Consciousness explained by coherent quantum states within microtubules in the cytoplasm. There, I just saved you a lot of reading time. Still very interesting reading. One example is the binary star, one of which is a pulsar - 20 kilometers across, 1.44 time the mass of the sun, spinning 17 times a second!

5out of 5Mr Shahabi–One of the hardest books I've read in a long time, mayhaps its because of the fact that Penrose used methamatical and academic explanation method rather than simplifying facts and me bieng an illiterate and haven't finished middle school yet had its own turmoil reason why this book was a bit heavy on the reading experience, but rich with information never the less.

4out of 5Michael–Penrose proposes that quantum mechanics are at the heart of human consciousness, and the human reality. It leaves the reader to assume that the brain is nothing more than a bio-chemical-electrical computer that has been tinkered with by evolution. Marvelous and thought-provoking illustrations leave little room for doubt about this theory.

5out of 5David–Much of this book was a bit too hard on the mathematics for a grade C GCSE underachiever like myself, but I persevered and read through much of the work. However, I just thought that there wasn't much of an argument, nor much of a solution put forward by Penrose. Too much thinking in terms of absolutes, and not enough thinking in terms of a theory of consciousness.

5out of 5R.J. O'Connor–Extremely thought provoking and a real wake up call for those assuming we will achieve the singularity in a few short decades. The theories espoused here are truly amazing, and if shown to be true will change the way we think about just about everything.