Biology as a discipline has long been motivated by a question that it has nonetheless deferred and resisted: What is life? Indeed, what is an organism, a virus, or a species? Dr. Wells' research examines why these questions remain, and must remain, unresolved. He argues that any determination of an essence of life necessarily assumes that the essence is both recalcitrant to evolution and separable from the environment. These assumptions create the necessity of a discrete origin, one that will bring into being the ready-made, impervious-to-evolution essence. Yet does "life," or anything else, have an essence - or an origin? Or, are "life" and similar categories (species, organism, even origin) necessarily indeterminate to the degree that they reflect evolutionary process? What metaphysical assumptions does this formulation expose, challenge, and make? Equally problematic, how is "evolution" itself to be thought if "evolution" calls into question the terms by which we understand its happening?