Julianne Moore's character of Maude Lebowski is one of the more confusing in the film. While The Dude himself might be seen as a Deadbeat Everyman character, can Maude be seen as an archetypal Everywoman? Her existence seems to be primarily to satirize wealth and affluence, as she is shown to be the true power in the Lebowski family, granting her father a stipend from which he can enjoy a certain level of comfort. Further, she is completely independent and engages in a peculiar artist's lifestyle. These things aside, she is a rather charming character intellectually, as her obvious flaunting of her education over The Dude occurs solely to make him uncomfortable (her second appearance in the "Vagina" scene).
These things aside, Maude can also be seen as a parody of true feminism. This can be seen primarily through her aforementioned arrogance, but also through her final actions in the film (the "Jeffrey. Love me." scene). Maude conceives a child with The Dude, the epitome of a deadbeat, simply because of the fact he is a deadbeat. She wishes to raise the child by herself, without any fatherly influence over the potential son or daughter. Coming from a single parent household myself, I see this as a pretty horrendous idea.
So, we have Maude Lebowski as a self-described feminist, but in truth a potentially poor parent who thinks she can handle everything by herself. Perhaps, in the end, all the characters are nihilists. That is a funny sentiment, is it not? Maude should try believing in something outside of her own tired ideals before trying to force them upon someone else. That is only my opinion, of course.