"The mind of the subject will struggle to create memories where none exist." · 3:41pm Apr 18th, 2013
So said Robert Lutece in OverHype Infinite. Yes, it was he, not Rosalind! Not that there is a difference, anyhow.
But anyway. I know, I know, trying to make sense in MLP's finale is an... odd job, but I can't help trying to make it less stupid. So without further ado, let's put more thought into this than all of Studio B together!
When Twilight cast the spell, it cannot have only altered the others' destinies as they seem to be missing the memories of their older lives. Not only that, but they even carry memories of a life they would've lived had this been their destiny all along. What's interesting is that they remember things going perfectly well, until this day. Now, one could say that she "just" included a mind variant on the spell to implant them with false memories, but that'd be 1. already impressive and 2. boring. Also, it'd fail to explain certain things and their necessity. So instead, here's a far more interesting theory.
I'm sure you know the Multiverse theory by this point. There are literally an infinite number of universes, each technically a shelled off reality, but all connected by their collective subconscious. Yes, indeed, the Magic Flow. To those who know where the doors are, reality is but a stage. So what really happened?
Well, as it turns out, Starswirl was a bit wiser than you'd expect him to. He was the first to theorise about the Magic Flow. However, even he was not powerful enough to allow himself more than a few quick scratches of it. Enter Twilight Sparkle. The incarnation of magical power in Equestria. For her, it was but easy to overcome the borders. So what did she do then?
Since there are infinite universes, that means that there is one where the Mane 6 have their talents arranged as shown in the episode. While casting the spell, she accidentally reached out towards that or those universe(s) and pulled something from it. No, not the ponies, but the energy which makes them. Back in her own world, she infused Ponyville with the essence of their respective counterparts in that world. There may be variables, such as for what one earns their cutie mark, but there are also constants. There are always ponies like the Mane 6. There is always a Twilight Sparkle who incarnates the world. There is always a Ponyville and a princess who tries to disturb the balance.
Now, as mentioned, Twilight is a constant. She doesn't notice much from this infusion as there is no difference between herself and her in other universes. Even if there was, I'd doubt that a soul as strong as hers would be heavily influenced by such a bit of energy. The others? Not so much.
You see, the foreign energy invades them and (temporarily) overwrites the link to the Flow which they already have. Thus their destiny is overwritten and their cutie mark adapts. But there is more to one's essence than that. Right in this moment, the Mane 6 exist across two different planes, that which houses their bodies and that which gave them their destiny. Taking the random example of Applejack, she is a farmer, which shows its greatest remains in her physiology, but she is also a fashionista. She perceives being both, a state that she finds highly disagreeable.
In fact, her brain can't handle the different inputs. Her energy is that of a designer and brings such memories with it, of a life on a plane where she is one, but her brain still has the memories of her home plane inscribed into it, supported by her body's build. That discrepancy overloads her, and she attempts to form a story out of that which doesn't create a paradox. Thus, when she wakes up in the Carousel Boutique, she will at first experience major shocks as her mind struggles to comprehend, but eventually come to the conclusion that this is what she's lived all along.
Now, talents are one thing, but practice is the most. Thus, while she remembers being good at dressmaking, (after all, the Applejack on the other plane is,) she lacks the physical memory to do it right, which means that she sucks cock at it. Making sense so far, right?
But it doesn't stop there. Since nopony else seems to notice, it is logical to assume that they (with the possible exclusion of Twilight, if the intrusion is to have any effect on her) also got injected with their parallel selves. But since there is no difference between their selves here and on the other plane, they don't notice much of it. They do, however, carry the memory of the Mane 6 as they are now within them, and will use it to replace the old one in order to avoid a paradox. Believe me, it is NOT pleasant to have to deal with one, so the mind will go to any lengths to avoid it.
When everything is back to how it used to be, which can be seen with Pinkie, they go back to the other memory without even noticing. Clever. But now that that's out of the way, here's where it gets a little tricky.
This is an awesome theory, but it doesn't explain the necessity of the Elements. After all, using a memory spell to resurface the old memories or, in fact, just TELLING them what's wrong would work, right? No, of course not. In order to avoid a mental breakdown in the face of the giant paradox which would be their lives, they stick to their foreign memories, as their destinies are still changed and the only way in which they now make sense is, in fact, that they've lived a different life than they have.
So, what Twilight does is the following. She appeals to their physical memory (practice) which still gives them the skills associated with their old talents even though they no longer have them. Fluttershy subconsciously remembers how to feed what animals, Dash knows her flight routines, et cetera. That might work, but it needs another component to break through the bonds of logic.
That's right, the Elements of Harmony. They too are a constant across worlds, yet unique to the world they belong into. Powerful artifacts that allow the Mane 6 to harness the energy of the world, to funnel the Magic Flow's energy through Twilight, and binds them to said energy. Yes, they are an unalterable connection to the selves they truly are. If used while in a situation that puts their mind into a state like the body remembers, they allow their wearer to break free of the influence and regain their true destiny. Once that has happened, there is no more conflict between what is and what had to have had been. Thus, their mind reopens the memories that are still within them in physical form, dismissing the ethereal ones.
Had enough yet? Well, with a bit of determination, we can think this further. With an infinite number of universes, there is also an infinite number of those where Twilight did and didn't cast the spell. And in those where she did, there is another infinite number of those where she failed to rescue them. And, once again, there is an infinite number of ones where they either got repracticed to execute their new talents or simply rediscovered what they are practiced in, furthermore doing that even though it is not their destiny.
But chin up, that means that there's also at least one where Twilight cast it, succeeded, told Celestia and all that destiny stuff to fuck off, and took all of her friends on a holiday to Paris.
This needs to become a fic. It seems fairly plausible from what I can understand.
1017864 Considered.
But I have those other two projects to finish!
Lol, JK, fuck my open projects. It'd be a real toughie to bring across, though.
Maybe if there were two Luteces walking Twilight through it without her noticing?
It'd still be a mess no one would understand. Then again, so is Infinite, and everyone seems to line up to get that game's cock up their arse, don't they?
Yes I am quite bitter at Infinite, because it's a pure example of shitty storytelling (a game that requires the fans to guess that much in order to even slightly make sense does NOT have good storytelling) and still getting hyped for it.
1017864 Also, if you think about it, it fits really well with the given canon. The spell could very well be referring to what I've been describing. Plus that the courier reappears later.
Workin' on it!
1021712
Had to reread so that my memory is current.
Anyways, what a lot of this makes me wonder is this: if there is a multiverse that can be accessed via the doorways, then what if this is a way to explain how someone like Celestia can be so confident in her ability to guide Twilight into realizing her destiny? What would destiny be then but one of the constants that follow a pony or cutie mark?
I may not be able to grasp some of the implications of the concept, but it has me thinking on it. In the canon universe, Celestia, Luna, and/or Cadence, might be able to share an ability that allows them to sense the Magic Flow such an extent as to allow them to manipulate the progression of their universe. Not saying that they'd be the only ones as Star Swirl might have been one to try to understand it, partially going by what you have mentioned.
Because of this, the Alicorns have a wisdom that runs deeper than most and are able to preform as they do for the sake of those around them. Going by this, it might be a reason as to why Luna might succumb to the Nightmare since losing the hope that she gained through her ability could have led her to want a drastic change. Although the comics rip that ill formed idea apart.
Even though I could go into how the multiverse and Magic Flow relate to such things as Cutie Marks, Celestia's reason for giving Twilight Alicorn status, and other such ideas, this is a late coming comment by a guy who doesn't really know what he's saying.
Still, your idea is very fascinating. Sorry to have commented so late, though.
1023914 I'm trying my best to make this idea somewhat comprehensible as a fic. Trying.
My theory is that the princesses can sense the Flow around them and perhaps even peer into nearby universes, but are unable to actually manipulate those. Still, a useful ability to have, especially as the idea of time is but a farce. Lives, lived, will live. How does Celestia seem to calmly react to life-threatening crises, like Twilight's entry exam, Discord's escape, the Crystal Empire, and so on? It appears that she knows how to react to each one, where she can send Twilight and where she'd need help.
Luna's transformation was but the consequence of yet another lost popularity contest, when they'd gone to the Drawn Imagery Fair and nopony had visited her own stand. In all seriousness though, yes, perhaps she expected more power than simple knowledge. Perhaps she saw grim constants and hoped to prevent them in her own reality. Or maybe she saw a brighter world than was her own, due to different variables.
As I see it, destinies may be constants across the Multiverse, but not the ponies with them. Except one of course, Twilight is a constant. There is always a flareout of magic, a seeming banishment, an evolution beyond. It is always destined that she becomes a princess, but... whether she does is not.