Why does Jane Austen choose abstact qualities as titles for some of her novels?
Very interesting question. The answer relates to the didactic purpose of those novels, or what Austen is trying to teach us or show us through the characters and action in those novels. Obviously your question refers to the two key novels of Pride and Prejudice and Sense and Sensibility. The important thing to note is how in both these novels characters represents the abstract qualities of the title. For example, Lizzie Bennet clearly represents prejudice in her quick rejection of Darcy that she struggles to overcome in the rest of the novel, just as Darcy represents pride. Likewise, Eleanor Dashwood represents sense - she is not one to be swept away by the sensibility of her sister Marianne. The abstract titles therefore helps us as readers to identify the focus of Austen and indicates, also, the conflict that key characters need to face and overcome to reach that happy ending and marriage. Note how the ending is only possible by these characters in some way overcoming or realising their faults and excesses and being able to successfully strike a balance.