Untidy Evolution: Evolving Messy Gates for Fault Tolerance

The exploitation of the physical characteristics has already been demonstrated in the intrinsic evolution of electronic circuits. This paper is an initial attempt at creating a world in which "physics" can be exploited in simulation. As a starting point we investigate a model of gate-like components with added noise. We refer to this as a kind of messiness. The principal idea behind these messy gates is that artificial evolution makes a virtue of the untidiness. We are ultimately trying to study the question: What kind of components should we use in artificial evolution? Several experiments are described that show that the messy circuits have a natural robustness to noise, as well as an implicit faulttolerance. In addition, it was relatively easy for evolution to generate novel circuits that were surprisingly efficient.