Many points used to argue in favor of the theory either already require having
accepted it as fact -- in which case the conclusion would be used as support
for the evidence that's supposed to support the conclusion, a logical fallacy
known as "circular reasoning" that absolutely is never valid in a debate -- or
require making some leaps in assumption that have shaky support at best, are
defeated by Occam's Razor at times ("all things being equal, the most simple
explanation is the best"), or are outright contradicted by information in the
original story or other official materials.
In fact, the matter of witch immortality is altogether *impossible*, as it
is outright contradicted by the "WITCHES" entry in the Final Fantasy VIII
Ultimania guide, which states that witches have a normal lifespan:
(Translated by DarkAngel)
"SORCERESSES
Said to have existed from time immemorial to the present day, the sorceresses
are women who are said to have received their powers from the old god, Hyne.
There is, however, no hard evidence to support this claim. Extraordinarily
powerful, many sorceresses have harboured ambitions to rule over the world --
as a result, many people have come to equate the Sorceress with fear. However,
there are also many Sorceresses who have chosen to live a quiet life sheltered
away from civilized society; as such, the actual number of Sorceresses and the
amount of power shared between them remains unknown.
The potential to become a sorceress is determined by one's capacity to wield
such power -- their natural affinity for magic. This factor helps to determine
Sorceress candidates for when a Sorceress passes on all of her power into the
next Sorceress. The giving and receiving of power can be made between any two
individuals -- it not necessary for them to be related by blood. A Sorceress's
lifespan is the same as a normal human's, however they cannot die until they
have passed on their power to the next Sorceress."
----
NOTE: The Ultimania is a guidebook published by Square(-Enix) which besides
containing an immense amount of data on monster statistics and battle
mechanics, also contains information about the plot intended to supplement
the game. In other words it's where Square fill in (some of) the blanks left
in the game.
----
Since it is quite obvious that Ultimecia lives too far into the future for
any of the in-game characters to live to see her rise to power within a normal
human lifespan, it is clear that Rinoa cannot become Ultimecia even if she is
a witch. The game states that Ultimecia lives "many generations" ahead of the
present era, and even the most feeble interpretation of "many" would
not allow Rinoa to become Ultimecia.
While the Ultimania states that witches cannot die until they have passed on
their powers, in all cases where we see witches fatally wounded, they either
die immediately or shortly thereafter, suggesting that they either choose to
die then and there so as to end their suffering, or that their bodies force
them to give up their powers. The latter notion is supported by the fact that
Ultimecia is still trying to defy her fate during the ending, even while her
body is forcing her to give up her powers.
We know this because she states "I...can't...disappear yet," which is
certainly not a statement of defiance regarding dying *with* her powers, as
she couldn't anyway according to the Ultimania. This was a statement made in
defiance of dying at all, which she would if she gave up her powers.
Seeing as how she didn't want to die yet does, we can only conclude that
witches' bodies force them to give up their powers when the time of their
natural death has arrived -- in which case Rinoa couldn't have remained alive
by simply choosing to hold onto her powers despite having reached the end of
her natural lifespan. Rinoa *will* die before Ultimecia is born. Rinoa is
*not* immortal.
Rinoa is *not* Ultimecia.
While one might still yet argue that Rinoa could have been placed in the same
kind of seal that Adel was, and that this cryogenically preserved her far
into the future until she was released, such a notion is never suggested to
have occurred by any of the information we do have -- nor do we even know that
this process prevents aging.
In any case, trying to find a means around the declared authorial intent that
witches aren't immortal that would still allow for one to live for centuries
into the future despite no other indication that this does or even can place
seems to be somewhat defeating the point of an argument for authorial intent.
Besides, there's already a perfectly valid and well-supported explanation of
Ultimecia's origin anyway, with said origin not being dependent on Rinoa in
any form whatsoever -- and based solely on in-game details. Refer to
TheOnionKnight's "The Unjust Persecution" article below.
The final word: The conclusion that is drawn by this document, its authors, and
which we believe to be supported by the in-game evidence, extra textual
materials, and principle of Occam's Razor is thus: Rinoa *is not* and
*cannot* be Ultimecia. The theory is altogether not plausible nor reasonably
possible.
Source:
http://www.gamefaqs.com/console/psx/file/197343/34215