Gah, this discussion poisons The Lifestream too.
To me, there's two obvious ways to read "symbol" in this line. One calls for Cloud being representative of other things that are important to Aerith without necessarily being so himself. That is, at its most basic meaning, what a "symbol" is.
I don't think anyone's taking that reading, though.
The other way calls for Cloud being an example or even a summary of what's important to Aerith. I think this is how "symbol" is being used in this line, and also how it's usually used.
In much the same way that Aerith is a symbol of Cloud's guilt. She isn't arbitrarily so, the way "symbol" is used by definition -- the way that the wolf symbol Cloud wears is symbolic of his self-imposed loneliness. There's obviously no real connection between the two things.
If I'm not being clear, Aerith isn't a symbol of Cloud's guilt in the literal sense, being a detached representative without a tactile connection to his guilt. She, instead, summarizes and exemplifies his guilt.
As a symbol of his guilt, she summarizes all that he feels guilt for.
In much the same way, I read the line from Case of the Lifestream White as saying that Cloud is a summary of what's important to Aerith. As I read it, Cloud is being called her friend and koibito, and his status then makes him a symbol of what's important to her.
In other words, the way the line comes across for me is that the part before the dash explains the part following the dash, and the part following the dash summarizes the part before.
As in: "My car is my means of going to work, my tool for getting to the store -- a symbol of my ability to travel to faraway places."
I have pointed out before in other threads and mako pointed this out. Aerith is thinking about Cloud because of what Sephy is doing in the lifestream. She is trying to protect the planet. And in doing so she starts to worry. And she is most worried about Cloud because of him. So Cloud is her symbol of everything that she is trying to protect.
Just like Aerith is a symbol of Cloud's failures/sins. Or better yet Denzel represents redemption for Cloud. Would Clouds PoV go something like this?
"Denzil was Clouds hometown, his mother, Aerith and Zack--A symbol of all he wanted redemption for."
I don't think that's a good example. Denzel obviously couldn't literally be Cloud's hometown, his mother, Aerith or Zack. Cloud literally is Aerith's friend and koibito.
Going back to the car example I used, the car is not a symbol of my means of going to work or to the store. It literally is my tool for doing those things, and its status as such explains its capacity to be a summary of my ability to travel to faraway places.
Likewise, I believe the line being analyzed should be read such that Cloud -- as Aerith's friend and koibito -- is a summary of what's important to her.
What's important to her isn't just limited to that, obviously, but, then, Cloud's guilt isn't limited to Aerith, and my ability to travel to faraway places isn't limited to my car.
There could be a number of symbols for what's important to Aerith, or for my ability to travel -- and there
are a number of symbols of Cloud's guilt (Zack, the wolf, Aerith, etc.). Certain qualities of those things are what cause them to be symbols of his guilt, however.
In the case of this line from Case of the Lifestream White, Cloud's qualities as Aerith's friend and koibito cause him to be a symbol/summary/example of what's important to Aerith.
