In answering the question why we should care about an author’s intention, C. S. Lewis gives two answers in his book An Experiment in Criticism.
"Why," they ask, "should I turn from a real present experience—what the poem means to me, what happens to me when I read it—to inquire about the poet’s intentions or reconstructions, always uncertain of what it may have meant to his contemporaries?"
There seem to be two answers. One, is that the poem in my head which I make from my mistranslations of Chaucer or misunderstandings of Donne, may not be so good as the work Chaucer or Donne actually made.
Secondly, why not have both? After enjoying what I made of…