This article considers the notion of the invention as an instrumentalconcept in designing an interactive music system. The derivation of theidea is traced from Dreyfus' Bach and the Patterns of Invention. Issues ofthe nature of the interactive musical context are problematised on the basisof ideas from Adorno and Lyotard. The invention is presented as a mechanismfor implementing the concepts of the embodiment and distribution of musicalactivity, which are shown to be generalisable. The relationship of composerand computer is considered in the light of a ‘prosthetic culture’. Itis suggested that a crucial property of the invention is that ofself-simulation.