Sunday, July 27, 2008

Programming The Universe, Part One

I have just finished reading the Part One of a remarkable book by Seth Lloyd, a professor of Mechanical Engineering at MIT. The title is Programming the Universe. Although it says "programming" in title, readers, however, do not really need to know how to program before they may understand the content. The book introduces some newest progress on quantum computing in an illuminating way. Despite of the easiness of reading, the book shows compelling mind of the author that may lead advanced readers into deep thinking of the future about not only the computers but also the Web.

Here are a few quotes from the Part One I feel greatly impressed. Moreover, I have made a few comments on each of these quotes. I will post again about the Part Two of the book once I finish reading it. This book is really a great one for anybody who likes to think deep.

Information-processing revolution

"Every information-processing revolution is associated with a new technology---the computer, the book, the brain, DNA. These technologies allow information to be registered and processed according to a set of rules." (pg. 16)

Actually, it is not only a sequence of technology evolution but also a sequence of the evolution of mind presentation. DNA is the basis of biological bodies. Hence it is where mind is based. Human brain is where mind generates, books are where mind embodied externally in physical form, and computer programs are where mind embodied externally in digital form.

The author, however, neglected another important technology related to the information-processing revolution. It is World Wide Web. The Web is more than a computer, and it is more than a large cluster of computers. The difference between information processing through the Web and the information processing through computers is the same as the difference between information processing through computers and information processing through books. On the Web, we are a very different set of rules of information processing from the rules guiding the information process in a personal computer.

Precision and the amount of information

"If you have an infinite number of alternatives, then you have an infinite amount of information, ..." (pg. 21)

In fact, to any question we can distinguish answers from a digital computer or from the nature. What we need to do is continuously asking for more details of the answer. Any digital computer (no matter how powerful it is) has a limit of its computational precision. That is, it may only provide information until certain amount of quantity. By contrast, the nature essentially have no limit on its ability of telling the details.

On the other hand, an ideal quantum computer would be indistinguishable from the nature. If we ask a question to both an ideal quantum computer and to the nature, we cannot distinguish their answers because both of them have the ability of provide infinite details. Ideally, quantum computers support ultimate precision of information description.

Can such a type of quantum computers be truly built? Probably not or otherwise we would have reconstructed the whole universe. But it at least shows the compelling computational power quantum computers may have, which is beyond many of us can imagine.

Meaning of information

"If you don't know how a message is to be interpreted, then you don't know its meaning. ... Meaning is a bit like pornography: you know it when you see it." (pg. 25)

"... for computers, ambiguity is a bug. ... The ambiguity of human language is not a bug, it's a bonus!" (pg. 27)

Meaning is a popular but confusing word that we watch frequently now due to the timely discussion of Semantic Web. In the book, Seth stated his viewpoint: meaning actually does not exist until a message is measured by a pre-specified interpretation procedure. When we agree to a meaning, actually we commit to the procedure of interpretation prior to the coherence of the results of interpretation.

Moreover, Seth pointed out that ambiguity in nature is the basis of variety of the nature. When single digital computers generally prohibit ambiguity, we actually have lost the ability to describe a powerful feature of the natural universe. By Seth, quantum computers may regain this power of computation. Before the age of quantum computing, however, can we, at least partially, implement ambiguity through World Wide Web?

It is hard to answer the previous question. On the other hand, it is almost sure that the current W3C-version Semantic Web is not favorite to ambiguity. Is it a major drawback in the current Semantic Web project according to the vision of quantum computing in the book?

Uncertain and inscrutable aspect of computing

"In fact, it is just when we behave rationally, moving logically, like a computer, from step to step, that our behavior becomes provably unpredictable. Rationality combines with self-reference to make our actions intrinsically paradoxical and uncertain. ... Computers certainly possess the ability to reason and the capacity for self-reference. And just because they do, their actions are intrinsically inscrutable." (pg. 36)

Although I have learned the theory of computation in college, it is still a refreshing of mind for me to read Seth's discussion about the reason of uncertainty existed in computing. Actually, uncertainty in computing is not caused by any irrational statement or illogical derivation. By contrast, uncertainty is a natural existence only if we have self referenced ourselves, which is a legal and normal action in computing. For example, when I have specified a link back to my own blog, in theory Thinking Space is already uncomputable when somebody wants to arbitrarily reason over the site using digital computers.

My question is, however, can the Web solve this basic problem of computation to a new extend if we don't treat the Web as a cluster of digital computers? The difference between the Web and a cluster of digital computers is that the Web is indeed a society of humans plus computers!

Information and energy

"... in the story of universe told in this book, the primary actor in the physical history is information. Ultimately, information and energy play complementary roles in the universe: Energy makes physical systems do things. Information tells them what to do." (pg. 40)

"Entropy is the information contained in a physical system that is invisible to us." (pg. 41)

"Free energy is energy in a highly ordered form associated with a relatively low amount of entropy. ... The relatively small amount of information required to describe this energy makes it available for us: that's why it's called free." (pg. 42-43)

"... it's clear that energy and information (visible and invisible) are the two primary actors in the universal drama. ... Energy is conserved. Information never decreases. ... To do anything requires energy. To specify what is done requires information. Energy and information are by nature (no pun intended) intertwined." (pd. 44)

The discussion between energy and information is an interesting and very informational part of the book.

As we all know, the First Law and Second Law of Thermodynamics are two fundamental laws that describe the universe. In short, the First Law tells that the total amount of energy in any closed system is conserved, and the Second Law tells that the total amount of entropy in any closed system never decreases.

In the book, Seth illuminatingly mapped entropy to information. Since entropy is a measurement of the workable energy in a closed system, entropy is equivalent to information that describes the details of the system. Therefore, the Second Law may be reinterpreted as that the total amount of information in any close system never decreases.

In order to make things be more interesting, let's watch Adam Lindemann's original discussion of Harmonious (Mind) Age and my explanation of the Harmonious Age. Actually, Adam expresses the shift of human society in terms of energy and emphasized that human mind is a new state of energy that may eventually lead to a more harmonious stage of human society. By contrast, I interpreted the same thing using mind in its aspect of information and emphasized that the ever-increasing amount of mind/information in the world must eventually lead to a stage that mind becomes the primary type of asset of human society. By this evolution, humanity would be more respectful in general since the value of individuals will be finally measured by the superiority of their mind in contrast to the amount of land or capital they have occupied.

What a harmony between our discussion and the analysis in Seth's book!

Order from chaos (the butterfly effect)

"Chance is a crucial element of the language of nature. Every roll of the quantum dice injects a few more bits of detail into the world. As these details accumulate, they form the seeds for all the variety of the universe." (pg. 50)

Doing quantum computing is like throwing many dice simultaneously in parallel. We may be sure that one result must be what we expect. But we don't know which one of all the results is the one until it discloses itself. Actually, this is also how the nature performs.

At the same time, I would like to ask whether the Web is, will be, or should be operated in this way too. If we do view the Web to be humans plus computers, probably we may achieve this quality of computation even before the eventual realization of quantum computing.


gljirain said...

Hi, Yihong:
Just a quick thought, it might seems rediculous:
When people's value is evaluated by amount of land or capital they have, the change of this value is possible by working hard, taking new venture, or making rebellions in the worst case. If instead evaluation of mind becomes the frontier, without the buffer of capital or land with which the evaluation is done, for those who has a low score initially, whose mind is not so impressive and isn't possible to change significantly, isn't genocide of the other group with high scores in the 'mind test' the only option left for them?

What did I say...

Good post, Yihong.

Keep going!


John Rodrigues said...

Yihong: Enjoyed your insightful review. There is a thesis in the book that quantum computers simulate the universe that is doing the computation, and each can be analog or digital, therefore programming them is equivalent. An interesting claim is that since building a machine often results in observing new natural laws, machines can actually drive scientific discovery. Thanks.

Yihong Ding said...

Tianlun and John,

Thank you for the comments and I have learned from both of you too. ;-)

Mind, information, energy, quantum computing. All of them are complicated topics and there might not be one "correct" answer to these issues at all. No matter whatever, the book is great and I would like to recommend it to anybody who likes to think.