The scientific aim which distinguishes applied social psychological research from basic social psychological research is that of using social psychological theory to develop interventions meant to rectify social and practical problems in hopes of fostering a flourishing or thriving social sphere. In developing their interventions, however, many applied social psychologists have failed to consider their pre-investigatory philosophical commitments, commitments which imply the kind of flourishing social life that may come as a result of interventions rooted in them. The aim of this dissertation is to invite applied social psychologists to consider if their frequently noted, yet often unexamined, commitment to psychological egoism (i.e., human nature is inescapably self-interested) and instrumentalism (i.e., human rationality is inherently calculative towards self-interest) imply the kind of thriving social life they truly intend for their interventions to foster, or if other philosophical commitments might allow them to better fulfill that scientific aim. To do this, a comparative analysis is given between the vision of social flourishing implied in psychological egoism and instrumentalism, as illustrated in the prevalent Social Exchange Theory and its interventions, referred to as the modern vision, and an alternate vision implied in the Aristotelian understanding of human nature with its concomitant interventions, referred to as the Aristotelian vision. Overall, this dissertation suggests that the Aristotelian vision of a flourishing social life shies away from the instrumentalizing of human relationships implied by the egoistic vision and thus provides more fertile ground for applied social psychologists to accomplish their aim.