Stephen Wolfram on Natural Selection

A New Kind of Science ^ | 2002 | Stephen Wolfram

[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.

[betty boop]

I wonder why we chose the number system that we did.... If we look at five sticks, it's easy to see that adding a stick will obtain the next number. But if we look at a pile of sand, we don't know what the next number is without more information. Was the pile created a cup at a time, or a bucket at a time? Using a constant percentage between numbers, we don't need more information, we just add x% more sand. The constant percentage approach is Markovian (depends only on the step before it). The brain likes Markov processes; it strives to create Markovian hierarchies.

I don't know whether we humans "chose" the number system, or whether we are just simply programmed in such a way as to "resonate" to the structure we have. Take, for example, perfect numbers. I've read that the ancient Sumerians -- ca 3000 B.C. -- were already familiar with them. Euclid derived the first known equation for (even) perfect numbers around 300 B.C. To this day, there are only a relative few -- I forget the exact number, but it's under 30 -- that have been identified. The expectation is that the total number of perfect numbers is infinite. But even with vastly increased computational power made available to us through electronic computers, it's extraordinarily difficult to identify new cases. Thought not a single one we know about is odd, in theory an odd perfect number should be out there. Mathematicians have been working for decades trying to find one; so far, to no avail.

It's so interesting what you said about the brain "liking Markov processes; it strives to create Markovian hierarchies." That link about autistic savants was fascinating -- suggesting that somehow, the conceptual processes of the mind (which are conscious) somehow can occlude or smother unconscious processes -- which are every bit as complex and computationally intensive, if not more so.

Oddly, Plato produced a fairly well developed model of consciousness around 300 B.C. (That era seems to have been the locus in time of an unprecedented, extraordinary outburst in human consciousness, the like of which [arguably] has yet to be repeated in human history.) For Plato, the intellect -- nous -- sits like a little boat atop the depthless sea of the unconscious mind. Plato thought that the unconscious mind contained all knowledge absolutely; the processes of the intellect involved dredging up the contents of the unconscious and making it available to the conscious mind. All learning, all knowledge, for Plato, was thus a "remembering" in consciousness of what the unconscious already knows.

A Russian mathematician, P. D. Ouspensky, succinctly stated this concept: "Nothing is outside of us; but we forget this at every sound."

Pretty wild, huh?

Thanks for the marvellous links, monkey -- times two! best, bb.

[Alamo-Girl]

Thank you so very much for your reply and most especially, for sharing each step of your reasoning! I’m thrilled to read all that you compose!

Wolfram: ”…whether the underlying rules of the universe will seem simple -- with respect to forms of description that we as humans currently use…”

The Ontological Question:

[Wolfram] tells us he suspects that virtually all kinds of systems, at least here on earth, that are not obviously simple are fundamentally computationally equivalent…. So if pattern recognition is part of what’s needed to identify computational sophistication -- intelligence -- then it seems likely we humans do better at this than rocks. What would be the meaning of biological evolution, if humans and rocks were fundamentally computationally equivalent, anyway?

No kidding! It seems that circular reasoning is an all-too-frequent consequence in theoretical and mathematical physics - when they go out of their way to stay within the natural realm.

For instance, in the Hawking touted theory of “multiple universes from multiple quantum fluctuations” – the theory itself requires that all other theoretical universes share some of the same physical laws of our own universe. Not likely, not likely at all.

Much like the Wolfram theory is apparently determined to not attribute anything extraordinary to the human mind, the multiple universe theory attempts to neutralize the obvious conclusion of the Anthropic principle, i.e. the extraordinary improbability of the physical laws in our universe being just right to support life. Lurkers might enjoy this guy’s website to explore the issues: Ian’s Cosmic Matters

Likewise, to avoid the consequences of the universe having a “beginning” – Einstein proposed the Cosmological Constant which he later withdrew in the face of the Hubble evidence to the contrary.

IMHO, the real or imagined prejudice that scientists must see “the natural realm is all that there is” - will continue to lead to circular reasoning and error.

The Epistemological Question.

Wolfram: “At times the role of mathematics in science has been used in philosophy as an indicator of the ultimate power of human thinking. In the mid-1900s, especially among physicists, there was occasionally some surprise expressed about the effectiveness of mathematics in the natural sciences. One explanation advanced by Albert Einstein was that the only physical laws we can recognize are ones that are easy to express in our system of mathematics.”

Here I lean toward Wolfram’s view – which in this particular area – is closer to Penrose’s “take” on the intrinsics of math. The unexpected simplicity and richness of mathematics are breathtaking; Penrose observed:

When mathematicians come upon their results are they just producing elaborate mental constructions that have no actual reality, but whose power and elegance is sufficient to simply fool even their inventors into believing that these mere mental constructions are "real"? Or are mathematicians really uncovering truths which are, in fact, already "there" - truths whose existence is quite independent of the mathematicians' activities? I think that, by now, it must be quite clear to the reader that I am an adherent to the second, rather than the first, view, at least with regard to such structures as complex numbers and the Mandelbrot set.

To me, math is the vessel of discovery at this level – the means to observe logic and form so that we can become aware of that which we cannot suspect much less, apprehend. The implication of course is that intelligence or conscientiousness lies at the root of “all that there is.”

The Cosmological Question.

Wolfram: “Models based on traditional mathematics equations -- in which space and time appear just as abstract symbolic variables -- have never had to make much distinction between these two views. But in trying to understand the ultimate underlying mechanisms of the universe, I believe that one must inevitably distinguish between these views.”

I believe Wolfram has stopped short and it makes me sad. He should exclude both space and time in looking for the underlying mechanisms of the universe. We already know that space and time transform (Lorenz transformations.) We already know that both are qualities of the extension of field (Einstein’s Relativity.)

I believe it was Freeper Doctor Stochastic who observed that, for the scientist, beyond a certain point “there be dragons.”

Well, I think it is high time the great minds of today like Penrose, Hawking, Wolfram – lay aside that prejudice and go where they are afraid “dragons” might be. They need to look behind space-time and behind particles - to the underlying wavelike structures, the fields and the geometry.

I believe an algorithm lies therein – something of elegance and simplicity, something that points to intelligence or conscientiousness at the root - but they will never find it by manufacturing theory to justify a naturalistic view.

[js1138]

even though their underlying rules are really simple, systems like cellular automata can end up doing all sorts of complicated things--things completely beyond what one can foresee by looking at their rules...

I'm having trouble understanding how this argues against selection as a fundamental process in design.

I am thankful for a nearly f.free thread. Quite enjoyable.

[js1138]

we are, among other things, certainly not "fault tolerant." :^)

We are amazingly fault tolerant from an engineering standpoint. We can lose billions of neurons with scarcely any change in our behavior. One of the great French writers literally had half a brain. (Of course he only had to impress the French)

[Junior]

Bump.

[betty boop]

One of the great French writers literally had half a brain. (Of course he only had to impress the French)

Hahahahahaha!!!!!! I just love it, js1138. I take your point about humans being fault-tolerant "from an engineering standpoint." Thanks for your kind words. We have some really great people on this thread.

[RightWhale]

The implication of course is that intelligence or conscientiousness lies at the root of “all that there is.”

Consciousness? If so, then perhaps there is just a trace of Gnosticism in the cosmology.

[Alamo-Girl]

Indeed, conscientiousness should have been consciousness - which only goes to prove that my spell checker is not intelligent (LOL!)

And yes, that trace of Gnosticism is what IMHO the scientists dread - so much so that they resort to circular reasoning and the ilk.

[forsnax5]

We are amazingly fault tolerant from an engineering standpoint.

We are also amazingly faulty from a programming standpoint. :)

The computer industry has endevoured to make computers completely flawless from an engineering standpoint, and, by and large, they've been very successful. Barring catasrophic failures, computers don't "forget" things.

Have you ever wondered what your mind would be like if you never forgot anything? If you could recount every word of every conversation you ever heard? Computers have that capability, and I have to think that it would get in the way of an AI.

An AI would have to be designed to "forget" things or, at least, to compartmentalize, prioritize, and selectively ignore the constant flow of input in the same manner as a human mind does.

[js1138]

I think our brains are more analog than digital. Analog computers are faster, but less precise. They are, at the very least, a hybrid.

If you tried to build a digital computer with components as slow as neurons, it would be less powerful than a pocket calculator. Analog computers are inherently parallel -- every part contributes instantly to the output. Well, not quite instantly, but there is no "computation".

[gore3000]

. Indeed, the computational processes going on in a rock (at the particle level at least)

I agree with you here that this seems quite silly. Wonder why he went so far out in left field to make such a statement.

Thus we are dealing with the world in a manner that may be fundamentally constrained by the nature of the tools we use to explore and describe it, and/or limitations in the way human beings process information coming from the outside world (i.e., via sense perception and its mediation by a hierarchy of physical structures in our bodies and brains), not to mention our finite and contingent position within the universe.

In this I agree wholeheartedly. I do not think that man will ever be capable of fully understanding the universe. Seems to me each time we seem to get close to an answer, we end up seeing vast new questions which we cannot answer. I see nothing wrong with using new and different tools, I think this is helpful, new tools give new insights. I just doubt the ultimate success of the quest.

[Nebullis]

This site has a collection of reviews. I read the review by Kadanoff that echoes the familiar lines I'm hearing.

[forsnax5]

I think our brains are more analog than digital.

I certainly don't think digitally. ;)

But what I was getting at is what I see as the primary problem with programming an AI -- currently, the AI platform is digital. The random, free association glitches of a mind (the glitches that create those odd linkages that result in AHA moments) are really what makes a mind work, not computational ability.

I am thankful for a nearly f.free thread. Quite enjoyable.

Here's why:

f.Christian signed up 1998-10-17. This account will be suspended until 2002-09-11 14:10:00.

[RightWhale]

the ultimate success of the quest

Depends what we are trying to do, doesn't it?

What are we trying to do? If it is to understand the universe, we understood it 4000 years ago. If it is to travel between the stars and galaxies, we have a ways to go.

[gore3000]

Interesting guy with some interesting ideas. Have to find out more of what he thinks, thanks.

[gore3000]

These ideas don't bring you any closer to the supernatural.

Never heard of a rock writing an algorithm!

[gore3000]

I believe an algorithm lies therein – something of elegance and simplicity, something that points to intelligence or conscientiousness at the root - but they will never find it by manufacturing theory to justify a naturalistic view.

Perhaps scientists should follow the hint that they have already discerned, that there is beauty in the universe. It would be incredibly funny if the proper avenue towards the search for truth is not naturalistic science, but aesthetics.

[gore3000]

the ultimate success of the quest -me-

Depends what we are trying to do, doesn't it?

What are we trying to do? If it is to understand the universe, we understood it 4000 years ago. If it is to travel between the stars and galaxies, we have a ways to go.

I feel the same way. I don't think we will ever have the ultimate answer in this life. However, the fun is in the search. I do want us to explore the universe and keep looking for ways to make it happen.

[Phaedrus]

Here's a link to Chapter 3 of Roger Penrose's Emperor's New Mind ... [B]ased upon what you've been saying, I figured you would probably be interested in his perspective, if you haven't seen it already.

Fabulous link, Alamo-Girl! No, I hadn't seen the text although I had been aware of the book. Some FReepers have given it a mixed review and so it wasn't on my "list". NOW I've got to go buy it. Many Thanks!

[Phaedrus]

You quickly undermine anything useful or truthful if you allow non-material or supernatural explanations.

Oh, I don't believe this at all, Nebullis. Human curiosity, the urge to know, is far too fundamental, and it will seek answers where they can be found. And valid evidence encompasses all of human perception and experience, a much broader range of events and facts than is permitted by philosophical materialism. The Universe is much more strange, wondrous and mysterious than our scientific prejudices will admit and, again, we have nothing like all the answers just yet. The assumption that we DO have the answers leads to myopia and denial IMHO. But my "position" and belief is even more radical than this. I believe we can know truth directly, that this ability is inbuilt, and that evidence for this is that beauty is self-evident. Robert Pirsig in Zen and the Art ... performed a little experiment with his college students that convinced him and me that they indeed understood excellence without having it explained.