In Philip Roth’s novels, the desire of the protagonist constitutes the typical feature of the novel narrative. Based on a meticulous reading of The Breast through the lens of story and discourse of the narrative, this paper analyzes the desirous cause, utterance, and effect, and identifies the carnival poetic characteristics of Roth’s fiction. It is held that the “possible world” is in a sense the libido-driven result of the transition between the desire and the reality, which is of significance to understand the political farce that might be triggered by the American free desire and ethical system.