One of the more difficult issues that evolutionary theory has contended with over the years has centered around the role of the word “purpose.” Does life have a purpose or are we just random chemical processes that manage to copy themselves? I’m about to try and convince you that 1) The question as I just asked it is a set of false alternatives, 2) that people today pose the question in this manner because they have an inadequate understanding of causality, and 3) that the reasons for this difficulty are historical. So I’m going to have to start by telling you some stuff about the history of science and philosophy.
Most people seem to be willing to agree that other people are capable of acting with a purpose “in mind.” In fact, we often associate purposive or goal-oriented behavior with the property of “having a mind.” Well, a few centuries ago, “having a mind” was also connected to “having a soul.” And since everybody knew that only humans had souls, Descartes did not have to make much ado about pinning a dog to a board and having it vivisected alive for purposes of inquiry into the workings of the soulless machine. These days the concept of an eternal soul has drifted out of fashion, and this has contributed to the growing awareness that most vertebrates, at the very least, appear to have minds and are capable of suffering and vanity just like us. The trouble with life is that this purposiveness appears to extend all the way down to things which we agree clearly don’t have “minds,” such as bacteria. Also, despite the fact that we know that evolution is itself not being directed by any consciousness, it certainly appears to be in some way increasing in complexity as time has passed. What could it mean for nature to be acting with a purpose, but not with a purpose “in mind?” The scientific response to this question was delayed by, or perhaps took a necessary detour through, the deterministic interpretation of classical mechanics. What do I mean by this?
We call a system “deterministic” if we believe that mechanics can tell us exactly what this system will be doing at some future point. It’s like how we’re certain that a ball will roll down a hill, or that a particle will descend into a potential well, to use two equally simple examples. There are two kinds of mechanics, classical and quantum. There are some differences between them, and you might have heard alot about these differences. What you might not have heard as much about is the similarities between them, and furthermore the fact that neither discipline constitutes, by itself, the whole of physics. Thermodynamics developed as a distinct discipline apart from either kind of mechanics and these disciplines were not unified until Boltzmann laid the foundations for statistical mechanics, at the end of the 19th century. Both classical and quantum mechanics, however, deal with the mechanisms which govern the motion of individual objects, whether bodies or wave functions. Furthermore, the fundamental rules of mechanics are equations which are time-reversible and must be derived by abstracting away from the multiplicity of reality and imagining the behavior of one single thing, a body being subjected to a force or a particle in a box which you see is actually a standing wave--but not until you think about what its like if its the only particle in the box.
Abstracting away from reality to the behavior of a single object has been one of the great achievements of modern science, and no discipline has been more successful and had more predictive force than mechanics. But we know, thanks to Poincare and Boltzmann and others who came later in the 20th century, that the behavior of many things is not at all like the behavior of one thing. Crucially, the behavior of many things can display a property we call irreversibility. One thing by itself can’t do anything irreversible. But an ensemble can, and once irreversibility enters the world, so does history.
But the success of mechanics spawned the idea that nature as a whole might be deterministic. And reality is counter-intuitive: If I can know exactly where one thing will be at some point in the future, what’s keeping me from knowing where everything will be at some point in the future? Only my ignorance, right? This view is most often expressed in Laplace’s famous, but ultimately delirious fantasy that if one knew the precise position and momentum of every particle in the universe then it would be possible to predict absolutely all future states of the universe. This is the limit case of the view that the nature is fundamentally made up of little billiard balls whizzing around in space, somehow brought into a kind of clockwork regularity at the level of stars and planets by an absentee God who wound up the clock, wrote down Newton’s laws of motion, and then left it to mankind to discern the inscrutable meaning behind the contraptions resulting from the accumulation of God’s pure reason.
To be clear, I don’t think anyone ever really believed this, maybe not even Laplace himself, but the public understanding of why nature is non-deterministic is often incorrectly associated with quantum mechanics. While it’s true that the quantum theory was also a decisive blow to the belief in mechanistic determinism, the reality is that this view was discredited long before the development of quantum theory. Again right at the end of the 19th century, Poincare demonstrated decisively that Newtonian mechanics itself was never deterministic to begin with. I hope to devote a post at some point in the future to Poincare’s ideas, because they are a model of both beauty and subtlety.
But before Poincare developed the basic ideas of what would come to be called “chaos theory” (I don’t like this name though-remind me to tell you why), this other guy named Darwin wrote a book that became pretty famous. If any creationists have made it this far, let me be clear right now that I am about to direct my comments against neo-Darwinism, the view of evolution developed through the “synthesis” of Darwinism with molecular biology. Darwin obviously never heard the words gene or genome. So please do not trot out any of what I’m about to say as in any way calling into question the clear truth the earth is about 4 billion years old and all life on it has differentiated from a common source. I say differentiated to stress the point which people often forget: The mass of the earth has not appreciably changed over time, evolution doesn’t make “more” stuff, it keeps recombining the stuff that’s already here in more and more intricate ways. So that’s what’s been going on on this planet, mass gaining in complexity because it is turned in ever more cycles in the ever-widening gyre driven by the solar flux.
So then on to neo-Darwinism. I’m assuming you’ve heard of DNA? Yea biology made a lot of gains in the last century, but it brought along with it a lot of theoretical baggage because of its inadequate contact with the developments being made in physics at the same time. You see, the people who were synthesizing the concept of the genome with the idea of natural selection wanted, more than anything, to be able to describe the process of evolution entirely in terms of random genetic variation. Why? Because that would reduce the concept of evolution to a set of “deterministic” chemical mechanisms and thereby prove that evolution by natural selection was a truly "objective" theory. In order to accomplish this reduction, what needed to be done was to rid the theory of evolution of all traces of “purposive” description. Evolution HAD to to be the result of random genetic variation, otherwise the door was left open for this intelligent design nonsense. The biological community at this point seems to have been unprepared for the idea that a non-equilibrium process can display spontaneous directedness, and thus lacked the necessary imagination to forge a third option between design by an extra-physical intelligence and blind, dumb luck. The Greek word for the purpose or goal of a process is Telos, and so this period in the history of biology was also a war on “Teleology.”
I would list Monod and Ghiselin as the best proponents of this position, and I have great respect for these men's accomplishments as biologists. There's another, more famous smarty-pants who sells A LOT of books that is also associated with Neo-Darwinism but I'd rather not say his name. Mayr also deserves mention because he got so sick of the argument that he made up two new words: teleonomic and teleomatic, to describe things that behave “as if” they had a purpose but which we know don’t really because “blind, dumb matter” isn’t special like we very privileged thinking, intentional things. Teleomatic referred to the most basic level of dumb-matter trying to deceive us and turn us into animists: stones falling to earth and other phenomena that the theory of elements made seem purposive (the earth element "seeks" more earth element) which the theory of gravity “reduced to mechanism.” Teleonomic was supposed to cover the intricately organized processes of development (the “plan” of organismal development is another very thorny metaphor in these debates) as well as some “instinctive” behaviors, while teleological could finally be preserved exclusively for those things with brains which are out to get their way. Obviously the line between the three is a bit blurry on every side (pick the boundary on either side of “teleonomic” and try and identify that line for yourself). I’m sympathetic to the approach because it’s a sincere attempt to think clearly about a difficult problem, but it sidesteps the real difficulties by not seeing the nature beneath the linguistic morass.
Meanwhile, Monod’s famous dictum that evolution represents “chance caught on the wing” has become the de facto public understanding of the “metaphysics” of evolution: Blind, purposeless accidents that happily provide some greater chance of survival (at least long enough to reproduce) slowly accumulating against a backdrop of random variation. Life is unquestionably historical and chance has surely played a deep causal role in determining many of the particularities of evolved organisms, but I believe this view commits two errors.
First, it presupposes a mistaken view of what it means to “reduce to mechanisms” as the only form of “good, scientific objectivity.” I mentioned this briefly already and will expand further on this point in future posts.
Second, and more importantly, it fails to understand that “chance” in nature is constrained by the physical conditions of the evolution of the universe. You see, we’re pretty certain that the universe is expanding and that expansion is helping to maintain a disequilibrium between kinetic and potential energy. This allows dissipative processes, like stars and people, to continue to be “energetically favorable.” This isn’t super complicated. Think about the sun. It’s way hotter than the rest of space. Therefore the particles in the sun have much greater average kinetic energy than the particles in space (all I just said is that the hotter ones are moving faster). But the sun and space are in thermal contact, just like ice and water. What happens if you leave them together long enough? Yea, they ought to become the same temperature. So the sun is radiating out into space because it's hot as hell and it "wants" to make space the same temperature as it so it can settle down and stop radiating...but space keeps expanding, and its actually getting colder...so the sun keeps radiating. Does it really "want" to stop?
Let’s make the jump into statistical mechanical reasoning: The sun, and any non-equilibrium structure (you’re hotter than the room too) is a locus of improbability in the basic distribution of stuff in the universe. What happens to improbable configurations as time goes by? They “dissipate” into more probable configurations, all by themself. Nothing magical, just the process of the improbable becoming the probable. The structures or processes performing the dissipation, however, may persist so long as the fuel source or “gradient” that feeds the dissipation is sufficient to pay the cost of maintaining the internal organization required to continue the process of dissipation. All fuels represent probabilistic compressions of chemical or some other form of energy. The sun is fueled by the fusion of hydrogen into helium, and so the sun has some life-expectancy value just like you, mortal. And just like the sun, you get to exist because you are an organized process designed to equalize the improbability in the distribution of energy between a fuel source and an entropy sink (thats what food and shit really are!) The fact, however, that dissipation is probabilistically likely in the first place is due to our mother, the expanding sink of space, which we have wrongly characterized as a cold, indifferent void. Once we have had time to unpack these ideas in greater detail it should become possible for you to understand how thermodynamics has provided the physical rationale for, and prescribed the direction of, the evolution of life on earth.
So everything I just told you I learned from Jeffrey Wicken, who is in my estimation the most important American thinker since Richard Feynman and easily the most underappreciated. Had you ever heard of him? Exactly. This is mostly the peculiar fate of a man trying to communicate profound philosophical insights to the contemporary scientific community. Anyway Wicken’s premise was simple: the second law of thermodynamics is teleological. That’s it. But with this understanding firmly in mind, natural selection is absolutely relieved of “the burden of the architect.” There is purpose in nature, because it is an irreducible element of all irreversible processes--they produce entropy. Or, saying the same thing in a way that is more familiar to biologists, irreversible processes reduce free energy gradients. There is absolutely nothing “intentional” about this “purpose.” It is an emergent, statistical property of any sufficiently large ensemble of matter. So there’s our first baby step on the road to demonstrating that life is natural. If the question is “How can a universe that has no goal or intention in mind spontaneously produce beings that exhibit goal-oriented behavior?” Then we have, as our first clue, the insight that the universe is, against all reason, “doing” something: it is probabilistically increasing the number of available quantum microstates in time, which is the technical way of saying in language our current understanding of the second law. Explaining the second law (and the first) will require its own post which will tell its own childish story, beginning with Boltzmann and his ferocious insight turned into suicidal mania through Schrodinger’s notions about “negentropy” to Wicken’s synthesis of biological and physical dynamics. It is a sad history, full of confusion and polemics just like the century that nurtured it.
Jeffrey Wicken, 1942-2002
Thumbnail of Evolutionary Tree here.