The Physical Basis of Coding and Reliability in Biological Evolution

Within the intellectual discipline of the physicist there has developed a belief in the existence of general and universal theories of nature, and it is the search for such theories which may be said to guide and justify the intellectual efforts of the physicist as well as the design of most physics experiments. What a physicist means by a ‘good theory’ cannot be exhaustively spelled out. Of course it must include ‘fitting the data’ or ‘predicting observations’ in some general sense. However, much deeper and more obscure criteria are also applied, often tacitly or intuitively, to evaluate the quality of a physical theory. For example, general theories can never be ‘just so’ stories which are only built up bit by bit as data accumulate. General physical theories often stem from relatively simple hypotheses that can be checked by experiment such as the constancy of the speed of light and the discrete energies of photons from atoms, but they must also be founded upon broad principles that express concepts of conservation, invariance, or symmetry. These abstract principles come to be accepted because from our experience we find that in some sense they appear unavoidable. In other words, without such principles it is difficult even to imagine what we mean by a general physical theory of the universe.