I am trying to get a definition for feminism. Usually it is defined as some sort of doctrine or movement advocating social equality between men and women. But this cannot be correct because there are fathers who advocate equally shared child custody among divorced parents, and no one calls them feminists.
There are also feminists who promote privileges for women because of natural inequalities. Equality is not what they want. They want to advance women's rights and interests regardless of any comparison to men. These feminists often contradict the feminists who claim to want equality.
It is also hard to pin down the scope of feminism. It doesn't seem to be limited to economics, politics, literature, or moral philosophy. It could related to almost anything.
The only common thread that I see among feminists is that they all seem to have belief that society is somehow disadvantageous to women. Therefore, here is my definition:
Feminism -- An incoherent collection of ideas characterized by women griping about how the world works.