Let's Do The Time Warp Again

Yes, it's the obvious title. So sue me.

I was having a think in the shower this morning (as you do), and had a thought pop into my head. It was kind of a cool thought. It led to a couple other cool thoughts. They suggest a character for a story, but I'm not quite sure yet what the story would be. I'm also pretty sure I don't have the chops to write either character.

The subject: Time travel. But not as you know it.

Time travel is, of course, a well-worn device in science fiction. It goes right back to one of the founding fathers, H. G. Wells. Most time travel works either discontinuously (you disappear from one time and appear in another, like Back to the Future or Terminator) or at exceptional speeds (like Wells' Time Machine). This allows the central character to leap to other eras, which is of course the interesting use of time travel.

I'm not even going to discuss phone booth methodologies

But what if we approached it slightly differently. First, we accept Einstein's space-time construct, in which time is just a fourth dimension on top of height, width, and length. This implies that one can move along that axis if one can figure out how. Except, actually, we are all moving along that axis. We are all time travelers, but traveling in a fixed direction (in the direction of increasing entropy) and at a fixed rate of speed (one second per second).

What if we introduced a time traveler who had no control over the speed of their travel, but could change the direction of travel?

So this person (let's make her female to make the pronouns easier) always travels at one second per second. But she can reverse course. Now, this does not allow her to undo her actions per se (like the excellent One Minute Time Machine). If you walk forward and then walk back, you aren't undoing your movement. She's just pulling a u-turn in time. There would be two of her in the room. There's no inherent paradox in that, if time is just another dimension.

Where paradox does come into play, of course, is the interaction of cause and effect. Our poor human brains assume that the cause must come before the effect in time, because that's what we've always observed. (Yes, some quantum experiments have demonstrated effects that occur before their causes, but I don't even pretend to understand that.) This is where paradoxes come into play. Suppose that our time traveler did something stupid. She reverses course, and tells her earlier version not to do the stupid thing. Which means she doesn't do the stupid thing. So does she still go back to tell herself not to do the stupid thing? 

For the purposes of this character, I'm going to say that, yes, she does. And, in fact, the stupid thing never happens. There is no "initial loop" where she actually did the stupid thing. She just trusts what her future self says, and doesn't do it. But she then remembers to go back and tell herself not to do it.

What if she forgets? Then she doesn't go back. And she never went back. She always forgets. What if she forgets, the stupid thing happens, so she remembers, so she goes back, so the stupid thing doesn't happen, so she forgets? Infinite loop? No, that's a simple Schrodinger's cat scenario. She both does and does not forget. When someone else observes her, it collapses into one reality or the other. The actual collapse is a chaotic system with highly sensitive dependence on initial conditions. In common terms, it's a crap shoot which reality takes precedence.

This is terribly complex. And really calls free will into question. Which obviously could be a theme in the story. There are also all sorts of other wacky cause and effect scenarios that you could play out. Our time traveler is pinned down by a gunman. Suddenly she also appears behind the gunman and disarms him. She walks across the now safe room to behind the gunman. She reverses time, and stands there until the gunman is armed again. Then she starts going forward again and disarms him. 

What if we introduced a time traveler that was unable to change the direction of travel, but could control speed?

Oh, this is a whole different ball of wax. Cause and effect are no longer an issue, because everything continues to happen in the same order. But she can choose how quickly or slowly she moves in relation to everything else. She can hang out for two days in the space of two minutes, or jump ahead through two boring days in two minutes.

What kinds of problem-solving techniques does this open up? Well, if she gets shot, she can take six weeks to self-medicate and heal before returning fire. Or if she's getting shot at, she can just zip forward an hour until the gunman gets bored and leaves. She could rob a store by wandering in during normal business hours, zipping forward to when it is closed, take what she wants, and zip forward again to the next morning, and casually walking out. (Hopefully she was clever enough to hide her face from cameras.)

By maintaining a fixed direction, this bypasses most of the abuses of time travel. She can't go back and give herself winning lottery numbers. She can't become her own grandma. She also can't kill someone before they do the thing that makes her want to kill them. Most of those headaches are just gone. But that means that most of the interesting philosophical questions of time travel are gone. This is basically now just a superhero with a cool set of potential effects.