Temperature in Natural and Arti(cid:12)cial Systems

Recent experiments in evolutionary electronics have shown how artiicial evolution can craft extremely eecient electronic circuits by manipulating a real physical silicon medium. Each individual circuit is physically instantiated in a recon-gurable chip (FPGA) for its tness evaluation, so evolution can exploit all of the natural physical properties exhibited by the electronic medium, resulting in circuits well tailored to it. This can only be done properly by rigorously rejecting conventional design methods. Artiicial evolution is then faced with a similar problem to that encountered in nature: how to construct a system from processes which all vary with temperature, such that the system can perform adequately over a wide range of temperatures? It is beneecial to do this in a more natural way than simply forbidding all analogue continuous-time dynamics, as conventional digital design does. Engineering proposals are formulated by analysing the correspondences between nature and evolutionary electronics | some of these are promising and surprising. There are wider implications for ALife, in that thermal considerations cannot be as easily ignored asìmplementation details' as might have been thought.