Lily's conversation with Mrs. Trenor in Chapter Seven provides a good example of how the past plays an important role in present society. We learn that Carry has been associated in the past with two European nobility figures, Prince Varigliano and Lord Hubert. We learn later that Lily was once engaged to the prince, but the engagement was broken at the last minute when Lily was caught flirting with another man. Lily has a number of skeletons in her closet, all of which Mrs. Dorset knows about and will use to harm Lily when the occasion arises. The past is never forgotten in this society; it can always come back to haunt anyone.
Lily also begins to get a sense that she is sliding back toward her old life, before she was an aspiring member of society. This foreshadows her upcoming social decline; at the end of the novel she has been removed from society altogether and joins the working classes. However, we should also note how frequently Lily's mood changes in the novel. She is usually at one extreme or another: freedom or slavery. Interestingly, both states are based on her financial status. When Lily has come into money, she feels wholly free. Whenever she feels burdened by debt, she feels enslaved. Earlier on in the novel, when Lily is staying at the Bellomont, she even asks herself whether the maid who helps tidy the Bellomont is better off than she, because the maid is not a slave to debt, clothing and gambling like Lily. The freedom-versus-slavery motif comes up frequently in later chapters, particularly when Lily faces the problem of how to pay off her debt to Gus Trenor.
As discussed in the Context section, The House of Mirth was written just over a decade before the emergence of the Modernist movement, which took an interest in the workings of the mind, among other things. Modernism saw the development of the stream-of-consciousness style used by Virginia Woolf, T.S. Eliot and William Faulkner. Some of the roots of that interest in the workings of the mind also can be seen in Wharton, who includes a map of Lily's thought process in Chapter Seven. When Lily hears about the stock market, she immediately thinks about whether or not it could benefit her. To decide this, she thinks about her friends and whether or not they have benefited, which also answers the question of whether or not the stock market would be a socially acceptable concept. Deciding that her friends have profited from stocks, Lily decides that she too should get involved. She then has to figure out who will help her, and she realizes that Trenor can take care of her finances without compromising her social standing at all because Trenor is already married. She then asks Trenor to help her, and he readily assents. Thus, every step of Lily's thought process involves a calculation of how an idea could benefit her and whether or not her friends have also made use of the idea. This is an important insight into Lily's value system as a character and an effective literary technique on the part of Wharton.
One of Wharton's tasks in the novel is to portray some of the ironies of society, most of which are related to money. Ideally, because Lily needs money the most in order to join society, she should be the one who marries a rich man such as Gryce. Instead, Gryce marries Evie Van Osburgh, a woman who is already extraordinarily wealthy and has no need for money. It is also ironic that even though Lily and Selden love one another, Lily feels that she cannot marry him because he does not have enough money. In the latter case, society's emphasis on social stature and money places people in situations that force them to act against their will.