[Art] Criticism's job:

"Much criticism is apparently based on the mistaken notion that because art is mysterious, criticism should be too. But criticism and art are not synonymous. Criticism's job is to clarify art's mystery without destroying it.

Robert Adams, Beauty in Photography: Essays in Defense of Traditional Values.

This seems to be the biggest problem and challenge both of art criticism and of aesthetics. Some art leaves us wanting—sometimes even needing—commentary, or clarity. Beauty almost always needs no explanation to be perceived.  You will convince me much more easily that sunsets are beautiful by showing me one, rather than explaining the science of light, and cloud formations to me.

And yet, sometimes we want to know why sunsets are beautiful. We feel something while watching the sun sink and rise, and we want to understand that feeling. It feels right, but how does it relate to the rest of life? Does the full spectrum of light on display for ten minutes before it leaves say anything about the nature of existence and the meaning of the cosmos?

What we want clarified is art's significance to us, and our philosophy and theology and ethics. We want to fit beauty cohesively into a worldview. The problem is once we start talking about the significance of a wild rose, we usually end up destroying that original significance, the significance it had as we happened upon it in the middle of a drab wood. 

Adams understands this paradox, and does a good job at clarifying with destroying. I would recommend this collection of essays.