Tenet (Part V)
TENET (Part V) The Practice of Time Travel Not Explained
We are examining the practice of how to write a time travel story, which is, in theory, a story that should be impossible to write. There are several minor or halfway cheats by which this can be done. These are discussed below.
I call the explanation of paradox in ‘Timesweepers’ and those in stories like them “halfway” because the writer uses part of the explanation to explain paradoxes away, but not consistently.
There is a little bit of fatalism, a little bit of coincidences happening for no reason, and a little bit of myriad time branches, but always the number of branches is restricted for one reason or another.
Another example of such halfway worldbuilding, and one that is much more stark, is the malicious universe of ‘Try to Change the Past’ by Fritz Leiber.
In that story, soldiers in the Change War between two rival factions of time travelers are recruited at the moment of their death. The protagonist, going AWOL, attempts to undo his murder before it happens, by pre-retroactively unloading or removing the murder weapon, and finds all his attempts are in vain. The same death wound reappears regardless, caused by a different cause. In the Change War universe, cause and effect proactively alter events to create coincidences to bring about the foreordained result, no matter how unlikely the coincidence needs to be.
In effect, the timestream in the Change War universe does form branches, but the universe prunes them immediately, using any excuse, no matter how farfetched, to do so.
A Change War universe, simply put, is ruled by a particularly iron force of fate. It is a halfway explanation, because fate uses coincidences to make events happen for no reason. Fate puts her thumb on the scales, so that it looks as if you can change the past and know the future, but, upon examination, no, not really.
Such a biased universe, however, is one that allows the writer to display his cleverness more clearly, particularly if Fate is more forgiving than she is in the Change War universe.
For purposes of drama, if the act of time travel itself has a side effect, or produces a pollution, such as encouraging the breakdown of all cause and effect, the time traveler has a time machine, but the cost of running it may make certain visits to the past or future, certain eras or events (the ones the writer wishes not to revisit with paradoxes) simply off limits.
This is a halfway explanation simply because it runs the risk of seeming arbitrary: the writer still needs to invent what would happen if the time traveler tried to kill his young grandfather, and mention it in the text, lest he endanger the reader’s willing suspension of disbelief.
In other words, if there is a cost to time travel itself, something has to happen when the bill comes due: and this will be one of the three options discussed earlier, namely, fatalism, or acausality, or myriadism, but with the added variation that someone or something, malign fate or the Time Police or your own grandson trying to keep his own past intact, will show up to hinder the time traveler.
A well-regarded “halfway” explanation is to have the time traveler be allowed to make all the changes he wishes, but Fate arranges coincidences to bring the new timeline back into parallel with the original, as if destiny had inertia, so that the time traveler can change the events, but the final result is largely the same.
So, for example, Fate in such a universe allows you to kill your grandfather in the year before he met your grandmother, but then when she shows up, the only person able to fill the hole in time left open is you, who may well look and act much the same as grandpa, so Fate will trick or force you into that role.
So Fate will urge or demand you to commit incest you in with grandma, whom you apparently will not recognize until it is too late, and you will be your own grandpa, as in the famous song.
This is a nice and neat explanation, except supposing you are not a Robert Heinlein character, and do not want to marry your young and pretty grandma, there is no explanation of what happens if you shoot yourself, or her, or double back on your own timeline to interrupt the wedding.
Or, rather, the ingenuity of the author must again be invoked to come up with clever ways to undo everything the time traveler does, without making it obvious that he can do nothing of consequence.
I confess I rather like this explanation, because it reminds me of a Bible story: Esther is told that she must risk her life to save her people, because this is the task heaven gave her. But if she does not, heaven will find another way to accomplish the same end, and save the people by other means, but woe unto her, for she will not be spared.
In time travel story terms, this like a version of the Change War idea which is moralistic rather than nihilistic. Esther is being granted a role to play in the future events, which are foreordained, but her part in them is not foreordained, but, rather, depend on her willingness. Her actions still have moral consequences, which rebound on her.
However, again, this explanation of a biased fate, or fate with inertia, work better for prophecy than for time travel, because the question revisiting and redoing a failed outcome does not come up.
The biased fate explanation will work, provided it is not examined too closely.
If Fate is strict and malicious, as she is in Leiber’s story, any attempt to change the past is thwarted by a coincidence. The chain of cause and effect leading to the coincidence merely appears as needed, out of nowhere, for no reason. So the explanation preventing the grandfather paradox is another paradox: fatalism is saved by acausal chaos, that is, events arising from nothing.
But using a paradox to explain a paradox explains nothing. The Change War cannot take place in the Change War Universe, if it were consistent, because no soldiers on either side of the war can change the past. There is nothing to fight about and no way to fight.
It is an explanation that does not actually explain.
In any case, if Fate is granted the power to create events out of nowhere, deus ex machina, merely for the purpose of getting fate back on track, then she need only create one single event, and save herself all the bother of doing more:
By Niven’s law, far easier than creating a coincidence of astronomical proportions to recreate the exact murder wound without the murder weapon, the universe, if followed the path of least resistance, would merely kill the first inventor of time travel, and prune any branch where time travel is possible the moment it forms.
Again, in the far more forgiving universe of the film trilogy BACK TO THE FUTURE, when the time traveler is about to be erased due to events his changing events leading to his own birth, he is warned by seeing photos or fingers fade, and can take quick action to do deliberately what Fritz Leiber’s universe does automatically.
Likewise, the explanation does not explain. If McFly fades from existence in the middle of a Chuck Berry song, then, logically, he also fades, or will fade, or had faded, or will have had faded, from existence before he hopped into the time-traveling DeLorean, hence before he, by mishap, preventing his parents from meeting, and thus it never happened — or had never happened; or will have had never happened.
If consistent, self-cancelling paradoxes in the Back-to-the-Future universe would fade from existence and cancel themselves before they happened, and time travel would be perfectly safe. In which case, if McFly cannot change the past, he never did, and there is no movie.
Moreover, and if Doc Brown can zap McFly’s girlfriend Jennifer in 2015 with a flashy thing to stun her, he could have done this selfsame thing to older Biff from the future two minutes before Biff buys the almanac and joyrides in the time-car to give it to his younger self — whereupon older Biff, who has no memory of such a visit, should fade from existence, then or earlier, and not have had done it. Why can Biff change his own past, but not McFly?
And, again, applying Niven’s Law, we see that, in the timeline formed by Biff of 2015 using the time machine, not only would Doc Brown fade because he died before inventing the time machine, so would the time machine … in which case, time travel is never invented, and all is safe.
Until all the events of the first movie then fade, and the opening of the second, including the scene where Biff of 2015 uses the time machine. This is self cancelling interference of a type that cancels its own cancellation.
For better or worse, fun as they are, halfway explanations routinely break the rules of their own make-believe.
The ending of the third Back-to-the-Future film is a perfect case in point. Doc Brown reappears at the moment the time-traveling DeLorean is destroyed in a time-traveling steam locomotive. Doc shows that he is married his true love and has fathered cute children. Doc Brown cheerfully laughs and says “Your future has not been written yet — no one’s has. Your future is whatever you make it. So make it a good one!” The music swells. The locomotive flies off into the sunset. Applause.
It is a great scene. It is a wondrous scene. It is a rightly well-beloved scene.
It also makes no sense at all.
If the future is whatever you make it, then what was the point of the second movie, which was spent trying to undo a time paradox, so that the folly of time travel could be undone, and the whole point of why Doc Brown wanted the time machine destroyed before it destroyed the universe?
Why destroy a time traveling motorcar in order to build a time traveling locomotive? Nothing in the film indicates any event to bring about Doc Brown’s change of heart, nor is the audience told that the rules of time travel do not threaten universe-destroying paradoxes after all.
That wonderful end line was not earned by any of the events seen in the trilogy of films coming before it.
The real theme which really should have come from the story told was that of Doctor Faust or Frankenstein, namely, that there are mysteries into which science should not peer, lest you accidently prevent your parents from meeting, and erase yourself.
And even a harmless visit to 2015 can result in an unexpected catastrophe, so you can never return to your own year, but instead you return in the rain to see your own gravestone. But no one wants that grim ending and that grim theme to cap a lighthearted adventure comedy.
So, the writers spun up the Animaniac’s Wheel of Morality, and picked the theme and moral from another story, and bumperstickered it hastily on this one. Which is as it should be, because it preserved the mood of the work.
It must be said that while there are three consistent ways around the Grandfather Paradox, and countless inconsistent ways, there is also the fourth way around the paradox: which is, of course, is merely never to bring it up at all.
That is, perhaps, the best way.
For this reason, my objection to time travel stories does not extend to that great majority of them, which, to be frank, do not address any ramifications of time travel at all.
In THE TIME MACHINE of H. G. Wells, the titular time machine serves the same use as the twister in THE WONDERFUL WIZARD OF OZ by Baum, the spooky Apache cave in A PRINCESS OF MARS by Burroughs, or the titular wardrobe made from magic lumber sitting in the spare room in THE LION THE WITCH AND THE WARDROBE by C. S. Lewis.
Namely, the time machine in this story, and those inspired by it, serves is merely as the stage machinery meant to carry the protagonist to the scene of the action.
The machine needs to be stolen by Morlocks shortly upon landing. Or, it needs to be out of fuel, such that it must be hit by a lightning bolt before the flux capacitor has enough power to work again.
This is because the machine is not needed for the adventure to play out, and, indeed, if it were in working order, it would solve too many problems, perhaps all of them.
Otherwise, the time traveler can go backward to the hour before Weena is kidnapped by Morlocks, and escort her neatly out of harm’s way before they arrive; or he can visit himself a moment before he falls in front of his grandfather’s car, and prevent his young version from preventing his parents from meeting.
It should come as no surprise that, the most famous time traveler of all time, the nameless Doctor of DOCTOR WHO, rides in a broken time machine.
His blue police-callbox-shaped time travel machine is broken hence unreliable precisely so that once the Doctor and his companions are landed in the Court of Kublai Khan or beneath the Pyramids of Mars, no one can use the machine to go back a minute nor an hour nor a day, and warn of the ambush of Cybermen nor the treason of the Master in disguise.
Likewise, the whole point of Irwin Allen’s television show THE TIME TUNNEL was that, in every episode, Doug and Tony the time travelers had no control over in what year they landed, nor could they leave at will, much less go back a day and replay the scene. As with the TARDIS, the Time Tunnel was unreliable.
But the one nagging question that always hangs over such stories is precisely why, once the machine is fixed and working properly, the time travelers of that day and year do not return with a toolkit in hand to repair the current machine, or, better yet, give the current time travelers a lift backward and forward by an hour or a day, to time-travel them out of their messes.
Even asking such a question answers it: it would spoil the fun. Only a killjoy, some grumpy curmudgeon who hated time travel stories would even ask such a question. Such time machines are fated never to be repaired until the day the castaways from Gilligan’s Island are rescued.
Time travel adventure stories are meant to allow your Connecticut hero to outwit Merlin the Magician with an almanac predicting the next solar eclipse, or to defeat armored knights with a modern firearms and electrified barbed wire, while mocking English monarchy.
They are meant to allow your hero to visit Nostradamus, or Robin Hood, or Napoleon, or rescue a lovely cavegirl from a dinosaur, and so on.
Or to chase Jack the Ripper to modern day San Francisco.
Or to see how a township from West Virginia would fare if flung into the midst of the Thirty Years War of 1632.
Or to visit the remote far future and see the Darwinian results of the English class system carried to an absurd and hideous extreme.
In sum, the point of time travel adventure stories is to visit the landscape and people not within our reach. That the adventure is set in the Stone Age or the Court of King Arthur is no more barrier to the imagination than if set on Mars, or a world circling Arcturus.
No explanation of what would happen if the time traveler doubled back on himself and tried to change the past is offered in tales of this kind, simply because the question never comes up. Neither does the idea of using the time machine itself to solve the problem come up, depending on how quickly the thing is stolen by Morlocks, or is otherwise whisked offstage.
But whether a halfway explanation is offered, or no explanation is offered, overthinking the matter inevitably diminishes suspension of disbelief.
The explanation for this is not hard to find.
About John C Wright
John C. Wright is a practicing philosopher, a retired attorney, newspaperman, and newspaper editor, and a published author of science fiction. Once a Houyhnhnm, he was expelled from the august ranks of purely rational beings when he fell in love; but retains an honorary title.
