An Urgent Comment on Time Travel
One of the most popular shows on Netflix, Umbrella Academy, concerns time travel. For reasons that are especially salient now, the idea of having one’s molecules dematerialized and reconstituted in a gentler time is an appealing diversion. As a fictional device, it’s especially attractive, because—and this is true in Umbrella Academy—the notion that one could jump back in time gives us emotional control over horrors past and present. Who among us hasn’t fantasized about traveling back in time to Vienna, 1907, when Hitler was a mediocre artist with big dreams and altering the course of history there once and for all? Portland fans would love to engineer a re-selection of the 1984 NBA draft and choose Michael Jordan instead of Sam Bowie. It’s all so seductive.
Or, to put this in beerier terms, think how events might have unspooled given a little historical push. I despair that stopping milkshake IPAs is beyond a simple time-traveler, since that style had many parents. (A TV show based on the concept—Quantum Milkshake Hunters—does have its appeal, though.) But nitro taps? All you’d have to do is convince Michael Ash that he’d be better served teaching mathematics than going off to London to work for a brewery. Nitro may never have been invented. Wish Pilsner Urquell had never been sold? No doubt there’s a remedy in the trusty old DeLorean.
The real question, the urgent question of today’s headline, is: would it work? Time travel is dicey business. Presented in myriad forms, written and filmed, certain guidelines have emerged. For example: you cannot meet yourself. This creates a time paradox and such an encounter inevitably results in bad things—explosions, typically. This is disappointing news for those of us who wish to go have a beer with ourselves in an earlier, more exciting time in life.
According to fictional quantum law (FQL), time travel is more appropriately used to stop some bad event from happening. So if you muse about traveling back and preventing yourself from doing something stupid, that’s kosher—so long as you don’t encounter your younger self along the way. (This is also on-point for an alcohol blog since that event is 97% likely to have involved Cuervo or Hamm’s.)
As a service to those of you currently at work building a time machine, I’d like to correct the record. The movies have it wrong. Time is not like a ribbon of film we can follow backward and forward, always witnessing the same events. Rather, it is a a line of causality that is limited only by the numerical possibilities of any act in a given situation. Which is to say that it is dynamic and mutable, as Hugh Everett postulated in 1957. The second your time machine rematerializes in 1973, you are in an entirely new world, one now disconnected from the first 1973. Causality will start from scratch.
Allow me to elaborate.
The Stopping-Yourself-From-Doing-Something-Stupid Paradox
Let’s start with the intervention that is supposed to work. Imagine this entirely hypothetical example that in no way resembles my own life. You’re at a party as a young person, perhaps in college. Due to poor judgment following several hours of drinking, you begin a misguided romantic relationship with a partner whom sober-you knew to be inappropriate. To prevent a series of painful minor tragedies that will result, you want to travel back and prevent this from happening. If it were a movie, you’d choose a roundabout approach (remember, FQL dictates you can’t interact with yourself!) and hijinks would ensue. If you succeeded, it would reset the timeline, that rendezvous would never happen, and all memories of the years would vanish.
Wrong. The events already happened to you. You can never make them unhappen. Instead, the moment you beamed into the “past,” it becomes an entirely different temporal location and all the people you see, while closely resembling those you knew, are different. The other you is not you; meddling in their life will change them, but not you. Should you wish to return to your time, you would find the true paradox in the situation. Nothing at all would have changed, because you returned to your own time. The other you is living a much happier young-adulthood (maybe), and saving a lot of money on therapy. To travel backward is to visit a new world you have inadvertently created. You, of course, also reset your own timeline. You are able return to a temporal state in which all external phenomena appear to be unaffected, but you of course have changed. You are now tethered to the reality you visited, spookily, one might say, and at a distance. As a consequence you have created yet another new reality and must live in it.
The Having-a-Beer-With-Yourself Paradox
According to FQL, one cannot occupy space in multiple times. If I wanted to travel back to the Yukon Tavern in 1990 to witness my 22-year-old self playing pool with friends, FQL dictates such an event would either (or both) create a cataclysm or (and) cause great risk to my current self because of all the ways I would “disrupt the timeline.”
(And boy, would I love to travel back to the Yukon Tavern in 1990. Owned by septugenarian redhead Vivian McCarty—her head was still very much red, if not naturally so—this small Southeast Portland pub would get so smoky on weekend nights you literally could barely see from the bar to the far wall. Pitchers of cheap beer were crazy cheap ($2.35 if memory serves), and a tray of off-brand Lil Smokies sausages, full of bone fragments and gristle, set you back a buck. Often, Viv would be overseeing matters behind the bar. It was sublime.)
Hogwash. Nothing unusual would happen to the space-time continuum. The reason, and here we go back to Everett, is that the moment I returned to 1990, time split. Now young-Jeff goes on his own timeline. He is no longer connected through causality to me (old-Jeff). If I told him to avoid going to Wisconsin for grad school, I wouldn’t immediately cease to know my wife, whom I met there. Young-Jeff wouldn’t ever meet Sally, for sure. But the line of causality that I have already experienced has already happened in my world. I am no longer this Jeff. These are the infinite worlds of quantum time. By traveling backward I have only caused them to intersect.
Time is not a substance. It doesn’t care if we pack the Yukon with Jeffs. If a hundred different Jeffs from a hundred different times all appeared in the Yukon—well, Viv would have had a lucrative night.
Of course, time-travel discussions are a standard of pub life. Many a delightful hour has started with the words, “If you could go back in time, what…?” I am all for them. But please, understand quantum behavior before you dive in. Observe the quantum rules, people!
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