Tin's The Rules of Reading and her mention of the "perfect reader" reminded me of one of the lessons our Filipino teacher taught us in college. The complaint was how much didactic many stories have become--and it's not just limited to the Philippines but Western culture in general. In fact, we've been trained to ask "what's the moral of the story" when the lesson of the story isn't necessarily a question of right versus wrong or good vs bad. Hansel and Gretel, for example, isn't necessarily a story of good vs evil, but a competition of wits (or if you take the actual story in its context, a story of hunger in general [the family, Hansel and Gretel, the witch]).
Our preconceptions can simply alter how we might interpret anything we read. I mean to most Filipinos, we all know about Noli Me Tangere, and we've been conditioned to treat it with reverence. But I wonder how other people would interpret Noli Me Tangere, never having heard of Jose Rizal. A better example for the Philippines is perhaps the Bible. A lot of Filipinos treat it with reverence but that simply impedes me from talking about it in a non-religious context. I was telling a batchmate at how The Bible is really a book of myths in the same way Greek Gods were myths. Of course he was reluctant to talk about it as he perceived it as insulting to talk about a culture's beliefs as if it were mere myth. Jeffrey Ford even postulates that the Bible is a book about "the creative power of language", an idea that many educated but anti-Christians might initially scoff at simply because the Bible is a representative of all they dislike about religion.
Perhaps a better and more "practical" analogy might be lateral thinking. Usually this might come in the form of a mathematical question such as "If it takes one man to dig a ditch in one hour, how long would it take two men to dig one ditch?" and answer it with other questions like "is there sufficient equipment?" or "what material is the ditch made of?" depending on other variables that isn't readily available in the lead question. It's out-of-the-box thinking and the problem with conventional reading lessons is that it doesn't encourage such thinking but rather promotes the established interpretation of a story.
I think it's rare for a story to be completely stand-alone. The author makes several assumptions about his or her readers--we're all part of the same collective consciousness. A writer doesn't really explain what a human is for example, or enumerate each and every difference between male and female (but they do cite instances of their roles in the current cultural context, such as a Westerner writing about how females are portrayed in say, Chinese culture). Every reader makes assumptions, even if it's as simple as the sun rising in the morning and the sun setting in the evening. If aliens were to read our books (and somehow translate the language), I'm sure they'll be baffled by several of our assumptions.
As for "the perfect reader", it's an impossible designation (at least taking into consideration human limitations) simply because there's so much human experiences and cultural relativity that no single person is able to familiarize themselves with all of them. Better yet, if a state of "the perfect reader" could be achieved, why limit it to reading? Wouldn't this person be a great psychologist as well? Or anthropologist? Perhaps even a bureaucrat, who can satiate various nations and promote world peace.
Of course having said that, there is value to being a "good" reader. If we can understand various texts and their contexts, how much more can we understand other people? Unfortunately, it's also been my experience that the two aren't exclusive. I've met people who are smart and understanding when it comes to texts but mean and impatient when it comes to people. We have to keep in mind that books don't talk back, and if a person has a certain interpretation of a text, the text itself won't complain and say "hey, you're reading me wrong!" (assuming of course it is possible to read a text "wrong"). Most likely, readers will feel confident and smug about their interpretation until they run into a contrary belief. At that point, they'll either re-evaluate their earlier interpretation or start a debate of which is the "correct" version.
I think that in the end, paradigms can never be eliminated (and it is difficult to write a story that takes no paradigm into consideration) but let's also be aware that we, as readers, bring a certain paradigm when reading a story.