Research on the relationship between design and the creation of knowledge is a relatively recent phenomenon. In architecture, for instance, it was not so long ago that designers tended to view knowledge with disdain, as a hindrance to unfettered creativity or an encapsulation of “freeze-dried prejudices.”1 Recently, however, the American Institute of Architects (AIA) devoted the December 2004 issue of its AIA Journal entirely to the theme of knowledge, which strongly suggests that times are changing. Increasingly, the act of designing is considered to be or involve some kind of knowledge production.2 This directly follows from the type of knowledge designing relies on, which is practicebased and tacit,3 (i.e., embedded within the very act of designing).4 On the other hand, it is possible—at least in a rough and ready way—to appreciate the distinction between the aim, or intention, of producing knowledge and other aims,5 such as designing an object or a building. To state it a bit more bluntly, a client typically hires an architect to design a building, not to produce knowledge. Why then is it so difficult to set clear boundaries between design and scholarly research? Questions about the relationship between both are far from new. According to Nigel Cross, they reappear about every forty years,6 and have been written about by many authors before. Already in 1973, Horst Rittel and Melvin Webber pointed out the difference between the kind of problems designers and planners deal with and those that scientists handle.7 More recently, Johannes Eekels and Norbert Roozenburg made a methodological comparison of the structures of design and research in engineering, and concluded that both are strongly interwoven and mutually dependent, yet fundamentally different.8 Although it seems time to move on from making all sorts of comparisons between design and research, this paper tries to shed more light on the issue from a conceptual and psychological point of view. To this end, it calls in the philosophy of mind—rather than the philosophy of science, as is usually the case9 —and more precisely the notion of intentionality. Instead of considering design as a mix of knowledge creation and application, the process is decomposed into distinct yet interacting mental acts, in which designers establish relationships with (objects in) the world. A detailed analysis of this relationship forms the basis for a nuanced, yet fundamental, comparison with