Visual art, language, and music fall along a spectrum whose two ends are the “representative” and the “nonrepresentative.” By “representation” I mean of the physical world.
Historically, a visual art like painting, from Lascaux to the Impressionists, has been focused on the representation of things—animals, people, gods (which were then considered “things,” and usually took the form of an animal, person, or hybrid thereof), plants, landscapes, and so on. Even artistic traditions that de-emphasized representation, like Islam that forebade the representation of life (unsuccessfully, as evinced by Persian miniatures and illuminated manuscripts), the decoration of mosques combined mathematical patterning with calligraphy, that is, the representation of physical letters in a physical book. (Admittedly the book in question, the Qur’an, was believed to exist in an abstract or spiritual form in heaven.) It took the invention of photography to force painting out of its innate tendency toward representation. The 20th century produced, accordingly, more “abstract” art than any other century on record—for all I know they invented the term, and quite possibly the genre itself—art that is neither patterned, in the manner of mosque art, nor representative of things, in the manner of most painting until then. It should come as no surprise that painting saw a serious drop in popularity and cultural centrality over this century, and that the eyes of the society have turned to photographs and films heavy in special effects (which are, essentially, the sum of thousands of artfully altered photographs) to get their fix of visual awe. Visual art going predominantly non-representative is the equivalent of music going primarily representative.
Because music, at the other end of the spectrum, is stubbornly non-representative: The “tone poem” was a minor genre in Western classical music, and short-lived; Chopin’s etudes sometimes carry names like “Winter Wind” or “Ocean,” but the names aren’t Chopin’s, and there’s little chance a new listener, not told the nickname, would light on that particular phrase if asked to give it one. You almost never find music, anywhere, in any culture, striving to reproduce the noise of traffic, conversations, birds, or machinery. If anything, representative or mimetic sounds are a rarely utilized musical effect, never the musical substance. Music knows exactly what it is. The only purer abstraction is mathematics; it is at the limit of the spectrum, as it can represent reality, not through mimetic sound, but only through the abstraction of number; people have always sensed a kinship between mathematics and music, and the two are indeed neighbors. Music tends to leave representation to the lyrics, and its influence frequently drives the lyrics, too, into abstract Yeah’s and Ooo’s. This is why song lyrics so rarely transfer effectively onto the page.
That is where language, the hybrid, the dual-purpose medium, holds sway. Unlike visual art, where abstraction is a minority tradition, and music, where representation is a minority tradition, language has no minority tradition. There is a massive amount of abstract use of language—religious commentaries, philosophical tracts, political talking-points, scientific papers, some kinds of poems, and, er, blog entries. There is a likewise massive amount of representative use of language–fiction, much of poetry, and forms of nonfiction like travel writing and instructive technical writing, like anatomy books and assembly manuals. Note that those two forms almost always require pictures or diagrams to go with them; their descriptions, like the spinous process projects posteriorly from the confluence of the laminae, attempt the work to which visual art is naturally best suited. Note that fiction is squarely part of the representative half of language; even a “mathematical romance” like Edwin Abbott’s Flatland succeeds, in its descriptions of the social interactions of geometric shapes, by oblique reference to Victorian society.
Note also that poetry can sing at either end of the spectrum in a way fiction can’t. This doesn’t just have to do with the “imagery” or “music” of poetry. The abstract line by Pope, “A little learning is a dangerous thing,” is a lovely line, but so are Bishop’s highly descriptive lines about a fish, and so is John William Burgon’s hybrid line about Petra, “a rose-red city half as old as time.” The finest poetry tends to hybridize the two like this—Pope himself knew this, and followed up the nonrepresentative line quoted above with “Drink deep, or taste not the Pierian spring.” It shows us the mechanism and centrality of metaphor in poetry: Metaphor, at its best, can hybridize the representative and nonrepresentative, as when Emily Dickenson’s soul shuts a door. Etymologically, metaphor carries over—from one side of the spectrum to the other. It can do this precisely because language is in the middle; the distance traveled is not so great. There is no equivalent of metaphor in either of the flanking arts of painting or music.
This is, incidentally, why the God of Genesis’s artistic medium of choice was language. He neither painted creation, nor played creation on an instrument, but spoke it using language–for language is the only creative medium in which you can link what physically is not and what physically is, turning, by fiat of metaphor, the ethereal into real earth.