How do you say "physics" in the tongue of biology?

Okay, so we have our chimpanzee banging away at typewriters.  Each keystroke is assumed to be random (this is a thought problem, not a hiring problem).  Let’s limit the keys to the twenty six letters of the alphabet so I don’t have to count the keys on my laptop.  How long does it take our pan troglodytes to produce Shakespeare’s Richard the Third? 

Well, our hairy scribe will produce one “n” about every twenty-six strokes.  Multiply 26 by 26 and that is how many strokes will be needed to produce the first two letters “no”.  Assuming that Bonzo types 260 letters a minute, how long will it take him to turn out Now is the Winter of Our Discontent Made Glorious Summer by this Son of York?

I once actually calculated this out and quickly determined that it would take more time than the kosmos has existed for our chimp or indeed a whole army of chimps to get even halfway through that first line. 

I like to use this popular thought problem to test my philosophy students.  Could chimpanzees produce a Shakespeare play by random typing?  The answer is that not only could they do so but they would inevitably do so, given enough resources including time.  The problem is that the requirements are so vast as to be, for all practical purposes, impossible.  She who agrees with what I have just said is capable of thinking logically.  He who refuses to acknowledge even the contingent possibility is not. 

One might say that Darwin explained how it was not only possible but actual that that random typing produced chimpanzees.  What you need is some means of saving the good letters.  If every good letter survives and every bad letter perishes, then every twenty six strokes will get you one letter closer to My Kingdom for a Horse! 

Darwin can explain how you get from the simplest replicating organisms to certified public accountants because replicating organisms, by definition, have a means of saving and compiling the good letters in the DNA (or RNA) script.  But how do you get from inorganic chemistry to those UR organisms? 

Physicist Jeremy England has an intriguing guess.  His work is discussed in “How do you say “life” in Physics” by Alison Eck in Nautilus.  England addresses the problem that life presents to physicists. 

To the physicist steeped in statistical mechanics, life can, in this sense, appear miraculous. The second law of thermodynamics demands that for a closed system—like a gas in a box, or the universe as a whole—disorder must increase over time. Snow melts into a puddle, but a puddle does not (on its own) spontaneously take the shape of a snowflake. Were you to see a puddle do this, you’d assume you were watching a movie in reverse, as if time were moving backward. The second law imposes an irreversibility on the behavior of large groups of particles, allowing us to play with words like “past,” “present,” and “future.”


The arrow of time points in the direction of disorder. The arrow of life, however, points the opposite way. From a simple, dull seed grows an intricately structured flower, and from the lifeless Earth, forests and jungles. How is it that the rules governing those atoms we call “life” could be so drastically different from those that govern the rest of the atoms in the universe?

England’s guess is that the solution turns on irreversible shifts in states of atoms.  Here is my version, which mixes the metaphors in the Nautilus articles.  Someone jumping a fence with a pogo can jump back, given that she has enough energy to do so.  That’s a reversible change in state.  Someone being shot out of a canon cannot return.  His flight is irreversible. 

How does this work at the atomic level? 

A group of atoms could take a burst of external energy and use it to transform itself into a new configuration—jumping the fence, so to speak. If the atoms dissipate the energy while they transform, the change could be irreversible. They could always use the next burst of energy that comes along to transition back, and often they will. But sometimes they won’t. Sometimes they’ll use that next burst to transition into yet another new state, dissipating their energy once again, transforming themselves step by step. In this way, dissipation doesn’t ensure irreversibility, but irreversibility requires dissipation.

Now, if I understand the argument, a shift in a configuration of atoms that dissipates the energy required to effect it is a means of saving information.  If the configuration acquires more energy and then jumps to yet another new configuration, then information is in effect compiled.  The third configuration has a history.  To really understand what it is, you would have to know the steps that led up to it.  To the extent that that is true, the history involves the compiling of information.  The gaggle of atoms is saving the good letters. 

This is a very long way from explaining how genuine organisms emerge out of the inorganic soup.  It doesn’t give us any idea of the chimpanzee typing odds.  It does give us an idea of how the simplest mechanics might have produced a selection pressure that tilted inorganic processes towards the emergence of life. 

The origin of life is one of the major mysteries.  The fact that life did emerge on planet Earth tells us that inorganic nature contained within it the seeds of life.  I like that idea.  England may be onto an important clue as to where those seeds lay and how they germinated.  

The Uphill, the Downhill, & the Corner Round

I have been walking up high of late, in the Bighorn Mountains of Wyoming.  I haven’t had much time for reading or for this blog, but I did pick up Addy Pross’ What is Life again tonight. 

Pross argues that there is a law governing “dynamic kinetic systems” (i.e., living organisms) that is analogous to the second law of thermodynamics.  Systems governed by the second law tend toward more chemically, physically, and especially thermal stable states.  Here is the second law:

The entropy of an isolated system never decreases. 

That is to say, an isolated system (one in which no additional energy is supplied) tends toward thermal equilibrium.  An ice cube floating in a glass of scotch represents a highly order system (low entropy): the cold and the warm stuff are neatly separated.  As the ice melts, the system becomes steadily less ordered until it reaches equilibrium (high entropy). 

Systems governed by Pross’ analogous law tend toward more stable replication.  Here is Pross’ new law:

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

This law would underwrite the course of evolution.  Ants, for example, are very kinetically stable so they remain in their form for a very long period in evolutionary history.  Okay. 

All material transformations, including all that go on in living organisms, are governed by the second law.  Only replicators are governed by the Pross law.  Replicators include all organisms but also replicating molecules like RNA. 

Here is an analogy that I think captures this point.  Consider an alley that slopes slightly downhill.  It ends in an intersection with a second alley that slopes from right to left.  A boulder rolling down the first alley will always go left when it reaches the junction, because boulders always roll downhill. 

A man walking down the first alley is just as much subject to the laws of gravity as the boulder.  Nonetheless, the man may turn right at the junction and walk uphill.  In order to accomplish this task, the solitary walker must expend stored reserves of energy.  If he wants to keep resisting gravity, he will eventually have to replenish his store of energy‑perhaps at the pub atop the hill. 

The existence of uphill walkers, while scrupulously observant of the second law of thermodynamics, seems to depend also on Pross’ second law.  Organisms exist in forms that are more dynamically stable in the environmental niches that they occupy than the forms from which they evolved. 

All that seems reasonable; however, it still seems to me that dynamic stability is a very different kettle of fish from thermodynamic stability.  The latter needs only material and efficient causation, as Aristotle described them.  The latter, this rock bumped that rock and made it move, is underwritten in modern physics by the second law.  Pross’ law of dynamic kinetic stability requires Aristotle’s other two causes: formal (it is this kind of organism) and final (it is up to something). 

The big problem for modern biology is how to reconcile the two pairs of Aristotelian causation.  Pross’ highly critical discussion of theories about the origin of life illustrates this very well. 

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.