I was talking to Justin the other day about symbolism in art (The Fountain in particular) and came to some interesting realizations about the subconscious mind. Feel free not to read this email if you don't care, but since you are a philosopher and a poet, I figured the discussion might interest you.
We were talking about why people find art pretentious, and what "pretentious" means in the first place. For instance, a whole lot of people consider The Fountain pretentious, and I think it's because The Fountain is a story told entirely in symbolism. I personally find symbolism to be an extremely powerful means of communication, since symbols are the language of the unconscious mind. By using symbols rather than direct communication, the artist can bypass the conscious mind altogether and send messages directly to the subconscious mind. The subconscious mind is then the part of the mind which processes the story and deduces what's going on; thus the meaning and the plot can percolate up into the conscious mind, leading to a sudden conscious realization that requires no direct explanation nor laborious conscious deduction. I call this subconscious inference: the subconscious uses clues given by the movie to infer what is going on, then the conscious mind comes to a sudden, powerful realization based on these inferences that have been happening at a deeper layer.
Because you find The Fountain to be an extremely powerful film, I'm going to assume that you're using subconscious inference when you watch it. However, I find that most people don't watch The Fountain this way. Most people either don't have any idea what's going on in the film (they think it's about a guy who lives for 1000 years and eventually becomes a spaceman) or they understand exactly what Aronofsky is trying to convey, but they say "What's the point? He could have told that story in five minutes without bothering to make a whole film out of it. And why did he use all that stupid symbolism when he could have just told the story directly?" (I've known some extremely intelligent people to have the latter viewpoint.)
That latter group of people tend to find The Fountain pretentious. To them, Aronofsky is telling a simple story, but unnecessarily obfuscating it with symbolism. In thinking about why this is the case, I've come to the conclusion that most people do not have a very strong connection between the conscious and subconscious minds. In fact, I think a lot of people are blocking out their subconscious minds.
The group of people who completely don't understand the Fountain are usually what our society would consider "normal people". They aren't intellectuals, try not to think about things too much, and spend most of their time seeking out mindless entertainment in the form of TV shows and American comedies as well as thoughtless social interaction. They exist at a cultural rather than individual level; they are completely a product of pop culture and spend as little time having their own individual thoughts and ideas as possible. Thinking about things differently from other people would make them weird, and the last thing they want to be is weird. (This description is a charicature but I'm sure you get the idea.) These people do not appreciate art because they don't understand it. Art speaks to the subconscious, but these people do not allow art to penetrate their subconscious at all. Because they don't like admitting that art has some meaning that they do not grasp, they call people who do enjoy art "pretentious" - they are only pretending to understand/enjoy this nonsensical, stupid art because it makes them seem smarter.
The group of people who understand The Fountain but find it entirely pointless are the stereotypical intellectuals. Their existence occurs entirely in the intellect, i.e. the conscious mind. They take pride in thinking about things a lot, and in understanding things consciously. They think so loudly about everything that the chatter of their conscious minds drowns out anything their subconsciouses are trying to say. To them, symbolism is something to "figure out" consciously, and so they focus their conscious efforts on figuring out what the different symbols mean. Many of them find The Fountain pretentious because they feel like it could have told the entire story without any of the symbolism, and that the symbolism is just an attempt at "being artistic". Also, some of them enjoy The Fountain because they can understand and discuss the symbols with their other intellectual friends at a very conscious level; these are the people who are typically considered pretentious themselves.
It should be noted I would actually consider some art pretentious. Specifically, I'd consider a lot of modern art pretentious because it's "meta-art", making an intellectual comment on the state of the world of art, and trying to define what could be considered art; I imagine a lot of the people who make this kind of art, which is to be interpreted intellectually rather than emotionally/subconsciously, do not have a very good connection to their emotions or their subconscious, and do not understand art at anything but an intellectual level.
Anyway, the conclusion I've come to from all of this discussion is that artists, true artists I mean, use symbolism because it speaks directly to the subconscious; these people are artists precisely because of their connection with the subconscious mind, and their ability to communicate with others at a subconscious level rather than a conscious, intellectual one. This is true of true composers as well; powerful music causes emotional/subconscious understanding.