An important aspect of PBL problems is the affordances that they hold for engaging students in discussion of important content knowledge. In this paper, I argue that one can analyze a problem in terms of a deep problem space and a broader learning space to identify the conceptual ideas for potential engagement. The problem space refers to the specific ideas and concepts that are part of the goals of the problem at hand. The learning space includes those aspects of the problem space and also includes the broader space of related conceptual ideas such as the anatomy and physiology related to a particular disorder or the pathology and clinical medicine of other disorders that might be considered as part of a differential diagnosis. This idea is tested in an exploratory analysis of a PBL tutorial conducted by Howard Barrows. The results demonstrate that much of students' talk is focused in these related conceptual spaces and a substantial amount of the overall learning space is engaged in the group discussion. These results have implications for understanding the affordances of problems and providing another lens on how learning unfolds in a PBL problem. It also provides another means for evaluation of learning and assessment of discursive productivity in PBL groups.