Daniel Little's post at Understanding Society starts to go interesting places--the kinds of places I'd like to go, honestly--about the links between literature and the social sciences. What does each reflect of the other? What can be understood of the other discipline through the reflection process? Literature can produce perspectives, drawn from different places (the narrator or the point of view, the author), that can be studied in systematic fashion.
Can a work of fiction have realistic, referential content? Is a novel sometimes an empirical statement? Can a fictional character truthfully represent aspect of what it is like to be black in America, South Asian in Manchester, or gay in a suburban Illinois high school? For that matter, can a novel be faulted for "getting it wrong" -- for example, for representing an American Muslim as being completely oblivious to issues of racism? Or is "right" and "wrong" out of place when it comes to evaluating the relationship between a novel and the world?
Here is one possible answer: fiction is always fiction, and normally does not have empirical validity. If we want to make empirical statements about social relations, class attitudes, or typical social values of specific groups, we need to do so based on valid methods of social research: surveys, focus groups, interviews, and observations of behavior. And we need to analyze the data we collect according to valid methods of aggregation and inference. That is what is required in order to arrive at knowledge about the social world.
Another very different response goes along these lines. Novelists are sometimes skilled social observers, and some of these are also skilled "painters" or evokers of what they have seen. A great novelist can pull together his/her many insights and observations into a powerful description of a fictional world or experience that captures an important sociological truth about the society depicted. So these novelists do in fact gain knowledge of social life through observation, and they represent that knowledge through the fiction they produce. Both parts of this epistemic process are subject to criticism; but both are valid knowledge practices.
According to the second view, readers have the possibility of gaining real knowledge about the social world through the novel. Seen in this way, a novelist is somewhat akin to an ethnographer, trying to make sense of a complex system of behaviors and meanings and expressing his/her findings in a way that is truthful to the social reality observed.