Unlimited Pancomputationalism

Abstract This chapter considers unlimited pancomputationalism, which in its simplest form holds that every physical system implements every computation. It briefly reviews the origins of unlimited pancomputationalism and considers in detail the most precise and influential arguments that support it. It analyzes these arguments through the lens of our evaluation framework, reveals the underlying computational descriptions of physical systems employed in these arguments to be weak, and discusses what one must accept about the nature of physical computation to accept these arguments. It concludes that, in failing to satisfy criterion PCE (physical-computational equivalence) and thus failing to ensure that formal features of computations are fully and faithfully reflected in physical dynamics of systems taken to implement them, the physical systems employed in arguments for unlimited pancomputationalism lack meaningful signatures of computation. This undercuts the strongest arguments for unlimited pancomputationalism and identifies the missing ingredient responsible for their failure: physical-computational equivalence.