1 comments about An Introduction to Gravity Modification: A Guide to Using Laithwaite's and Podkletnov's Experiments and the Physics of Forces for Empirical Results.

1. An excellent book on generating force fields both mechanically and electrically. His theories on how this all works fits the data that he has collected very well. I just wish that he had an explanation for the time that it takes for the weight loss effects to occur with the electical circuits.
   
   Overall a great read that tickles the mind into thinking about the what could be with just a little more work.

2 comments about Traveling at the Speed of Thought: Einstein and the Quest for Gravitational Waves.

1. Beware, this is not pop science book. In my opinion, "...introduces readers..." and "accessibly written...", as indicated in the marketing comments, are not accurate representations of the level of this book. The fact that no equations are given in the text should not lead to you think this is easy reading.
   
   Instead, this is a scholarly historical analysis, where knowledge of concepts such as "unimodular coordinates", "metric tensor", "linearized approximation of general relativity", just to name a few, are taken for granted as no introduction is given of them. Not even the concept of "gravitational waves" is introduced. Graduate level training of Special and General Relativity is a requirement.
   
   I believe this is a great contribution to the historical analysis of this subject, but the target audience needs to be stated correctly.



2. I felt the single review of this book highly underrated it, and since it almost scared me away from purchasing it, I wanted to offset it with a positive one. I would have missed out if I had listened to it! I absorbed this book in just a few days, really enjoying the historical account presented and learning a number of interesting things about gravitational waves along the way.
   
   While Kennefick's work does include references to some technical terms, they are given definitions and in some cases enlightening explanations. I found it pleasant to follow the story in any case by simply not letting myself get bogged down from not having a deep, graduate level, mathematical understanding of general relativity. I am proof that is not required to appreciate this book.
   
   One particularly positive aspect is the overall focus on the role of analogies in science. The first chapter was a gem for this reason, but the intriguing theme of differing personal approaches to using analogies is woven throughout the entire book.
   
   Overall, I would say that if you enjoy historical biographies of science/math personas where technical discussion slips in here and there, you would have a good chance of liking this work.

4 comments about A Journey into Gravity and Spacetime ("Scientific American" Library).

1. This is truely an amazing book. Wheeler does for General Relativity what Hawking did for Cosmology in "A Brief History of Time", and in some sense they are similar books. However Wheeler has a unique, quirky style of writing that makes the book an entertaining adventure to read.

   Wheeler is able to pull off a major accomplishment: He explains Einstein's General Relativity in a clear, straightforward manner, with a minimum of math. It's "conventional wisdom" that General Relativity is seriously serious stuff, the domain of hardcore Physics geeks. That doesn't faze Wheeler. He leads the reader along, gleefully pointing out the scenery, making it all look quite simple and understandable. And then all of a sudden, when you least expect it, you find he's derived and presented Einstein's field equations with only a teensy-tiny bit of algebra! Even if you know this stuff already, his presentation makes you think about it with a new perspective.

   And did I mention the illustrations? They are really exceptional.

   If you have any interest or dealings with GR, ya gotta have this book!




2. This author is one of the most briliant, the most optimistic, and the most enthusiastic writer in all of physics, and in this book, his competence as a physicist and his deep fascination with the physical world is brought out dramatically. He is clearly a man who is feeling a powerful sense of exhiliration of the discoveries now taking place in all areas of knowledge. His foundation and his theme in the book is a simple geometric principle, namely that the boundary of a boundary is zero. He then guides the reader, assumed to have a rudimentary knowledge of mathematics, in a splendid presentation of the power of this principle in gravitational physics.

   The first chapter is an overview of the history behind the subject, via the work of people who contributed to our current understanding of gravity. And then, with a masterfull use of diagrams he gives the reader a taste of the simplicity of the equivalence principle and the need to tack on an additional dimension (time) to the 3-dimensional space of everyday experience. The Pound-Rebka experiment is discussed as one that illustrates the idea of the spacetime interval, and the role of time dilation is discussed via the possibility of practical space travel. And such enthusiasm in his dialog: "the universe will grow ever more exciting", he says, and looking at the developments now taking place in today's science, he is indeed correct.

   Chapter 4 gives a fascinating overview of what the author calls the boomerang, which illustrates the action of curvature on nearby test masses. This thought experiment involves the motion of a spacecraft through an imaginary tunnel through the Earth. The author analyzes the motion from the standpoint of Newtonian physics and general relativity. Curvature as the "grammar of gravity" is the topic of the next chapter, with illustrations of the paths of ants on spaces of zero, positive, and negative curvature. A very intuitive treatment of parallel transport around a closed path on a curved surface is given. The tides are discussed as a natural manifestation of the gravitational influence of the Moon on Earth.

   Must difficult for a layman to understand is how spacetime acts on masive objects, but the author explains it brilliantly in the next chapter, taught via the concept of "momenergy". This entity is a 4-vector, and the author uses it to show how its creation in a spacetime region can be written as the sum of 8 terms, reflecting the fact that the "boundary" of a four-dimensional block in spacetime consists of eight three-dimensional cubes. That the contents of these cubes sum to zero is the famous "boundary of a boundary is zero", which is discussed in the next chapter. This chapter is one of the best explanations ever given (at this level) of the physics behind spacetime curvature and massive objects. The actual mathematical quantification of curvature is detailed in chapters 8 and 9, using elementary mathematics. The author discusses nicely the famous Scharwzschild geometry.

   Concepts of a more concrete nature are discussed in chapter 10, wherein the author discusses the famous Pound-Rebka experiment and planetary motion. This is followed by a discussion of the elusive gravitational waves in chapter 11. Again with a clever use of illustrations, the author explains the transverse property of gravitational waves, and compares gravitational waves with electromagnetic waves. The role of the quadrupole moment in the creation of gravitational waves is brought out briliantly by the author. He discusses briefly various attempts to detect gravitational waves.

   Black holes are the topic of chapter 12, wherein the famous Penrose process for extracting energy from a black hole is discussed, and the "no-hair" theorem for black holes. A neat symbolic representation of the Bekenstein number of a black hole is given. The role of the Hawking process, connection quantum processes with the physics of black holes is briefly discussed. The author ends the book with a look at the expansion of the universe, the missing mass problem, and another very interesting topic that has gained much attention recently: the concept of gravitomagnetism. This is a "weak-field" prediction of general relativity, and predicts that the rotation of the Earth should influence the motion of orbiting satellites. This topic is currently bringing together ideas such as the quantum Zeno effect, Mach's principle, and the notorious "frame dragging" effect in general relativity. Experiments do measure it are currently in play and in the proposal stage, namely the LAGEOS and LAGEOS II experiments, which measure the gravitomagnetic orbital perturbation, which is known as the Lense-Thirring effect.




3. The interrelation of gravity and spacetime is a formidable subject to describe; the author does so with excellence. The diagrams and charts reinforce the understanding.

   Unfortunately when a key subject left me rather clueless, (Boundary of a Boundary) I spent quite a few frustrated hours being uncertain on whether or not to continue reading without the support of the material on those pages. As it turned out, the subject became clearer once I read on and returned again. I never did grasp it as completely as the rest of the book.

   The book contains the most enlightening description of transverse wave propagation I've ever seen. It also helps solidify one's understanding of interval and relativity.

   Not a book to be read overnight.




4. This is a beautiful, poetic, and generous book. I found that after reading and mulling over each section, I could eventually visualize how space was behaving under the influence of mass, and could also see why one needed to choose one's point of view carefully to understand the physics.

   The book is intended as an introduction to general relativity, without much tensor formalism, but it does not neglect the geometrical underpinnings. It presents a very nice way to get at the physics, with creative and light-hearted diagrams.

   I'm not so sure that Wheeler's own poems, which introduce many of the chapters, are a great success, but I admire and salute him for including them. Even his poetry helps to open additional doors to understanding general relativity.

   A book that is truly beautiful.

No comments about On Space and Time.

5 comments about Einstein, Bohr and the Quantum Dilemma: From Quantum Theory to Quantum Information.

1. This book is an excellent introduction, summary of and history of the debate on interpretation of quantum theory, a subject which demands careful reading. As such, it may be read to profit by those interested in some of the twists and turns of "received opinion". It is not for those who might like their pages covered in equations (- the text discusses J S Bell's elucidation of Von Neumann's errors on the subject of hidden variable theories - a clear case where the mathematics concealed rather than revealed). The book is widely referenced which should have enough range of material to satisfy and extend readers at all levels. In my top ten on the subject area.



2. I have found this to be an extremely helpful book due to my interests in physics. It is an interesting philosophical taint on a subject matter which is mostly fought in obscure mathematics. I would highly recommend this book to anyone with an interest in quantum physics philosophies.



3. This is not a textbook; it is a combined history and introduction to modern physics. It is clear, well written and a good starting point for anyone interested in Relativity or Quantum Theory.



4. For students of physics, professional physicists and interested lay persons this is undoubtedly the most complete and objective overview of the many 'interpretations' of quantum mechanics as of today. For those interested in looking "behind the mathematical formalism of QM" an absolute must read.
   
   One minor point of critique though: this book explicitly addresses lay persons (which is supposedly why you won't find many equations in the book). Although in chapters 2 - 4 prof Whitaker splendidly epitomizes the evolution of classical (with a glance at relativity) and quantum mechanics, I fear those readers not already familiar with physics may find this a little too terse (a lot of ground is covered in very few pages). Chapters 5 - 7 explaining the Bohr-Einstein debate and Bell's theorem are simply splendid reading for everyone. Chapter 8, rounding up recent developments, is very comprehensive, but again, the average lay person may find the summaries of quite a number of recent articles a bit tedious in the end (but ideal for students or physicists). Chapter 9 introduces quantum information theory, again a very good overview, but in my opinion a bit out of place and surely a subject that is worthy of a book on its own.
   
   All in all, there are many good popular science books out there explaining one or two QM interpretations, but this one covers them all, and it's absolutely the best explaining the Bohr-Einstein debate and the impact of Bell's theorem on this debate.



5. This is a good book about the Einstein and Bohr debates and doesn't
   delve into complex math but you won't find any great insights into
   things.
   
   
   John

No comments about Classical Field Theory (Dover Books on Physics).

1 comments about Gravitational Waves: Volume 1: Theory and Experiments Volume 1: Theory and Experiments.

1. This text fills a void and will be a standard reference. I am quite happy to see so much great physics of graviational waves assembled coherently in one spot. Both geometrical and field theoretical approaches are given equally thoughful consideration in the theoretical layout (which I am slogging through currently). Recommended for GW researchers and those interesting in GWs.

1 comments about Remarkable Physicists: From Galileo to Yukawa.

1. Of course I understand that Ioan James's intention of writing this book is to give us a more " human " aspect about the physicists and not a work on the theory of physics. I fully agree. However he should at least state
   at least very briefly about the achievement of the great physicist!! Take for an example, in describing Ampere, he does not even mention about the Ampere's law!!! I think at least in describing various physicists, he should at least state briefly about what contribution of those hysicists. Just on sentence about the equation of the laws would make this book far more interesting! Otherwise, just mention the date of birth, when the phyicist went to univerisity, when he married, when he died etc. I would ask, then what make this physicists worthy of a brief biography and separae them from just an ordinary people?????????????????

5 comments about Mass Control: Engineering Human Consciousness.

1. Recently, through amazon.com, I have become aware of a phenomenon called mind-control. After reading about it in "Acid Dreams" by Martin Lee, I knew that the American Government and the CIA coercively tested people with mind-controlling substances such as LSD. I knew of it, but hadn't really thought about it.

   I would come to learn through reading this book (and others) that this phenomenon did not begin in the US, but rather in Nazi Germany during World War II. People placed in concentration camps under the Nazi regime were used for scientific "experiments" by doctors, inclduing the infamous Josef Mengele. After the war, many Nazis escaped to the United States through the help of rich and powerful British and Americans.

   At the height of the cold war, America was in competition with Russia regarding technological advancement. Russian Soviets began testing their people with mind-control techniques. When the American government learned of this, they did everything in their power to be one step ahead of the Soviets and began their own mind-control tests - by, among others, the Nazi scientists who were "invited" to America.

   What were the results of theses tests? Who were the people that were being tested with mind-control? What happened to them? Moreover, are there mind-control tests still being conducted today? By whom? Why? You will find all the answers in this book. And it is shocking and disturbing.

   The purpose of this book is NOT to illicit human emotions, but rather to tell the truth - relying on factual evidence. It is not science fiction; it is reality. And the real world is very scary. The proposed "New World Order" is even scarier. Jim Keith spells it all out thoroughly in each chapter.

   This is a highly informative and well-researched book . I recommend - no, urge YOU to read it. Remember: The truth will set you free. And our freedom is at stake. It's up to each of us to do what we can in order to truly live in the "land of the free."

   Begin with reading this book.




2. Jim Keith meticulously researched this book, ... I challenge anyone who thinks this is a work of "fiction" to come to that conclusion after first visiting the following websites where you can learn a lot of factual information about the MKULTRA program which verifies what Keith is saying: ... Website of John Mecca who is under MKULTRA Mind Control and who is trying hard to warn people. ...That is the website of Advocacy Committee Human Experimentation Survivors- and Mind Control These are people who have suffered the torment of the damned at the hands of the CIA, which is doing the bidding of the Illuminati to set the stage for forcing us into a psychocivilized society with everyone to be put under electronic mind control.Check out this website which shows actual US patents on Mind Control/Behavioral Modification Technology.... and this is only the tip of the iceburg because its the declassified stuff: ...

   Check out this free online book: Blueprint for a Prison Planet- The Plan to Microchip Humanity: ...

   Check out ...Anti NSA Section, last bullet pointed item is a lawsuit of John St.Claire Akwei vs NSA. In it he details NSA's scientific capabilities for doing Remote Neural Monitoring. Akwei is one of thousands of victims of CIA black ops human experimentation.

   Also, I happen to know that Jim Keith was killed for writing this book. He is no longer alive. He was a friend of mine, and what happened to him could happen to me at any time for trying to expose the same things. Sometimes truth is stranger than fiction. The people who gave this book bad reviews are either fools or NSA debunkers who don't want people to read the book.




3. First of all, i wasn't sent out here by the "Illuminati," i couldn't tell you if they really exist or not.
   
   But I will tell you that Jim Keith died because he broke his knee and didn't go to the hospital when it happened, he died of a blood clot during surgery. (...)
   
   Persoanlly, I believe that a few of the things Keith has brought up in this book are correct. I'm sure there is CIA experimenting and other crooked things going on, and i think microchip implants are a bigger threat than people realize. But that does not mean that this should be looked at as a gospel.



4. We are compelled to ... copy and paste almost the whole another's reader review, where I found almost all what we are not only thinking but directly first hand KNOWING, not only as "firm believer" rather as working to "collect proofs" and helping direct victims on this field.
   "To convince me of their point of view by eliciting emotion rather than reason...": how much I think this to be a mighty favour for changing real facts to mere lined up suggestions. "I tend to regard every word that follows with considerable suspicion. I'm querky that way, having learned long ago that emotion is the fastest way to short circuit reason.": thanks Cathy (Oregon, USA) for your words!
   "Agenda?, October 17, 2001
   Reviewer: Cathy (Oregon, USA) - See all my reviews
   ...Hey, I'm a firm believer that the U.S. government lies and performs harmful experiments on it's citizens on a regular basis. We have proof of that, lots of it. That said, when some one attempts to convince me of their point of view by eliciting emotion rather than reason, as Mr. Keith does, I tend to regard every word that follows with considerable suspicion. I'm querky that way, having learned long ago that emotion is the fastest way to short circuit reason.
   Mr. Keith buries us in references and offical sounding partial quotes from important people and important sounding people hoping that we the reader won't notice the constant use of buz words meant to elicit emotion rather than reason. "The Elite", "greed", "world wide conspiracy", the "ruling class", "eminent stuffed shirts". On and on, over and over, emotional buz words meant to illicit the we vs them response, where "we", the reader, are good and "they" are evil. Again, in order to elicit the "oh, my god" from us, he uses phrases such as "may have been a member of", without ever offering any proof of actual membership in this awful organization or "it has been reported", but he never tells us who reported these awful things.
   This book was especially dissapointing for me, because for the most part I agree with the idea that there are "beings" trying to control our thought. As if our "free press" doesn't do a superb job already. I admit that I finally gave up on this book some where around chapter 10. I'd just had it. I suspect that there are truths to be found here, but I was unable to get past Mr. Keith's style to find any. Maybe you can get past this, obviously from some of the previous reviews, some readers don't even notice it. Me, I'm the suspicious type and this book caused me to think that maybe there is LESS, not MORE with respect to the idea of mind control."



5. CIA fundeded psychiatric studies, programs and experiments using mind control and brainwashing. Subliminal messages, mkultra, haarp, LSD experiments, electro-magnetic brainwave manipulation. I'm a little skeptical of the "I was a mind controlled sex slave for world elites" and the satanic ritual abuse claims but other than those all this stuff is documented and checks out pretty well. Its depressing to see just how evil the us government is, but nothing surprises me anymore.

5 comments about The Large, the Small and the Human Mind.

1. Turned off by the strong AI type point of view of consciousness, yet looking for a scientific explanation, I have repeatedly turned to Penrose's work hoping he would have enlightening ideas. At first, he seems to be on the right track, but when he starts making conclusions, things go awry.
   As a biology student, I can say that his understanding of biology seems mediocre at best. And physics may be even worse - in fact his skepticism about the "flatness" of the universe has recently been rendered bascially obsolete.
   I feel that the unified brain quantum undulation camp, if you will (penrose, zohar) paint themselves into a frightful corner. For instance, penrose never explains why his microtubule ideas would apply to the brain in particular...we've got oodles of them in every cell in our body! Basically, these ideas try to strike out against the strong AI poing of view, but actually create a new version of it! It's not the neuron construction, they say, instead it's a mechanism even more arbitrarily linked to the brain!
   Penrose seems to be a great mathematician...and should stick to that. Still searching for explanations...



2. Let me first say something about Roger Penrose. One notices how certain other mathematicians and mathematical physicists speak of him. He is not only admired and respected; it seems that he is positively enjoyed! This may be a bit surprising when one notices that Penrose is something of a thorn in the side of several popular ideas in contemporary physics (and psychology). Cosmic inflation theories and ideas regarding the fundamental nature of quantum uncertainty find a formidable and articulate critic in the Oxford mathematician. Of the somewhat less popular, but ever fanciful "many-worlds" interpretation of quantum superpositioning, Penrose says "[the 'many-worlds' view] is not a very economical description of the Universe but I think things are rather worse than that for the many-worlds description. It is not just its lack of economy that worries me. The main problem is that it does not really solve the problem." He brings the same mental rapier to what he has called "the missing science" of mind and to the idea of computational / artificial intelligence. It is the problem of superpositioning described by Schrodinger and the decoherence caused by quantum measurement that prompt Penrose's search for an 'objective reduction' (OR) of quantum state vectors, the key ingredient in a "revolutionary" physical theory that remains a mystery. He speculates that this physical mystery may be related to the mystery of consciousness. He is unconvincing in this regard, but his ideas and arguments are quite interesting.
   Well, let me now take this a bit further. Penrose also seems to terribly irk certain others! In particular he really raises the hackles of proponents of strong AI and the Dawkins/Dennett camp of 'consciousness-is-merely-mechanism' dogmatists. His views are much closer to those of perhaps most mathematicians and philosophers and stand on a deeper logical footing than do the doctrines that the human mind is mere biology. Let me say that I agree with Penrose in that the 'simple biology' view is never going to win this argument for reasons that can be demonstrated by the application of mathematical logic. To say that Penrose "doesn't understand biology" is to miss the point. The author freely admits, "there is a good deal of speculation in many of these ideas". Of course there is; science is largely -- we might even say wholly -- speculation. A more perceptive analysis would suggest that those committed to a rigid materialistic aesthetic don't understand (don't want to understand) the mathematics. Those who summarily dismiss Penrose do so unwisely. Given his contributions to mathematics (e.g., Penrose tiling, computability, mathematical logic) and his stature within the mathematics community, and given that the history of mathematics is essentially written by mathematicians, Roger Penrose may come to be considered the greatest mathematician of his generation. Given his work on black holes and space-time geometry (he recognizes the apparent "flatness" of the universe but suggests a more elegant geometry to describe that flatness), he may be one of his day's greatest physicists as well. Should his hunch ("OR") one day prove "true", his stature would approach that of a Newton or Einstein. The point being that any scientist who avoids or ignores Penrose's views, or is inclined to dismiss them by erroneously characterizing them, does so, as I say, unwisely.
   Chapters 4, 5, and 6 are challenges to Penrose from A. Shimony, N. Cartwright, and S. Hawking, respectively. Apart from Shimony's discussion of A. N. Whitehead's views, its not on a par with the author's discourses; Cartwright suggests that nature may be a mess of "patchwork" laws (her view itself seems a horrible mess), and Hawking is disappointingly flippant. Penrose certainly meets these challenges.
   I must say that the "controversy" over Penrose's Platonism is nothing less than nonsensical. Hawking complains "basically, he's a Platonist," as though calling him an offensive name and thereby granting the reader cause to disregard Penrose's arguments. That's unfortunate. Most of history's great minds have been Platonists; even Aristotle*, so often cited as the philosophical godfather of reductionism, was arguably a Platonist. Augustine, Kepler, Descartes, Pascal, Newton, Leibniz, Kant, Linnaeus, Einstein*, Schrödinger, Gödel, Whitehead -- the list of Platonists is long and impressive. As Penrose has said, "... it is my direct personal impression that the considerable majority of working mathematicians are at least 'weak' Platonists." Yet it seems as if some who call themselves "positivists" feel a calling to be science's mind-police. I suggest that this should be the real controversy... So-called positivists would do well to honesty consider Gödel's observation that the idea that mind/mentality is simply material is nothing more than the "prejudice of our time."
   There is a rather child-like glee in the way Penrose sees and uses mathematics. His investigations and speculations are those of an extremely astute mind having fun! In his aggressive curiosity, his boldness, his clear-eyed honesty about the frailties of human thought and the limits of science, it seems to me that Penrose is something of a treasure and an inspiration. As he candidly states, "... the world-view that present-day physicists tend to present may well be grossly overstated as to its closeness to completion, or even to its correctness!" This volume presents a concise look at the Penrose ideas/arguments and even if nothing much ever comes of these arguments, they present a shining example of the kind of creative thinking that moves science into new frontiers.
   *(footnote: While recognizing that it can easily be argued that Aristotle and Einstein were not "strong" Platonists, it seems obvious to me that they were each Platonists in some fundamental ways. I consider them to have been "weak" Platonists.)



3. As my background is mainly in the brain sciences, I was most interested in what Penrose had to say about consciousness and the brain in this book, so I'll concentrate mostly on the chapter that had to do with that. This is not to say I didn't enjoy the other chapters, just that I'm not as qualified to critique those as I am the one on the brain. There has been a lot of speculation in recent years about such things as computability and the brain, quantum consciousness, and so on, and I was interested to find out what Penrose might have to say about that.

   One of Penrose's major ideas in this chapter is his demonstration that consciousness, although perhaps mathematical, isn't computable, in the sense that you could program a computer to simulate it. Penrose uses the example of geometric tilings or polyominos that are deterministic in their coverage of the Euclidean plane, but that aren't computable, to show this. Since, as Penrose points out, there are plenty of mathematical concepts that aren't computable and that can't be done on a computer, but that the human mind can understand, Penrose concludes that there is something beyond computability in both pure mathematics and the human brain.

   This is interesting, and Penrose might be right about that. However, I must point out that while consciousness itself may not be computable (and I'm not really prepared to conclude this for sure at this point, because of what I'm about to say), nevertheless, many aspects of the brain's functioning have been shown to be computable, so I'd like to discuss that briefly.

   For example, sensory neurophysiology has been shown to be both quite mathematical and computational as a result of the work of a pioneering mathematician by the name of David Marr 25 years ago, whose ideas revolutionized neurobiology almost overnight, after which the field was never the same. Marr examined a number of different fundamental sensory mechanisms, and showed, for the first time, that the way in which the visual system was processing light information was consistent with the operation of certain sophisticated spatial-frequency filtering transforms that are well-known in many engineering applications. To mention just a few of his important ideas, Marr's demonstrations that retinal receptive-field geometry could be derived by Fourier transformation of spatial-frequency sensitivity data, that edges and contours could be detected by finding zero crossings in the light gradient by taking the Laplacian or second directional derivative, that excitatory and inhibitory receptive fields could be constructed from "DOG" functions (the difference of two Gaussians), and that the visual system used a two-dimensional convolution integral with a Gaussian prefilter as an operator for bandwidth optimization on the retinal light distribution, were more powerful than anything that had been seen up to that time.

   It was as if vision research suddenly acquired its own Newtonian Principia Mathematica, or perhaps General Relativity Theory, in terms of the new explanatory power Marr's theories provided. Basically, in one fell swoop sensory neurobiology also became an area of theoretical physics rather than purely biology, giving the area a rigor and elegance never before seen--an amazing achievement for a young man who died so prematurely from leukemia at the age of 36.

   The main point of all this is that all of these mechanisms are both mathematical and computable, although the way in which they're done in the brain is probably more like how a computer would use numerical analysis to solve a differential equation, rather than using the original equations in a purely analytical way themselves. Since Marr's time, there has been further progress in this area, such as the great Bela Julesz's demonstrations that the visual system can extract and compute binocular disparity cues point-by-point for depth information from abstract, non-representational pictures or textures such as random-dot stereograms, the extension of Marr's ideas about monochromatic edge detection into color edge detection, the mathematical bases of non-linear visual field distortions present in optical illusions, and many other areas.

   Furthermore, in the last few years, the nature of consciousness itself has been shown to be composed of many different separate mechanisms in the brain that are being coordinated in time in order for consciousness to occur. It simply isn't one process or central program that runs in the brain, nor is there a "master" brain center that one can point to where it can be said that consciousness resides. I'm sure the progress of this research will also have implications for ideas about the nature and computability of consciousness.

   So overall, a fascinating and enjoyable discussion about the brain and consciousness by Penrose, even if I don't completely accept one of his major ideas about it for the reasons that I discuss above.




4. Penrose concisely manages to give us an overview about 3 somehow interconnected fields, the mathematically described large-scale world, the deterministic quantum microcosm and the recently emergent mind science. His major aspiration is to see the new generation of scientists erecting a bridge between the quantum world and the always controversial substance of conscience.

   Having in his mind (in a neo-platonic way) the idealistic nature of mathematics that apply to the physical world as a well-justified model, he firstly presents some themes from cosmology and abstract mathematics (e.g. hyperbolic, Riemann geometry), and why, in his opinion, Guth's inflationary universe theory, has weak points (see also Penrose's book- Difficulties with inflationary cosmology) In chapter 2 ,quantum physics related, he gives us interesting examples (the paradox& puzzles reference shows his great sense of humor) and explain us how wavefunction's reduction can assist us to deal with the probabilistic nature of events in this level.
   In the most interesting third one, he is concerned to lay an in-depth foundation between quantum procedures through neurons, so as to explain his main belief - brain function (that creates conscience) can't be simulated through A.I. Even though I tend to prefer J.Searle opinion (presented in his book Mind,Brain & Science) Penrose's points are adequately justified, thus leaving an open window for Free Will.

   In the next three chapters certain Penrose's point's are opposed from Shimony (physician, philosopher) Nancy Cartwright(logician, philosopher) and the renowned Steven Hawking.
   Shimony in a formalistic language, but slightly excessive for the common reader, finally makes a conjecture about a hyperselection law, in order to avoid quantum dualism, while Mrs Cartwright sets a contronversy against the usefulness of a perception that sets Physics the only explanatory science for mind theory and not for example Biology.(which for Penrose is reduced to Physics)
   Hawking denies an indispensable and direct correlation between quantum gravity and the yet inextricable conscience and in chapter 7 Penrose responds to all so as to end this dialectically fair and fruitful discussion.

   Overall this was worth my time, not only for this subject's great interest but because Penrose explains his thesis, clearly and distinctly.The uprising need for 'popular' science is reflected and adequately satisfied through this lucid book which succinctly presents a contemporary overview in a 'hot' scientific field.

   Even non-expert readers (no special background in maths or physics is needed) will be able to follow and admire the ongoing revolution of scientific thought.Given it was written in'97 I'm looking forward and will benevolently embrace another similar work of a splendid thinker such as Penrose




5. I see others have praised this book richly and a couple others poorly. One reviewer said one needed to be a mathematician and a physicist to understand the book. It would certainly help, but Penrose describes enough about the function of the math concepts he invokes so that I can follow him (and even in maths one has to have studied things like those density matrices to really understand in depth). I do understand about computability and problems which have been proven non-computable, and I think he is possibly right, that 'mind', because it shares/crosses the quantum/macro world boundaries, cannot be easily mathematically described without finding a 'bridge' between those worlds. I found his description/hypothesis about the microtubules fascinating (and again I am not a biologist but I am not disturbed that he didn't try to explain or prove his hunch regarding the possible functioning of these structures).
   I appreciated the book for the wonderfully clear style as well as the content.