Are the intentions of a speaker or writer relevant to determining the meaning of what they say or write? It seems common to suppose so. For example, people will often try to argue for an interpretation of a book by citing statements the author has made about her thought process in writing it. At the same time, it seems obvious that, even if there is merit to this approach, it can only be pushed so far. If J.K. Rowing said, " Harry Potter is really about a time travelling cyborg sent back to 1917 to intercept the Zimmerman telegram--that's what I intended," we wouldn't take her at her word. If she really meant to convey that "meaning" she simply failed. Considerations like this make me wonder if the intention of the author is relevant at all. (After all, it would be kind of weird to suppose that authorial intent bears on the justification of moderate, plausible interpretations, but not on extreme interpretations.)

I really dislike doing this, but variations on your questions have been asked before, and some good answers put up. Please see: http://www.askphilosophers.org/question/3587 Other questions and answers pertain to your broader question, which is not about works of fiction, but about 'speakers and writers' more generally. But I'll add, re your nicely absurd J. K. Rowling interpretation, that even this would have SOME bearing on how we read the Harry Potter books. We might suspect that Rowling was clinically insane, and scour the books for further evidence; we might suspect that she was a prankster, and again scour the books looking for meta-fictional jokes; we might suspect she was writing a time-travelling cyborg novel and looking to promote it, and again we might then return to Harry Potter using it to help us imagine what the new novel would be like. The point is, the author clearly has some connection to the book(s). Either, then, we ENTIRELY discount the author when...