Langdon is the perfect man to uncover Saunière’s secret. On one hand, he is like the reader—clueless about what is going on and why. On the other hand, as a professor of symbology, he is very knowledgeable and well equipped to solve the mystery. It seems that most of Langdon’s knowledge has been academic, with no real-life application. Here, he is given a chance to apply his puzzle-solving skills to an actual murder.

Silas is a masochist who lives by the motto “pain is good.” Pain is also at the foundation of his religious beliefs. Silas is a sinister representative of his religious group. His violent behavior, whether directed toward himself—the cilice belt, the self-flagellation—or toward others, as exemplified by his willingness to murder, makes his organization seem evil. Although what the philosophy “pain is good” has to do with the goals of the Teacher, and why Saunière was working against this group, is not yet known, the reader does know that Silas and his organization are threatening.

Langdon displays a wry sense of humor, especially in his musings on French culture. His academic specialty affects his outlook: he seems to see the world around him in terms of symbols. For example, his discussion of French culture arises from an analysis of its architecture and the Freudian symbols he perceives in its architecture. This way of perceiving the world may be helpful for solving Saunière’s murder, but it is also a limited method of perception.