Comments on "Let there be life; thermodynamic reflections on biogenesis and evolution" by Avshalom C. Elitzur.

This comment is in response to a paper previously published in the Journal entitled "Let there be life", by A. C. Elitzur. Elitzur ascribes to Eigen the proposal that life began with the appearance of an autocatalytic (self-replicating) molecule. This was discussed by biologists and philosophers in the nineteenth century. Eigen's proposal is moot: there never was a primeval soup. The absence of evidence is evidence of absence. Elitzur also confuses thermodynamics with statistical mechanics. The statistical equation of Boltzmann and Planck for entropy appears in discussions of statistical mechanics, not in discussions of classical thermodynamics. Elitzur calls the Second Law of Thermodynamics an explanation of evolution. On the contrary, his mentor Eigen wrote: "In physics we know of principles which cannot be reduced to any more fundamental laws. As axioms, they are abstracted from experience, their predictions being consistent with the consequences that can be subjected to experimental test. "Typical examples are the first and second law of thermodynamics. Darwin's principle of natural selection does not fall into the category of first principles." The reader is invited to compare the material in Elitzur's paper with the discussion in Yockey's (1992) book, Information Theory and Molecular Biology, Cambridge, Cambridge University Press.