Ever since she had been a student for Celestia, Twilight had always wondered what the limits of magic could be. No matter how much she delved into it, how many sleepless nights studying and thousands of spells cast, there was always something more to witness or learn or elaborate. It really felt like a bottomless well of surprises, so much that she wondered if even Celestia or Luna would have reached by now some sort of true mastery over any school of magic; or if they would ever; or if something like that would even be possible at all.
The delicious jasmine tea she was sipping in her library could do little to distract her from this.
The mere idea of fitting all the possible ways to bend reality into a single brain... all the combinations, nuances, leylines, of all the different schools... no, there couldn't really be such a way.
Or was there?
Maybe she would have to approach the problem from another angle. What if someone had already done that? She surely couldn't be the first overenthusiastic magician asking such a question. What if someone had succeeded? How would have they done that? If they couldn't have alone... would they have stored it somewhere? Recollective crystals perhaps? Fused books to their being? No, these were still finite solutions, and Twilight was looking for something effectively limitless, if not outright infinite. How would one achieve that? Maybe... maybe there could just be a way to ask the source directly? The very ambient magic, the receptacle of all possibilities? Figuring out a proper decoder would be like having a calculator to do the proper math for you, instantly, instead of running it through your head each time. It would make accessible schools of behaviour previously unheard, maybe un-thought of!
So what if this had already happened, in some form? One would perhaps leave a trace of magical radiation if she were fused with the ambient, or communicating with it in some way; the echoes of their inquiries may be traced, if one knew what she was looking for.
She quickly composed a detector spell in her mind and cast it: she located all traces of spells from every pony in Ponyville at first, but that wouldn't do. She'd need to go deeper... expand her range... trying to figure out a common pattern...
After interminable minutes of pure concentration, all of a sudden, she saw, like noticing a hidden pattern in a picture, that was always staring at her, being everywhere and nowhere, a soft reverb that she had always mistaken before for part of the magic ambient noise, until now. She gasped, shivers running through her spine from the enormous find.
She set her magic to resonate with it, and the vibrations in her horn grew; she fed it more power, and her horn started glowing with extra layers of overcharge. She'd have to catch the frequency as right and clearly as possible...
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Suddenly, Twilight Sparkle stopped feeling her own energy flow. And her body, for that matter. She just... was, an observer in the middle of a world more of thoughts and emotions than light and sound. It was... she felt like in the middle of a teleport, only she wasn't cruising along precise leylines this time, and she wasn't straining to concentrate on anything. In fact, she found that when she concentrated, waves of magic would ripple outwards from her being. That her every thought shaped the magic around her. That she herself in that moment was pure magic, possessed and directed by a consciousness.
A single thought, sharper and louder than the sea of ideas that comprised her horizon, reached her.
It spoke without words of a warm greeting to her.
It offered congratulations on reaching this existence like others did, both in the past and in the future "before" her (for truly, time and space had no meaning here)
Twilight wanted to inquire who she was talking to, and much like a wall would answer any sound with an echo of its own, the answer was immediately apparent to her, by the very fact that she asked. It was Arcane Scroll, a grand spellcaster that Twilight remembered for studying his contributions to alchemy and astrology, who the books said lead an intense life at the court of Princess Celestia and Luna, more than 1200 years before her time, and who died young in his studio.
Twilight realized what all this meant. Here in this world, magic was closer than thought itself. Magic was the very place she was in, it was a part of her, or she was a part of magic, and all she could have ever wanted to know about it were plain in front of her, much like a rainbow would display all the possible colours. She could study magic, the ultimate force of change, from within, so much so that any event she'd fantasize of occurring would just be thought into being, faster than instantly.
She thought of Celestia, of completing her studies, of the tasks that she would ask of the prodigal unicorn, and just as she did so, it had already happened: all the victories against evil with her friends, all the celebratory parties, the coronation at Celestia's side, her career as a teacher at Celestia's School for Gifted Unicorns. It was all in her memory. It was part of her. It had all happened. It was all done.
Each time she thought or wanted something, it had already been fulfilled. She had possessed and wielded magic beyond comprehension. She had discovered new schools of magic and optimized, if not outright revolutionized all the existing ones.
She had already returned in Ponyville to her friends to tell them of this fantastic tale.