And Yet Again, More Railgun/Index Physics

Steven posted his promised discussion about the physics of Touma’s Imagine Breaker power over at Chizumatic. It’s very spoiler-filled, as is my response below. It started as a comment, but just kept going. I don’t know how to characterize it; it’s not exactly an agreement, nor is it a rebuttal. I’m just killing a few more catgirls by pointing out some implications in the worldview. Below the fold, since there’s spoilers.


Ok, if you take the name of Touma’s power, and assume that magic is “externally powered reality alteration” as opposed to a psionic’s “internally powered reality alteration” then it makes sense that Touma can cancel magic as well as psioncis. It doesn’t require a 3rd power type, which is what I was postulating (from lack of a better alternative). I felt that was a “messy” explanation, but didn’t have any other that could explain how his power worked.

Unfortunately, based on this explanation, it’s theoretically possible for someone to generate an “altered reality” (that is, use a power) that is greater than Touma’s ability to cancel it. Logically, such a someone would probably be the source of the external powers; that is, an angel or other such magical source. After all, we see an angel’s power cause changes all across the world (President Kuroko, lol!). What level is that power? Yet Touma wasn’t affected? In brief, would such beings be subject to the same limits as human beings? Probably not. It just may be that Touma’s not met a magic user strong enough to channel that much power from an external source. If he meets the source directly and depends on his power, he might be in for a nasty surprise.

A possible inconsistency: We twice see ability users devastate areas measured in hundreds of square feet, but Touma not only shields himself, he protects a cone shaped area immediately behind and to either side. Also, he negates Mikoto’s iron sand-swords all the way back to her hands. In other words, the power has to touch him, but once it does, he has an amorphous area of effect that extends beyond skin contact.

What are the implications for magically or psionically accelerated objects tossed at him? If there had been a glass counter between him and the Graviton Bomber, would he have been cut by the flying glass?

As Steven pointed out,Touma is not immune to swords; nor was he immune to having a subway collapsed on top of him (a fate he narrowly avoided). Yet he was immune to having a summoned car dropped on him? Does that mean the substance of the car was inherently magical?

I still believe he is not immune to a railgun shot — but only assuming he is beyond the end of the field Mikoto generates to fire the coin. If she generates her field all the way through the target (him) to guide the coin (likely, given her accuracy with such an aerodynamically unstable object), it would fail the instant the field touched Touma, before the coin began to move forward.

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5 Responses to And Yet Again, More Railgun/Index Physics

  1. I thought I might need to deal with the question of why Touma didn’t prevent the explosion entirely. I think there are two ways to retcon that.

    The one I like better is this: Touma can’t run time backwards. When the edge of the explosion reaches him and he touches it, what’s already happened is permanent as far as he’s concerned. He can’t retroactively nullify it. But he can prevent it from continuing to spread past him and into the area behind him, and that’s what he does do.

    As to the railgun attack, the entire path of the coin is the same as the explosion. Whether Mikoto is using electric fields on the coin or not, she is using her power to move it, in the sense that what it does after she thinks she’s ceasing to use electric fields is still the result of her imagination rendered physical by her power. So the coin would stop once it struck Touma’s right hand, and fall on the floor.

    However, as I think I’ve mentioned elsewhere, I don’t think that Mikoto is really firing a projectile. What she’s doing is to vaporize the metal and use it to create a plasma channel for an electricity attack. So the channel would stop at the point where it touched his hand, and any electric arc passing down it wouldn’t connect to him and zorch him.

    I don’t remember the specific event of a summoned car failing to drop on him. Where/when was that?

  2. Also note that when Touma cancelled Mikoto’s iron-sand whip, he wasn’t doing so retroactively. He cancelled its existence going forward, and that works in terms of his power and his conception of what it can do. Cancelling an entire explosion, however, would require time paradoxes, so he doesn’t do that.

  3. Oops, I didn’t use any spoiler tags. I apologize.

  4. ONE MORE THING… Show ▼

  5. Ubu Roi says:

    Well, I’m not concerned about either preventing the explosion entirely, or the iron-sand whip, because I assumed both of those work as you described; the point I was making was that his power is not strictly limited to touch range; it’s contact range — as long as he contacts any part of the power manifestation, he’s able to nullify the entire power.

    Most of the time, that is. Show ▼

    This implies that, while he still “leans” on his right hand as a mental crutch, Touma subconsciously realizes how his power works and can manifest it without using his hand.

    And finally, on the railgun, I still think the coin never leaves the vicinity of Mikoto’s hand. If she’s not turning it into plasma, the field collapses as soon as it touches Touma (and as I state above, not necessarily his right hand), thus the coin might go no more than a few feet. If she is doing the plasma/lightning trick, then the same problem still occurs. The plasma has to be controlled by a magnetic field in order to travel in a straight line. As soon as that magnetic field touches Touma, it collapses. So at worst, there’s a ball of expanding plasma right in front of Mikoto’s hand.

    There’s also still the incident Show ▼

    And most importantly, does the author actually think about this stuff, or are we killing catgirls for no reason?

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