Thumos, often translated “spirit” or “spirited part”, acts as an intermediary between reason and appetite, imposing the dictates of reason on our irrational desires and pleasures. Yet the precise nature and function of the thumos is poorly understood and it has often been the object of criticism. Those who have defended it have portrayed it as essentially honour-seeking, reflecting the social dimension of our existence. Beginning from an analysis of the Homeric thumos, this chapter argues that those who see the essence of thumos as lying in honour or self-esteem are mistaken, and that thumos represents a primitive drive for excellence or pre-eminence, with the desire for honour and recognition being merely derivative. Its sensitivity to reason is the result of the fact that it depends on a certain rational conception of goodness for orientation. Rather than being an accidental property, its sensitivity to reason is built into its very constitution.