How important is understanding artists' intentions when encountering art?

If I am privy to the intentions of an artist in making a particular work, which doesn't often happen, my enjoyment and appraisal of the work will be restricted to a judgement I'd rather not make. Namely, whether this work a successful realization of the artist's intention, which is a closed system. I'd rather imagine the work as an animal that is complete, alive, and quite unable to make answer to any clever questions. So, no, although I do find it helpful to know a few basic biographical details about the artist.