Some ideas for a new epistemology, encompassing practical action, based on the concept of reflective practice, are presented. The term reflective practitioner was first suggested by Schon (1983) in an analysis of the need to define the nature of practical competence. The prevailing culture of technical rationality, which depends on science for it rigor, is compared with that of the “wise engineer” promoted by Elms (1989). Worldview, quality, systems thinking, and responsibility are discussed as preliminaries to an analysis of reflective practice. The model is based on the passing of hierarchically structured sets of message patterns from perception to reflection to action. Intelligence is defined as an ability to construct, evaluate, and act on alternative scenarios of the future in the reflective phase. Design involves the construction of scenarios where imagined artifacts operate to achieve predefined needs for some defined person(s). Rigor for the reflective practitioner stems from the achieving of appropriate objectives. The similarities and differences between science and engineering become apparent when both are viewed as examples of reflective practice.