The problem of risk and uncertainty continues to plague social scientific enquiry, and thereby ostensibly imposes epistemological limits to knowledge. In this paper I explore this issue in relation to the writings and theoretical contributions of Frank Knight, one of the most illustrious economic thinkers of the twentieth century. Knight’s contributions essentially constructed a means for assessing and measuring risk in various facets of social activity. However, despite Knight’s insights and the methodological schema he constructed for probability analysis, remarkably few scholars from the social sciences have drawn upon his work. Ironically, Knight long ago bequeathed to us much that we need to know to theorise more effectively and accommodate risk and uncertainty. Copyright © 2010 Taylor & Francis.