Stephen Wolfram on Natural Selection

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….

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.

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.

Thank you oh so very much for your reply, betty boop! I thoroughly enjoy your meditation/speculations! I find myself agreeing with you on virtually everything and only have a few observations to add.

BTW, I’m sorry it has taken so long to reply, I’ve been out of town until just yesterday – and there is so much “meat” in your posts, I wanted to mull them over really well before attempting a reply.

I wonder if Wolfram’s religious attitude isn’t but a form of naturalism with a twist. In the Western religions (Judaism, Christianity, and Islam) there is a distinct separation between the spiritual realm and the natural realm. I understand that the Eastern religions are focused on a oneness which is the universe, and in some beliefs, when a spirit departs one form it is recycled into another – a kind of naturalism with a conscience which is homogeneous to the whole.

Looking at it that way, a spiritual realm and a Creator would be excluded per se because the view only marginally exceeds the pure naturalist view of “all that there is.” That is, Wolfram would only wander beyond all things physical into some form of intelligence to the extent necessary to accept what he believes to exist, i.e. a primordial algorithm.

And that’s where I believe he hesitates and thus falls short of what he could achieve. He specifically eschews a separate spiritual realm or Creator (emphasis mine:)

“In any case, knowing a complete and ultimate model does make it impossible to have miracles or divine interventions that come outside the laws of the universe – though working out what will happen on the basis of these laws may nevertheless be irreducibly difficult.”

I agree with you, that his theological speculations constitute his fundamental “world view,” and thus supply the overriding context in which he conducts his exploration. And whereas he excuses himself in the quote you mentioned, as you observe the disease is systematic reductionism!

I do agree that we should not throw the baby out with the bath water. Wolfram’s new kind of science is a giant step in the right direction, IMHO. And yes, I agree with your assessment that world class scientists in our age are compelled to explain all things in naturalist terms in order to be taken seriously. Wolfram dares to make a step beyond and will no doubt suffer for it!

I wonder if he actually senses the need to go beyond the “Buddhist” limitation but restrains himself. What you observe about the irony of it is so very true: human thinking doesn’t much matter in the Buddhist universe, at least in terms of social relations, or relations to the wider world. Any thinking that is being committed at all under such a thought regime is, in a way, designed to extinguish thought itself which, if considered as such at all, is usually identified as a reliable source of human pain.

If he does sense the full picture, with all his personal success, perhaps he will eventually throw caution to the wind and say what needs to be said, that the primordial algorithm is a creation and not a Creator, that God is – outside of the natural realm, i.e. the creation (space, time, energy, momentum, geometry, etc.)

The Scripture you quote is one of the most revealing IMHO: In the beginning was the Word. And the Word was God, and the Word was with God. That passage in John 1 goes on to say that Christ is the Word made flesh and that all that was created was by Him. The Bible tells us repeatedly that He spoke it into being.

In my view, the Word is the “DNA” of God, and the Bible is one of His names – a description of Himself. After four decades of walking with the Lord, the beauty and simplicity of it is become clear to me.

As you observe, Christianity meets Wolfram’s characteristics for the model:

(1) Wolfram: Its initial conditions are simple, to which you observe the Word constitutes the simplest of initial conditions

(2) Wolfram: Its rules of conduct are simple, to which you observe People who read the Bible know (or should know) how simple the rules of the universe and of human being and existence really are

(3) Wolfram: Its model describes a system designed to unfold in time, to which you observe The rules were definitely intended to unfold over time.

Sigh. Wolfram however stops short of admitting to anything beyond the natural realm (with the Buddist twist.) The conclusion he draws is therefore inescapable – man can indeed be replaced by machine.

And that’s where Roger Penrose runs right past him by observing that artificial intelligence has its limitations and that the algorithm itself, in many instances, exists apart from our own ability to sense it. For instance, when even our greatest minds stand awestruck by the implication of complex numbers and the Mandelbrot set.

Thank you oh so very much for this wonderful conversation!!!

I had to set Wolfram aside for a while, but I linked a stray thought today, and perhaps this has already been addressed:

Wolfram has pointed out his machine solutions to many mathematical situations as being possibly the way math will be done and the basic three equations, Laplace, heat, and wave, are only a tiny spectrum of possible math of use in science.

However, it turns out that most interesting differential equation type of math as used in science these days is already being done on machine since it actually can't be done by hand. The solutions that can be derived by hand are very limited and few and far between, and already solved long ago.

So what this means is that Wolfram is mainly pointing out what is already happening in applied math. He has noted a few classes of solution that aren't trivial and aren't chaotic, but that probably isn't important since a chaotic solution might be the desired solution depending on the conditions, initial and boundary conditions. Wolfram's book, therefore is interesting on some level, but a mathematician could blast through it in a very short time and a philosopher might like to stay a while longer just for the wealth of examples that might spark an idea. All the same, it is a fine coffee-table book and ought to be popular at Mensa meetings.

All the same, the book should do some good for those who aren't intending to develop their math or science skills to a high level.

I am still digesting this work, read over the summer. Still, the take you give above, somehow or other, doesn't seem to comport with what I understand Wolfram had in mind WRT the present work. I rather thought he was challenging the sufficiency of math or science skills as they are presently understood and critically assessed.

Think about it. Here's a dude who spent some 20 years digitally modelling every and any "complex system" that he could lay his hands on. Including everything from simple programs of his own design, the evolution of which were stipulated by means of various "neighbor rules"; to the typical rotational habit of vegetal leaves on their stems; to the binary digit sequence of pi, primes, or Fibonacci numbers; to virtually anything else that came to his notice that was the least bit "digitally model-able." (Regarding his method, I got the distinct notion that the universe might look a tad "different" in Base Two than it does in Base Ten....)

At the end of the day, he found all the systems he was able to model resolve (in one way or another) into a mere 256 patterns -- 2 to the 8th power. Which themselves resolve into only four (2 to the 2nd power) different classes.

Class 1 cellular automata rapidly evolve either into uniformity or extinction; Class 2 CAs resolve into the redundancy of predictable patterns; Class 3 exhibit patterning, but such patterns as do not communicate information to future iterations of the program; Class 4 -- and there are only a teeny few of these, maybe two or three (Wolfram's "jury" is still "out" on that one) -- exhibits patterning that does communicate with future iterations of the program -- to such degree that the future iterations depend in some way on the iterations of the past.

Wolfram, I gather, wants us to look at the behavior of complex, dynamic systems per se. This is what he hopes will give us a "new model of science."

Against this experiential background, truly he does challenge present-day scientific orthodoxies (for example, biological Natural Selection or the Law of Entropy Increase). But he only does so -- it is my firm conviction -- because he loves science so much that he wants to keep it honest.

My two cents worth. FWIW.

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