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

3.83  ·  Rating Details  ·  705 Ratings  ·  39 Reviews
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 ...more
Paperback, 480 pages
Published August 22nd 1996 by Oxford University Press, USA (first published 1994)
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Aug 08, 2015 Ahmad rated it it was amazing  ·  review of another edition
Shelves: science
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 ...more
Alex Zakharov
Jun 24, 2014 Alex Zakharov rated it it was amazing
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 ...more
Jan 04, 2015 Rajith added it
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
Kerem Cankocak
May 12, 2016 Kerem Cankocak rated it it was amazing  ·  review of another edition
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.
Rian (͡° ͜ʖ ͡°) 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 ...more
Todd 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
Ravi 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
Andreas K.
Nov 13, 2014 Andreas K. rated it liked it
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
George Hohbach
Feb 21, 2016 George Hohbach rated it really liked it
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
A De
Dec 07, 2014 A De rated it it was amazing
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 ...more
Ben Phillips
May 24, 2009 Ben Phillips rated it it was ok
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
Jason Hoskins
Dec 07, 2011 Jason Hoskins rated it it was amazing
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 ...more
Sep 23, 2012 Ronen rated it really liked it
Shelves: science, philosophy
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
Don Rea
Jun 02, 2007 Don Rea rated it it was amazing
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
Dr. Marco
Sep 06, 2015 Dr. Marco rated it it was amazing
Recommends it for: Everybody
Recommended to Dr. by: A Friend
This book is substantially better written than Dr. Penrose's first
book on the subject of consciousness and artificial intelligence.
I would recommend this book to anyone that wants to understand the
limitations of mechanized intelligence vs the power of the human
Ian Murray-Watson
Apr 16, 2015 Ian Murray-Watson rated it really liked it
Great as far as it goes. Like many scientists - though it would be more accurate to say like most people - Penrose has his blind spots and prejudices. Someimtes you wonder why they refuse to see what's in front of their noses (cf. Hidden in Plain Sight)
R.J. O'Connor
May 22, 2014 R.J. O'Connor rated it really liked it
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.
Iliyan Bobev
Mar 01, 2015 Iliyan Bobev rated it liked it  ·  review of another edition
Shelves: pop-sci
I liked Emperor's new Mind better. This one has more narrow scope. There is a lot of repetition of the core idea, apart from few intriguing ones towards the end.
May 16, 2014 Ant rated it it was amazing
Shelves: science
It's one of those books that makes things clear in your mind in a way that stays with you. Penrose is the man.
Unnikrishnan Rajan
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.
Aug 27, 2012 David rated it it was ok
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.
Ahmed Xahabi
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.
Dec 23, 2015 Jaza42 rated it did not like it  ·  review of another edition
I could write a long review about why I think this book have little to no credibility in its claims, but I'll just quote a footnote:

"As an outsider to the subject of neuroanatomy..."

Enough said.
Rob Springer
Sep 05, 2009 Rob Springer rated it liked it
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.

Nov 07, 2008 Michael rated it really liked it  ·  review of another edition
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.
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!
Sep 02, 2010 Ronny rated it liked it
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...
Bradley Hughes
Jul 03, 2011 Bradley Hughes rated it really liked it
Great book, but pretty freakin' confusing (at least as I remember it.. this was a long time ago). As I recall, most of Penrose's ideas on weak and strong AIs have been rejected by the research community.. but his exposition is good, and his work is always thought provoking.
Aug 15, 2013 Laurent rated it really liked it
Continuation of The Emperor New Mind but more focused on specific and in my sense less relevant details. If I had to choose between the two, I would pick The Emperor... over this book; which is somewhat redundant.
Dec 07, 2007 Bria rated it really liked it  ·  review of another edition
I learned Godel's Incompleteness Theorem from this book, and it came to the exact opposite conclusion using it that a book on a similar topic came to using the theorem some 20 years earlier. Go figure.
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Sir Roger Penrose OM FRS is an English mathematical physicist and Emeritus Rouse Ball Professor of Mathematics at the Mathematical Institute, University of Oxford and Emeritus Fellow of Wadham College. He has received a number of prizes and awards, including the 1988 Wolf Prize for physics which he shared with Stephen Hawking for their contribution to our understanding of the universe. He is renow ...more
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