Posted on 09/04/2002 11:23:46 AM PDT by betty boop
Stephen Wolfram on Natural Selection
Excerpts from A New Kind of Science, ©2002, Stephen Wolfram, LLC
The basic notion that organisms tend to evolve to achieve a maximum fitness has certainly in the past been very useful in providing a general framework for understanding the historical progression of species, and in yielding specific explanations for various fairly simple properties of particular species.
But in present-day thinking about biology the notion has tended to be taken to an extreme, so that especially among those not in daily contact with detailed data on biological systems it has come to be assumed that essentially every feature of every organism can be explained on the basis of it somehow maximizing the fitness of the organism.
It is certainly recognized that some aspects of current organisms are in effect holdovers from earlier stages in biological evolution. And there is also increasing awareness that the actual process of growth and development within an individual organism can make it easier or more difficult for particular kinds of structures to occur.
But beyond this there is a surprisingly universal conviction that any significant property that one sees in any organism must be there because it in essence serves a purpose in maximizing the fitness of the organism.
Often it is at first quite unclear what this purpose might be, but at least in fairly simple cases, some kind of hypothesis can usually be constructed. And having settled on a supposed purpose it often seems quite marvelous how ingenious biology has been in finding a solution that achieves that purpose….
But it is my strong suspicion that such purposes in fact have very little to do with the real reasons that these particular features exist. For instead…what I believe is that these features actually arise in essence just because they are easy to produce with fairly simple programs. And indeed as one looks at more and more complex features of biological organisms ¯ notably texture and pigmentation patterns ¯ it becomes increasingly difficult to find any credible purpose at all that would be served by the details of what one sees.
In the past, the idea of optimization for some sophisticated purpose seemed to be the only conceivable explanation for the level of complexity that is seen in many biological systems. But with the discovery…that it takes only a simple program to produce behavior of great complexity [for example, Wolfram’s Rule 110 cellular automaton ¯ a very simple program with two-color, nearest neighbor rules], a quite different ¯ and ultimately much more predictive ¯ kind of explanation immediately becomes possible.
In the course of biological evolution random mutations will in effect cause a whole sequence of programs to be tried…. Some programs will presumably lead to organisms that are more successful than others, and natural selection will cause these programs eventually to dominate. But in most cases I strongly suspect that it is comparatively coarse features that tend to determine the success of an organism ¯ not all the details of any complex behavior that may occur….
On the basis of traditional biological thinking one would tend to assume that whatever complexity one saw must in the end be carefully crafted to satisfy some elaborate set of constraints. But what I believe instead is that the vast majority of the complexity we see in biological systems actually has its origin in the purely abstract fact that among randomly chosen programs many give rise to complex behavior….
So how can one tell if this is really the case?
One circumstantial piece of evidence is that one already sees considerable complexity even in very early fossil organisms. Over the course of the past billion or so years, more and more organs and other devices have appeared. But the most obvious outward signs of complexity, manifest for example in textures and other morphological features, seem to have already been present even from very early times.
And indeed there is every indication that the level of complexity of individual parts of organisms has not changed much in at least several hundred million years. So this suggests that somehow the complexity we see must arise from some straightforward and general mechanism ¯ and not, for example, from a mechanism that relies on elaborate refinement through a long process of biological evolution….
…[W]hile natural selection is often touted as a force of almost arbitrary power, I have increasingly come to believe that in fact its power is remarkably limited. And indeed, what I suspect is that in the end natural selection can only operate in a meaningful way on systems or parts of systems whose behavior is in some sense quite simple.
If a particular part of an organism always grows, say, in a simple straight line, then it is fairly easy to imagine that natural selection could succeed in picking out the optimal length for any given environment. But what if an organism can grow in a more complex way…? My strong suspicion is that in such a case natural selection will normally be able to achieve very little.
There are several reasons for this, all somewhat related.
First, with more complex behavior, there are typically a huge number of possible variations, and in a realistic population of organisms it becomes infeasible for any significant fraction of these variations to be explored.
Second, complex behavior inevitably involves many elaborate details, and since different ones of these details may happen to be the deciding factors in the fates of individual organisms, it becomes very difficult for natural selection to act in a consistent and definitive way.
Third, whenever the overall behavior of a system is more complex than its underlying program, almost any mutation in the program will lead to a whole collection of detailed changes in the behavior, so that natural selection has no opportunity to pick out changes which are beneficial from those which are not.
Fourth, if random mutations can only, say, increase or decrease a length, then even if one mutation goes in the wrong direction, it is easy for another mutation to recover by going in the opposite direction. But if there are in effect many possible directions, it becomes much more difficult to recover from missteps, and to exhibit any form of systematic convergence.
And finally…for anything beyond the very simplest forms of behavior, iterative random searches rapidly tend to get stuck, and make at best excruciatingly slow progress towards any kind of global optimum….
It has often been claimed that natural selection is what makes systems in biology able to exhibit so much more complexity than systems that we explicitly construct in engineering. But my strong suspicion is that in fact the main effect of natural selection is almost exactly the opposite: it tends to make biological systems avoid complexity, and to be more like systems in engineering.
When one does engineering, one normally operates under the constraint that the systems one builds must behave in a way that is readily predictable and understandable. And in order to achieve this one typically limits oneself to constructing systems out of fairly small numbers of components whose behavior and interactions are somehow simple.
But systems in nature need not in general operate under the constraint that their behavior should be predictable and understandable. And what this means is that in a sense they can use any number of components of any kind ¯ with the result…that the behavior they produce can often be highly complex.
However, if natural selection is to be successful at systematically molding the properties of a system then once again there are limitations on the kinds of components that the system can have. And indeed, it seems that what is needed are components that behave in simple and somewhat independent ways ¯ much as in traditional engineering.
At some level it is not surprising that there should be an analogy between engineering and natural selection. For both cases can be viewed as trying to create systems that will achieve or optimize some goal….
…[I]n the end, therefore, what I conclude is that many of the most obvious features of complexity in biological organisms arise in a sense not because of natural selection, but rather in spite of it.
One wag described it as the costliest vanity book ever.
But what I believe instead is that the vast majority of the complexity we see in biological systems actually has its origin in the purely abstract fact that among randomly chosen programs many give rise to complex behavior….I suspect Wolfram has just independently discovered neutral mutations and is needlessly agog. But then I read things like,
Third, whenever the overall behavior of a system is more complex than its underlying program, almost any mutation in the program will lead to a whole collection of detailed changes in the behavior, so that natural selection has no opportunity to pick out changes which are beneficial from those which are not.and think that Wolfram does not appreciate the way in which natural selection sculpts a population. Although of course the genetic composition of a population changes under selection pressure, individual genes are not often directly selected in or out. Individual organisms are.
In sexual species, just about every organism is genetically unique. A species is a swarm of similar genomes. A species under pressure to change its adaptation is being sculpted by selection in that those best able to get along in a new way are the most likely to make it. The pruning is continuous so long as the selection pressures stay the same. It's done at the organism level. Nothing is operating at the level where Wolfram is imagining the difficulty.
Probably true.
He is a mathematician looking at how complexity arises from simple computer programs.
I know you can draw very nice mountains with fractals, but that doesn't exactly mean that mountians come from computer algorithms.
He treats with and disposes of chaos at about page 100.
He treats with and disposes of fractals by page 30.
Stephen Wolfram is a well-known scientist and the creator of Mathematica. He is widely regarded as one of the world's most original scientists, as well as an important innovator in computing and software technology.
Born in London in 1959, Wolfram was educated at Eton, Oxford, and Caltech. He published his first scientific paper at the age of 15, and had received his Ph.D. in theoretical physics from Caltech by the age of 20. Wolfram's early scientific work was mainly in high-energy physics, quantum field theory, and cosmology, and included several now-classic results. Having started to use computers in 1973, Wolfram rapidly became a leader in the emerging field of scientific computing, and in 1979 he began the construction of SMP--the first modern computer algebra system--which he released commercially in 1981.
Exactly! This could be the key. Or maybe not. Checking it out, though.
The best I have found thus far is a consortium that I have been following for years. The group continues to grow and develop their theory in various disciplines.
So here is my first candidate(s) for you: Space-Time-Matter Consortium
I may also end up dismissing the book as trivial. But not yet.
It sure does shake up one’s paradigms, Lysander. But that’s essentially what Wolfram is trying to do with this book. As he puts it, he wants traditional mathematicians and scientists to “retrain their intuition.” He apparently believes that certain basic assumptions of the sciences are incorrect. A particularly famous one is the assumption that complex behavior must have complex causes. He repeatedly shows that this is untrue by modeling all kinds of systems, natural, physical, mathematical. And what he has discovered is that apparently random, extraordinarily complex behavior can be generated by the evolution of very simple rules. His piece de resistence is the Principle of Computational Equivalence, which holds that a fundamental unity exists across a vast range of systems and processes in nature and elsewhere; and that despite all their differences in detail, every system that is not obviously simple can be viewed as corresponding to a computation that is ultimately equivalent in its sophistication. Two important corollaries are universality and computational irreducibility. The presence of the latter ultimately means that there are limits to human knowledge and to human thinking itself that are quite likely impossible to overcome. Which sounds like something a philosopher might say, but it’s certainly not what we expect to hear from a scientist….
But then again, maybe he’s just been looking at computer screens too long: The systems he models are executed as computer graphics, whose behavior can be analyzed just by looking. He’s looked at millions of them over the past 20 years. It’s simply uncanny how often particular sorts of patterns can be seen in the evolution of widely disparate systems.
Anyhoot, there’s a lot of “food for thought” in this book. I'll be working through its implications for some time to come, I'm sure.
The universe as a whole seems to have done that since the time we can see in the cosmic microwave background. At the time it contained a thin gas of hydrogen, helium, and a little lithium. And the laws of physics.
His piece de resistence is the Principle of Computational Equivalence, which holds that a fundamental unity exists across a vast range of systems and processes in nature and elsewhere; and that despite all their differences in detail, every system that is not obviously simple can be viewed as corresponding to a computation that is ultimately equivalent in its sophistication.
There are already known limited examples of that, too. Lots of relationships in physics involve inverse-square laws. The equations of electrostatics turn out to apply to a lot of seemingly unrelated problems. I'm told there are here are other examples. But I'm not sure if it goes as far as Wolfram suggests, or if that's exactly what he's talking about.
I agree. Complexity right now is too complicated.
I do. I largely agree. I don't agree with Wolfram's pretense that these ideas are new. They are culled from the biology literature.
The Evolutionists, and here Wolfram, are fond of speaking as though "natural selection" were some sort of motive intelligence driving perceived evolution toward some unknown end, even while admitting that nature, inclusive of the creatures populating it, can compose little more than a passive context and therefore must be largely undirective. I guess I would say that there is an imputation of activeness and directedness to "natural selection" by "scientific" thinkers and writers to which I object. It has not been shown. Wolfram seems to some extent to agree.
Wolfram also easily adopts the notion that mutation is or can be an effective mechanism of positive change or growth in complexity. Mutation operates like a rifle shot through intricate electronic machinery and I think it highly doubtful that positive change can occur in this fashion, even given an almost unlimited timeframe. Multiple rifle shots, to me, add up to massive damage and little else.
But he clearly is thinking "outside the box" and that's a good beginning in my opinion. Truly "outside the box" thinking would assume that consciousness came first.
Hmmmm .... sounds a bit like a twist on Penrose's The Emperor's New Mind (a good review) - Roger Penrose argues against the viability of artificial intelligence. In Chapter 10, "The non-algorithmic nature of mathematical insight" he argues that by consciousness, people have insight into mathematical truth.
I have yet to read the book. Judging by the above prose, it looks like it might be rough sledding, although I'm always happy to see somebody get a dig in on "random" natural selection.
What I really want to know, and what I haven't heard any of his peers yet weigh in on, is: Does he offer anything new?
Did you enjoy the book, BB?
Hello beckett! Does Wolfram offer anything new? I’m hardly the person to ask that question, for I don’t have a background in either mathematics or the sciences, and so am not steeped in the relevant literature. One of the reasons I wanted to read this book was to try to correct this problem!
The sense I get from reading it, however, is that Wolfram is not trying to promote new, developed theories that attack thorny problems in math and science, or that strike down existing theories wholesale, but rather is trying to show us a new way of seeing things, of imagining alternative concepts and methods so that heretofore intransigent problems can be attacked from a new perspective. He tells us throughout that this “new science” is in its very early stages; so he’s merely pointing out the new direction, and bidding us to Go Look! for ourselves. Generally what he does is to indicate what he sees as potential shortcomings or inconsistencies of existing methods, and making suggestions on how math and science could perhaps advance by "retraining the intuition" and trying out some new things.
I gather what is really new here is that he’s essentially applying the concepts and techniques in computer modeling to other fields. I can see how this guy could look pretty “pasty” and nervous – he’s said to have been a “night owl” for the past 20 years, looking at millions of graphical “pictures,” doing his programming, trying to design ways to make his cellular automata emulate other dynamic systems, etc., etc. I think perhaps in his own mind he believes that certain universal cellular automata could be modified and/or reconfigured in a way that would make them useful as a kind of “master decryption key” to unlock the secrets of the universe that so far have been withheld from human understanding.
Whether or not this sort of thing will work in the end, neither he nor we know for sure at this point. But I can see this effort as conceivably proving to be an enormously useful exercise. For by studying the behavior of systems just as systems -- that is, without reference to the details of particular systems -- perhaps new insights can be gleaned with very broad applications to systems generally. This sounds eminently reasonable to me.
Speaking from the background I do have (philosophy), I’d say this book is enormously valuable as a work in epistemology. He tries to avoid engaging issues of metaphysics, mostly successfully, sticking to the rationalist approach of modern science.
But this book, if its theories and methods hold, has extraordinary implications for cosmology. Wolfram acknowledges that he “believes that every feature of our universe does indeed come from an ultimate discrete model.” He is as aware as any of us, however, that he himself has not yet found it, and that it may not even be possible for it to be found with empirical methods. Further, he acknowledges there may be limits to the sorts of things he’s doing in this book, for he says, in the Endnotes for Chapter 8: “Implications for Everyday Systems,”
“In the early chapters of this book what I have said can mostly be said with absolute certainty, since it is based on observations about the behavior of purely abstract systems that I have explicitly constructed. But in this chapter, I study actual systems that exist in nature, and as a result, most of what I say cannot be said with any absolute certainty, but instead must involve a significant component of hypothesis. For I no longer control the basic rules of the systems I am studying, and instead I must just try to deduce these rules from observation – with the potential that despite my best efforts my deductions could simply be incorrect.” [Itals added.]
In a certain way, this passage evokes Eric Voegelin for me….
It may be said, perhaps, the Wolfram engages in a certain amount of “proselytizing” and/or self-promotion. But the guy’s no megalomaniac, IMHO.
Truly I liked -- like -- this book. I find the Endnotes particularly fascinating. I just keep dipping into them, for the panoramic view of the history of human knowledge that they provide, especially in the fields of math and science; but Wolfram treats perennial philosophical problems, as well. He goes back to the ancient world, then brings you “up-to-date” on current issues/problems in, say, quantum field theory….
Pretty heady, amazing stuff! We’ll have to wait for his scientific peers to weigh in (assuming he has any! :^) ), and I expect that will take time. Wolfram is a pioneer. Perhaps others will follow him where he’s gone to, in due course. All my best – bb.
It's going to be a while. Active scientists and mathematicians wouldn't have had the time to slog through this book and find the inspired nuggets as yet. All the reviews I have seen so far indicate superficial reading by the critic.
Except yours. You seem to be in synch with Wolfram. Do you know him personally or . . . are you actually Wolfram in person?
LOL, RightWhale!!! No, and No!
Perhaps I'm just naturally sympathetic to him. In the first place, I don't have an "ox" for him to "gore" -- meaning, being a non-scientist, there's no way that I could react to him defensively, which I might do if I were a scientist, and my pet theory was coming under seeming attack. I'm just trying to understand what the man is saying, and just find statements like the following one exciting and intriguing (which is relevant to your Reply #35 on this thread):
"Present-day physics almost always assumes that space is a perfect continuum, in which objects can be placed at absolutely any position. But one can certainly imagine that space could work very differently....
"In our everyday experience space nevertheless appears to be continuous. But then so, for example, do fluids like air and water. And yet in the case of fluids we know that at an underlying level they are composed of discrete molecules. And in fact over the course of the past century a great many aspects of the physical world that at first seemed continuous have in the end been discovered to be built up from discrete elements. And I very strongly suspect that this will also be true of space.
"Particle physics experiments have shown that space acts as a continuum down to distances of around [Planck length].... But there is absolutely no reason to think that discrete elements will not be found at still smaller distances."
Here's the big kicker for me coming up next:
"And indeed, in the past one of the main reasons that space has been assumed to be a perfect continuum is that this makes it easier to handle in the context of traditional mathematics...."
To my way of thinking, this is like trying to make the universe fit our categories, instead of the other way around. Elsewhere Wolfram notes that the calculus fundamentally assumes perfect continuousness. So it seems reasonable to infer that models premissed on calculus may not be sufficiently accurate in describing "what is," and indeed may be systematically ignoring aspects of reality necessary to the behavior of what is being observed.
THEN a page later, a HUGE kicker: "...[I]f the ultimate model for the universe is to be as simple as possible, then it seems much more plausible that both space and its contents should somehow be made of the same stuff -- so that in a sense space becomes the only thing in the universe."
WOW. Needless to say, this looks like pretty radical stuff...at least to me. If the insight is incorrect, then nothing's been lost. But if it is correct, then we humans have got some big-time exploring to do.
Thanks so much for writing, RightWhale. best, bb.
This is where Wolfram and I would part thinking. In my view he should have kept going, it's even more fundamental than that.
IMHO, he should have followed Descartes, and grasped to comprehend zero - nothing - Ayn Sof.
At the most fundamental level of thought, it makes no sense to me to root anything to a physical law or geometry.
My two cents...
But it is my strong suspicion that such purposes in fact have very little to do with the real reasons that these particular features exist.
Perhaps evolution is part of a larger system, and the scientific emphasis on detail and numerical evidence occludes it.
It is difficult to explain much of modern human behavior using evolutionary arguments or the painful field of evolutionary psychology. Why does someone become a starving artist? Nietzsche's vague Will to Power provides a more meaningful answer than evolutionary rationalizations.
Wherefore all the social changes we've seen in our lifetime? Why do we develop the technology we do, and the art? What is the implicit goal of humanity? Ah, well. Survival of the fittest explains it all.
As CAs, renormalization, chaos, and many other new ideas are applied to the workings of the brain, "I suspect" (Wolfram) we will see a revolution in human understanding.
At the most fundamental level of thought, it makes no sense to me to root anything to a physical law or geometry.
Interesting comment. My first reaction was that it is not that kind of book. But you raise the question, can theology (or, in science, those multiverse sorts of questions) be perceived by extrapolation.
I would make only the general statement that extrapolation of a process (like CAs) gives a warmer feeling than equations that "blow up" at a point.
I was objecting to circular reasoning. In this case, he was attributing all within space including space itself as manifestation of space.
It's the same kind of circular reasoning that invalidates "quantum universes from quantum fluctuations" - i.e. the spawning of new universes is theorized based upon the known physical laws of this one.
IMHO, to really grasp the concept of "all that there is" one has to remove all things existing because all of these (space, time, matter, energy, momentum, geometry) are qualities of the extension of field (gravity, electromagnetism, strong and weak atomic force.) They don't pre-exist.
And to do that, it seems we must start from zero. True, the concept is theological also - but it is the point at which I believe the greatest simplicity of algorithm can manifest - probably geometric in form.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.