Literature is such a crazily awesome subject. I've only had one Lit. class so far here at the university, and that was more of an introduction and overview than an actual class. But I'm looking forward to beginning in earnest.
One of my reasons for loving literature so much was, until recently, more instinctively felt than verbalized. I always have found the fact that you can look at one book from a million points of view and still get something out of it to be perfectly exhilarating. During my meeting with my academic advisor the other day, my advisor (a philosophy professor who is really awesome, btw) showed me a way of describing what it is exactly that literature does.
It's a simple way of thinking about it, and one that has lain behind my education since kindergarten. Nonetheless, this is really my first experience thinking about the distinction between literature and other branches of learning in such clear terms. Philosophy, literature, and history are the three categories under which the rest of the academic disciplines appear. They each represent a different approach to the world and the exploration of reality. Philosophy concerns itself primarily with reason - so under that heading come the physical sciences, logic, math, politics, etc. History is a "looking -back" and judgment on the way philosophical and literary concepts have worked out in the past. Literature, however, is characterized by its introduction of the imagination into thinking.
This last item - literature is exploration of reality through the imagination - it's the obvious reason for the multiplicity of ways to look at a good book. The author must work imaginatively to write a good book. But the reader has just as much of a reason to exercise the imagination. With this, you can come to view the work from a perspective almost identical with that of the writer, or you can find another interpretation which ties into the general feel and theme of the book but is almost totally opposite to the former.
Being a good reader requires almost as much work as being a good writer, I am inclined to believe. I am quite aware that writing holds very distinct challenges, but if literature is the branch encompassing both reading and writing, both use essentially the same method to explore the world. Euphoria-inducing concept, isn't it?