Summary: The authors argue that social work is as much a practical-moral activity as it is a technical-rational one. In order to pursue these themes, they explore the place of realist knowledge in social work and their alternative position on the complexities and ambiguities of practice. Findings: Social work has long been troubled by the adequacy of its claims to professional status and about its possession of appropriate levels of knowledge and expertise. The dominant responses to this have been managerialist and procedural, or rational and technical, as represented in the evidence-based practice movement. This article acknowledges the contribution of such approaches, but argues that they are unrealistic in that they fail to recognize the practical-moral dimensions of social work and the role of emotion and normative judgement in assessment and intervention. Applications: The problem of judgement is an essential area for exploration. The range of rationalities upon which social workers depend in making their judgements requires rigorous analysis and debate within the profession. This article opens up a discursive space in which to rethink our understanding of knowledge making in social work.