Customer Reviews

Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos

5 star:		(16)
4 star:		(13)
3 star:		(4)
2 star:		(3)
1 star:		(5)

 

 

Great ideas lead to short papers in peer-reviewed journals. Often, the more prestigious the journal (Science, Nature), the shorter is the paper because of space constraints. Not so good ideas, on the other hand, lead to rambling books. The author is well published and certainly knows this. The premise here is that the universe is a quantum computer. Okay. What is it computing? Seth Lloyd asserts that it is computing itself. From here on the argument becomes circular. The universe is what it is because it is doing what it is doing. Computation is defined in a general way as essentially any kind of atomic change in state. Therefore, interactions (between particles) become synonymous with computation. The problem here is that when you equate something that clearly exists (the universe) with something which in fact really does not (a quantum computer is hypothetical, you cannot go out and buy one) you define the latter in terms most favorable to yourself. So, since an atom flipping states is equivalent to flipping bits, the physical world performs computation. Since the physical world follows quantum laws, it must be a quantum computer. At some point the whole thing becomes an issue of semantics.

The section on quantum computing could have been interesting. That quantum computers would potentially be very powerful we know. That they can simultaneously work on multiple questions is also clear enough. That so far they have done no more than factor the number 15 we might infer from the absence of any publicity. Lloyd points out that they should be able to factor a 400 digit number with ease. While I understand that they would do this by working on multiple problems simultaneously, what I am curious to know is how we would extract the desired answer (i.e. the 200 digit numbers that ARE factors) from all the other answers (i.e. the far more numerous numbers that are NOT factors) from this quantum computer. I am sure there is an answer, but where it matters the author is strangely silent.

In buying this book I naively assumed that computation is a well-defined process that conforms to certain principles. If the universe computes, it must do certain things, but not others. This might be expected to impose new constraints on the behavior of the universe and allow us to make predictions about where it is going and learn where it has been. Unfortunately, computation, as used here, is nothing of the sort. Any interaction becomes a computation and the universe is under no new constraints. It is simply doing what we already know it is doing and the theory gives us nothing new. It is simply another way of looking at the same thing. The underlying thesis could have been stated in a few pages and hardly seems to merit an entire book.

I've always admired the notion (first promulgated by Voltaire?) that the true measure of intelligence is the ability to simultaneously comprehend two mutually contradictory ideas. So I tend to take a mellow approach to ideas that I disagree with. However, this book angered me, not because of its ideas, but because of its serious flaws.

The first serious flaw is that the author cannot keep his ego from seeping into the text. He regales us with triumphant tales of how he confounded his students with deep questions and then nobly revealed the true answers. Sheesh, man, why use the dialog approach using weaklings as your interlocutors? Pit yourself against somebody who can do more than behave as your straight man. Argue with yourself, if you have to! But presenting yourself as the all-knowing professor rubbed my fur the wrong way.

The problem of author vanity permeates the entire book. At no point does the author admit to uncertainty, or present two sides of a case, or even admit that anything he writes is controversial. One gets the strong impression that everything is crystal clear to this author. That impression raises my hackles.

The overwhelming self-assurance of the author explodes in his face when he gets it wrong. In the section "Exorcising Maxwell's Demon" in Chapter 4, he writes:

"The full exorcism of the demon was not accomplished until recently. (I played some part in this ceremony myself.)"

Perhaps Mr. Lloyd is older than I imagine. The exorcism of Maxwell's Demon was accomplished by Leon Brilloun, the physicist who patented the atomic bomb, in a paper published in 1951. Mr. Brilloun does not mention any contribution by Mr. Lloyd. It would appear that Mr. Lloyd is unaware of Mr. Brilloun's paper. Worse, his explanation of the exorcism of Maxwell's Demon is a turgid mess that makes no sense at all. Between claiming credit for another man's achievement and botching the explanation of Maxwell's Demon, I reached the limit of my tolerance. I literally threw the book away from me at that point.

Perhaps the material after Chapter 4 redeems the book; I do not know, because I did not read it.

The other serious flaw in the book is its smarmy vagueness. In attempting to avoid the intimidating reliance on mathematical and technical definitions, Mr. Lloyd resorts to poetic phrasings. These would be acceptable if they weren't so damned cute -- and if they made sense. For example, in attempting to make clear the difference between energy and information he writes, "Energy makes physical systems do things. Information tells them what to do." At first glance, that seems a pithy observation. But go back and read it again; what is the author really saying? Does energy give molecules speed, and information give them direction? Does the energy in an A-bomb make the bang and information tells it what to destroy?

I was disconcerted by the author's fuzziness regarding information. He never defined it -- which is not necessarily a fatal flaw, given that a book for the educated public should not burden its readers with undue technical detail. But he used the term in such a myriad of ways that I started to think that he was using it to refer to any magically powerful force. Information, in this book, seems capable of performing wondrous feats.

Physics is finally coming to terms with the concept of information as a physical concept. The change began after World War II and has been edging forward for fifty years; in the last ten years, progress has accelerated. A clearer concept of information and its relationship to the physical universe is emerging. Mr. Lloyd misses one of the most important factors in this process: that information itself is inextricably bound with the concept of time, in something like the way that mass and energy are bound together, only more complex. It is not information that is the fundamental quantity; it is information flow, or bandwidth.

In Programming the Universe, Seth Lloyd, Professor of Mechanical Engineering at MIT and the designer of the first feasible quantum computer, presents an arresting new paradigm of the cosmos: The universe itself is a giant quantum computer.

Lloyd's hypothesis is that all physical systems register and process information. Life, language, human beings, society, culture--all owe their existence to the intrinsic ability of matter and energy to process information. When systems evolve dynamically in time, asserts Lloyd, they transform and process that information.

"The goal of this book," the author writes, "is to reveal the fundamental role that information plays in the universe. . . . By understanding how the universe computes, we can understand why it is complex."

A critic for Publishers Weekly writes, "[Lloyd's] hypothesis bears important implications for the red-hot evolution-versus-intelligent design debate." It comes as no great surprise that Lloyd, a scientist, comes down on the side of evolution.

"The conventional picture of the universe in terms of physics," writes Lloyd, "is based on the paradigm of the universe of a machine. Contemporary physics is based on the mechanistic paradigm, in which the world is analyzed in terms of its underlying mechanisms; in fact, the mechanistic paradigm is the basis for all of modern science. . . . The primary quantity of interest in the mechanistic paradigm is energy."

In his famous equation, E=mc2, Albert Einstein asserted the fundamental equivalence of matter and energy. But the universe, Lloyd asserts, is more than matter/energy: "This book advocates a new paradigm, an extension of the powerful mechanistic paradigm. I suggest thinking about the world not simply as a machine, but as a machine that processes information. In this paradigm, there are two primary quantities, energy and information, standing on an equal footing and playing off each other."

As a giant quantum computer, the universe possesses the same information processing power as a universal quantum computer, and this quantum-computational power of the universe provides a direct explanation for its intricacy, diversity, and complexity.

What then are the implications of Lloyd's hypothesis for "the red-hot evolution-versus-intelligent design debate"? Lloyd argues that the complexity of the universe evolved from the "simple universe" of the Big Bang, which occurred some 14 billion years ago. How, then, does one explain the universe's present complexity?

Asserting that complexity arose out of simplicity, Lloyd argues that the "intelligent design" (complexity) of the universe is not the work of an Intelligent Designer but is a result of the evolution of the universe itself. The giant quantum computer operates according to the natural principles of physics and then develops and processes its own information.

According to Lloyd, there is no "ghost in the machine," no Intelligent Mind or Spirit that designed the universe. On the contrary, the evolution of the universe occurred according to the actions, interactions, and reactions of its various physical components (atoms, electrons, protons, neurons, photons, quarks, and other subatomic particles). These physical (and chemical and biological)developments were (and are) spurred on to new complex combinations by entropy, gravity, and quantum fluctuations in the fabric of space/time.

The universe is not "a random collocation of atoms"; although one must not ignore Heisenberg's "uncertainty principle," the atoms and subatomic particles largely "behave" according to the universe's internally generated program. There is a duality in the universe, but it is not the duality of Mind vs. matter; it is the duality characteristic of the quantum nature of matter. For example, photons mysteriously behave both as particles and as waves.

"The medieval philosopher William of Occam," writes Lloyd, "was interested in finding the simplest explanation for observed phenomena. Pluralitas non est ponenda sin necessitate, he declared: 'Plurality should not be posited without necessity.' Occam urged us to accept simple explanations for phenomena over complex ones."

Employing Occam's razor, Lloyd rejects the metaphysical (mystical, spiritualistic, and supernatural) claims of Creationists and advocates of so-called intelligent design. The modified mechanistic model of the universe that Lloyd champions is non-theistic, natural, secular, and humanistic.

In some places, Programming the Universe is difficult to understand. Computer gurus and physicists will be better equipped to follow Lloyd's arguments. The main points of his hypothesis, however, are clear, and he often lightens the text with humorous quips and amusing anecdotes.

Roy E. Perry of Nolensville (rperry1778@aol.com) is an advertising copywriter at a Nashville publishing house. He is an amateur philosopher, Civil War buff, lover of classical music, avid chess player, and aficionado of fine literature.

The author says that the universe is a computer because it manipulates matter in an automatic, unthinking way - just like a computer.
But surely this is a circular argument? As the computer works by using the laws of physics, it is a truism to say that the laws of physics themselves constitute a computation. What does this statement actually tell us?
I was hoping that the book would put some flesh on the author's idea, but after reading it I'm still waiting.
At any point in the history of humanity, we have used our most sophisticated knowledge for explanatory purposes. When the most sophisticated machine was a clock, we described the universe as a clockwork machine. Now that the cleverest thing we know is quantum theory, we get books like this.

Basically, there are two kinds of books on science for the general reader. The first and awful kind is written to make the mysteries of science a kind of Gee Whiz experience. The problem is that the explanations are so poor and misleading that the reader is actually further from a proper understanding of what modern science is about than they were before they read the book. The second kind is written by someone who not only has a profound insight into the topic they are sharing with the reader, they also have a special ability for stating things clearly and for making them less mysterious. This very interesting book is of the second kind and I recommend it to anyone who wants to think more clearly about quantum mechanics. Not the fake and misleading kind of popular fiction and the entertainment media, but of the kind that will actually help you understand the fabric of our universe.

While I am no scientist, and I cannot pretend to be able to explain everything in this book to you, I do feel that I have read the best explanations of the two-slit single electron interference pattern demonstration and the concepts of entanglement and decoherence. Seth Lloyd does a fine job of keeping these things understandable for those of us who are interested but clearly lack the proper background to delve into this stuff as he does.

This book would be superb for intelligent young people who are demonstrating a talent for science and engineering. I suspect that this book will results in stimulating a number of brilliant young minds to fine scientific careers. Possibly a few of them will work their way to becoming students of Dr. Lloyd at MIT. I am sure that this will be one of the positive outcomes of this strangely cool book.

I must admit that as I read through the book there was more than one time where my head was swimming, but the author makes his case well and the last two chapters pull everything together in a strong way that invite the reader to further study of this topic. The basic idea of the book is that, and realize that I am likely getting this wrong, as the energy created during the inflationary period of the big bang cooled and precipitated into matter, there was free energy (the stuff we use for "work" and that does things) and entropy. Entropy is a knottier problem than the casual observer might think. Dr. Lloyd says that a portion of entropy is really information. It is the universe processing and describing itself. The author demonstrates this to us in a step-by-step way that provides the reader with at least a sense of understanding. Dr. Lloyd does say at one point that if you don't experience dizziness when thinking about quantum mechanics you aren't trying hard enough (or words to this effect).

Dr. Lloyd demonstrates much of this to us through the notion of quantum computing (designing the first feasible quantum computer is one of the author's accomplishments) and how information is created and processed at the atomic level by manipulating quantum structures through the notion of manipulating qubits.

This is an extension of the mechanistic view of the Universe that has been so popular in physics and engineering for the past few centuries and it should help young people, who think so easily in the language of bits and processing, to build strong intuitions about the quantum reality. These intuitions will allow them to go further and faster than those of us who formed our ideas in the classical model of things. Simply because we find the probabilistic view of matter counterintuitive does limit us, whereas a young person who grows up learning about reality as a probability event will find grasping the realities of quantum mechanics almost natural. This is the real service this book can provide young people and those of us with more antiquated notions of things.

Strongly recommended.

Seth Lloyd thinks really big thoughts. Like, "In addition to matter and energy, can we also think of the universe as being made up of information?"

That puts Lloyd into pretty rare company right there, but there's more; he also has a great way with words and writes with a sense of humor. This book is as heady as anything I've ever read, but Lloyd keeps it understandable and engaging for the layperson.

If this is sounding far better than two stars, it's because we haven't hit the downside yet - the book's structure; there isn't any. It's almost like being in the head of a brilliant quantum physicist starting at one randomly selected point in time and finishing at another randomly selected point in time. The good news is that our time there doesn't start earlier or end later; it really gets that old.

That's too bad, because Lloyd has so much going in his favor. The topic seems to be there, but Lloyd doesn't seem to have decided what the point of the topic is. Will quantum computers be very important and here's what you should know about how they calculate? Is the universe more clearly understood when you look at it as a quantum computer? Is there no God because the Universe as a quantum computer doesn't need one?

All these ideas are there in their nascent stages, but none become a central theme and none get developed to the point where they become really interesting to think about.

Good raw material gone to waste. I'd almost like to see Lloyd start over with a central theme and write it again, because I think there's a REALLY good book (and quite possibly several) in this man's head.

Computations are everywhere. Sure, your modern day laptop computer is doing a lot of computation. But look further and you will find computation everywhere.

In Seth Lloyds book, we are taken on a journey, where we start with the dance of atoms and light. All we need to produce everything we see. Here quantum fluctuations inject information (virtual particles) into empty vacuum for the laws of nature to process (i.e. to compute).

Pretty amazing computation this atomic dance btw. To simulate accurately just a just a tiny fraction of the universe on a classical computer for just a fraction of second - say just a few hundreds atoms for less than a second - would be outside the reach of modern computers. Here we would need something better - a quantum computer.

Actually, according to Seth Lloyd, the universe is indistinguishable from a quantum computer. The universe supports quantum computation and can be efficiently simulated by a quantum computer. Put another way - when two physics systems can simulate each other efficiently - they are logically equivalent. No easy trick though - to simulate the entire universe - in order to it, a quantum computer would need exactly as many qubits as the universe. Talk about Jupitor sized computers.

Still, quantum computers can do stuff that normal classical computers cant do. With Shors factoring algorithm a quantum computer can factor large numbers far more efficiently than a classical computer. And with Grovers search algorithm quantum computers can find things much faster then classical computers etc.

All very well described in the book. So ok, the book gives an insight into computation with atoms in a quantum world. And perhaps this is more than enough for most readers to come to grasps with - Surely, it alone will keep humanity occupied for decades to come. Still, for a book that claims to take on computation in all its glory a lot of stones are left unturned.

E.g. we all know that work is being done on quantum gravity theories. What is computation like here? I suspect that Seth Lloyd wanted to keep the reading "light" and as compact as possible or perhaps he thinks quantum gravity theories will add nothing new to our understanding of computation - but ignoring these questions in the book, whatever his opinion, seems strange.

If there is no efficient algorithm for simulating quantum systems on classical computers. Then - If a quantum computer can't simulate a quantum gravity computer that would highlight yet another huge leap in computing power? And wouldn't the gates of quantum gravity computer work at scales where there is no causality? If a quantum gravity computer can see its result before running its algorithms - it is essential the same as quantum computer strapped to a timemachine. But not a word about such ideas in Seth Lloyds book?

I.e. Quantum gravity does away with cause and effect. In classical computing one thing follows after another. "if" is usually followed by "then". Even quantum computers has this notion of input followed by output. Quantum gravity computers will not be constrained by such considerations. Noone knows how space and time act on the scale of quantum gravity, but there will certainly be no such thing as a fixed sequence of processing steps.

And what about logic in the world of quantum computers?

I.e. Sets are merely the most familiar example of the more general concept of a topos. A topos is a somewhat technical concept. But all topos share one feature, they give rise to their own variety of logic. Sets obey the laws of standard logic and boolean alegebra. For a general topos one would new definitions for AND, OR and NOT operations. Boolean algebra would normally allow a statement to be either true or false. However, this turns out out to be the exception in the world of topos. Normally one find statements to true, false and all shades of grey in between. E.g. in the world of quantum physics - the associated topos might allow a statement to be both true and false and all in between..

This is all only hinted at in lloyds book. One might suspect that he thinks such ideas are above a casual reader. But come on - would a casual reader pick up a book on quantum computations anyway?

And what about the brain - what kind of computations do we have here? If Seth Lloyd thinks that we have nothing but classical computation here - he should have said so. But he gives us nothing here.

A comment about physicists Freeman Dysons remark that mind and intelligence are "woven into the fabric of the universe" would have been appropriate imho.

But ok - quantum computers are only getting started and something like IBMs Blue Gene computer with these 280 trillion calculations per second - the current record - would have been hard to imagine back in 1942, when classical computers got started. So we shouldn't be surprised that not all is crystal clear in the world of quantum computers as we speak.

-Simon

This book has been a true breakthrough for me. Not only it reveals the fundamental role of the "information" concept for a thorough understanding of reality (or the Universe), but also, by following the quantum computing approach, it gives the best, clearest introduction to such a difficult concept as entropy, and to quantum physics. It is simply stunning to see how "qubits" simply wipe away the dust and mist of the traditional way of looking at these matters. It merits 5 stars only for this.

But there's the main thesis of the book: at least since the Greeks there have been two major propositions for what we may call "the principles" of the Universe: on the one hand Mathematics (Pythagoras, Plato) or the more popular dualistic notion of "form" and "stuff" (or matter) as given by Aristotle. The current statement of this dilemma is wonderfully expressed by John Archibald Wheeler's "It from bit". And like before the bet is set by those who lean to one or the other side, i.e to the "it" side or the "bit" side. I think that the beauty, the Occam's razor simplicity of this book in dealing with the fundamental concepts (the laws) of physics is a clear sign that the "bit" party has the advantage now. So, really, we might be ready for a new change of paradigm that will be significant for new development, not only of physics, but of our knowldege of reality as a whole.

As for myself, I've just ordered "Quantum Computing and Quantum Information", the basic text by Nielsen and Chuang. And also "Quantum Aspects of Life" by Abbott, Davies and Pati. This is the "new way" now to explore ...

As if quantum theory wasn't enough to stretch the limits of comprehension, now information theory is emerging and stretching those limits even further.

Black holes acting as incredibly accurate quantum computers? That's just a start. How about the universe itself being a computer?

This is the intriguing assertion of Seth Lloyd in his new book, Programming the Universe: A Quantum Computer Scientist Takes On the Cosmos.

"The Universe is a quantum computer. ...What does the universe compute? It computes itself. The universe computes its own behavior. As soon as the universe began, it began computing."

The idea, in various forms, has been around for awhile. Ed Fredkin has been developing the idea since the 60's. Though his website is a bit technical for the average reader, a superb article by Robert Wright in The Atlantic Monthly captures both the essential ideas and the man himself.

According to his theory of digital physics, information is more fundamental than matter and energy. He believes that atoms, electrons, and quarks consist ultimately of bits--binary units of information, like those that are the currency of computation in a personal computer or a pocket calculator. And he believes that the behavior of those bits, and thus of the entire universe, is governed by a single programming rule. This rule, Fredkin says, is something fairly simple, something vastly less arcane than the mathematical constructs that conventional physicists use to explain the dynamics of physical reality. Yet through ceaseless repetition--by tirelessly taking information it has just transformed and transforming it further--it has generated pervasive complexity. Fredkin calls this rule, with discernible reverence, "the cause and prime mover of everything."

This "prime mover of everything" is a class of computer programs known as cellular automata which were invented by John von Neumann in the 1950s. More recently Stephen Wolfram has explored cellular automata in great detail in his monumental work, A New Kind of Science, in which he sees this form of analysis and understanding as ushering in a new method of doing science. The cellular automaton is a lattice of cells, which can have a finite number of states. These states result from rules which advance in discrete steps and which simultaneously update the lattice. Wolfram explored hundreds of these rules through computer analysis.

So the universe could itself be a process of working out these computational processes according to some rule. And if so, then our picture of the nature of reality changes dramatically:

Fredkin believes that automata will more faithfully mirror reality as they are applied to its more fundamental levels and the rules needed to model the motion of molecules, atoms, electrons, and quarks are uncovered. And he believes that at the most fundamental level (whatever that turns out to be) the automaton will describe the physical world with perfect precision, because at that level the universe is a cellular automaton, in three dimensions--a crystalline lattice of interacting logic units, each one "deciding" zillions of times per second whether it will be off or on at the next point in time. The information thus produced, Fredkin says, is the fabric of reality, the stuff of which matter and energy are made. An electron, in Fredkin's universe, is nothing more than a pattern of information, and an orbiting electron is nothing more than that pattern moving.

This universe is no longer the continuous process that our perceptual system sees. Rather it is a discrete process of events. The physicist John Wheeler entitled an article on this understanding as "It from Bit"-a phrase that has become a popular way of encapsulating the idea.

Back to Seth Lloyd. He is working at this interface of computer science and physics-- what Robert Wright calls the "twilight zone of modern science". He surveys the basic
principles of quantum computing, exploring questions such as: How much information is there in the universe? How much was present at the Big Bang? Can we re-create it on a giant quantum computer? How is information related to entropy? He answers these questions with surprising clarity for ideas that are so foreign to our everyday understanding.

The strength in Lloyd's book is the presentation of the core ideas of quantum computing. Those of a more philosophical bent might have wished for more speculation on the implications of his model. However, he does end his book with a "Personal Note: The Consolation of Information," in which he describes the tragic death of his teacher and friend Heinz Pagels. They were hiking together in the Colorado mountains when Heinz slipped and fell. After the rescue efforts, he was left with trying to make sense of what happened. He concludes his book with this reflection:
Heinz's body and brain are gone. The information his cells processed is wrapped up in the Earth's slow process. He has lost consciousness, thought, and action. But we have not entirely lost him. While he lived, Heinz programmed his own piece of the universe. The resulting computation unfolds in us and around us: the vivid thoughts and outrageous behavior he impressed on us still flourish in our thoughts and behavior and have their own vivid and outrageous consequences. Heinz's piece of the universal computation goes on.

Loving quotes like this: "Feynman conjectured, and I proved, that..." The book is not a physical text nor a work of literature. Something in between, or nothing. I lost interest in the text just after about 50 pages or so.. Although I browsed through the remaining pages. The guy can't write. I did not see any new or interesting ideas in the book either. I do not know what the author was trying to convey. It is obvious that the universe processes information. What's new?