Time and time again in House of Mirth, society is presented as a "gilded cage." In New York at the tail end of the Victorian era, the members of the social elite find themselves confined by their own self-imposed rules. Women must marry for money, men must bring home the bacon, single girls aren't allowed to get too close to married men, women who expect to marry shouldn't be smoking or playing cards for money, etc., etc. The novel explores the notion of social determinism – its characters are born into specific social roles, expected to play their parts, and unsuited to any other sort of life. A socialite wife of a rich man is incapable of being a mechanic the same way a fish is incapable of living on dry land. This sort of Darwinian restriction is just another form of overwhelming confinement.
Social manacles can not be broken in House of Mirth.
House of Mirth argues that deterministic social manacles can in fact be broken.