You don't say what novel you are reading, but I can explain to you how to determine the theme for yourself. A theme is a main idea that the author is trying to get across with his or her work. One way to determine a theme is to try to find words or phrases or events that are repeated at different points in the novel. If the author repeats something, it is likely because he or she wants you to notice them because they are clues to the theme.

Another thing to notice is paradox. If there is a contradiction in a character, or the plot. Paradoxes are used to cause you to ask questions. If you ask why questions about paradoxes, your answers will most likely bring you to the theme.

How can I identify the main themes of a novel?

Reading a novel to discover themes is an early stage of learning how to read critically and organize your response in terms of analytic structures rather than simply plot summary and chronology.

As you read through the novel, look for similarities in ideas, situations, imagery, or emotions which recur across multiple characters and places in the plot. For example, in Jane Austen's novels, there is an implicit assumption that gentleman marry among their own class, and a recurring theme of the conflict between gentry as a cultural/social construct and as an economic one. This leads to a second theme of whether social mobility, and the rise of urban fortunes, destabilized the organic unity of class fusing the cultural with the economic.

A typical ideological theme would be whether natural and human law, or nature and civilization, conflict with each other (e.g. in Antigone) or reflect each other (Pope -- But when t'examine every part he came/Nature and Homer were, he found, the same.")