Upon beginning their school-based teaching practica, teacher candidates enter a realm of practice that is at once uncertain, vulnerable, and particular, and where good educational practice centers on teacher's ability to see and to judge and to act ethically with others in concrete situations and ways. An important question for teacher education is: how do teacher candidates begin to acquire this capacity? This article draws on Martha Nussbaum's Aristotelian-inspired concept of "discernment" to explore how people begin to grasp "phronesis" or practical wisdom in teaching by becoming more responsive to the ethical character of classroom particulars while on practicum in ITE. The discussion is grounded in a teacher candidate's comments while on practicum at a Canadian elementary school to illustrate how becoming an ethical teacher is bound up in becoming perceptive, in opening oneself to the value and special wonder of the particular, in feeling the appropriate emotions about what one chooses, and by engaging in a play of thought about classroom particulars and educational universals.