Practical reasoning refers to a teacher's capacity to discern particulars and make wise judgements about how to act in pedagogical situations. But how do teachers know what is right? How are teachers' preferences to be grounded and their choices justified? I explore the disciplines as one source of moral perception. Assuming that narrative unities underscore the coherence and continuity of an individual's experience, I generated data in the context of a 2-year teacher education programme. The case study of an aspiring teacher of secondary school language arts illustrates how the intellectual virtues of a discipline can influence a student teacher's practical reasoning. I conclude that teacher educators must attend to the complex ways in which a prospective teacher's prior discipline may influence aspiring teachers' orientations to experience, their consideration of educational ends, and, finally, their characters.