I still like the full circle section. Its kind of a gimmick, but I'm a sucker for it, I guess. I love that part, and the song is perfect from start to finish. The album is pretty good too.
I kind of think of this section as DT's lyrical equivalent of famous third movement of Luciano Berio's Sinfonia, also even like Joyce's Finnegans Wake (preceded by T.S. Eliott's The Wasteland). Yes it is quite 'postmodern' in essence, though not as much in the deconstructionist-linguistic sense inasmuch as in a more pure innocent homage sense.
Though if I were to extract some philosophy from it, it is of the irony and inescapability of influence and aspiration in art (in the context of this, of a prog metal band 20 years into their career at the time).
https://en.wikipedia.org/wiki/Sinfonia_(Berio)#Third_movementI bring in these comparisons not because Dream Theater themselves (apart from their amazing musicianship) are doing anything wildly experimental but because Octavarium really is an attempt to be DT's Kantian
Ding an sich (Thing-In-Itself), making the arbitrariness of the lyrics of Full Circle very deliberate in the context of the song's message and personal meaning to the band itself in 2005.