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Monday, December 7, 2009

Evolution: Optimizing a Definition of Fitness

We think of evolution as a process that optimizes organisms (things) through the filter of fitness. Fitness as means - the species - as end. I have long suspected that this interpretation is wrong-headed, and results in conceptual mistakes that ripple though all of science, blinding us to much that could be understood about the Universe, process, and the basic shape and behavior of reality.

So let's flip it. We'll instead, re-frame evolution as a process that uses things (organisms, species, systems, ideas, etc.) as a means (channel, resource, armature, vehicle) for the optimization of fitness. From this inverted vantage, optimizing the criteria of fitness is the goal – species, nothing more than a convenient means.

It always feels wrong to talk of evolution's "goals".  Certainly a universe doesn't start out with a plan or agenda.  Things like plans and agendas are only possible within advanced abstraction apparatus like a brain or computer.  Universe's start out simple and chaotic.  Only chance causal interactions played out amongst a universe sized accumulation of matter and force over ridiculous amounts of time will lead to the types of rare and energy demanding structures that can "think" up things like plans and agendas.  So when I talk here of "a process that optimizes",  I make use concepts and terms that are more generally associated with self, ideation, and will – with the products of advanced abstraction machinery found in humans and maybe eventually in thinking machines.  But what I mean to convey is the direction of a process.  That processes have direction and that direction is (or can be) independent of the types of advanced computation necessary for things like planing and intent is in fact, the exact conceptual jump that the idea or discovery of "evolution" demands.  Evolution = direction without intent.

The directionality we see in evolving systems (all systems) is blatantly and obviously non-random.  Our job then is to understand, explain, and ultimately, exploit this understanding. Because we humans have trouble imagining non-random direction coming from systems without a brain, a soul, an agenda, we are left with a slim set of emotionally acceptable options; anthropomorphizing the universe and evolution, inserting a deity, or simply rejecting evolution (or reality) out of hand.  The non-emotional option, the science option, evolution, recovers from this dissonance through the application of inductive logic, physical evidence, and frankly, by simply offering a emotionally dissonant option.

The thesis of this essay is the suggestion that evolution might be agnostic to optimization of species and is instead simply using species as a conduit for the optimization of this thing called fitness.  That fitness might in fact be more real, and species, ethereal.

This entire domain is so fraught with potential miss-interpretation.  I feel a constant urge to over-explain, to be extra careful, to make sure the reader isn't thinking one thing when I mean something else.  For instance I feel a need to define the term "species", especially because I am using it in a more general way than is usually required within the boundaries of its original domain, biology.  This is because I am convinced that evolution is a universal process, that it has nothing in particular to do with biology or life, that it happens in all systems, all of the time, an unavoidable aspect of any reality.

So when I write "species"  I mean the thing or system that is "evolving" – the animal, the planet, the culture, the idea, the group attitude in line at the post office this morning.  And in the context of this essay, I use "species" to mean the thing upon which "fitness" acts (as judge, jury, pimp, or executioner).  Species is the thing, fitness the criteria that molds the thing.

But by this definition, species is corporal and measurable, suggesting that fitness is… is what?  If we are talking about something, shouldn't we have some way of examining it, measuring it, comparing it, holding it in our hands, flipping it over, squeezing it, spitting it open and looking at its parts?  That seems a more reasonable proposition for species than for fitness.

We like to think we can man-handle a thing like species, take it to the lab and do lab things.  But maybe that is more illusion than truth.  We can dissect a frog, but that particular frog isn't really the species "frog".  The species "frog" is an average, a canonical concept, a Platonic solid, a moving target, an arbitrarily bounded collection, a gelatinous arrow through foggy potentialities.

I was in route to show that "fitness" is a real thing, but all I accomplished was a picking away at the real-ness of "species".  Maybe that will end up being more helpful anyway.  The colloquial image of species, even amongst evolution theorists has always seemed more visceral, more thing-like than fitness.  We point to a single nervous animal on the savanna and declare, "that is gazelle".  Worse, we often fail to make a semantics distinction between that declaration and the categorical; "gazelle is that".  That fitness is a much harder thing to point to, really doesn't mean it is less real, or as I have shown, that real-ness applies to either.

Now that I've reduced both species and fitness to the realm of concept, it should be easier to argue my thesis.

Even at the concept level, "species" is a thorny concept fraught with pedagogy and hubris.  It is hard to look at a penguin, a porpoise, or a planet and imagine something more amazing, more evolved than its current form.  Which probably goes a long way to explain why we have a natural tendency to overlay onto the concept "species" notions of perfect form, of an apex, a pre-determined goal.  But this certainly has less to do with species and more to do with the limits of our cognitive facility.  It would be absurd to assume that this particular now is in some way special, that forms are complete and that we just happen to inhabit the planet just at the point when evolution has finally and completely finished its big 14 billion year project.

OK, the apologies have been met out, the slippery territory marked, the standard arguments abutted, the inconsistencies delineated, the usual misinterpretations admitted. These are standard precursors to any serious discussion in the study of evolution and bare witness to both the complexity of the subject and the apparent inability of the brain to readily make sense of its many dimensions.

So why should I want to reorder the relative hierarchy of fitness and species?  For one, I have always felt the standard Darwinian definition of evolution to be a bit circular.  Wow, before that comment ruins my standing, I had better get to work defending Darwin.  I am a "standard model" realist.  Darwin got most or all of evolution correct.  Especially if you restrict your focus to biology.  Darwin is the dude!  The positions I detail here are meant as additions, as icing on the cake Darwin baked.  But Darwin built his theory around life and his bio-centrist focus on evolution restricts and warps the applicable idea-space it scopes.  I always say that Darwin explained the how of evolution with regard to biology, and that I am interested in the why of evolution with regard to all systems.

To restrict the scope of evolution to biology, is to somehow draw a line in the sand between life and not-life, a special sauce within life that categorically separates it from all other systems.  I can't find that line.  So I am left with the responsibility of understanding and defining evolution as a domain independent attribute of any system or system of systems.

Structurally, all systems are ordered as hierarchical stacks.  Each level receives aggregate structures from lower (previously constructed) levels and produces from these, new super-aggragates, that it in turn passes to the next higher level.  That this process of aggregate layering is historically dependent is obvious.  The non-obvious mapping is to energy.  The lowest levels of the hierarchy, the earliest levels, represent high energy processes, energy levels that would rip apart aggregates at higher levels.  In this universe, all systems are built upon the aggregation processes laid down in the earliest moments, aggregations that occur at the upper limits of heat and pressure –  strings, quarks, sub-atomic particles, atoms, molecules.  Each corresponding to a matching environmental energy level, an energy level that is cooler and less pressurized than the ones that came before it.  The universe gets cooler and more dispersed.  Always.  The growth of complexity, evolution, is dependent upon this predictable and unavoidable dissipation of energy over time.

Those who would argue that life is special, that evolution is exclusive to it, well they are obligated to draw a definitive boundary between life and everything else, and because life, like everything else, is dependent upon the historical layering of aggregate systems, will have to draw that line historically.  They will have to show a moment in time before which there was not life or evolution and after which there was life and evolution.

There are many ways to define life in order that such a line could be drawn.  If you say, as most do, that life is that set of systems that incorporate and utilize both R and D Nucleic acids, well there is surely some moment in the past which would accurately delineate those earlier systems which didn't have both RNA and  DNA, from the later systems that did.  Such a definition is some what arbitrary, but all categorical definitions are.  But if you seek instead to hinge your definition of life to the process of evolution, then you are faced with a tautologically intractable problem.  Either you must accept the nonsensical proposition that the universe started with RNA/DNA preformed, or the more rational causal proposition that evolution is independent of and proceeded biology, preparing over vast periods of time, the aggregate ingredients necessary for the super-aggregate we call life.  If you insist despite this logic, that evolution is a property exclusive to biology, then you are left with the thorny problem of defining aggregation processes happening simultaneous to and independent of biology.  Processes that continue to produce atoms, molecules, stars, planets, galaxies, cultures, ideas, sand dunes, ocean currents, etc. And, you must also show how these continuous and omnipresent processes are qualitatively different when they happen outside of systems that use RNA and DNA from those that do.  But that isn't enough, you must also show either that no system after biology will ever evolve, of that the entire future of evolution will happen within the confines of biological systems.

The evidence and logic weighs overwhelmingly on the side of life being an arbitrarily bounded category, and evolution defining a process unbounded by domain, history, or complexity. Both of which are difficult concepts for humans to accept.  We like to think we belong to a category made exclusive by some secret sauce, some magic that applies in some measure only to life, and which has reached its zenith in the human form or spirit.  We like to imagine evolution to be that process that shaped the shapeless gasses of primal soup into the perfect form that we now enjoy.  Wow.  The ego and hubris drips and pools.

If I may, back to fitness.  The above arguments are crafted to shake we humans free of our innate bio/human/self centrism and to show how such hubris works to emphasize contemporary corporal form over timeless ephemeral process, placing a sort of artificial spotlight on species and downgrading the in contrast, fitness.  Its only natural.  And it is wrong.

The tendency to focus on species is easy to understand.  If you are looking at an animal and asking questions about evolution and process it is only natural that the scope of your thinking would be restricted to that animal, that species, that family of life and its struggle to survive.  Even when you back your self out to a vantage wide enough to include all of life, the full fan of Linnaean Taxonomy over the full 4.5 billion year crawl, the focus is still thing, still survival, still some sort of cosmic engineering project.  It is only when you back all the way out, when you look at all that is, the entire Universe, every moment since the big bang, life and the stuff between, in, and of it, that you might be forced to ask questions big enough to frame the why of evolution.

The why of evolution has to be big enough to comfortably hold all change, all systems, any aggregate and any aggregate chain, not just those that succeed, not just those that are fit, not just things that can be called things… everything!  Any process that explains the existence of one system should also be able to explain every other system.  Universality, at this depth of scope demands a bigger reason than can be explained by the concept "species".  Darwin's big how in biology then becomes a local mapping to a specific domain.  It isn't wrong, it just isn't universal.  You can know everything about pianos, but won't really understand music until you know enough about enough instruments that you begin to see the formative patterns that unite, from which all instruments are informed.

Species, be it a valid concept at all, must be but a subset, an example, a non-special representative, a member of a perfectly inclusive, and domain independent set.  Sets that include everything are not informative as a set.  So we look elsewhere.  That species, as a label, pointing to the subject of evolution, can equally be applied to any thing, forces us to look elsewhere for that which explains the big why of change. Change must not reside in thing, product, tailings, result, or even detritus.  If the big why isn't thing, but has to explain thing, any thing, all things, than the big why must be a process or action or modifier or pressure.  Some common attribute of any change regardless of domain.  What process is agnostic to domain?

In a word, entropy. In an attempt to determine the maximum work that could be extracted from any source of energy, steam era engineers teased apart the relationship between source and output and found an intriguing and strangely universal leakage.  Energy, when used, degrades, diffuses, is no longer as useful or available to the original process.  When scientists discovered the same leak, this time with structure, a strange universality began to appear.  Energy and information, force and structure, an unexpected symmetry.  Then Einstein revealed the exact relationship between energy, time, space, and mass, allowing thermodynamic transforms on all physical terms.  Despite initial objections by Stephen Hawking (and others attracted to the notion that nooks and crannies of the universe might provide respite from the second law's rigid causal prescriptions), Leonard Susskind and others have brought both the quantum world of the impossibly small and the black hole world of the impossibly big, together under a shared entropic umbrella.  What we are left with, like it or not, is a universal.  A universal that is universal to all physical domains and dimensions, regardless of scale.  Wow. That doesn't happen very often in nature.  That hasn't happened in science.  Ever.  Significant?

In his 1927 book, The Nature of the Physical World, Sir Arthur Eddington, put it this way:

"The law that entropy always increases, holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations - then so much the worse for Maxwell's equations. If it is found to be contradicted by observation - well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."

Any theory or assessment of evolution that is not written in response to thermodynamics, information theory, and entropy would seem to be a theory not particularly interested in validity.  That the laws of thermodynamics and evolution both direct their unblinking stares upon the domain of change would seem to me an invitation to at least begin to consider the possibility of a concerted union between the two.

[more to come…]

Randall Reetz

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