Chapter 9:
To the Past
WHAT STARTED my change of heart was my realization of the difference in how I treated Alice. Now I loved her. In another world, “I’d” hated her. In some worlds, “I’d” treated her as a tool; in some “I” was neutral; and in some, “my” heart swayed between emotions unsteadily. Parallel worlds, by their nature, look very similar but are still different somehow. Possibilities have meaning because they are different. They exist to be different. The same thing is never generated twice. Differences are normal—but what do they stem from?
In Alice’s case, the answer was simple. It all came down to the conditions of how I asked her the truth about Yukari’s death, whether I threatened her or persuaded her or guilted her or forgave her. That was clear at a glance, so until now, I’d never given a second thought. I just assumed that the differences in how I treated Alice came from the branching paths the world took in the past.
“But Alice told me it would only make sense for branches to occur right now, whether we’re talking about possibilities or parallel worlds. For quanta, there is no continuous past nor a predictable future. We just feel a certain way, but there is no real past. There’s no future, either. All there is, is a slice of one Planck time we call the present.”
“So what are you getting at?”
“It’s always the case that the present ‘I’ is the origin of the branch, whether it’s a branch in the future or the past. Do you understand now? The differences don’t come from the past. It’s ‘we’ who are generated first, and it’s ‘our’ differences that branch out in both directions, into the future and into the past. It’s not the case that I exist as someone who loves Alice because I made up with her. It’s that first a parallel world or possible me is generated who loves Alice, and then a branch of the past is created in which I made up with Alice, to justify it. Forget about common sense—the process doesn’t create the results. The results lead to the cause. Do you remember what I did for Yukari when we were in junior high?”
“Yes, of course. I trained myself in the naginata so I’d be ready for anything. It sure did prepare me for a lot of stuff that happened.”
Right. I’d taken my naginata practice seriously so I could face dangers headed my way. I was still keeping it up now that I was at Jaunt, and it had gotten me out of a lot of tight spots. If I hadn’t kept fit, I probably wouldn’t have made it this far.
“In that case, when did I learn about quantum mechanics?”
“Huh?”
“Naginata training? No, have you forgotten? You have to remember. After Yukari left, I dropped the naginata and read books nonstop. Right. I didn’t train for almost a year. So I ought to be out of shape, but here I am, fit as if I’d never taken a break. Then what happened to the past in which I studied?”
“Well…”
“At that time, the ‘anything’ I had to be ready for was getting into Jaunt. That’s why I studied like mad. Right? It had never crossed my mind that Yukari might have been murdered. There was no reason I should have been training physically. That’s the contradiction. But here I am, totally in shape. Now you get it, right? To reach the truth about Yukari, I needed mobility and stamina—so I changed the past. I threw away a past in which I buried my head in books and chose one in which I kept training. I never realized it because our knowledge is shared, but I’ve probably unconsciously made a lot of changes to the past without realizing it. My treatment of Alice must be like that. Understand?”
“You’re saying…we can create branches in the past, not just the future?”
“Yes. I’m saying, if we branch the past the right way—”
We said the next thought in unison. “We might be able to create a world in which Yukari is alive.”
Something deep inside me told me there was something wrong here, like I was missing something important. But I had to try.
“You really think we can do that?”
“Why wouldn’t we be able to? Haven’t we learned that in physics notation, the past and the future are the same? What doesn’t make sense is not being able to change the past if you can change the future.”
“But if you change the past, aren’t there, like, time paradoxes? What would happen to the present ‘me’ who isn’t me? Would she just never have existed?”
“I think so. Wave function collapse and loss of interference are irreversible. In other words, you can’t go back. And all ‘my’ information comes from wave function collapse or loss of interference—it’s the only way to get it. So we must be sharing our knowledge and experience through some kind of quantum teleportation or something. Well, actually, I’m just a dilettante when it comes to physics. I don’t know what the real situation is. But there is one thing I can say: ‘I’ decided ‘I’ would advance like light, right?”
Yes, absolutely that was what I’d decided. I’d advance like a ray of light. I’d try all possible paths, find the correct route that got there in the shortest time, and reach my objective, no matter what. I’d thought this path was “determined.” I’d thought this path was correct. But I was wrong. That was all there was to it. I was wrong from the first step—from when I decided my objective. My learning of the truth of Yukari’s death and my revenge on those who caused it were both secondary to my true objective, and having become aware of what that was, this route I’d thought was determined turned out to be just another branch, a possibility destined to disappear.
I thought I’d opened Schrödinger’s box with the cat alive, but I was mistaken: the world wasn’t determined yet. If it wouldn’t lead to the solution, I didn’t need this world.
“Okay. That’s how I go.”
I never had a choice in the first place.
I hung up and cast my eyes on my bed, staring at Alice’s sleeping face for a while. I quietly brought my face close to hers, softly dropping a kiss on her eyelid.
I’m sorry. And thank you, Alice. I love you, but I have to advance. So…
“Goodbye.”
“And with that…