Review of “Into the Cool”

 Eric D. Schneider and Dorion Sagan, Into the Cool: Energy Flow, Thermodynamics and Life, Chicago: University of Chicago Press (2006)

This is a book with an attitude – a vision of the universe, biological evolution and the very “purpose” of life on Earth that is derived from a distinctive view of thermodynamics – and of life.  It is grounded in science, but it is not a scientific treatise.  It argues the case for a provocative “interpretation” of the scientific literature in thermodynamics and bioenergetics – ranging from physics to ecology, physiology and even economics.  Though I have a fundamental disagreement with their thesis (their interpretation), I also believe this book has much merit and makes a distinctive contribution to a much-debated subject.

As with the previous work of these authors, this book provides a very readable, interesting, even masterful presentation.  It is also (mostly) technically sound.  The authors also provide an excellent and very informative review of the historical background, and the voluminous theoretical literature on thermodynamics and evolution.  Though I am fairly familiar with the writings in this area, there is much here that was new to me.  It is evident that this book was deeply and thoughtfully researched, and their treatment is very responsible, even when I disagree with their interpretations.  Key concepts are clearly defined and luminously illustrated, and the vision that Schneider and Sagan present is well argued.  The many graphic illustrations are also illuminating and add to the book’s appeal.  With the exception of a few highly technical passages that get a bit bogged down in the details, or an occasional digression, this book makes a very good and interesting “read” – as the cliché goes.  While there have been many other, more technical books related to this general topic, this one stands out as being perhaps the most comprehensive and accessible treatment that I have seen.

Schneider and Sagan’s thesis, in brief, is that energy flows have not only powered the evolutionary process but have organized it and defined its overall trajectory.  Life’s trends, they say, stem from the second law of thermodynamics (the so-called entropy law), which refers to an inherent tendency of ordered “free energy” in nature to dissipate and become entropic, or unusable for doing further work.  Schneider and Sagan claim that energy flows “generate, perpetuate, elaborate,” biological complexity.  “Life is organized by energy flows.” It was “sired by energy flow.”  It is “ruled” by energy and its transformations.  Indeed, the second law of thermodynamics defines the very “purpose” of life.  “Nature abhors a gradient,” they claim, and life arose in order to reduce energy gradients – in much the same way that tornadoes serve to dissipate the pent up energy in the gradient between high and low pressure air masses.  The emergence of life is “causally connected to the second law,” they say.  Indeed, the second law is variously characterized by Schneider and Sagan as a force that “governs,” “organizes,” “selects,” “generates,” “determines,” “mandates,” “pushes” and “leads to” biological structure and organization.  The second law is the “source” for the overall directionality observed in evolution, they say.

First, let me offer a brief comment about the underlying vision that “drives” this book.   What the authors are proposing here could be characterized as a “naturalistic teleology.”  In accordance with the classic distinction first drawn by Colin Pittendrigh and later promoted by Mayr, Dobzhansky, Ayala and others, teleology refers to an “external” purposiveness – a prior “intent” in nature to achieve a certain outcome or end-state.  “Teleonomy,” on the other hand, refers to the evolved internal purposiveness of living systems, which exhibit cybernetic properties and pursue the “internal” goal of survival and reproduction in an always contingent environment.  What Schneider and Sagan seem to be proposing in this book, in effect, is an external teleology.  They seek to endow the second law of thermodynamics – which describes in formal mathematical terms a tendency for available energy to dissipate and become entropic – with the properties of a “force” that gives rise to various phenomena that serve its purposes (such as tornadoes, Bénard cells and living systems).  These phenomena are said to be mandated/organized/ determined by the energy gradients that are in turn mandated by the second law.

There can be no doubt that energy, and energy gradients, play an important role in potentiating and powering life on Earth.  But do energy flows really superimpose an external purpose on the evolved purposes of living systems?  Do they really determine the directionality in evolution?  This proposition involves what might be called the fallacy of misplaced teleology.  In what was for me an ultimately unsatisfying final chapter of the book,“On Purpose,” the authors defend the view that deterministic physical consequences, or functional effects, could be said to impose a purpose on the recipient, or the instrumentality, or the “vehicle”.  Quite apart from the contrary evidence that living systems often superimpose their internal purposes on energy gradients, such a teleological segue is a slippery slope.  It could just as well be said that the purpose of gravity is to create free energy, or that the ultimate purpose of gravity is to create life on Earth, or that the purpose of the universe is to create life, since life does flow from all of these dynamics.  Or that the purpose of life is to encapsulate the dynamics of the universe.  Despite their assiduous efforts, the authors failed to convince me that the purpose of life is to degrade energy gradients.

A significant part of my problem with this book is that the authors seem to be trying to walk a fine line theoretically.  They want to hype the role and “power” of thermodynamics and the second law in evolution, but they are also constrained by their knowledge of real-world biology.  So they speak of thermodynamics and natural selection as having a dual role in evolution, which tacitly undercuts their thesis.  They even acknowledge various qualifiers, complications and limitations that real-world biology imposes on a monolithic thermodynamic determinism.  Indeed, this is reflected in some of the internal contradictions and contrary evidence they mention.  Yet the authors also tend to gloss over these problems, rather than treating them as serious challenges to their underlying thesis.  One suspects that the authors are trying to have it both ways.  This will not do.

Apart from my fundamental concern about their thesis, there are a number of specific criticisms – some minor but a few more serious. I will mention some of them in the order in which they arose, not in order of their importance.

First, their treatment of Erwin Schrödinger, an important figure in thermodynamic theory (among other things), strikes me as involving some “puffery.”  They attribute insights to him that were hardly news, like the role of mutations in evolution. This goes back to August Weismann at the beginning of the century, and to the rise  of population genetics – e.g., Fischer, Wright, Haldane, Morgan, Dobzhansky and others – in the 1930s.  Also, as the authors themselves later acknowledge (one of a number of tacit internal rebuttals/contradictions in their presentation), the role of energy in evolution was a theme that long predated Schrödinger.  Later on in the book they also mention Lamarck, Spencer, Boltzmann, Gibbs and especially Lotka, whose contributions to the vision Schneider and Sagan present are then described in some detail.  Also, it was Leo Szilard, in his famous 1929 paper (and his doctoral thesis) on Maxwell’s demon, who first introduced the role of information into thermodynamics.  Indeed, Schrödinger’s most significant contribution to the authors’ thesis, perhaps, was the problematical concept (and formalization) of “negative entropy.” (The term “negentropy” was actually coined by Brillouin.)  As for Schrödinger’s claim that negative entropy on Earth must be paid for with an entropy increase elsewhere in the universe, my question is, so what?  It represents an infinitesimal fraction of the total and would have occurred in any case.  It didn’t change any outcomes.  Of course, global warming on Earth is a more immediate, local problem, but its impact has been well-recognized and understood without recourse to the second law.

There is also a certain amount of “puffing” of thermodynamics and the second law in their treatment. Temperature gradients in the universe represent “organization”, they claim.   But, like many other theorists, they conflate energetic “order”, or available energy, with physical order and utilize the term “organization” for both.  However, organization implies cybernetic properties, functional/engineering design, information and feedback.  There is a fundamental distinction between Bénard cells (an example cited ad nauseam by thermodynamic determinists) and living cells.  The former do not utilize information or feedback, do not deploy a functional division of labor, do not reproduce, and do not evolve, among other things.

Furthermore, thermodynamics did not “discover” the arrow of time.  Humans knew about it long before Clausius came along. The second law added an irreversible principle to the theoretically reversible laws of Newtonian physics.  But if the second law may provide some scientific evidence for time’s arrow, does this mean, therefore, that the anti-entropic action of gravity, which is generating new free energy as we speak, reverses the arrow of time? (Of course, the evidence for the Big Bang theory and an evolving universe is far more compelling than the second law.)

Indeed, an unintended example of the theoretical problem that gravity poses to conventional thermodynamics is found in the authors’ illustration involving a box of marbles.  Schneider and Sagan claim that, given some shaking (i.e., some energy inputs, not entropy!), the 10,000 marbles in one corner compartment will be randomly distributed throughout the various compartments, and the probability is minute that Humpty Dumpty could re-aggregate them, according to the second law.  Actually, if the box is tipped on end with one corner pointing down, and if it is given a few more shakes, gravity will do the rest (much like those hand-held kids’ toys).  I’ll come back to the problem that gravity creates for conventional thermodynamics theory below.

There is also a hint in the book of a deep contradiction to their thesis about the directive role of energy gradients and the second law in evolution.  They concede that a flow of energy is not enough.  A “correct suite” of dynamic and kinetic constraints is required.  And, they later add, so are a number of other raw materials, as well as oxygen for aerobes.  So, why is it that life is sparse to non-existent in some parts of the globe?  (Or on other planets for that matter). These barren areas (like the Sahara Desert) are not exceptions that prove the rule; they reflect the fact that life is a “package deal,” requiring a long list of “sufficient conditions,” not just the “necessary condition” of available energy.  For instance, as the authors well know, usable nitrogen is often the limiting factor for biological productivity in an ecosystem, rather than energy constraints. Indeed, the authors tell us that progressive changes in the degree of ecosystem organization to accommodate greater energy flows leads to more energy degradation – entropy.  Well, of course, but more entropy than what?  Is there more degradation and entropy increases than, say, in the Sahara Desert?

Indeed, the role of stress in disrupting ecosystem relationships seems to me like prima facie evidence that the second law is not a hegemon.  It’s another of several examples where the authors, because they also have deep knowledge of biology, inadvertently undercut the hype associated with their thesis.  As they acknowledge, thermodynamics is necessary but not sufficient.  They speak of a “thin line” between the higher purpose of gradient reduction and biological survival. On the contrary, the multi-faceted problem of survival and reproduction takes priority and energy is a means.

The authors also approvingly cite Jeffrey Wicken’s linkage of the second law to mutations, suggesting that this represents another major influence that the entropy law exerts in evolution.  But this is a bit of a reach.  First, we now appreciate that mutations are only one of various sources of innovation/variation in evolution.  But more important, Wicken’s view involved the use of an expansive, highly contentious definition of entropy as a phenomenon that encompasses any kind of physical disorder.  Wicken assumed that a tendency to physical disorder, like energetic entropy, is an inherent tendency in the universe.  This oft-repeated assertion was not original with Wicken; it can be traced back to Boltzmann, and it is now commonplace (if ill-considered) among modern physicists.  This is another example of the inadequacy of 19th century thermodynamics as an explanation for the dynamics of the universe.  If there’s entropy in everything, why is the Earth (not to mention all the other stars and planets in the universe) not dissipating and flying off into space?  Nuclear and chemical bonds play a role, but the main reason is because gravity is a vastly important anti-entropic influence in the universe; it regularly contradicts the second law!  Indeed, far from being an example of entropy, mutations may occur for various reasons, some of which are actually energy-driven!

Schneider and Sagan also bring black holes into their discussion. Stephen Hawking’s contributions notwithstanding, we still don’t know much about the nature or the “contents” of black holes.  The authors might also wish to consider the implications of the growing conviction among cosmologists that a vast sea of dark energy comprises perhaps 70% of the total mass of the universe.  Dark matter may constitute another 20%. So only about 5% is ordinary matter/energy, it is believed.  In this light, energy gradients and entropy in the universe may be a trivial matter.

Finally, a focus on thermodynamics and the second law without references to the contrary role of gravity is myopic, as noted above.  The influence of gravity challenges the claim that second law is an inexorable, omnipotent “force” in nature.  Not only is gravity non-entropic but it is the ultimate progenitor of the predominant source of available energy (via stellar nucleosynthesis) that powers living systems.  And more available energy is being generated even as the existing “stock” is being depleted.  Indeed, some of this non-entropic energy is also utilized directly by living systems, via waterfalls, water currents, tidal energy and by using gravity itself.

So we need to keep the second law of thermodynamics in its place as an influence but hardly the purpose of life. This vision masks and discounts our more compelling biological purpose.

Category: Publications