After the Turing Machine

Problems in implementing DNA and other types of molecular computers stem from the inherent physical nature of molecules and their reactions. The current theory of computation makes assumptions that at best are very crude approximations of the physical chemistry. A theory which took into account the physical chemistry would likely be very diierent from what we have now and should help in designing more optimal molecular computing systems. In this paper I describe brieey the discordance between these assumptions and the physical chemistry; indicate some of the properties a more physically realistic model might have; and sketch some of the possibilities for a computing system which exploited the physical chemistry. We are developing a model for networks of biochemical reactions and molecules incorporating treatments of both continuous and discrete aspects of biochemical systems. The formal system of the model provides an example of what a CPC might be if the problems of encoding and design were solved. Moreover the model may be useful in resolving design issues once it is suuciently populated with data.