While the interpretations here range into the awesome and onwards, I feel a little compelled to rain on the parade... Sorry.

Wazzat about the rain? Well, see, all of these interpretations involve a lot of effort/thinking on our side, with hardly any hints in the game itself (debatable, okay, especially considering the translation). Either Square's authors are veeeery very subtle and trying as hard as you like, or such theories is pure guess-work. Considering the medium of delivery, I question the likelihood that Square aimed such an in-depth philosophical reasoning at the people who were likely to own a Playstation. Maybe the market looks different in Japan (What? People old enough to go to a bar, owning PSXes??), I don't know, but for such intricate interpretations to be true, the storytelling has to be unbelievably ambitious... At any rate, I don't believe it.