Elaborate reflections on a simple manifesto

In an earlier article (^{McFall, 1991}), I urged clinical psychologists to work toward the goal of integrating science and practice and proposed the adoption of a principle and two corollaries aimed at achieving this goal. In general, I argued that all aspects of clinical psychology must be guided by the highest scientific and ethical standards, that clinical practice be limited to empirically supported procedures, and that clinical training be devoted to producing clinical scientists. In the present article, I elaborate and defend these points by offering reflections on a number of submitted questions provoked by the earlier article. I address four major issues: the philosophical foundations for a scientific epistemology, the implications of this epistemology for clinical practice, the implications for clinical training, and the likely impact of adopting this epistemology on the field of clinical psychology.