Comparative and case study researchers have responded to critiques of their methods by developing formal procedures to validate theoretical claims through set theoretical logics of causal conditions. This 'logico-formalist turn' has involved the stricter application of the schemas of set theory and the philosophy of logic to raise validation standards of theoretical and causal claims in comparative historical research. This paper critiques these solutions from a critical realist standpoint. It argues that the cost of such a defense has been the retention of positivist assumptions of causal inference and the downplaying of the importance of interpretive and theory-building work in comparative and case study research. By contrast, critical realism's process of retroduction sees causal analysis not as proceeding inductively from empirical observation to causal proposition, but rather points out the constant epistemic shift from the level of empirical observation to that of the theoretical description of intransitive causal powers. The paper highlights the ways in which the meta-theoretical perspective of critical realism makes possible a full break with both positivism and the implicit empiricism of the logico-formalist turn.