Chapter 3 begins with a discussion of Freud’s theory that religion and morality are rooted in two taboos: murder and incest. Kristeva writes that Freud’s position on murder has been well-established. However, she believes he has incorrectly overlooked the issue of incest. By focusing on incest, Kristeva reveals that the danger of incest is not so much a societal danger but rather the fearful danger of nondifferentiation. That is, the evolving subject in the preverbal developmental stage has not differentiated themselves from the object. The fear resides in the subject’s potential for never separating from the mother and being subsumed by her. The developing subject then moves toward the un-naming of the mother, the relegation of the mother as “Other,“ and the ultimate rejection of the maternal/feminine in favor of the symbolic father. For Kristeva, the subject-in-process’s fear is not castration or losing body parts but being subsumed by the mother.

Kristeva next turns toward discussing ways religion shifts secular filth to sacred defilement. She references Mary Douglas’s work on defilement, then argues that “filth is not a quality itself, but it applies only to what relates to a boundary and, more particularly, represents the object jettisoned out of that boundary, its other side, a margin” (69).