This chapter follows the suggestion to draw on a broader set of hermeneutical, life science perspectives to get a better and more qualified assessment of scientifically substantiated knowledge. The chapter discusses lay knowledge based on the case of chronic illness and risk of disease. We claim that when the knowledge interest includes biological, psychological and social conditions, this requires an interpretative integration of lay knowledge and scientific knowledge. Such an approach provides better insight into health-related behavior, and therefore promotes focus on the social determinants of health.