On Philosophical Foundation of Lyee: Interaction Theories and Lyee Bipin INDURKHYA Tokyo University of Agriculture and Technology Koganei, Tokyo (JAPAN) Abstract: This paper aims to examine the philosophical foundation of Lyee. In particular, Lyee’s hypotheses are compared with those of the interaction view of cognition, and a number of parallels are noted. Based on these connections, I propose some extensions and elaborations of Lyee that might make it more widely applicable to areas other than software engineering. In particular, I suggest three areas of cognitive science where Lyee methodology might be relevant. These areas are: 1) modeling the interaction of a cognitive agent with its environment, 2) modeling the social interaction of a number of agents sharing an environment, and 3) modeling creativity of cognition. 1. Introduction Lyee is a methodology for designing and implementing software systems, which, according to its inventor, is derived from the philosophical traditions of Leibniz, Spinoza, and Wittgenstein [16, 20]. Though in the domain of software design Lyee has been shown to be remarkably successful — several ongoing projects are further exploring and evaluating the effectiveness of Lyee, comparing it with other methods and elaborating it along the way — its philosophical foundation are not clearly articulated. Various papers about Lyee contain a brief discussion of its philosophical motivation [15, 16, 17, 18, 20], but these discussions are too short to really do justice to the philosophical traditions on which Lyee is based. The most comprehensive paper about the theory underlying Lyee is perhaps [19], which contains a number of axioms and rules but there is very little in terms of motivation, background and intuitive explanations. One may naturally ask here why bother looking under the hood of something that seems to work well. If the inventors of Lyee have hit upon a method to make large software systems intuitively, efficiently and economically, that seems a godsend. Why bother with its philosophical roots, whatever they may be — they hardly seem relevant for a practical software engineer. However, I think there are two major reasons for exploring beneath the success stories of Lyee. One is that if Lyee seems such an effective methodology for designing large software systems, understanding its theoretical foundation is bound to reveal us something about the very nature of software itself. Needless to say, the relevance of this matter for even a practical software engineer cannot be overstated. The other reason is that according to the inventors of Lyee, the methodology is based on the philosophical observations about the very nature of cognition. This naturally leads one to wonder if this methodology might be applicable to other domains as well. For example, can the ideas behind Lyee be used to do cognitive robotics? Can they be applied to design creativity support systems? And so on. In order to realize the full potential of Lyee methodology in domains other than software design, it is imperative that its