Daniel Dennett's excellent book Consciousness Explained extracts a very funny cartoon from Scientific American, in which two professors stare at a blackboard showing a formula full of complex algebra. In the middle of the formula appears the sentence, "THEN A MIRACLE OCCURS". One professor points to the statement and says to the other, "I think you should be more explicit here in step two."

Roger Penrose isn't just any old boffin: he is the Emeritus Rouse Ball Professor of Mathematics at Oxford University and has been knighted for his services to Science. The Emperor's New Mind is his attempt to crack that perennial philosophical chestnut, the Consciousness/Artificial Intelligence problem. Penrose's view is that Strong AI is simply wrong and that a computer could never replicate (functionally or actually) what we know as "consciousness".

Right. Take a deep breath here. For it's a scary thing for a mere mortal (with a decidedly ordinary bachelor's degree in the humanities) to say something like this about the one of the cleverest men on the planet, but I can't see any way around it: In this book Roger Penrose completely, totally, misses the point. Insofar as it's considered an entry on the Consciousness/AI debate, The Emperor's New Mind - all 583 pages of it - is all but worthless.

There. I said it.

Then again, nearly 500 of those pages don't even purport to be about consciousness, so perhaps all is not lost. Instead, they contain an extremely dense, at times fascinating, but uniformly (and I use the word deliberately) dazzling overview of the more esoteric parts of modern mathematics, physics and cosmology. While Penrose thinks it is necessary background, it isn't - it amounts to an extremely long winded appeal to authority:
One is left with the firm impression that the Rouse Ball Professor of Mathematics at Oxford University is a very, very smart chap, and that one really ought to see that what ever he says goes. This is no small irony, given the title of his book. For if anyone is holding himself out as being a tailor purveying a cloth that only the cleverest people can see, it's Roger Penrose.

Here's where I think he goes wrong. Firstly, his attempt to undermine the AI position is founded on purely mathematical reasoning. Pure mathematics is a closed logical system. Its truths aren't falsifiable, so by themselves have no explanatory force. Mathematical statements (such as "1+1=2") are necessarily true for all time and all universes so, ipso facto, they can't - by themselves - tell us anything about any particular universe. Yet that is just what Penrose asks them to do. He invokes Gödel's theorem of undecidability, perhaps to counter the argument I have just made, but it isn't convincing - being logically unable to prove all truths in a particular set (even though you know they are true) is very different from being able to falsify them. Without that power, you have no explanatory traction in the outside world. Penrose's entire attack on Strong AI is based on an unfalsifiable, and therefore non-content carrying, argument.

Another error is to assume an algorithm must have been designed for the purpose for which it is used, and must work perfectly to be of any use. Natural selection illustrates that this is simply not the case. An algorithm may have a number of useful unintended by-products, and an algorithm can be extremely useful even when we know it to be completely misconceived at every level: take Newtonian mechanics as a good example. We've known for a century it isn't correct but in most practical circumstances it works fine.

Which brings me to my next point: for all the learning Penrose includes on Mandelbrot sets, phase space, entropy and Hawking Radiation, The Emperor's New Mind is conspicuous for what it leaves out: The bibliography contains no reference to Karl Popper nor the general philosophy of science - which might have helped him on the issue of falsifiability - nor crucially to a number of writers who have been very influential on the modern mind/AI question: Daniel Dennett is barely mentioned (Dennett's writing probably represents the "forefront" of the consciousness debate), nor is Richard Dawkins well-referenced, despite having written compellingly (and, being a zoologist, with a great deal more expertise) on the question of algorithms in natural selection. Indeed, Penrose doesn't clearly present the arguments of any particular supporter of strong AI, but rather chooses to generalise loosely as if he is convinced his mathematical deductions can carry the day, and that AI doesn't present a significant challenge. Douglas Hofstadter is given a little space, and John Searle and his largely discredited Chinese Room Experiment a fair space, but other than that the only philosopher Penrose seems to be aware of is Plato.

Another thinker Penrose doesn't seem familiar with is William of Occam. Instead of doing some background reading (and applying a little common sense), Penrose has launched a theory which (as he proudly proclaims) takes us to the ends of time and the universe and back to the smallest subatomic particles to explain (in ways he freely admits he doesn't understand) an everyday, prosaic (but still extremely hard to grasp) phenomenon. In its interstellar journey Penrose's theory drifts very close to dualism, and close (but not quite so close, perhaps) to positing (or needing) some sort of God to work. That will give succour in some quarters, but not the ones Penrose has in mind, I suspect.

Occam's Razor would require that such untestable and speculative suppositions be rejected unless no other explanation is available. Penrose would protest there are none; Dennett, Dawkins, Hofstadter and their colleagues and adherents (including me) would beg to differ, and point to a lot of literature that Penrose hasn't read. In any case one would think that Penrose's own intuition (which he claims helps him to see truth despite Gödel undecidability!) ought to help him see his theory is, as Jeremy Bentham would say, "nonsense on stilts".

Ultimately, when Penrose says "quantum theory explains consciousness" he is really saying no more than "something magic happens!" or even "THEN A MIRACLE OCCURS".

Mr Penrose, I think you should be more explicit here in step two. ( )

I think the main aim of this book is to argue that consciousness is not just produced by a computer like mechanism, using just algorithms, but instead using something more complicated. It goes into topics like quantum mechanics to try and find examples of non computable things which could perhaps be playing a part in the way the mind can do things which a computer cannot.
The book is quite heavy on the maths and physics, so anyone without any familiarity would probably struggle, though would probably not be reading this book anyway. I found some of it hard going, but it was easy enough to get the general gist of the various things he goes at length to explain, and their relevance, without having to get your head around every complicated equation.
I think that some of his theories are enticing, and altogether this was a good read, but perhaps could have benefited from a more decisive outcome. But due to the nature of this subject, it probably wasn't possible for the author to make the conclusion much more satisfying, so it is understandable it was left as it is. I'm definitely going to seek out the sequel though, hopefully for a better insight into his theories of consciousness. ( )

Arguing against artificial intelligence, and exploring the mystery of the mind and consciousness, Roger Penrose takes the reader on the most engaging and creative tour of modern physics, cosmology, mathematics and philosophy that has ever been written.

I could not possibly finish this infuriating book. ( )

Quite interesting, gets rather heavy and over detailed in places. Less contentious than his later books. Haven't finished it! ( )