New Criticals

As I tried to argue in my last post, life did not begin with a set of chemical relationships attempting to solve the problem of how to persist--this endows molecules with a foresight that has no physical basis. Rather, life was a solution to the opposite problem, the same problem the sun has: It can’t give itself away fast enough. Only once an autocatalytic organization emerged in the prebiotic chemical reaction matrix did the problem of survival, and thus the restricted economy aspect of Darwinian evolution, emerge. Before that, the problem was not “How am I going to survive and reproduce?” but rather, for each entrapped molecule stuck in an energy processing cycle with other molecules, “How can I get back to my ground state as fast as possible?” It is the necessary short-sightedness of inert molecules that creates the possibility of their activity being collectively frustrated: each molecule’s attempt to minimize it’s own free energy merely passes the excitation onto another in such a way that the ensemble never reaches equilibrium, and consequently further structuring through energy flows leads to networks of chemical-energy flows that become more and more removed from equilibrium and thus more and more organized.

So when we talk about the organization, or the “information content” of a cell, what we really mean is every aspect of the distribution of matter and energy inside that cell that is displaced from its equilibrium value. At the present state of the art, we can't calculate a cell's overall displacement from equilibrium. As a first approximation, it would require knowing the chemical affinity of every molecule in the cell for every other molecule in the cell, and in addition the energy involved in concentrating, confining, and adsorbing molecules onto membrane surfaces. We're getting closer to being able to do traditional physics on these problems, however, and in the future I hope to discuss some of the current approaches.

But if you know anything about cell biology, you realize this definition precludes the possibility that the information in a cell be reducible to the organism’s genome. The idea that it would be is a consequence of the mistaken view that DNA contains all of the information necessary to reproduce itself. Nowhere in nature do we see either DNA or RNA reproducing “itself” without the aid of proteins, lipids, and other components of the intracellular matrix. Cells reproduce, nothing less complex than a cell performs this autocatalytic activity. A cell is the first structure that we may legitimately call “a self.” Thus, nothing less complex than a cell is alive. Though this does not necessarily imply that single-celled organisms which we observe today are the simplest possible organisms, it does, however, mean that reproduction is not a property of any individual molecule.