There was a review by Fairfield Porter from the 1950s about Mark Rothko, one of the more hallowed names in American art. Porter says something like, "Yeah, Rothko paints rectangles of color. They have mass but no weight." That's not in any way a detraction, but it's a description. And it has nothing to do with the spiritual dimension. The main thing is as an intelligent viewer, to identify just what those things are that it does, that those rectangles do, and then not assume that they do these things over here. I don't know why that's challenging.