Addy Pross' Non-Reductionist Reductionism

To a man who makes shoes, the whole world is made of leather.

That proverb, Chinese in origin if I remember correctly, came to mind tonight as I read more of Addy Pross’ What is Life.  This is one of those beautiful little books that bare the soul of a complex science to amateurs like me.  Pross clearly intends to answer the question in a reductionist fashion.  Biology, he dares to say at one point, is just another branch of chemistry.  Well, the whole world is made of chemicals.  Is biology really reducible to chemistry?  No.

In chapter 4: ‘Stability and Instability’, Pross gives us a tour of basic chemistry.  Chemical reactions move “downhill,” i.e., from states of higher free energy to states of lower free energy.  Sometimes, I gather, they have to get over a “hump,” and in those cases a catalyst is required. 

To employ my own analogy, an avalanche occurs when an unstable sheet of snow begins to slide downhill.  The catalyst may have been some fool yodeling.  The result is a ton of snow on top of a group of helpless skiers, at which point the situation is distressingly more stable than the original state. 

Similarly, a mixture of hydrogen and oxygen gas is higher in energy than water.  It requires a spark (the catalyst) to get the former to combine into the latter, but once the combination has happened water is relatively stable.  Good thing, that.  Two cheers for the second law of thermodynamics. 

Pross then makes a distinction between two kinds of stability: static and dynamic.  Water molecules are statically stable.  Once formed, a molecule of water remains materially what it is pretty much forever.  A river, by contrast, is dynamically stable.  The Thames River has been flowing, he tells us, for around thirty million years—longer than there has been an England.  Yet the water in it is constantly renewed.  As Heraclitus famously observed, you can’t step in the same river twice. 

Self-replicating molecules (e.g., RNA) are capable of achieving dynamic stability.  They form and decay by a constant exchange of basic building blocks.  In one experiment, more robust RNA chains emerged from less robust versions.  All populations of living organisms achieve some measure of dynamic stability.  Cyanobacteria have been in business for more than two billion years!  That makes geography look short sighted. 

Pross goes all in by arguing that the stability achieved by such populations of organisms is more than analogous to the chemical stability governed by the second law of thermodynamics (which just states that isolated molecular systems always go from less stable to more stable states).  He proposes a version of the second law for dynamic stability:

Replicating chemical systems will tend to be transformed from (dynamically) kinetically less stable to (dynamically) kinetically more stable. 

So the elegant symmetry of chemical reactions is reproduced at the level of organic systems.  Thus is biology consumed by chemistry. 

Color me underwhelmed.  Granted, I am only half way through the book; however, it seems to me that dynamic stability just isn’t another version of static stability.  It is a whole ‘nuther’ animal, as we would say down South.  To be sure, everything going on in living organisms has to obey the laws of thermodynamics.  Organisms, however, obey rules that are not derived from those chemical laws.  The stability of populations in a given ecosystem incorporates chemical stability but it is not reducible to the laws of chemistry.  Biology is a more comprehensive science than chemistry.  Sorry. 

Nonetheless, I am very grateful to Pross for this argument.  I think that he has conceded all the ground he hoped to occupy.  I also think that his dynamic stability is pretty much what Aristotle was aiming at in his treatment of the soul.  Aristotle’s soul is precisely the communication of organic form over time by means of a constant exchange of matter (and I would add, energy) with the outside world.  Aristotle was a vehement opponent of reductionism.  Pross’ reductionism isn’t reductionism at all, thus confirming the Philosopher’s point. 

Organisms Are Not Machines

One of the most brilliant essays on the history of science that I ever read was Adam Smith’s ‘History of Astronomy’.  Smith explains the difference between ancient or classical astronomy and modern astronomy as a difference in metaphors.  For the ancients, the central metaphor was natural growth.  They thus understood the heavens as essentially biological phenomena writ large.  For moderns, the central metaphor is the machine.  In the course of his essay, Smith presents an account of human understanding in distinctly mechanical terms. 

We want our understanding to move from the phenomena to the explanation as smoothly as possible, so we build our explanations as we would build a ramp for a rolling ball.  Gaps in the ramp require the ball to jump violently from one part to another, thus creating shock.  Analogously, gaps in explanation produce the shock of surprise, which is unpleasant.  So we try to build a continuous set of ramps in our explanations over which the understanding can flow smoothly. 

Of course, Smith’s point included a note of caution.  His mechanistic account of human reason, however serious one might take it, is still just a metaphor.  One cannot take it seriously, but it is brilliant nonetheless. 

Tonight I read Steve Talbott’s essay “The Unbearable Wholeness of Beings”, in The New Atlantis.  It is a very strong critique of mechanism in biology.  Talbott argues that modern biologists use two distinct sets of terminology, one appropriate to physics and chemistry and the other to living organisms; however, they do not recognize that the two languages are distinct or bother to carefully define their terms and sort out the differences.  This, he thinks, results in profound confusions. 

Think first of a living dog, then of a decomposing corpse. At the moment of death, all the living processes normally studied by the biologist rapidly disintegrate. The corpse remains subject to the same laws of physics and chemistry as the live dog, but now, with the cessation of life, we see those laws strictly in their own terms, without anything the life scientist is distinctively concerned about. The dramatic change in his descriptive language as he moves between the living and the dead tells us just about everything we need to know.

No biologist who had been speaking of the behavior of the living dog will now speak in the same way of the corpse’s “behavior.” Nor will he refer to certain physical changes in the corpse as reflexes, just as he will never mention the corpse’s responses to stimuli, or the functions of its organs, or the processes of development being undergone by the decomposing tissues.

Virtually the same collection of molecules exists in the canine cells during the moments immediately before and after death. But after the fateful transition no one will any longer think of genes as being regulated, nor will anyone refer to normal or proper chromosome functioning.

Talbott points out that the mechanistic models that once seemed so promising in biology have been demolished.  The simple line of causation from gene to protein to trait certainly fit Smith’s model of a series of ramps.  We know understand that that model is hopelessly simplistic.  There are innumerable feedback loops between genes and their products and profound influences on each process exercised by the various systems that make up any organism.  Even at the level of a single cell, the operation is vastly complex.  Organisms are not machines. 

Here is the heart of the matter: The parts of a clock are put together in a certain way; the parts of an organism grow within an integral unity from the very start. They do not add themselves together to form a whole, but rather progressively differentiate themselves out of the prior wholeness of seed or germ. They are growing even as they begin functioning, and their functioning is a contribution toward their growing. The parts never were and never are completely separate, never are assembled. A specific bit of food taken in from outside never becomes some new, recognizable part, added to the rest; rather, it is metabolically transformed and assimilated by the ruling unity that is already there. The structures performing this work, such as they are, are themselves being formed out of the work. Does any of this sound remotely like a machine?

When, on the other hand, we do build machines, we impose our designs upon them from without, articulating the parts together so that by means of their external relations they can perform the functions or achieve the purposes we intended for them. Those same relations give us our explanation of the machine’s physical performance.

He identifies three themes that distinguish organisms from machines.  One is the relationship between the parts and the whole.  In machines, the functioning of the whole is a simple sum of the action of all the parts.  The organism is imposed from outside by the designer.  Organisms are different. 

The form, existence, and activities of the parts depend upon, and arise from — are in some sense caused by — the whole, which is therefore expressed in one way or another through every part. This is much like the relation between individual words and their context — which is not surprising, since language is itself an expression of organic life.

A machine has no agenda; only the manufacturers and operators have agendas. 

Biological activities are carried out as if “with a view toward” or “for the sake of” some end. The organism “aims” to develop and sustain itself as a being with its own particular character.

While a machine may incorporate feedback loops, the operation is still a linear process that proceeds from the actions of the parts.  In an organism, the parts are what they are because of the feedback loops. 

To give an archetypal example, as the embryo polarizes into anterior and posterior, each pole is not only “opposite” to the other, but necessarily implied in the other. Each pole is properly formed only by virtue of the other’s being formed. Neither is a unilateral cause of the other.

Most interestingly, Talbott argues that the failure to recognize non-mechanistic character of living organisms leads many biologists to attribute mysterious powers to such things as DNA. 

To say, as Nobel laureate Max Delbrück once did, that DNA could be conceived in the manner of Aristotle’s First Cause and Unmoved Mover, since it “acts, creates form and development, and is not changed in the process”[37] — well, that’s a stupefying blind spot, a blind spot that to one degree or another dominated the entire era of molecular biology through the turn of the current century. It was already recognized and warned against by the German botanist Fritz Noll in 1903, who pointed out how (in E.S. Russell’s paraphrase) “the chief theorists have tried to solve the problem of development by assuming a material and particulate basis [today’s ‘gene’], without however attempting to explain how the mere presence of material elements could exert a controlling influence on development. They have been forced to ascribe to such abstract material units properties and powers with which they would hesitate to credit the cell as a whole.”[38]

Weiss emphasizes very much the same point: because there is no possible way to make global sense of genes and their myriad companion molecules by remaining at their level, researchers have “simply bestowed upon the gene the faculty of spontaneity, the power of ‘dictating,’ ‘informing,’ ‘regulating,’ ‘controlling,’ etc.”[39] And today, one could add, there is at least an equal emphasis on how other molecules “regulate” and “control” the genes! Clearly something isn’t working in this picture of mechanistic control. And the proof lies in the covert, inconsistent, and perhaps unconscious invocation of higher coordinating powers through the use of these loaded words — words that owe their meaning ultimately to the mind, with its power to understand information, to contextualize it, to regulate on the basis of it, and to act in service of an overall goal.

This strikes me as quite correct.  Organisms are Aristotelian wholes.  Unlike machines, the organism strives to maintain its being by controlling and incorporating subordinate organisms and cells, each of which is trying to do the same.  We have come a long way beyond Aristotle’s biology only to arrive at Aristotle’s biology. 

What is a Species?

Here is a simple illustration that has come in handy when I explain natural selection.  I like to call it my Natural Selection Medicine Wheel, but in this diagram it looks more like a medicine rectangle.  

 I expect that the diagram will be self-explanatory to anyone who understands natural selection.  Consider a population of elk living, let us say, in Wind Cave National Park.  A heard of such elk blundering in the campsite my son and I set up last year.  The population phenotype indicates the observable animals, including their physical traits and behaviors.  From a few cases of observation, that means a bull and a lot of cows and maybe a few young male offspring. 

When the rut comes, all the healthy adults will seek to mate.  Pretty much all the cows will be successful.  The bulls will have to fight, and the biggest bull with the biggest antlers and attitude will succeed.  Most of the males will not be successful. 

That challenge will determine the makeup of the population genotype that will be carried by the cows and that will determine the next generation.  If indeed the largest, best armed males get almost all the cows, the next generation of sons will be similarly well-endowed. 

One of the most persistent questions in the philosophy of biology is what a species is.  Zoological classification looks for a number of identifying characteristics.  However useful that is, to say that a species is an essential bundle of characteristics is called essentialism and that is largely discredited. 

Another approach looks to phylogeny.  A species is one of the main branches on the tree of life.  The trunk forks here to produce deer and elk; there, to produce humans and chimpanzees.  That’s not bad, but it is rather arbitrary.  Which forks indicate a species and which a sub species? 

The best answer in the scholarship is that a species is a population of interbreeding organisms.  Of course, it raises the question whether two populations of organisms that could interbreed but presently do not are the same species or not? 

I am inclined to approach the problem in the spirit of classical philosophy.  Aristotle was torn between two answers to the basic question.  One is that the species is this here group of animals, pawing the turf and breathing mist into the air.  The second is that the species is the species form, for that is what persists over time.  I happen to think that Plato is the better guide on this question. 

I think that the species is indeed a form rather than a particular collection of meat and hoofs.  The form is precisely the wheel that I illustrate above.  The species is the dynamic by which some population phenotype produces a population genotype which… .  It may be said that this account works only for sexually reproducing organisms.  I reply that that is because only such creatures sort themselves into a species.  Common sense can tell us the difference between a wolf and a bear.  The dynamic of natural selection as I illustrate it above is the ultimate reality underlying that difference.  

Biology At Odds With Physics

I have been reading What is Life?  How Chemistry Becomes Biology, by AddyPross.  Pross proposes to answer Erwin Schrödinger’s famous question with the tools of systems chemistry.  Don’t ask me what that is; I am only on the first chapter.  It is a very good chapter.  He sets forth very clearly and forcefully what may be the deepest problem for modern natural science. 

Biology has more principles than physics.  Nothing in living organisms contradicts the principles of physics; however, living organisms are governed by principles that are utterly alien to and seem at least to go radically against the current of the non-living world.  Pross considers a number of such cases. 

One is that living organisms display teleonomy.  This is a sanitized version of the older word, teleology.  I believe the coinage belongs to Ernst Myer.  It means that living organisms have an agenda.  They act for a purpose.  Predators pursue prey, boys pursue girls, and bacteria swim toward food and away from toxins. 

The very existence of teleonomy, however, leads to a strange, even weird reality: in some fundamental sense we are simultaneously living in two worlds, each governed by its own set of rules—the laws of physics and chemistry within the inanimate world and the teleonomic principle that dominates the biological world.  Indeed, given the existence of two distinct worlds we find ourselves interacting quite differently with each of those worlds.  

A man and a bag of hammers will fall at the same rate from a ledge but the man can try not to fall whereas the bag doesn’t care.  Once someone has thrown a rock at me I must depend on the laws of physics to avoid it; however, I might try to persuade him not to throw it in the first place.  Again, nothing is the laws of physics is contradicted by the organisms behavior but nothing in the laws of physics could allow us to expect or account for or predict the organisms behavior. 

A second feature of living organisms that is astonishing from the perspective of physics is that they are constantly recreating themselves.  An organism is in some senses like a machine: it has a general function and is composed of parts with functions that contribute to the operation of the whole.  However, a clock does not repair itself.  An organism, by contrast, is constantly rebuilding all its parts and exchanging matter with the outside world. 

Pross observes that if you meet a friend you haven’t seen for years and look at him with the eyes of physics, you are looking at a wholly new individual.  Almost all the molecular constituents that made up his physical body when last you saw him are gone.  Hundreds of billions of new cells are born in our bodies every day and in each cell the proteins are constantly being remanufactured.  Yet you are looking at the same person. 

A third feature of organisms I will mention is their resistance to equilibrium.  Put a bowl of water in a freezer.  You now have a state of disequilibrium.  The water is warmer than the surrounding environment.  In short order the heat in the water will leak out and the water will freeze.  The temperature of everything in the freezer will equalize.  That is what physics is comfortable with. 

Now put an arctic rodent in the freezer.  As long as the animal remains healthy it will maintain its body temperature well above the level of its surroundings, just bird resist gravity by beating its wings.  To live is to be stubbornly resistant to physical equilibrium. 

I can’t wait to find out what systems chemistry is and how it can reconcile the two worlds.  I am guessing, with one chapter under my belt, that this will not be a reductionist account of life.  As Hans Jonas has pointed out, the fact that living organisms emerged out of none living matter and consist of dead molecules is a two-edged sword.  On the one hand, means that all souls have material origins.  On the other hand, it means that dead matter has spiritual potential.  I like that just fine.