I argue that the two criteria traditionally identified as jointly sufficient for voluntary behavior according to Aristotle require qualification. Without such qualification, they admit troubling exceptions. Through minding these difficult examples, I conclude that a third condition mentioned by Aristotle – the eph' hēmin – is key to qualifying the original two criteria. What is eph' hēmin is that which is efficiently caused by appetite and teleologically caused by reason such that the agent could have, in theory, acted differently. I (...) propose that praise and blame are justified only when 1: the behavior is voluntary and 2: the agent is susceptible to the positive influences of appropriate praise and blame to help form, improve, or strengthen a good character. Through concentrating on the agent's affectability in morally salient situations, we may better understand the qualified criteria's role in voluntary human behavior in general. (shrink)