Caroline is trying to explain her invention to me but she's giggling a little, so it's hard for her to get it all out. I hate when she gets excited like this. She forgets to break eye contact, and with the smile it's a little unnerving. I need to get used to being around socially awkward people, my days have been filled with geniuses and savants since I started working at the University.
She's putting my hand on a metal plate, turning dials and talking about some scientist named Pinero and measuring the length of world lines - it's all a bit over my head, to be honest. I ask for the layman's summary, and the smile vanishes. Caroline tilts her head to the side like a cat, and for a second she's just staring at me.
"It means... I can measure you not in height or weight but in duration. I can tell you when you'll die."
A month ago this would have sounded absurd - and to some extent it still does - but more and more I've seen inventions that shake my views on reality. I was just supposed to be reporting back to my company on projects of interest, but they had underestimated how much of a scientific background it required. I spend half my time picking my jaw up off of the floor and the other half falling asleep, and sometimes I suspect those reactions don't match up at all with how revolutionary any given process actually is.
"Caroline," I say gently, "I have to say this sounds like a practical joke. Are you saying you can predict the future?"
She rolls her eyes but at the last second she stops herself and takes a deep breath. "No. Or, yes, but only one aspect of it. The machine can calculate - with one hundred percent accuracy - the time of your death." Last week I saw a box that seemed to negate gravity inside it. Before that, it was a crackling ball of energy that floated around the room. How much stranger was this?
"You said 'with a hundred percent accuracy'... you've tested this?"
"Extensively." she says, still looking right into my eyes. "I have tested eighty-seven lab animals, and all have died at the time predicted. Three have dates that haven't arrived yet, of course, but that can't be helped. Nearly all have reached their expiration dates."
"And... you're measuring me now?" The metal under my hand is slightly tingly, and I find that I'm suddenly a little nervous.
"Yes, listening for the... the echo. Just as Heinlein described."
"I thought you said it was someone named Pinero?" I say, and get a blank stare in return. From previous conversations with Caroline I believe that is the look she gives when she suspects a joke has been made but can't locate it. I go ahead and press onwards. "I have to say, Caroline, I'm not sure I like the idea of this thing. It seems like it avoids the whole issue of free will, of choice." Caroline just shrugs.
"That part is hard to explain," she says, "But I can try. The future has always been predetermined, the machine just lets us see what that end will be. There was a choice, but it's already been made. Those rats that I tested were destined to die long before I did anything." She's smiling again, excited to be talking about her invention. "To the layperson it can seem like it's making predictions, but just think of it as a communications device. It's not telling us what to do, it's telling us what is destined to happen."
This all still sounds crazy to me, but I can already see some of the uses for it if it's real. "You must have been testing a while. Rats live for, what, two years? Three?"
"For most it was less than twenty-four hours." Of course, she would have found some way to speed up the test. Some sort of Schrödinger's cat type of thing, or something. Whatever it is scientists use.
"Okay. So... did you make them sick, or have some sort of random thing that would poison them, or...?"
She gives me that blank look again. "No. Mostly I just cut them with a scalpel until they stopped moving."
I feel a little uncomfortable now. "So, okay, but... I mean, you didn't kill them... you just waited until the time the machine said and they died, right?"
Caroline is talking to me like a child, trying to use small words. "It's just a communication device. It can't kill anything itself, just tell you when they are destined to die. If it tells me that the rats should live for a week, a month, whatever... then I let them live. I'm just the messenger. I'm a little concerned with how many were meant to die after only a few minutes - seems a little bloodthirsty, doesn't it? But we do as we're told, and the good news is it's never been wrong. I really do kill them right on time, give or take a few seconds. It's quite exciting."
There's a quiet ding, and the machine prints out my destiny.