An Evolved Circuit, Intrinsic in Silicon, Entwined with Physics

`Intrinsic' Hardware Evolution is the use of artiicial evolution | such as a Genetic Algorithm | to design an electronic circuit automatically, where each tness evaluation is the measurement of a cir-cuit's performance when physically instantiated in a real reconngurable VLSI chip. This paper makes a detailed case-study of the rst such application of evolution directly to the connguration of a Field Programmable Gate Array (FPGA). Evolution is allowed to explore beyond the scope of conventional design methods, resulting in a highly eecient circuit with a richer structure and dynamics and a greater respect for the natural properties of the implementation medium than is usual. The application is a simple, but not toy, problem: a tone-discrimination task. Practical details are considered throughout.