Because design is a practice, a theory of design is not possible in the same sense as a theory of chemistry is. Socio-psychological theories of what designers do are not design theories. Knowledge of how to design cannot be reduced to theory, for reasons that grow out of the philosophy of science. This paper suggests, however, that there can be a theory of design in the sense of supporting theory, drawn from other disciplines, that employs a level or style of analysis that is uniquely suited to design practice. In particular, design theory might involve incompletely described objects or teleological explanation, since these are key features of design, and since the design process can be understood as moving from a functional description to a physical description of an object.
Hooker, John N.
"Is Design Theory Possible?,"
Journal of Information Technology Theory and Application (JITTA): Vol. 6
, Article 8.
Available at: http://aisel.aisnet.org/jitta/vol6/iss2/8