In Republic 1, Thrasymachus makes the radical claim that being just is ‘high-minded simplicity’ and being unjust is ‘good judgment’ (348c–e). Because injustice involves benefiting oneself, while justice involves benefiting others, the unjust are wise and good and the just are foolish and bad (348d–e). The “greedy craftsperson” argument (1.349b–350c) attempts to show that the unjust person's desire to outdo or have more than ( pleon echein) everyone is a symptom of her ignorance. Many commentaries have found the argument problematic (...) and unclear. However, this paper argues that the greedy craftsperson argument defends plausible constraints on the nature of justice and wisdom. (shrink)