Abstract
Milan Zelený has pointed out that Herbert Simon has a paradoxical distrust of human reason which he labelled as bounded whereas at the same time he had an unbounded, unlimited trust in the capacity of computers. As a result, Simon does not present an alternative concept of rationality but stays trapped in the concept of complete rationality, positing a machine (computer) in the ghost (the mind). This computational model of the mind seems to dominate even more recent thought about the human mind and behaviour, for instance the various research programmes related to heuristics. The purpose of this paper is to examine the metaphor of the mind as a computer or computation, discussing some of its roots, development and underlying assumptions as well as the ensuing blind spots, and, finally, briefly present some alternative conceptions of rationality. In a man-made world dominated by information and communication technology, metaphors, conceptions and models of the mind as well as those of computation shape – through system design and the user's use patterns – the very life we lead. System designers and users alike should be sensitive to these models, conceptions and metaphors.