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.
This is silly. The universe is far too simple to be explained by mathematics.
A *real* god would do it in but a single line of Perl.
I managed to get it a week ago because I work at a bookstore. I'm about halfway through, and so far it's overrated. The demonsrated cellular automata are very cool, but Wolfram constantly confuses similar behavior for causation. After the first 300 pages describing various kinds of CAs, he slips into pure "I suspect" and "Probably" and "Very likely" mode without really explaining why he suspects the things he does. The wildest thing he's stated so far (without any real evidence, just lots of "It is my strong belief") is that space and time are discrete on a very small scale, and are stuctured as a network of nodes. He doesn't (yet) go so far as saying that the universe is actually a simulation running in a computer. Maybe he will later in the book. Most of the rest of it seems to be concerned with the limits of computation.
In his credit, he does make a good argument that much of nature is based on processes analogous to CAs, particularly the growth of plants and pigmentation patterns on animals. But again there's lots of "I believe" and practically no "I've observed."
Looks like he's rediscovered chaos theory - simple input intp simple equations give complex outputs; he thinks he can find the simple input which generates the universe from a chaos producing equation.
The book sounds superficially like David Deutsch's "The Fabric of Reality", which tries to try everything together using a computational theory of reality + the multiverse intrepretation of quantum mechanics.
Deutsch believes that the simulation of something at a deep enough level is entirely equivalent to the real thing -- which is another way of stating this authors belief that reality is just an algorithm. I personally think it's at least as good a metaphysics as anything else I've read...
Websurfing done Right! StumbleUpon
augment your senses: http://sensebridge.net/
-
"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
In related news,
Bill Gates concurred while noting that those four lines of course referenced msie.dll to get the job done.
Four lines?! I don't know where this Wolfram guy was trained, but I can declare the constant 42 in a single line. Well, I suppose that does leave 3 lines for comments. And if anything was worth commenting...
Stephen is an amazing guy, and I'm sure what he's done is something absolutely marvellous. I'm also sure, however, that his attitude will continue to suck for great lengths of time. He's probably one of the most arrogant people on this planet. I think he said it best himself regarding what he thinks people will say about his book:
my opinion of the world at large isn't high enough for me really to be interested in what they have to say
Now, if that's not a bad attitude I don't know what is. I suppose he could be excused though. He's pretty much as close to the stereotype mad scientist recluse as anyone will ever get.
"If you think education is expensive, try ignorance" - Derek Bok
just remove all but 4 cr-lf's (\n)
"The Universe in 4 Lines of Code?"
Do you ever get the feeling there is a bug in one of those lines?
http://www.kubuntu.org/
As PERL is the swiss army chainsaw of computer programming, Mathematica is the swiss army chainsaw of mathematics. The syntax isn't as forgiving as PERL, but it's not bad. Here's a snippit I use for singular value decomposition:
{u, md, v} = svout;
Print["u is ", u//MatrixForm];
I've done the same thing with LAPACK and CLAPACK (scientific programming libraries) and in 3 lines of FORTRAN, C or C++ you haven't even started to define your data. In Mathematica, you're already done.
Then there's visualization. Running on a PC or via XWindows, Mathematica can do stunning graphics -- including interactive graphics -- with almost no coding. It's not entirely flexible (sort of like using SAS or SPSS' graphics routines), but again you can do astoundingly great things with almost no code.
In short, Mathematica is very close, for mathematics, to what PERL is for programming (or insert your favorite programming language or toolkit - but I think PERL fits best). While in the olden days of CGI everyone would have their own copy of cgi-lib.pl, now PERL has this functionality built in -- we just do stuff like do stuff like "my $query = new CGI;". In Mathematica, the language has evolved similarly so that stuff you needed to write lots of code for previously is now abstracted to a few functions. Like PERL's ability to use modules, you can write your own add-ons for Mathematica. Like PERL's POD, Mathematica can be used for documentation (and *was* used to write the Mathematica Book, and presumably Wolfram's new book).
Just a few words about Mathematica. Give it a try, if you're remotely interested in how this stuff works. You'll probably like it!
is that the observable universe is defined by calculus and differential equations in very small areas: planetery motion, for example, or atomic physics.
Phenomena like life, geology and the like are very badly behaved with respect to our standard mathematical tools and we all know this.
Wolfram is suggesting that cellular automata provide a simple framework for examining the phenomena outside of the "magic circle" of the calculus: i.e. most of life and the universe.
Of course, for a long time we've confused hard science with the application of calculus, which has effected what we consider "science" to be: if it is not an equation, we don't think it's scientific.
Well,
1> go talk to some biologists
2> get used to it: equations got us this far, but after this it may be increasingly about computation.
Consider, for example, the Four Color Theorem - the only existing proof of which requires a lot of computer power to grind through cases. Is it a valid proof? Probably - but not to the standards of mathematicians who grew up in the pre-computer age, to whom an exhaustively checked list of cases does not look like mathematics at all.
We'll see how Wolfram's work fares over time, but my bet is that it will fare Quite Well.
Hexayurt - open source refugee shelter,
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.
He got these ideas when one day he found that extremely complex events can be expressed in relatively simple equations. Seeing that complex events can be so reduced, that's where is '4 lines of code' is coming from. He believes that the falling of a raindrop is of equal complexity as the behavior of gases in a nebula - a single equation can predict both.
Maybe it can't be proven, per se, but nothing scientific can be. All scientific theories are that - just theories. None of it should be dogma, for that would violate the principles of science. There's nothing lost if such equations must be considered hypotheses that have yet to be proven wrong.
This isn't meant to create a tidy artificial universe. It's to prove that the real universe can be predicted by simple equations. Whether he succeeds or not - that's the problem. There's no middle ground. Either this will be the waste of a brilliant mind (read his background in the latest Wired) or the greatest revolution in the history of science and a certain Nobel Prize.
________
"And if the fool, or the pig, are of a different opinion...." -- J.S. Mill
This sounds a lot like Ed Fredkin's Digital Mechanics theories. Which isn't surpising, considering that Wolfram and Fredkin used to work together.
He's just trying to sell more copies of Mathematica!
That's not it. Wolfram is saying the exact opposite. He is saying the universe uses very little math. Just a few simple rules. Fancy math is a red herring, in my opinion. It explains nothing. On the contrary, it is our equations that are in dire need of an explanation, from Newton's gravity equation to Einstein's GR/SR equations. They only describe the evolution of matter but do not explain the causal mechanisms.
Real science is about causal mechanisms at the fundamental level where simple rules rule! This is where Wolfram's ideas are revolutionary. They will not be well received in academic circles. Academics hate simplicity because they can't show off with it.
surely you need relativistic mechanics to describe the orbits themselves
As I vaguely recall from a physics course long long ago, Newton's equations are not wrong. There is a derivative term that everyone assumes is a constant, but written as a derivative, which is not constant under relativistic effects. Written properly, Maxwell's equations would be still be valid with relativistic effects. Classical mechanics is just a simplification of relativistic mechanics.
Actually, I think that at least one of those lines will invoke the long processing cycle... I forget the exact number, but wasn't it 10^7 years?
People interested in the concept of the universe
as a digital computer should look at
http://www.digitalphilosophy.org.
Fredkin was thinking about this stuff long before Wolfram was born.
It could also be done in 6 lines of very readable Python code. *ducks*
-
Postulate 1: Knowledge is power
-
Postulate 2: Time is money
-
As every engineer knows, Power = Work/Time
-
Since: Knowledge = Power and Time = Money, then: Knowledge = Work/Money
-
Solving for Money, we get:
-
Money = Work/Knowledge
-
Thus, as knowledge approaches zero, money approaches infinity regardless of work done.
-
Conclusion: The less you know, the more you make (but then you probably knew that already).
There is this addendum"It is a greater offense to steal men's labor, than their clothes"
Wolfram's first CA book (the collection of his papers) is out of print but available for download at http://www.stephenwolfram.com/publications/books/c a-reprint/
That explains why the world is so F'd up: he couldn't read it six months later to debug it
:-p
Table-ized A.I.
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/
I haven't read the book (already ordered it), but I have a bone to pick with it. The first thing that is new about it is that it avoids peer review prior to publication.
We all know that the best way to advance in an area of knowledge is by getting criticism to our new ideas. The reason to do so before publication is that any scientists know how easy it is to fool one self and tries to avoid it, not by asking a few friends to read our stuff, but by asking the biggest experts in the best magazines (or by posting for free in a web site so everybody gets a crack at it).
By failing to follow this procedure Dr. Wolfram has open himself up to criticism that his book is not a scientific enterprise, but a commercial one...
Disclosure: I am a mathematician...
An algorithm is a pure expression of process; it has no meaning with execution and data contexts. Thus, I think Wolfram has gone beyond science into faith and religion... he may answer "how", but that is only part of an entire description of the universe that also asks "why" and "what."
Be that as it may, I am fond of heretics who shake the foundations of science with unorthodoxy. Wolfram is brilliant, if erratic, and I'll read his book simply to have my viewpoints challenged.
All about me
that probably explains why noone really understand the universe then...
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/
That last one is the most problematic. Wolfram says he doesn't expect people to understand him, or to get a negative reaction from the scientific community, and -- worse -- that this negative reaction is only to be expected etc. These are the early hallmarks of the crank.
Things to expect soon: A legion of amateur readers proclaiming him a genius and arguing that the indifferent reaction of mainstream science is somehow evidence that the book is right. Just remember: P(Cranky and Weird | Work of Genius) = High. P(Work of Genius | Cranky and Weird) = Very low.
Why? What is wrong with syntactically significant whitespace? I've heard many people say it's so bad, but nobody has ever told me why it's bad, other than that it's different and therefore they don't like it.