Thanks to Thelassa for the inspiration!
The idea of time is a persistent theme in Final Fantasy VIII. And apparently, time is used to support the Rinoa is Ultimecia theory, specifically that their connection is hinted throughout the game:
On the Ragnarok, Disc 3, as Rinoa dreads her impending future as a new sorceress, she states, “I don’t want the future. I want the present to stand still. I want to stay here with you.” This is reminiscent of time compression. Furthermore, in Centra, Rinoa contemplates the idea of fighting everyone and being killed by Squall. “I guess it’s okay if it’s you Squall. No one else.”
This is foreshadowing from Rinoa. The next is foreshadowing from Edea, controlled by Ultimecia.
After passing on her sorceress powers, and looking back on when she first saw Ultimecia as the orphanage, Edea tells Squall, “I now understand there is an end, no matter how painful it may be. Therefore, Squall, you must fight to the end! Even though it may bring tragedy to others.” She knows they must fight Ultimecia to complete the time paradox, but what tragedy is she referring to?
And finally, we have foreshadowing from Ultimecia, who reminiscences about “happy times” with somber wisdom:
As she dies, Ultimecia tells the SeeDs, “Reflect on your childhood. Your sensations. Your words. Your emotions. Time. It will not wait, no matter how hard you hold on. It escapes you.” For someone who has spoken so violently to her enemies, these melancholy words are very out of character if you take the story at face value alone.
The theory comes full circle.
The biggest question then is, how is Rinoa able to be in the final battle? Her presence alone would violate the Laws of thought, which are “the fundamental axiomatic rules rational discourse itself is often considered to be based”. These Laws dating back to the ancient Greek philosophers (found in the works of Plato, described in Aristotle). They are:
- The law of identity: ‘Whatever is, is.’
- ‘Nothing can both be and not be.’
- ‘Everything must either be or not be.’
Of course, what we think doesn’t determine reality, it only describes it. But we can’t envision Rinoa being Ultimecia for these reasons. It would simply be a contradiction for Rinoa to be in two different places at once. Even if technically she were different due to age, it would still fundamentally be her. Thus, Rinoa can’t be Rinoa, while at the same time not be Rinoa in favor of Ultimecia. This might escape the Grandfather Paradox, as Final Fantasy VIII’s world takes place in a Causal Loop. But it wouldn’t explain how her younger self would be present in front of her older self.
Also, consider that Ultimecia and Rinoa exist in a different time; the former in a casual loop and the latter having broken it. And even then, they still wouldn’t be able to exist on the same time, since they are the same person.
Rinoa is Rinoa and Ultimecia is Ultimecia, no other options are present.
Also, consider this from Thelassa:
I’ve never really bought the theory that Rinoa is Ultimecia. The biggest flaw in the argument is that having already lived through the time when Ultimecia tried to affect the future in the past and then traveling to the future where she is killed, Rinoa would know how that plan is going to work out for her. One could argue that having a GF affected her memory, but the game itself clearly shows that those memories can be triggered in familiar settings (when everyone starts remembering the orphanage as soon as Irvine mentions it). Rinoa would be reliving a major part of her past while possessing Edea, not to mention that she’d be possessing herself near the end, and that would simply have to jog her memory. She learned from Ellone that the past cannot be changed, which means it is impossible to change the present and future. Rinoa is a bit of an idiot, but she’s not dumb enough to try and Kompress time knowing full well that she herself was instrumental in preventing it.