Evolutionary Vectors

I have been reading Bernd Rosslenbroich’s book again: On the Origins of Autonomy: A New Look at the Major Transitions in Evolution.  Rosslenbroich notes that Darwin himself confronted the paradox of progress in evolutionary history and attempted to solve it 

A paradox occurs when the same phenomenon appears to present two, logically irreconcilable faces.  On the one hand, common descent from an Ur organism seems to produce only an increasingly diverse number of branching lineages.  As we survey the tree from bottom (earliest) to the top (presently existing organisms), each fork (plants fork from animals, mammals branch from reptiles, etc.) each new branch represents only the extension of original lineage into available ecological niches.  The driving force is natural selection, which is altogether undirected.  Evolutionary history flows, as flood waters do, around obstacles and into the next available plain.  Okay, I am mixing metaphors; the point is, in this account, slime mold amoebas and certified public accountants are equal in ontological status in so far as they both made it to the present moment. 

On the other hand, it seems obvious that multi-cellular organisms represent an advance beyond their single-celled ancestors, animals an advance beyond plants, mammals an advance beyond reptiles.  If evolution is driven by an undirected, efficient causation, how can we understand these apparent advances?  Darwin attempted to account for this by appealing to the idea of increasing fitness.  More advanced organisms are better able to survive and reproduce; why else would they have emerged in the first place? 

This explanation is untenable.  Cockroaches are more fit in terms of natural selection than elephants, slime molds than slimy politicians.  Darwin’s explanation fails.  Many biologists have been tempted to try to give up the idea of progress altogether; however, they have been unable to do so.  Ignoring the distinction between higher level and lower level organisms means ignoring a conspicuous feature of biological reality. 

Rosslenbroich demonstrates that this is a persistent problem in the philosophy of biology.  Biologists can’t do with and can’t do without a theory of progress.  Among the attempts to model progress in evolutionary history are: increasing complexity, increasing division of labor among cells, increasing efficiency or energy intensive activity, increasing genetic information, and increasing body size.  All seem to come up short of a satisfactory account of what distinguishes the lower levels of biological activity from the activities of the higher levels.  Without that, how can we understand how sentient moles and heartbroken playwrights emerged from the primordial soup?

Rosslenbroich’s answer is increasing autonomy.  The most basic feature of living organisms is that they build a barrier between themselves and their environment.  The simplest living cell builds a wall around itself.  Within that wall it maintains itself and controls interactions with the environment in order to resist equilibrium with its environment.  If the external environment is too salty, the cell blocks the admission of salt and so maintains its less salty interior.  If the internal self is polluted with waste, paste is passed on to the external environment. 

The efficient cause of the movements of a fallen leaf are external to the leaf: the autumn wind.  The efficient cause of the movements of a mouse or of the cat stalking the mouse, are internal to the one and the other. 

Rosslenbroich argues that what distinguishes higher from lower organisms is increasing autonomy.  The simplest cell builds a wall between itself and its environment and maintains the one against the other.  More complex cells build internal walls, protecting the nucleus against the rest of the cell.  Animals build walls around their organs and walls protecting brains and sex cells against the flow of energy and materials within the body.  The walls don’t have to be material.  A hive of bees distinguishes its social self from other insects. 

I think that this is dead spot on.  It explains the difference between the primitive and advanced organisms without any need to suppose a directed force in evolution.  Just as tectonic plates collide to rise up into mountains, so the forces of evolutionary history pushed up in the direction of increased autonomy.

I also think that it holds the answer to a number of basic philosophical questions.  To mention only one: the problem of personal identity.  The psychological self is one more advance in the expansion of biological autonomy.  

Progress & Evolution

The International Political Science Association has picked Poznań, Poland as the site for this year’s conference, after pulling out from Istanbul.  While I dearly wished to visit Turkey, I think this will be a wonderful place to visit.  It is close, by rail, to Berlin. 

Meanwhile, I have been reading a very interesting book.  On the Origins of Autonomy: A New Look at the Major Transitions in Evolution documents the thinking of Bernd Rosslenbroich, whose essays I relied heavily on when I presented a paper on autonomy at the IPSA two years ago. 

Rosslenbroich addresses a problem at the center of my attention as a modern representative of Plato: understanding the forms of organisms.  Here is his point of departure.  Modern evolutionary biology models the history of life on earth as a steadily branching tree.  At the root of the tree are the simplest, UR organisms: the first living things successfully replicating their forms by communicating information to successive generations and adapting successfully to their environments.  To present the model as a two dimensional image, the vertical dimension represents time and the horizontal dimension represents diversity.  Thus the tree branches out as more and more diverse organic forms emerge in evolutionary history. 

The tree metaphor is misleading in one fundamental respect.  The growth of a real tree is teleological in the sense that the mature oak is already contained in the acorn and its growth is constantly corrected according to that organic program.  The sapling progresses toward the oak.  Evolution is rather a mechanical process.  As the lineage of life extends through time, it pushes into new environmental niches and thus produces increasingly diverse forms. 

Rosslenbroich’s central idea is that evolutionary history cannot be understood without the idea of progress.  Just because the forces of selection and adaptation are mechanical and hence not goal directed doesn’t mean that there is no progression from lower to higher forms.  He argues that evolutionary history cannot be understood without some notion of progress and that all attempts to purge such notions from the language of biology inevitably fail. 

Consider that the tree of life might, conceivably have produced an increasing diversity of prokaryotic cells, differing only in the traits by which they adapt to diverse environments.  Obviously that is not what happened.  Eukaryotic cells, with a defined nucleus emerge and then later multicellular creatures.  Eventually the plants, reptiles, and mammals appear.  To articulate the difference between the fanciful and the actual scenarios, we need some coherent account of progress from lower to higher forms. 

As usual, Aristotle was way ahead of us.  His account of organic progress was based on the idea of the incorporation of simpler forms of organic processes within more complex forms.  Plants have only nutritive soul.  They feed and produce waste; grow, flourish, and then wither and die.  Animals have these same capacities, but also the powers to perceive at a distance and move about.  Human beings enjoy all the organic powers of plants and animals, but add the power of logos.  We are aware of the difference between perception and reality, what looks good and what is good. 

Rosslenbroich looks to ground the idea of evolutionary progress in increasing autonomy.  The essence of the organic lies in the resistance to the external environment.  All organisms are organized so as to maintain their internal states in shifting environmental conditions by finding sources of materials and energy and, always, by building walls against the environment within which these processes can work.  Over time, progressively more effective means of resisting the environment emerge.  Eukaryotic cells sequester their DNA within a more protected nucleus.  Warm blooded mammals can maintain their body heat and so forage at night. 

I think that this is dead spot on.  When I first read the work of the great philosopher Hans Jonas, I have thought that increasing dimensions of freedom was the key to understanding evolution.  I am gratified to find this same language in Rosslenbroich.  As Aristotle argued, human beings are more than just animals but we are at least animals.  Even if a group of chimpanzees could produce a copy of Richard the Third by random typing, and they can, given impossibly vast resources and time, they still couldn’t appreciate the play. 

Those who are afraid of evolutionary explanations of the human origins fear that such explanations reduce us to mere animals or worse to mere matter in motion.  Rosslenbroich shows us that such reduction is unwarranted and in fact impossible.  I am going well beyond his purpose here, but I submit that the freedom of the human soul, on which all the beautiful and noble things depend, is supported rather than undermined by an evolutionary account of the human being. 

ps.  I would point out that I wrote this post sitting on my deck in my tent.  It was a bit too chilly to sit out uncovered and I wanted to smoke a cigar while I wrote.  I can't do so inside because I am married.  That is how organisms seek autonomy.