There are three constant questions that plague the anthropologist.
1. What is the relationship between objectivity and subjectivity?
2. How do people come to 'know'?
3. Is it possible to do good?
They are interrelated. Any self-respecting anthropologist will have spent inordinate, crippling amount of times wrestling with these questions. In my humble opinion if you have not spent at least 10 excruciating nights up late, usually alone, with a bottle of wine convinced IT is all subjective, meaningless, and impossible to improve, then you are not really an anthropologist.... you may instead be a missionary (or an environmentalist).
The morning after these wine fueled pessimistic fits, you wake up and realize that your job is meager:
1) To describe the world in a slightly more accurate way than it is usually described, particularly in places and amongst people that are often ignored, despite inevitable subjectivity.
2) To perhaps, by some small measure, when you expect it the least, you slide an unjust world into an attitude that is slightly more kind and reasonable to the disenfranchised, the colonized, and the abused.
The difference between the anthropologist and the 'do gooder', the small ngo startup, or the aid worker abroad is in historical study. A true classical training that is found in books and libraries and not in the field.
It is this: you cannot get through a history of colonization without meeting the many well meaning men and women who believed they were helping people and instead caused genocide, famine, cultural disintegration, and slavery. This history is so common and so humbling that most anthropologists (particularly North, Central, and South American anthropologists) get incredibly nervous when people in common conversation talk about 'helping' anyone that is not a direct friend or family. At least I do. Hives, sweats, white-guilt ridden, nervousness.
Today I have been thinking that the distilled message of nearly all anthropological thought and writing, directed as much internally as out, is this: Try, please try, to be just a little less arrogant.
If this is the only accomplishment, then it is enough. And it would be a revolution.