Sunday, March 2, 2014

Book review: The Meaning of Life - On cactus finches, evolution and chaos


2014.03.20 update: Danish version

When I won my teaching award I knew to expect an interview in the school paper and, perhaps, the opportunity to speak about teaching at other departments.  However, I did not expect an invitation to speak at rotary meeting or a request to review a book for the University of Copenhagen alumni newsletter.  This blogpost is to collect my thoughts for the latter.

The review is part of a new series where alumni and university employees review books written by alumni. I was supplied a few possible author names but couldn't really find anything that looked appealing.  I briefly considered We, the Drowned because the story starts on the island where I grew up, but just couldn't see reading 700 pages by the deadline.

I finally got the idea to suggest a popular-science book.  The invitation stipulated fiction books so after my suggestion was shot down I could write a indignant e-mail on the importance of science literacy and be done with it.

Saxo.com (roughly, the Amazon.com of Denmark) lists only a handful of popular science books (isn't that sad?), but luckily one was written by a UC alum: The Meaning of Life - On cactus finches, evolution and chaos by Peter K. Busk (NB: I read the Danish version)  It looked interesting and was self-published, which I really like because I think that is the way of the future.  It's available only as an e-book (a 277 page PDF file) and costs 79 DKK (49 DKK for the English version).

The book outlines the case for the author's "theory of positive deltaS": that each individual living being is driven to maximize entropy (deltaS or chaos).  According to this theory, one excellent way of maximizing entropy is to produce offspring (i.e. more entropy producing units), but other ways include altruism, play, and consumerism - behavior that is difficult to explain via natural selection.

The book is divided into 10 chapters and each chapter is divided into short titled 1-2 page segments, which helps make the book very readable.  The first four chapters introduce the necessary scientific background to the non-expert: natural selection, the nature of a scientific theory, the laws of thermodynamics, and enzymes. This might sound like forbidding/boring stuff but the author makes use of some fun and memorable analogies: the genome becomes a handwritten book copied by medieval monks (polymerase enzymes) with varying degrees of sobriety who introduce errors in the text (mutations). Similarly, the first law of thermodynamics becomes a bookkeeper and entropy the result of a fox in the henhouse. These analgies worked very nicely for me and I actually learned a few new things about biology (the author is a molecular biologist) such as epigenetics and experiments performed to test natural selection.

Chapters 5 and 6 outlines the combination of natural selection and thermodynamics to form the theory of positive deltaS and present scientific observations that are consistent with the theory. The remaining four chapters interprets human behavior in terms of the theory and discusses its implications for pollution and overpopulation (and summarizes the book).  Humans are the masters of entropy production - turning chemical energy into heat - and this mastery has made us a superior species from a reproductive point of view but also a potential danger to ourselves. Can we save ourselves from overpopulation by maximizing our entropy production through other means than reproduction?

Is the theory right?  If you're asking to help you decide whether to read the book, the answer is "it doesn't matter". The facts in the book are correct, interesting and presented in an entertaining fashion and the interpretation of the facts in the light of the presented theory is sufficiently plausible (it would be hard to offer more solid quantitative or theoretical support in a book intended for the general reader) not to detract from the reading. I am happy I read it and I think you will be too.

By lucky coincidence (or possibly to maximize my entropy production) I came across this item while reading the book, which says many of the same things and links to a JCP paper with equations and everything.  To be a bit more precise the author (Jeremy England) uses non-equilibrium thermodynamics to argue "the more irreversible  the macroscopic process ... the more positive must be the minimum total entropy production".

England goes on to note that "that exponential growth of the kind just described [Darwinian "fitness"] is a highly irreversible process: in a selective sweep where the fittest replicator comes to dominate in a population, the future almost by definition looks very different from the past." (However, no argument is provided for whether replication provides the maximum irreversibility).

The equations indicate that "the replicator that dissipates more heat has the potential to grow accordingly faster. Moreover, we know by conservation of energy that this heat has to be generated in one of two different ways: either from energy initially stored in reactants out of which the replicator gets built (such as through the hydrolysis of sugar) or else from work done on the system by some time-varying external driving field (such as through the absorption of light during photosynthesis). In other words, basic thermodynamic constraints derived from exact considerations in statistical physics tell us that a self-replicator’s maximum potential fitness is set by how effectively it exploits sources of energy in its environment to catalyze its own reproduction. Thus, the empirical, biological fact that reproductive fitness is intimately linked to efficient metabolism now has a clear and simple basis in physics."

It looks like experiments and simulations are planned or underway to test this.  It look forward to seeing the results.


This work is licensed under a Creative Commons Attribution 4.0
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