Slashdot Mirror
The Universe in 4 Lines of Code?
serendigital writes "Stephen Wolfram, founder of Wolfram Research and creator of Mathematica has, after 10 years+ finished his book, "A New Kind of Science." In a "Wired" article entitled: The Man Who Cracked The Code to Everything ...," Steven Levy talks about how and why the book was written and more importantly, what it is about. The best part of the article is in this exchange: 'I've got to ask you,' I say. 'How long do you envision this rule of the universe to be?' ... 'I don't know. In Mathematica, for example, perhaps three, four lines of code.'" This book seems a little... nutty. But it's been submitted a bunch of times. If anyone wants to review it, go right ahead.
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"If anyone wants to review it, go right ahead."
Ouch... It'll be a while before any reviews get submitted, Michael -- it's HUGE! (Page 2 of the article: "At 1,280 pages, the book pushes the limit of what can be physically bound between two covers.") Levy talks about it dwarfing (!!!) a phone book... though it would depend on what phone book you're trying to dwarf.Wolfram's demands regarding publishing are interesting -- the book is going to cost $12 to actually produce (5x to 6x that of a "normal" book, though the extra size certainly has to be a factor!), and be priced at $45 -- it includes large quantities of high-rez graphics. Also, it went through alphas and betas, like software -- not versions or revisions as writers are familiar with.
Definitely something I'm going to read... although I doubt I'll achieve full comprehension. The "A New Kind of Science Explorer" software should be fun to play with -- but will I have to wait another 10 years for that?
"...America's great minds of today, teaching America's great minds of tomorrow. Poor bastards." -- A Beautiful Min
Quantum Mechanics has already suggested that both space and time are discrete on small scales, and I believe there is quite a bit of indirect evidence to support this claim. The discreteness is based on Planck's constant, and the unit length and unit time are approx.10^-33 cm and 10^-43 sec respectively (which if you do the math are equivalent if you equate 1 year and one 1 light year). All lengths of space or time are either multiples or one over a multiple of length.
The claim that they are structured as a network of nodes is certainly speculation, but it is at least a logical speculation. The points would probably have to be connected somehow.
As a letter writer to Salon points out, it seems that Wolfram thinks that he's discovered Complexity Theory all by himself. The Salon article certainly gives that impression -- not having read the book, I can't make my own judgment.
The Salon writer writes as if cellular automata were some silly mathematical curiosity (or worse, the writer thinks that CA is recent to computing) that Wolfram "rediscovered" and took seriously for the first time. Of course that's absurd.
The Santa Fe Institute was founded jointly around 1984 by the eminent Nobel Laureate, physicist Murray Gell-Mann, and several others. Stuart Kauffman has researched and written on complexity for many years.
I myself have been following, as a layperson, complexity theory for about fifteen years. In 1991 I had the opportunity to be an undergraduate intern -- an opportunity I didn't follow up on because of my severe academic workload, but an opportunity I will always regret not taking advantage of. Undergraduate intern positions are much more competitive now. This eleven years has made the difference between "bleeding edge" and "cutting edge". Or perhaps complexity theory is even mainstream. I've noticed a burgeoning graduate school interest in complexity studies programs.
Complexity theory intersects many disciplines, and it involves several related ideas such as chaos theory, modeling, self-reference, artificial life, and others. It's evolved into a fairly rigorous discipline, and the more formalized idea of "complex adaptive systems" forms the core. For those who have read Douglas Hofstadter's book, Godel, Escher, Bach, (a very influential book for many of us) published around '82, many of these ideas will be familiar.
Wolfram's quip that seems so risible is really only an overstatement of the central idea of complexity theory: that a limited number of "rules" can give rise to extremely complex behavior. This was the surprise of cellular automata, exemplified by Conway's "Life", invented in 1970. But the underlying idea goes as far back as John von Neumann. Wolfram has done some interesting work in CA. But it sure as hell isn't his idea. For many in the Slashdot community, this is all as familiar as the back of their hands. But apparently there's still a lot of people that should be aware of this stuff that are not.
Finally, many people here would probably be interested to know that SimCity's designer, and Maxis, have had some association with SFI. This makes sense because the emergent behaviors of complex systems are not (as a practical matter) deductively predictable -- their behavior must be studied. The techniques of systems modeling are requisite. SimCity was the general public's first accessible insight into just how fascinating and educational systems modeling can be.
The book
a ms/
http://www.wolframscience.com/
The downloadable code (4 lines, I suppose)
http://www.wolframscience.com/nks/progr
Stephen Wolfram
http://www.stephenwolfram.com/about-sw/
This is silly. The universe is far too simple to be explained by mathematics
Actually the book has more to do with cellular automatons than with mathematics,
although, arguably, you could describe cellular automatons using link theory (which is a theory of structure, logic and math, and Wolfram's automatons are specially well suited for it) and with more classic mathematical tools.
Here is my little biased review (biased because I have a take in that kind of stuff, only more mind related).
I wont reiterate the claims of the book because you can find all sorts of review that do that (oh wait, now that I reread this it appears I'm doing just that later, oh well, still not bad an intro, heh), suffice to say, this book could become the "Bible of Reductionism" for many generations of scientists to come. I do not use the word Bible trivially here, this book is about belief, and that is the biggest problem anybody will have with it. You can agree or disagree with Wolfram as to wether or not the boradness of his conclusions will hold up to scrutiny, but the transfer of those conclusions to to the real world is a completely different step. It is a matter of belief.
If you torture data sufficiently, it will confess to almost anything. (Fred Menger, Emory University Organic Chemist)
Nobody is immune to this mistake, a good part of the field of artificial intelligence research is faulty of the same (I myself do it often, but I don't publish), it is the reason why connectionism as a paradigm was so succesful among the community even if it still has to deliver on some of its most basic promises.
In a nutshell, Wolfram found a set of simple rules for cellular automatons that lead to complex behavior. The second part of his discovery is the principle of computational equivalence, again, summed up, it means that passed a 'threshold' (more or less), two computational processes can be regarded as equally complex. This is a BIG claim, one that will be investigated thoroughly by mathematicians. But the point is that if it holds, you have explained many things : randomess, free will, and you have put in terms that are all but vague what it means for connectionism to cross the threshold of self awareness (in a broad sense).
How, you aks, can he do that with cellular automatons ? Simple once you drop the concept of linear time. What he realized along with many other researchers (and I'll grab the opportunity to pat myself in the back and include myself in that group), is that time is a poorly defined concept today, until you dive into quantum physics when it starts to make sense. What is needed is to redefine causality. Again in a nutshell, classical causality says that an effect always follows a cause, but that is a definition that itself includes time, and since causality is supposed to define the arrow of time, this definition is not acceptable.
The new definition becomes "an effect always has a cause", now you can immediately see that the idea of causal directionality has been removed, but that doesnt mean that time flows backward, just like things didnt start falling up once Newton realized up and down were foolih concepts. Shortly put both future and past exert constraints on a local event (think about Marov states in the future and in the past). When equally balanced, those consraints map to classical quantum physics.
So Wolfram's cellular automatons integrate that concept, you can link events to cells that are in the same discrete time slice as your event. You can link to events in the past, or (like in classical physics), link to events in the future. That itself assumes that time is a discrete phenomenon, it is again a BIG assumption, it is a statement of Wolfram's belief (he uses that word) that time in the physical universe IS indeed discrete, and that thus, his discoveries about causal networks map directly to our world. Lets make it clear here that if he is wrong, then none of these claims map to the physical universe, and the book is just about having fun (a lot of it, tho) with computers and the concept of time (now of course that in itself could be very useful for quantum computing).
And then he goes on to describe how you can then use this stuff to make elemetary particles, or even space-time itself.
All in all this is genius stuff, if not completely revolutionary. I would describe it as the Game of Life meets Link Theory. It is a brilliant reformulation of Link Theory in terms of cellular automatons, and since Link Theory is a bit hard to work on, an easy way to use it with computers is extremely welcomed. For my part, I cannot wait for a version of Mathematica that integrates non-linear time processes. My own neural net models would become that much easy to write as I wouldn't have to deal with C++ journaling memory templates, and once quantum computers are out, I can just run the thing and not wait an arbitrary long time.
But again the flaw is one that we often make, if usually not that publicly: we start to believe in our stuff. Yes, it could work that way, but everything here is the result of a computer experiment, and that is the hard truth of it. It is a beautiful theory, easy to understand, even for the non scientist, but its predictions are minimal, distinguishing it from a physical model of reality in order to test it is going to be a hard task.
Arguably connectionism's biggest problem is that its promises are quite vague, and thus, it is hardly disprovable as a paradigm, and the same problem applies to Wolfram's work, it is very apealing, but things are explained in very tiny details or in broad strokes. There is no equation that will tell you the bigger picture because there is no bigger picture, the world is a soup of events, and as apealing as this might be, as natural as the patterns the simulation generated seems to be, this does not mean that the physical world is actually operating like this.
Even going further, it is worthless as a replacement for 'bigger laws', laws that supervene other laws, gaz propagation can be predicted by such laws, but Wolfram's laws are too tiny, their nature is to lead to chaos and non predictibility, to actually generate the supervenient laws, but again, predictive power is non existant or lower than current science.
But again, this will not prevent many from holding this book quasi religiously, even unknowingly (as many people do today with broad connectionism), because it is simple, elegant, and accounts for a lot, or so it seems (but again, some people think that the pyramids were built by aliens because they think it's simple, elegant, and explains a lot). This book will be about belief, in the next decades and centuries, it will be held as the Bible of Reductionism, because it provides the self consistent argument some philosophers like Dennett needed to explain away consciousness as a pure illusion.
This is my second problem with this book, Wolfram basically says he is presenting us with a theory of everything, but there is not much about perception, qualias, and more generally, the phenomenal aspects of consciousness. Wolfram, as the Priest of Reductionists I think he is going to become, simply leaves the matter out, talking about perception in terms of representational spaces (even if not in quite those terms), but the phenomenal aspect of those spaces is let out, as if we actually were Chalmers' zombies.
To conclude, this will be a delightful read for most slashdoters, at least, all of those with a scientific 'way of life' (no strong backround needed), they will see it as the crystalization of their materialistic views. Religious people might have a problem with this book as it depicts us as automatons, literally.
And then there are people like me, lost between the duality of phenomena and matter and the universe being-causally-closed-sad-state-of-affair. To us, sometimes known as naturalistic dualists (qualia as part of natural laws), the strong deterministic framework that Wolfram imposes seems to point to a strong epiphenomenalism for consciousness, where other theories based on quantum indeterminacy (and quantum theory has been throughly tested for 60+ years) do open possibilities of weak epiphenomenalism. In a few words, I'm not completely convinced by Wolfram's version of free will.
I'm a bit more than two third into the book, reading it quickly at first to grasp the feel of it, and then to read it slowly a second time, so it is possible that some of the things I have said may not be fair, and for this I apologize in advance.
I'm loving every part of it, and if you feel my remarks are too harsh, just assume that I'm jealous I didn't write it. If anything this will make mentioning reverse causation much easier in academia without being laughed at, and Link Theory is going to get a huge boost. Having made 4 computer languages already, I plan to have my fifth be able to run reverse causation in typical link theory problems or simulate my causal backpropagation neural network model. If I can use some of Wolfram's formalism to help this task and if he has cleared up the mess with causality, or helped people make the distinction between predictability and determinism for the rest of us too, then I'll be eternally grateful.
lone, dfx.
http://www.causaergsum.net/