Course Hero. "Les Misérables Study Guide." Course Hero. 12 Jan. 2017. Web. 20 Nov. 2018. <https://www.coursehero.com/lit/Les-Misérables/>.
Course Hero. (2017, January 12). Les Misérables Study Guide. In Course Hero. Retrieved November 20, 2018, from https://www.coursehero.com/lit/Les-Misérables/
(Course Hero, 2017)
Course Hero. "Les Misérables Study Guide." January 12, 2017. Accessed November 20, 2018. https://www.coursehero.com/lit/Les-Misérables/.
Course Hero, "Les Misérables Study Guide," January 12, 2017, accessed November 20, 2018, https://www.coursehero.com/lit/Les-Misérables/.
Part 3, Book 7 provides background for the story. It begins with an extended metaphor in which social structure is said to rest on a vast mine, which has sub-mines (for example, the religious mine, the economic mine, the revolutionary mine, and so forth). Below the mines is the abyss, where "the eyeless self howls, searches, gropes, and gnaws." From this region comes the "incurable ignorance" that "possesses the heart of man, and there becomes Evil."
The rest of this book describes four ruthless criminals. Guelemer is an assassin of massive physical proportions whose base is in the sewer. Babet is "thin and shrewd ... transparent but impenetrable." Claquesous comes out only at night and "came and went like an apparition." Montparnasse is only 20 and "lived by violent robbery," committing many murders. These four work together to prey on the citizens of Paris and are known collectively as Patron-Minette. When such individuals are exterminated, the narrator says, their tribe lives on to produce more.
The narrator doesn't explain the crimes of two of the criminals he describes but implies the four of them are capable of committing the worst offenses, including murder, and they are involved in a variety of criminal schemes. Hugo has no way to explain such human evil, except to say it is the result of "incurable ignorance," meaning there are people who are too bad to be rehabilitated. His metaphor seems to imply that, just as what is good about the social structure rests on unconscious, primordial, desire seeking the light or manifestation, the bad aspects of the social edifice are manifestations of an ignorance that wants to express itself as evil.