On the Subject of Objects: Four Views on Object Perception and Tool Use

  • Tarja Susi School of Humanities and Informatics, University of Skövde
  • Tom Ziemke School of Humanities and Informatics, University of Skövde
Keywords: functional tone, equipment, affordance, entry point, object, tool use


This paper addresses the relation between an agent and its environment, and more specifically, how subjects perceive object/artefacts/tools and their (possible) use. Four different conceptions of the relation between subject and object are compared here: functional tone (von Uexküll), equipment (Heidegger), affordance (Gibson), and entry point (Kirsh). even as these concepts have developed within different disciplines (theoretical biology, philosophy, psychology, and cognitive science) and in very different historical contexts, they are used more or less interchangeably in much of the literature, and typically conflated under the label of ‘affordance’. However, at closer inspection, they turn out to have not only similarities, but also substantial differences, which are identified and discussed here. Given that the relation between subjects and their objects is crucial to understanding human cognition and interaction with tools and technology, as well as robots’ interaction with their environment, we argue that these differences deserve some more attention than they have received so far.