Add to ORKGSeveral recent works point out that design is one of the main driver of innovation. Therefore, it is interesting to analyze how design contributes to these last process. The point of view we present in this communication assumes that design is based on a specific rational we called creative rationality. This paper aims at presenting its theoretical roots. Creative rationality derives from Vico's notion of Ingenium. Creative rationality explains the creation of new artifacts and knowledge by knoting in a ingenious way scattered knowledge. It depends on several cognitive, individual and social variables one can identify, measure, and combine in a unified model