We next revisited this question approximately two months before our wedding was set to be held. As I held Kazune in my arms, she sleepily asked, “Hey, Koyomi? Do you think we’ll really be able to get married?”
“Why do you say that?”
“Well, what if one of us parallel shifts on the big day?” she asked me. “Are we supposed to simply get married to that parallel self? Or should we stop the ceremony?”
This was probably her way of expressing pre-wedding jitters. I’d wondered the same thing myself, but I decided there was no point in thinking about it. Instead, I chose unfounded optimism. Whatever happens, happens. Looking back, however, it strikes me as a weird position for me to take. Maybe I was afraid to think about it too hard.
Now that Kazune was starting to agonize over it, however, I could feel the anxiety creeping back in. What was I going to do if something like that did happen? After failing to find an answer on my own, I suddenly remembered my father’s research.
At the ISRI where Kazune and I worked, each department was staffed by a small team with their own research objectives. My father’s team was focused on what we called IP stabilization.
Imaginary science was founded upon the concept of imaginary space, or an infinite probability space filled with imaginary elements. Variation in these elements gave shape to physical particles, and the differences caused by those variations were said to give form to parallel worlds. The pattern created by each world’s variable particles was called the Imaginary Elements Print, or IP for short.
Accordingly, the function of an IP band was to measure the differences between two IPs and quantify them in numerical form. However, they didn’t actually measure imaginary elements themselves, but rather the physical particles manifested by those imaginary elements. This was our workaround until we found a way to observe an imaginary space directly.
As for IP stabilization, it involved observing imaginary elements overlaid in an imaginary space, then freezing the quantum state and preventing any flux. Were we to achieve this, we would then be able to prevent parallel shifts, or so the theory went. The problem was, how could human beings measure imaginary elements when we couldn’t observe them? That was the key to my father’s research.
If we could achieve IP stabilization, then Kazune and I could “lock” our IPs for the day of the wedding to prevent any parallel shifts. That sort of thing was partly why the ISRI was researching it to begin with—that, and to prevent future parallel criminals from shifting away from their punishments.
Though we all worked at the same lab, ISRI teams were generally expected to keep their progress under wraps until they had achieved a certain degree of success. My father had accidentally leaked this information to me during a private conversation. He made me promise not to tell anyone, so I hadn’t said anything to Kazune yet, but…surely I was allowed to talk to him about it, right? Therefore, I went with him to the deserted lab over the weekend to ask him for advice regarding the wedding. He told me that his team hadn’t achieved IP stabilization yet, but even if they had, there were so many unknown variables and risks that it would likely be quite a while before they could test it on people.
“Koyomi…” he started. “I’m starting to think I should stop researching this.”
“What?! How come?” I couldn’t believe my ears. My father was practically married to his research! Could IP stabilization really be that challenging?
“First, what do you think a parallel world is?” he asked me.
“Um… A separate world that branches off from past events?”
“Right. In other words, a manifestation of possibility.”
“I beg your pardon?”
“Say your breakfast options this morning were onigiri or toast. If you picked onigiri, then the possibility of you picking toast is itself a parallel world. Each and every world in existence represents a choice we never made.”
I imagined two selves: one who ate onigiri and one who ate toast, each of them living in their own separate world.
“Now, let’s think about what IP stabilization really means. When it comes down to it, I fear it’s a lot like if we took away the toast and forced you to choose the other,” he said.
Ah. Admittedly, that sounded like a bad deal. After all, having the ability to choose was part of what made life so great.
“Choosing onigiri after some thought or having no other option. The outcome may seem the same, but the first case manifests two selves: one who ate onigiri and one who ate toast. In the second, there can only be the self who ate onigiri… You see?”
His analogy was easy to understand, but I found myself circling back to the start. It felt like we were taking breakfast way too seriously. Regardless, I gave my best answer.
“Okay, so parallel worlds represent possibilities, and IP stabilization erases those possibilities and makes it so no new parallel worlds are born. Right?”
“That’s right. The self who wants onigiri ends up killing off the self who wanted toast, all for his own gain. That’s what I fear IP stabilization is… I just can’t shake it.”
“Look, Dad, I get what you’re saying, but…”
This wasn’t about breakfast foods. This was about my wedding—a once-in-a-lifetime event. Even supposing he was right, in this particular case, the only possibility getting erased was the possibility of Kazune and me not getting married! Of course I wanted it gone!
When I explained this to him, he fell into thought for a long moment.
Eventually, he said to me, “When I married your mother, we didn’t have IP bands.”
No kidding. Back then, imaginary science possibly didn’t even exist yet. Those were the days when parallel worlds were still the stuff of fiction.
He then continued. “It’s possible the woman I married was actually a parallel self. But even if it was, I have no regrets—because I truly loved her.”
Love. He said it without a hint of embarrassment, and oddly enough, I found that I wasn’t embarrassed either.
“Even though we’re not together anymore, I still love her—every her in every world. I love everything about her, and that includes all her possibilities.”
“All her possibilities…?”
“That’s right. If you can do that, then you don’t need to lock your IP. Just have the wedding with your head held high.”
“I do get what you’re saying, but…” I realized I was repeating myself and fell silent.
Could I love all of Kazune’s possibilities? Including parallel Kazunes from other worlds? If so, then it wouldn’t matter if she shifted on our big day. I’d still end up marrying the woman I loved. Putting it simply, Dad was saying our parallel selves were still us.
I could understand his outlook. If I had to guess, I was probably capable of loving every Kazune. She’d shifted dozens of times since we started dating, and all of her parallel selves were still the same woman. The problem for me was the reverse. Could I accept my parallel selves loving my Kazune? It was an incredibly selfish question to ponder. Put another way, I was perfectly okay with cheating on Kazune, but she wasn’t allowed to do the same, even if the “other man” in this scenario was my parallel self.
My father waited quietly for me to finish thinking it through—but eventually, after the silence dragged on past his limit, he made a suggestion.
“What if you test it out?” he asked.
“What?”
“You know how the director’s research team has been working on a way to overwrite IP values in order to cause a controlled parallel shift? Well, their experiments have been successful.”
Finally, after all these years! My heart soared with excitement. In high school, when Kazune pretended she shifted here from a distant parallel world, I asked my father if there was any way to shift at will. At the time, he told me it was theoretically possible, but would take another ten years to achieve. Now that those ten years had passed, it was finally approaching the realm of possibility.
“If we can finalize this technology—optional shifting—the idea is that we’ll be able to send people home when they shift here from distant worlds and vice versa. So far, a handful of experiments using objects and animals have succeeded. At this stage, I’m told all that’s left is to run clinical trials.”
Now I understood what he was trying to say.
“There are a few obstacles, however. First, we have to apply for authorization from the Institutional Review Board at the Ministry of Health, Labor, and Welfare. That’s assuming we can resolve all the ethical and safety concerns…but frankly, a lot of times those concerns need clinical trials in order for us to figure out how to resolve them. It’s a catch-22. Even if we fudge the numbers in order to get the green light, the board will have regular inspections that interrupt the experiments.”
I always heard that clinical trials served as a hurdle in just about any field, not just scientific research. It all came down to how you chose to overcome that hurdle.
“Now, I wouldn’t go shouting this from the rooftops, but…one strategy that laboratories often utilize is to have fellow researchers serve as subjects in a mock clinical trial.”
Basically—secret, possibly illegal human experimentation.
“Of course, they’ll take the utmost precautions to make sure you’re safe. In accordance with official informed consent standards, patients are given a full explanation of the trial process and the risks involved. Participation is completely optional, but if the mock trial can establish proper safety protocols, then it’s another step toward official authorization.”
In summary, he was suggesting that I take part in the optional shift mock trial.