The melody is both entirely responsible for the structure of the music box and entirely produced by it. Analogizing to biology, Mechanism limits itself to the second move, explaining how cell functions and the activities of life are just ways of playing out genetic information. Notice first that, even if this Mechanist project is possible, it is in no way opposed to an account of soul that not only arises within structure but is also prior to it.* There is also, however, discontent with the Mechanist project within biology itself, even if popular biology is quiet about it. Strohman summarizes the basic problem:
Genes specify information necessary to make proteins and the genome provides a collective informational source. However, by itself a genome is passive: DNA, for example cannot make itself, and cannot construct a protein never mind an actual cellular function. DNA has been called the book of life by HGP [human genome project] scientists but for many other biologists DNA is not a book but simply a collection of words from which a meaningful story of life may be assembled.
*If the soul is the sort of thing the ancients thought it was – an ultimate cause of life in the living – we could not expect to find it by our contemporary methods until our sciences were complete. We want to start with the sort of causes most known to us, and even with these our account has a dizzying complexity that no one would expect to be complete any time soon. In fact, “complete science” might be as contradictory as “final hypothesis”, and for the same reason. So Mechanism might relate to soul as something it approaches at an infinite limit. Physics might relate likewise to God.