A model is proposed to explain how emotional and cognitive processes drive epistemic activities within individual scientists. In this account, emotion–cognition interactions produce cyclical phases of accommodative and assimilative epistemic activities, called thought experiments and empirical experiments, respectively. During thought experiments, scientists ruminate over troubling anomalies in order to generate the theoretical ingredients necessary for constructing new conjectures. During empirical experiments, scientists explore exciting conjectures in order to cover the empirical ground necessary to discover new anomalies. Critically, epistemic activities are accompanied and sustained by positive and negative emotional moods. The main virtue of the model is its specification of a coupled feedback mechanism that explains the dynamics and the temporal dependencies between empirical and theoretical activities underlying scientific discovery.