 Although the Greek philosophers agree that happiness requires virtue and hence that a happy person must have virtuous traits of character such as wisdom, bravery, temperance, and justice, they disagree about how to understand these traits. As explained in Section 2.1 above, several of Plato’s dialogues criticize the view that virtues are merely tendencies to act in particular ways. Bravery requires more than standing up against threats to oneself and others. Bravery also requires recognizing when standing up to these threats is reasonable and appropriate, and it requires acting on one’s recognition. This led the Greek moralists to conclude that virtuous traits of character have two aspects: (a) a behavioral aspect – doing particular kinds of action and (b) a psychological aspect – having the right motives, aims, concerns, and perspective. The Greek philosophers disagree mostly about what (b) involves. In particular, they differ about the role played in virtuous traits of character by cognitive states (e.g., knowledge and belief) on the one hand and affective states (e.g., desires, feelings, and emotions) on the other. Socrates and the Stoics argued that only cognitive states were necessary for virtue, whereas Plato and Aristotle argued that both cognitive and affective states were necessary.