Emerson's essay Art, is his theory on what art should be and do. Here's some of what he has to say.
Art is...
Rooted in the time, place, politics, religion, education of the artist. Art can transcend the particular to become universal when it speaks to, and partakes in, an "aboriginal Power." The universal language of art speaks of moral nature, purity, love and hope.
The greatest pictures are simple and "[seem] almost to call you by name." For Emerson, Raphael's The Transfiguration is "an eminent example." 
Art has not yet come to maturity unless it is practical, moral, and connected with the conscience. It should "make the poor and uncultivated feel that it addresses them with a voice of lofty cheer."
"Art is the need to create;" the creative impulse of spiritual activity.
Art should "exhilarate" and awaken in "the beholder the same sense of universal relation and power which the work evinced in the artist, and its highest effect is to make new artists."
Great art is inevitable: "the artist was drunk with a passion for form which he could not resist."
The value of art...
Lies in its history. Things like Egyptian hieroglyphics and Chinese idols "denote the height of the human soul in that hour." They are, therefore, "a stroke drawn in the portrait of that fate." The purpose of art then, when viewed from an historical perspective, is to "educate the perception of beauty." We need such education because, "we are immersed in beauty, but our eyes have no clear vision."
The virtue of art...
Lies in "detachment." Until an object is detached from "the embarrassing variety" there "can be enjoyment, contemplation, but no thought." The artist's power is his ability to detach and "magnify by detaching." Since every part is representative of the whole, the detached object(s) show us the world and teach us "the opulence of human nature."
The beauty of art...
"Though we travel the world over to find the beautiful, we must carry it with us, or we find it not."
The most beautiful art is that in which both beauty and usefulness are combined.
I have not really thought about art before. Yes, I've gone to galleries, there are artists that I love, a few paintings have made me cry. But I haven't thought about the kinds of things Emerson writes of in his essay. Some of what he says makes sense to me. I particularly like the idea of "useful" arts--beautiful and functional--which makes me think of the rugs, pottery and baskets of Native Americans or ancient Greek urns and vases, and even handicrafts like quilts and knitwear. I completely agree that art is always rooted in the particular but that it can transcend time and place (I hesitate to use the word universal because I find it to be a loaded concept). I don't think, however, that art needs to be moral. Nor do I think the value of art is solely historical and its purpose to educate. They are one of many facets but not the only.
I guess I have thought about art enough to be able to agree or disagree with Emerson, but not enough to be able to articulate my own theory. I respond to art on an emotional level. Knowing all about a certain piece, say
The Mona Lisa, does not inspire me to like the painting. I can appreciate it, but that means nothing really. I am not emotionally engaged by it. I saw Van Gogh's
Irises 
once at the Getty museum in California. The painting made me weep. Much of Van Gogh's work makes me cry. I don't know much about Van Gogh and I am not sure that if I did it would make a difference. All I know is that his art stirs me up. Maybe it is the beauty that does it and I'm going to have to get my hands on Elaine Scarry's book
On Beauty and Being Just that
Dorothy has been writing about so much.
I have widely digressed from Emerson. But that is the mark of a good essay, yes? It makes you think.
Next week's Emerson:
The Poet
