Weinstein argues that Plato's 'fighting spirit' in the Republic plays an essential role in rational agency.

Plato's 'Republic' constructs an ideal city composed of three parts, parallel to the soul's reason, appetites, and fighting spirit. But confusion and controversy have long surrounded this three-way division and especially the prominent role it assigns to angry and competitive spirit. In Plato's Three-fold City and Soul, Joshua I. Weinstein argues that, for Plato, determination and fortitude are not just expressions of our passionate or emotional natures, but also play an essential role in the rational agency of persons and polities. In the Republic's account, human life requires spirited courage as much as reasoned thought and nutritious food. The discussion ranges over Plato's explication of the logical and metaphysical foundations of justice and injustice, the failures of incomplete and dysfunctional cities, and the productive synergy of our tendencies and capacities that becomes fully evident only in the justice of a self-sufficient political community.