What-ifs, Alternates, and Parallels

This Entry is part of my 2018 A To Z Blogging Challenge, The Lighthouse Agent’s A to Z Guide. See the sidebar for a kind of explanation of my theme. If there is no sidebar on your device, check underneath the Comments section. Either way, the explanation should be directly underneath my 2018 A to Z Badge.


What-ifs, Alternates, and Parallels:

A Philosophy of Time Travel Primer



Blythe Fossdyke, Grad Student


Hello. Totally excited to be a part of this slim volume. Admin came to our Department, saying that one of us had to prepare something for this Guide. I volunteered. For some reason, that made everyone laugh. Professor Mwangi said something flattering about my writing style. How he personally always loves it when I present papers. Very nice man. Mysterious smile. Don’t always understand him.


Afterwards, Prof. Mwangi pulled me aside and told me I could write the intro. “Introduce the topic.” That’s what he told me. “I’ll write the actual—I mean, I’ll do the fiddly bits.”


Thrilled to be working with Boss Prof. Mwangi.


So now I introduce. I am to say what it is we do. What we study. Which is a bit of a poser.


Fundamental question: time. How does it work? What happens when something changes or stays the same? What happens when unlicensed time travelers go trampling all over it? All very theoretical, you know. I mean, we don’t know. We just don’t. We don’t know what happens to all the timelines we aren’t on. Do they disappear? Do they continue to exist in some parallel dimension? No clue. Not a sausage.


I mean, how would we know? If something is existing in a parallel world, I mean. We wouldn’t.


Or take this. Lighthouse alarm goes. Total Apocalypse outside. Wasn’t like that yesterday. Where has TWAWKI gone? Has it ceased to exist or what?


Sometimes I dream in time-diagrams, wake up thinking I’ve solved the thing at last. Find I haven’t. Am mildly distressed.


Prof. Mwangi says I should go back to doing things with numbers now. Goodbye.


The Philosophy of Time Travel—A Very Short Primer On An Extremely Complicated Topic

By M.G. Mwangi, Department Chair



Young Blythe is broadly correct when he states that we can be certain of very little when it comes to the Philosophy of Time Travel. We do, however, have certain theories. Most of the theories we have are compatible to one degree or another with our other theories, that is, they could all be true at the same time and in the same universe. Sometimes we have a certain amount of evidence supporting what we think. Sometimes we think a theory is implausible even though it is fairly well-supported by evidence.


Skimming Blythe’s nervous breakdown of an Introduction, I see that he has failed to lay certain foundational concepts before the reader. Really, the lad becomes worse and worse at communicating his ideas almost daily, even as he gets deeper and deeper into certain calculations that seem to lie at the heart of certain aspects of the mystery of time travel. One hopes that, by the time his calculations are at an end, he’ll still be capable of telling us a little about what he takes them to mean.


You know by now that time travelers are likely to cause Ripples if they do anything much in The Past. We call them Ripples because of the way they move through time, changing everything they touch, and then crash into The Present, which is when we notice them. We only notice them because we are within the ontologically hardened (or “Time-Shielded”) Lighthouse. To the citizens outside The Lighthouse, the new timeline is what has always been true.


Agents out in the field (i.e. The Past) may or may not notice that this The Past is different from the The Past they were expecting. For example, a late-20th-century-style SUV driving down a lane in Elizabethan England may or may not strike them as incongruous. This is, of course, partially due to their knowledge of the era, but it is mainly due to the length of time they have been away from The Lighthouse. If it has only been an hour or so since they stepped through their Door, they really should feel at least uneasy about that SUV. If they’ve been in The Past for a week or more, the residual time-shielding will have worn off, and they will feel that an SUV is a perfectly usual thing to see in Elizabethan England.


We in Philosophy of Time Travel are interested in several matters. Broadly, we are interested in what happens when something in The Past is changed. Is a parallel timeline generated at the changepoint? Does that mean there are lots of parallel worlds out there? And does this apply, not only to changes made in The Past, but also to every decision we make in The Present? Does every choice spawn a parallel world, a world in which the thing not selected is selected? If so, why? If not, why not?


Does, in fact, every What-If exist somewhere? “What if I’d done this instead of that?” “What if Hitler had been drowned at birth?” “What if someone had forcibly prevented Oscar Wilde from suing the Marquess of Queensberry for libel, say by locking him in a cellar or something until the urge had passed?” Are all of these scenarios played out somewhere, in some other world, a world created at the point where a choice is made? And do these parallel worlds ever touch? Do similar ones ever merge again?


The Time Travel Tech used by The Lighthouse is steered by The Core, which analyses masses of data to pinpoint exactly where a Ripple begins. Therefore, Agents are rarely (if ever) delivered to parallel universes. Probably. But reports of early time travel, and of the occasional Present-Day Unlicensed Time Traveler (PDUTT) when captured and brought in for questioning, suggest that this sort of thing can sometimes occur. Of course, it is, for the PDUTT, a popular excuse. “But! I am from a parallel dimension where time travel is completely legal! I can’t help it if I exactly resemble Jimmy “Jumps” Johnson, known PDUTT, who vanished from his lab recently after perfecting his own time-travel device. Heck, I am Jimmy “Jumps” Johnson. Only I’m parallel Jimmy “Jumps” Johnson.” You see how tempting that sort of story would be to any PDUTT.


I will close by presenting a diagram which illustrates a theory we have evidence for and yet do not believe.

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  1. “our timeline is all bendy” Love it!

    A-Zing this year at:
    Normally found at:

  2. This is all very fascinating (and the main reason I don’t write time travel stories!).

    • Yessss… this stuff is also the main reason I don’t write more time travel stories… but I think that as long as the time travel has consistent rules, and as long as those rules aren’t too silly, All May Yet Be Well. We shall see.

  3. And now my poor brain is all messed up 🙁

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