The emergence of ubiquitous computing as a new design paradigm poses significant challenges for human-computer interaction (HCI) and interaction design. Traditionally, HCI has taken place within a constrained and well-understood domain of experience—single users sitting at desks and interacting with conventionally-designed computers employing screens, keyboards and mice for interaction. New opportunities have engendered considerable interest in context-aware computing—computational systems that can sense and respond to aspects of the settings in which they are used. However, considerable confusion surrounds the notion of context—what it means, what it includes and what role it plays in interactive systems. This paper suggests that the representational stance implied by conventional interpretations of context misinterprets the role of context in everyday human activity, and proposes an alternative model that suggests different directions for design.