This paper argues that environmental design must, if it is to influence architectural design in any fundamental way, incorporate not only empirically-based theory derived from the social sciences, but architectural theory as well. With this argument as a premise, three phases in the history of architectural theory - Classical, Modern, and Post-Modern - are described in terms of both rhetoric (underlying goals) and strategy (their compositional principles). One important conclusion drawn from this analysis is that architectural theory has increasingly assumed a relativist stance, the deconstructionist position being the most extreme version of this. Given this lack of a consensual basis for design, environmental design research offers the possibility, through its empirically-based methodologies, of identifying the current cultural conventions by which built form is interpreted. Unfortunately, because this body of research has tended to ignore the significance of the compositional principles that are embedded in all architecture, this potential has barely been realized.