The usual juxtaposition of qualitative research against quantitative research makes it easy to miss the fact that qualitative research itself encompasses at least two traditions: positivist and interpretivist. Positivist work seeks to identify qualitative data with propositions that can then be tested or identified in other cases, while interpretive work seeks to combine those data into systems of belief whose manifestations are specific to a case. In this paper, I argue that discovering causal relationships is the province of positivist research, while discovering causal mechanisms is the province of interpretivists. I explain why absolutist claims for one or the other approach are mistaken, and argue that the combination of both makes more sense. Finally, I offer suggestions for combinations of positivist and interpretive work, both at the level of thought experiment and in actual data collection and analysis. Throughout, I draw my examples from recent studies of poverty, a field in which a small but distinguished tradition of qualitative studies of the poor has been joined by a growing body of both positivist and interpretive work.