I try to avoid [a] narrow, limiting definition of what literature is, what it can be used for, and how one ought to approach it, for two clear reasons. First, approaching literature is primarily an individual activity, and the great diversity of humanity must call for multiple subjective approaches to literature. And second, there are so many potentials for literature, it seems harmful to try and limit those uses.
Now, on the most fundamental level it is of course not true that "approaching literature is primarily an individual activity." Not only does the reading of works of literature involve at a minimum an interaction between writer and reader (and thus a kind of partnership), but "literature" is itself unavoidably a social/cultural/historical phenomenon to which the "individual" comes only through the mediation of cultural processes and of literary history.
Literature is "literature" because we have inherited this concept as a way of identifying a certain kind of imaginative writing deemed worthy of consideration in and of itself as something separate from ordinary discourse. The term has always been somewhat unstable (or at least so capacious in meaning that it can accomodate changing tastes and assumptions), but never has it been so completely relative as to mean whatever the "individual" reader wants it to mean, which is to in effect render it meaningless. If we want to hold on to "literature" as a category of writing acknowledged by everyone (or everyone interested in this kind of writing), then we have to also acknowledge that its contents can't be judged simply through "individual activity."
Previous readers and critics have inevitably left their traces on the books we now want to read "on our own." The very availability of these books for our reading pleasure has largely been determined by those previous readers' choices (many other books might have made their way to us, but haven't), and the urgency with which we want to read some books (the "classics") is also to a significant extent a consequence of critics' evauation and discussion of these books. This is not to say that works of literature must always be "historicized" in the manner now de rigueur in academic criticism, but simply to recognize that what we call "literature" is so as part of an ongoing historical process of reading and analysis.
Literary criticism as the act of sifting through what is offered as literature, of making discriminations and of judging works of fiction or poetry, is thus as integral a part of the literary enterprise as the creation and the "individual" reception of literary works. To suggest that a given poem, story, or novel is especially accomplished or disappointingly weak, according to articulatable standards, is not to rob the reader of his/her "subjective approach" but to provide a context against which the reader might measure his/her own response. To apply critical criteria derived from careful and extensive study of literary history and aesthetic precepts is not to belittle the reader's own standards but to encourage the reader to engage with that history and those precepts and apply them as well--an activity that will always have a "subjective" character to it.
I don't deny that "multiple" readers will ultimately find different "uses"--different elements of value--in the books they read. And I don't fully disagree with the notion that reading is at some point an "individual activity." The experience of reading poems and novels does indeed consist of the reader's fully attentive encounter with the text, but that encounter is first of all with the author's aesthetic methods, his/her "making" of the text, in the same way we encounter a painter's execution on the canvas or the composer's shaping of sound. Those methods are always themselves informed by the author's influences and familiarity with the past practices of the form, however, and thus we are returned to literature as a collective, and to that degree objective, endeavor.