The traditional view that an activity's comparative impact on collective welfare ought to guide resource allocation is refuted. A paradigm of a multisystem society with the non-fungibility of investment resources an essential issue in project appraisal is presented. (SLD)

Six case studies are discussed, which illustrate the experimental and pragmatic epistemological paradigms as they function independently, compete with one another, or complement each other. Researchers should consider not only the substantive goals of an evaluation, but also the epistemological goals. (SLD)