“Nope, the electrical pulse is, like this……”
Kazuto brought his right fist approached his spreading left palm.
“The synapse at the gap between neuron and neuron, is the sole transmitter of the substance. For the series of the ignition along the brain cells route, could that phenomenon be called the essence of the mind?”
“Hmm……”
At the same time Shino frowned, Asuna smiled in a confused manner as she said,
“More than this is already impossible, Kirito-kun~ Because until now, science is still unable to find the answer of ‘what is the mind’ right?
“Well, that may be true.”
Kazuto eventually smiled as he nodded.
“H-Hah!? Wait, the idea up to this point still can’t solve anything, can it?”
As Shino became furious and protested, Kazuto took a chance to glance at the damp street, before continuing to speak in a serious tone,
“But, there are humans who approach the answer with their own theory.”
“Their own…… theory?”
“«Quantum brain dynamics». It seems to have been proposed at the end of last century by an English scholar. After tackling the underlying theory for a long time, «RATH» has finally managed to create that machine which looks like a monster…… ——From this point on, I still can’t fully understand it yet. Just a moment ago, we talked about the structure of brain cell.”
Shino and Asuna nodded at the same time.
“The cell itself also has a frame to support its structure. It seems to be called «Microtubule». That frame doesn’t just support, but acts like a skull too. The brain within the brain cell.”
“H-Hah……?”
“That skull has the shape of a tube, in other words, the hollowed pipe. Of course it’s very tiny…… we’re talking about a diameter in nanometers, but it isn’t empty. There is something contained within the tube.”
Shino inadvertently exchanged glances with Asuna, before looking at Kazuto and asking in a low voice,
“What is inside……?”
“Light.”
Kazuto gave a short answer.
“A light particle…… or «Evanescent Photon» is what it’s called. This photon is, in other words, quantum. That existence is like indeterminism, it is endlessly fluctuating according to the probability theory. The fluctuations…… that is what the human mind is, according to the theory.
Right when she heard those words, Shino could feel a shudder running about from her spine to both her arms for some reason. The mind and fluctuating light. That mysterious yet beautiful image also welled up within her, at the same time, Isn’t that already the god’s domain? Such thought had appeared in her mind.
Asuna was also embraced by the same deep emotion, her brown pupils were blurred with anxiety light as she spoke in a slightly hoarse voice,
“Kirito-kun, the name of the new machine is…… «Soul Translator», right? Soul…… in other words, the collection of those lights is a human’s soul?”
“RATH engineers call it «Quantum Field». But, by giving the machine such a name, they must have thought about it already…… That quantum field, and the human’s soul.”
“But then, what does it mean? Soul Translator is the machine that doesn’t access the human brain, but the soul itself……?”
“When said like that, it doesn’t sound like a machine anymore, but a magic item in a game instead, huh.”
What he said had softened the atmosphere slightly, and Kazuto then continued speaking as he grinned,
“But, it isn’t an act of magic or god’s miracle. Let’s plunge into the explanation of its structure for a bit…… What it does is recording the spin and vector of each photon inside the microtubule, the «Qubit» unit data. In other words, the brain cell isn’t just a single gate switch to let electrical signals passing through, but it could be said that the cell itself is a unit of a quantum computer…… well, this part is already the limit of my understanding though……”
“It’s alright, I have already passed that limit a long time ago.”
“Me too……”
Shino and Asuna surrendered together before Kazuto exhaled his breath in relief.
“The collection of photons which is the memory of that computer, perhaps, it might even be the human’s soul…… RATH has given it an original name. «Fluctuating Light», which they abbreviated to——”
He paused slightly,
“«Fluctlight»”
“…………Fluct…Light.”
Shino softly repeated the coined term with a mysterious sound. If what they had been talking until this point was all true, then the Fluctlight also existed in her own head too. No, by saying so, what she thought was «her» was……
The shudder from earlier returned to Shino, she rubbed her arms which extended out of the sleeves of her summer uniform. Next to her, Asuna also made a movement which looked like she embraced herself, while she spoke in a small voice,
“——Reading the Fluctlight…… No, the machine which «Translates» it, is what Soul Translator does. In that case…… the translation isn’t just one way, right?”
Shino titled her head as she couldn’t understand the meaning of her words right away, at the same time, Asuna glanced at her, with pupils that were filled with the color of anxiety.
“Sinonon, think about it…… The AmuSphere we’re using isn’t just reading the movement commands sent to our body. It feeds the sight and hearing…… the five sensory signals into our brain, creating the experience of the virtual world. It’s the core of the FullDive technology used in that machine, right? Then, the Soul Translator which could do the same thing should be the next generation machine, isn’t it?
“……In other words…… it could write something into the soul of the person connected to it……?
At that point, both of them turned their gazes at Kazuto.
Although the black haired boy seemed to have hesitated a little, He nodded in agreement before long.
“Yeah…… Soul Translator, it’s too long, so RATH shortened it to «STL», that translation machine is bidirectional. In the hundreds billion qubit data holding a human’s Fluctlight, it translates and reads the words we understand, and at the same time, it translates and writes the information into a form we can read too. If it’s not the case, it’d be just as Asuna said, it won’t be possible to Dive into the virtual world. In short, it maintains and disposes the Fluctlight’s five sensory information, and fills in the information about what being seen, or the sound being heard.”
Then, Asuna leaned forward and asked what seemed to be her main question,
“Could it possibly be that…… could affect memory in the soul? Kirito-kun, you said just now that you don’t retain any memories during the Dive. This means Soul Translator…… STL could erase or overwrite your memory, doesn’t it?”
“No……”
Kazuto touched Asuna’s left hand briefly to relieve her as he shook his head.
“The part that maintains the long-term memory data is very large and the archival method is very complex, at the current state it could be said that it’s still out of reach. The reason that I don’t have any memory of the Dive is merely because it seemed to be intercepted along the route to that part. In other words, it isn’t completely erasing memory, it’s just I can’t get to remember it…… just like that.”
“But, I’m……scared, Kirito-kun. Something like manipulating memories……”
An anxious expression still remained on Asuna’s face.
“Besides, the person who brought that part-time job to you is Chrysheight…… no, Kikuoka-san of the Ministry of Internal Affairs and Communications, isn’t he? While I think he isn’t bad person, but I feel I can’t see even the tiny bit at the bottom of his heart. It’s somewhat similar to the Guild Leader. Somehow…… I feel like something bad is going to happen again……”
“……It’s true that he never shows what he’s
thinking. And I also don’t know his real social status nor professional duty, along with various things. But……”
As he cut off his words, Kazuto’s pupils seemed not to focus at any place in the shop as he spoke,
“On the first day of the debut of business-use first generation FullDive machine at the Shinjuku amusement part, I rode the first train to line up. At that time I was still in elementary school…… ‘This is it,’ that was what I thought. ‘This is the world that was calling me for a long time.’ On the first release day of Nerve Gear, I also bought it with the money I had been saving up…… and kept diving into various games. At that time, I really didn’t care about the real world. Eventually I was selected for SAO’s beta test, and that incident unfolded…… terrible numbers of people had died. After two years of being captive and returning, Sugou and Death Gun incidents continued occurring one after another. I…… want to know. About where the FullDive technology is heading…… About the meaning behind those incidents…… For the Soul Translator, although its functionality is entirely new, but its architecture uses the medical-use Medicuboid as a prototype.”
While Asuna, who faced downward, was listening to Kazuto’s words, her shoulders trembled. Shortly after that, her steady voice flew through the quiet shop’s interior,
“It’s my premonition. About what is inside the Soul Translator. What if it doesn’t end up as being a mere amusement machine…… Probably, there might be a dangerous side too. But……”
Kazuto imitated the motion of gripping his sword and swung it down as he spoke,
“Until now, no matter what world it was, I was always able to come back. This time too, I’ll surely come back. Well….. in the real world I’m just a weak and powerless gamer though.”
“……Even though without my back up, your back is wide open.”
Asuna gave a light smile while exhaling a short breath, then looked at the face of Shino who was sitting beside her.
“Really, this man has so much self-confidence.”
“Yeah, well, after all he’s the legendary Hero-sama anyway―”
From the conversation between Asuna and Kazuto, she could understood at once, even though it had words she heard for the first time, Shino didn’t try to interfere too much and instead spoke in a joking tone,
“I already read [All Records of SAO Incident] which came out last month―, it’s quite hard to believe this guy is the same [Black Swordsman] who appeared in that book.”
“O-Oi, stop it……”
Asuna giggled at the action of Kazuto who waved his hands while bent backward, as she said “Yeah, really,” while nodding.
“Written in that book, it was said this leader had a big influence among the capturing guilds, even though the record itself is fairly accurate, a great amount of bias was added into the character description. Like when Kirito fought against the orange players……”
“[When I unsheathe the second sword, no one is allowed to stand before me!]”
“Kyahahaha,” the two girls burst out into a grand laughter as Kazuto sat dejectedly on his chair with a blank expression. As Asuna felt relief and finally returned to her smiling face, Shino continued delivering the final blow,
“That book is also translated and is published in America. It means this Hero-sama is a world ranker now.”
“……After I went through great lengths to forget it…… And I already agreed to forward the royalty too.”
Shino was still smiling as Kazuto grumbled, she then recalled the question she had for a while and continued the topic,
“But, Kirito. After all, that STL does the same thing as AmuSphere, doesn’t it? Creating a VR world using polygons, then sending the image and sound into the connecting person’s brain, is there any point in spending large amounts of expenses on that machine?”
“Oo, that’s a good question.”
Kazuto straightened himself before giving a nod.
“What Sinon said just now, [Creating the VR world using polygons.] Polygons are, in other words, a collection of coordinates and surfaces…… the digital data. The current highly detailed modeling had reached the point where the trees or furniture is hard to distinguish from the real thing, but its essence is still the same.”
He then quickly operated the mobile terminal placed on the table, and started up a pre-installed mini-game. The futuristic race car which was slowly rotating on the demo screen had a sweet interior, the curved surface of its body also didn’t look awkward at all, it was indeed, a figure of a polygon model.
Shino lifted her face and slightly tilted her head.
“That’s, well…… in ALO or GGO, when too many players gather at the same place, the rendering of the objects sometimes can’t keep up. But aren’t the fundamental basis of AmuSphere and STL the same thing? To create the 3D model of something which practically doesn’t exist from nothing, for a user to both see and touch.”
“Yeah, that’s the point. Hmm…… how should I explain it……”
Kazuto was silent for a moment before lifting up the empty glass of Caffè Shakerato and showing it to Shino.
“Sinon, this glass exists in reality, right?”
“…………Yeah.”
While having a dubious expression, she gave a nod. Kazuto then brought the glass closer to her and said something difficult to understand,
“Now listen, this glass currently is in my hand, and at the same time it exists in Sinon’s consciousness…… or Sinon’s «Fluctlight» in RATH’s term. To be more accurate, the light which reflected off the glass is perceived in Sinon’s eyes, the electrical signal from retina changed into the glass object in the consciousness. Next, when I do this……”
Suddenly his left hand extended to completely block Shino’s eyes. She reflexly closed her eyelids, rendering her vision in dark grey with a faint tint of red.
“How is it, did the glass inside your consciousness suddenly disappear?”
As she didn’t know what Kazuto meant, Shino answered honestly immediately,
“……Really, I wouldn’t forget it that soon. From seeing it, I could remember its color and shape, it’s natural anyway. Ah…… but it progressively becomes vague though……”
“Yeah, that.”
After he drew his hand back, Shino opened her eyelids, and gave a light frown at Kazuto.
“Just what is ‘that’?”
“Listen…… at the time we see this glass or table or face of each other, the recreated record data is maintained in the sight processing section of Fluctlight. Even shutting the eyelids, it won’t disappear right away, it isn’t just a mere shadowgraph. Or else, the moment the glass can’t be seen, it’d fade off Sinon’s memory……”
Kazuto then hid the glass in his right hand under the table.
“The moment Sinon sees the glass, the same data of its form is input into the sight perception section of Fluctlight. It allows Sinon to continue seeing the glass which is now no longer on the table. At a precision far beyond that of the polygons…… Or it could be said that it’s exactly the same as the real thing.”
“…………It may be so in the theory…… But, it’s dealing with the retention of human’s consciousness, or in the other words, «Memory» isn’t it? The outside manipulating the memory without hypnotism, how it could be done……?”
Shino closed her mouth after speaking to this point.
Just a while earlier —— hadn’t Kazuto talked about the machine with that exact possibility? as she thought, Asuna, who had been listening quietly until this point, whispered in a low voice in place of Shino,
“The AmuSphere allows a user’s brain to see the polygon data…… While the STL writes it into the human’s consciousness… the short-term memory…… In short…… it’s not an artificial thing. The things in the world created by STL, sight, inquiries, touch…… are the same level as the real things in our consciousness, is that so……?”
Kazuto nodded and spoke as he placed the glass back up
on the table.
“Sighting memory information…… or «Mnemonic Visual Data» as RATH formally calls it. To me, as I still have the memory of the very first test Dive…… it was different. Completely different from the VR world created by AmuSphere. It was merely an empty space at the size of a narrow room, but I……”
He cut his words for a moment, a smile that seemed to be forced then floated to one side of his cheek, as Kazuto continued,
“……At first, I didn’t know that was the virtual world.”
Part 3
The virtual world, which is indistinguishable from the reality.
There was a lot of fiction from the last century which dealt with this theme. Shino could also recall at least five titles of novels or movies with this theme right away.
In an era where the implementation of FullDive technology was used in consumer devices such as the Nerve Gear and AmuSphere, we finally came to a point to doubt: «is this reality really the reality?» —— and as we could read something like that from articles or blogs all over the place, Shino had also felt anxious before her very first FullDive.
However, when the lid had actually opened, could it be relief or disappointment that such worry was unnecessary? The world which was created by AmuSphere was without a doubt, a miracle given birth by cutting edge technology. The virtual world which was perceived by the five senses was brilliantly beautiful —— but that was why it was noticeably different from the real world. The scenes she saw, the sounds she heard, the things she touched, everything was too pure, or in other words, was too simple. The air had no dust, the garments didn’t wrinkle, and the tables couldn’t be broken. The 3D objects which were created from digital codes were restricted by the manpower needed to design them, and the CPU’s power to display them. Of course she couldn’t know how this would change in the future, but at least with the current technology of 2026, creating a virtual world which was indistinguishable from reality was impossible——……
And that, was what Shino had thought. Until today, before she had heard Kirigaya Kazuto’s story.