What I'm going to argue is that "works of art" and "literature" are both such illusory categories. Defending them involves the same sort of sufperficial analysis that would characterize the category of "creatures with wings." They do not constitute definable realms of human activity about which useful and powerful propositions may be formed. Pynchon's Gravity's Rainbow and a freshman theme simply do not exhibit enough distinctive properties to allow us to claim that one is literature and the other is not. Neither does there exist any acceptable set of criteria by means of which one can say that Beethoven's Second Symphony is a work of art and a wadded up piece of paper is not. Hence neither "literature" nor "works of art" constitute a definable object of a definable discipline.
Now there is a substantially new study, about which I was just beginning to learn when my eyesight failed, which is a study of the book. That is clearly as subdivision of historical writing, but it is clearly a defensible sub-division as "literature" and "works of art" are not. It remains to be seen whether the results of that study are interesting and/or useful contributions to history, but I suspect that they will be, in the way that the study of "literature" and of "works of art" as distinct realms have not been.
Carrrol