Saturday, June 1, 2013

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. 

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