Customer Reviews

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

5 star:		(13)
4 star:		(5)
3 star:		(2)
2 star:		(3)
1 star:		(3)

 

 

This book is a significant improvement on Penrose's previous writing of similar scope, "The Emperor's New Mind", especially that he has more specific ideas on the actual biological manifestations of the noncomputational processes he seeks as basis for consciousness. Even if one does not agree with his arguments, there is a great amount of information on physics and so on, written in a style that makes the book a pleasure to read. A previous review mentioned that many have opposed the logical arguments from the first part of the book. Penrose, however, has replied quite well to many criticisms (see PSYCHE, an electronic journal on consciousness), and I think it is premature to pass final judgement. For an alternative, not necessarily incompatible, view of consciousness I highly recommend "The Feeling of What Happens" by the distinguished neurologist Antonio R. Damasio (or at least check out his article "How the Brain Creates the Mind" in Scientific American, December 1999).

Between the beautifully written prologue and epilogue, this book approaches a range of topics in modern physics in a unique and readable way. Through a continuation of some earlier work, Penrose furthers an argument for brain function and conciousness that many in the artificial intelligence field will not appreciate. He presents his case that the human mind will never be simulated with digital a computer, no matter how complex. But that is not his main focus of this book.

Even more facinating are his calculations which indicate how mathematically unique our existence is under the 2nd law of thermodynamics. To me, it's ultimately ironic that the physical principal which orders our universe and makes intelligent life possible (the 2nd law), is the result of an unimaginably improbable set of initial conditions. Although Penrose never invokes the concept of a creator or supreme being, in my mind, this poses an interesting challenge to those in the scientific community who claim our universe is simply the result of random particle collisions over a long period of time.

If we combine the concepts of similar structures scaling across space and time (tensegrity and fractals), with Penrose's ideas that consciousness may be associated with quantum gravity interactions in microtubules (present in all living cells), perhaps there is far more mystery and beauty to this existence than some would now believe...

This book was satisfying and throught provoking, and I highly recommend it to anyone interested in the mysteries of the very large and the very small.

Just opening this book to a random page and reading that page - sets one's mind on fire.

The basic thread running throughtout the book is that of 'what is computable and what is not'. The process of 'Understanding' as humans know it - Penrose argues - is NON-COMPUTABLE. He provides brilliant examples of how computers can 'solve' any problem - without 'understanding' what they are solving (e.g. DeepThought and the simple chess move which stumped it).

This theme in itself would make this a worthwhile read. However - this book offers further gems from Quantum Physics - with perhaps the simplest and best explanation of lesser known quantum paradoxes such as the 'delayed choice' experiments. Godel's theorem is also dealt with lucidly.

Few authors can tackle the issue of 'mind and conciousness' without stepping into some mystical/unscientific goo. Penrose stays scientific - and works from facts and well known experiments.

I do not know of any other book that tackles this subject so clearly - and in such an exciting fashion. From my perspective - this clearly deserves 5 stars.

Simple criticism is what Penrose does best. Finding contradictions, oxymorons, and mistakes is his specialty. His critique is certainly warranted now more than ever, as AI seems to be the slowest advancing field of all. In 1970s, we were 20 years from AI. Today, we are apparently 20 years from AI. I wager good money that in 2023, we will be 20 years from AI. How do we build something that we do not even know what it is? Is the mind computational? What is intelligence? These questions are still largely the realms of philosophy and not science. Thre are arguments, but the evidence is basically non-existent and largelly inferential; if it was any other field, literally negligable. But, some people argue, the very question of materialism rests in this quest. This is no necessarily true.

True AI is going to have to be more than a calculator. Actually, the best possible way to see if you believe in AI is to ask yourself: is a calculator a manifestation of AI? If not, there are problems with AI. Too many minds have built their fame and fortune arguing the opposite so the argument is not going away. Hence, I doubt this debate will be over any time soon.

However, in 20 years, I suspect nothing will have changed from the debate. Criticism of Shadows of the Mind usually involves oversimplification of Penrose's arguments. What you may think he says and what he does say are two completely different things.

Penrose has answered some criticism with rightful indignation in place. ....

Penrose is following the pathway started in THE EMPEROR'S NEW MIND - an exploration of the brain, consciousness, humanity and machine "thinking". I think Penrose would rather say machine "Computation" since he does not think of the human mind as an entity that can be explained in formula, alogrithms, or programs.

Rather our consciouness, our "knowing" that we are who we are is an evolutionary process made possible through quantum effects. That is Roger Penrose's argument and while it is an interesting one it is by no means definitive. What Penrose has done, though, is relentlessly investigate questions usually left unanswered and in most cases, unasked.

For example, how did consciousness happen? How did it evolve? Is it still evolving and can it be replicated? Once again, as in the EMPEROR, replication of an activity does not mean the same thing except to the outsider. If a computer plays chess and defeats the world champion, it is an astounding feat - not of chess playing but of computer building. Big Blue did nothing that it had not been programmed to do and that is our quandry - at what point would a machine ever begin to do what it wants and for what reason.

We developed psychologically and emotionally as we tried to adapt to our changing environment. Our uniqueness is due to many things, one of them being a left-right brain. To what conditions could a computer respond that would suddenly bring forth awareness? How would it grow and evolve outside of organic matter?

Shadows of the Mind is undoubtedly a less populist book than its predecessor "The Emperor's New Mind". It is also significantly more technical in places than the predecessor. Its purpose is to extend the Godel based arguments used in ENM in several directions. Firstly to attempt to address various criticisms of the central argument of the previous book and then to develop some new ones. Also there is a discussion of the application to Robotics. An example of this sort of discussion is whether any capability of a Robot to learn would undo any of the Robot restrictions deduced in his basic argument. After all learning (human or robotic) will imply going beyond previous restrictions and being aware of new facts.

So there is a subtle argument needed to continue to show that despite this, humans will come out on top. If you are interested in this kind of subtlety after reading ENM then this is the book for you.

In effect Penrose is right at the heart of the Mind-Machine debate in this book. I give an overview of this debate as follows:

We need to find a scientific theory of the Mind. So we can examine what kind of cognitive or thinking device it might be, recognising that it also thinks about Mathematics. For that we need a model of cognition sufficiently general: the Turing Machine model is available and generally considered to be that model - there are no obvious rivals. So one can focus on whether the Turing Machine model could really be a model for the Human Mathematical Mind. If the answer is "yes" we would conclude also: Robots could have Minds.

Penrose draws the conclusion about mathematical reasoning that:

G: "Human mathematicians are not using a knowably sound algorithm in order to ascertain mathematical truth".

This statement isn't quite the statement that the Mind is not a Turing Machine (algorithm here), and some critics have attempted to expose the gaps. In this book Penrose discusses several lines of argument to close the gap. A possible rebuttal might be: "could mathematicians just be using unsound algorithms" - the faulty machine argument. This is very close to questions in the foundations of mathematics itself - after all is this suggesting that mathematics itself is fundamentally unsound? If so where is that unsoundness? So Penrose comes round to the conclusion step by step and through 100 odd pages, that the statement G above implies that indeed the Mind is not a Turing Machine.

This latter conclusion however introduces another problem: if the Mind is not a Turing Machine / algorithm then what sort of (scientific) model exists for it? At the end of the book Penrose examines a generalisation of the Turing Machine model (called Oracle Machines and also due to Alan Turing) and determines that a statement similar to G also applies to that model class as well. Thus the story is left incomplete and I would be tempted to say that somewhere a model M exists of which we can deduce:

"Human mathematicians are using M to ascertain mathematical truth"

However Shadows of the Mind ends without a discovery of that model M. So maybe the answer lies in studying Quantum properties, or in other aspects of these obscure machine models? If you want to be able to study this question further Shadows needs to be studied (and "studied" is the word)!

This book is one of the most exciting of its kind.To me,the best science book I ever read. When talking about human brains it is not longer a matter of Computation or the Quantum Model. It's also a quest of one of our primary needs:the knowledge of our selves.Explained from a scientific point of view.It highlights however in a certain way the spiritual dimension of human beings.Without telling us directly,Penrose introduce on the reader's mind phylosophique and religious issues,as possible links on the explanation of the whole. It's true,we can't conclude(after reading the book)we have a definitive explanation,which has been proved right.However on this book,to my knowledge,it's the first time a scientist establish the link:Our Brains:Consciousness and the Quantum Model! If I compare to others books of its kind,such as Stephen Hawkins and Sir Roger Penrose in Space and Time,1995;Leon Lederman in God Particle,1995,Fred A.Wolf in Taking the Quantum Leap,1982 and Star Wave,1984;and finally the previous book of Penrose:The Emperor's New Mind,1990 I have to conclude on the fact that Penrose,on Shadows of the Mind goes beyond frontiers others could not reach before. And I have to analyze briefly the new aspects Penrose approach in a such visionary way:1)The strong possibility that physics(of particles)could be the basis of the appearance of high intellectual functions in our brains(which is quite opposite to the traditional scientific knowledge of the chemical basis being the cause)2)The strong possibility of the emerge of the highest intellectual function:consciousness into the most complex part of our brains:the neuronal synapses(microtubules)and 3)the possibility certain human brains could react differently from the average,because of a different physical arrangement. Of course,conclusions have not ben proved yet.However R.Penrose already advance on his book as examples, some clinical experiments which uses different anaesthetic on patients who loss consciousness;in order to prove his proposal of the new physical basis being the cause of that effect. To me these proposals,if some day proved right are revolutionary on the field of science and on the knowledge of our selves. The link he suggest between the Quantum Model applied to consciousness is not only unique up to now(to my knowledge),but could be the pathway which could lead us to the comprehension of one of the most intriguing,fascinating and really unknowed mystery:Our Brains:How come our consciousness could emerge on it and make us different from animals!And moreover it allows the reader to think on others possible dimensions of his proposals. I do agree:the book isn't for everybody.We have to like the subject and have already a certain knowledge on the matter. If you belong to that category,don't miss it!It's great! (...)

Roger Penrose has written a book which transcends all other efforts in probing the patterns of human reasoning. Although the book has generated controversy amongst mathematicians, few who have reviewed this work have stated categorically that he is wrong. Penrose's conclusions are unpleasant for those who believe in strong AI but they may very well be right. The potential reader considering purchasing this book should be aware that the book is technical and requires thought. Penrose does not make allowances for sloppy thinking (although, one has the feeling Penrose thinks he is making allowances). If you are open minded, not given to leaping to conclusions, and genuinely curious about science and human thought, this book plus The Emperor's New Mind, are definitely books for you.

"Shadows of the Mind" addresses first, all of the arguments Professor Penrose had to counter regarding the assertions he made in "The Emperor's New Mind." He then goes on to hint at an approach to the subject of consciousness, the great puzzle that science has heretofore been unable to tackle, and has therefore denied.

It provides an exceptional mental excursion into the questions surrounding the subject of consciousness, as well as the peculiar nature of matter.

Why is it that a physicist is the one to tackle this subject as opposed to a biologist?

Professor Penrose suggests that physicists may be in a better position to comprehend how matter really behaves than biologists are.

Read it for yourself to see whether he is right. I have no doubt about it!

Roger Penrose received a ton of feedback after writing the Emperor's New Mind. Some of it was downright unflattering as I recall. But he thoughtfully answered his critics, getting more specific about his attack on strong AI and consciousness and is to be applauded for the effort. He goes deeper into the concepts within this book and now proposes more concrete ideas fro alternatives in this book. I still disagree with his conclusions, but that does not diminish the book in the least. It is well though out well presented and is just a pure exercise for the brain. Penrose deserves the accolades for tackling this difficult and as it turns out "touchy" subject.