46. AN EXPERIMENT IN TIME TRAVEL - In Which A Teacher Attempts To Prove Time Travel Impossible

Inspired by listening to Olivia Coombes talking about the philosophy of time travel on a recent episode of The Panpsycast philosophy podcast, I was reminded, sadly, that I have already empirically proven the impossibility of time travel several times over in my career as a teacher. Or at least I have attempted to.

The experiment is simple.

Whenever a student asks me my thoughts on time travel I tell them we can do an experiment. I look at the clock, look at the date, and tell the whole class to remember the date and a time, two minutes into the future (say, if asked at 11:49pm on Thursday May 7th: 11:51pm Thursday May 7th). I then make a request:

“If time travel becomes possible in any of our lifetimes, do you swear you will come back here, to school, at TIME X on DATE Y, and tell us?”

The class usually all agree.

I have done this with every class I have ever taught at one point or another, across ten years of teaching within a secondary school environment, and with university undergraduate classes before that. I have also done it with groups of friends, family and random people I have met along the way.

At no point so far has a single group I have made the request of been interrupted two minutes later by a visitor from the future.

Therefore, using hundreds of people as data points for over a decade, I have demonstrated the impossibility of time travel.

Or have I?

Clearly not, as many of my deep thinking students have pointed out.

First, if I have proven the impossibility of time travel, I have only pointed out its impossibility in our lifetime. Sad though it may be, given the young age of some of the people I have tried this experiment with, time travel may become possible just after the youngest of us has died. Or perhaps I have just been unlucky, asking only people who will all die tragically early (the Twilight Zone version I considered for several years teaching in the same school was that a terrible accident will befall the school - a fire or building collapse that killed us all before we reached the age of time travel’s impossibility. The final scene of such an episode would be a group of time travelling explorers, a la Ray Bradbury’s A Sound of Thunder, walking past the old school site and recounting the terrible tragedy that took the lives of everyone in it. But I digress…) The point is - time travel may still be possible, just at some point beyond the lifetime of me or my subjects of the experiment.

But we don’t all have to die to point out the flaws in the theory.

Time travel could become possible within our lifetimes but:

1) it is incredibly expensive and none of us can afford it.

2) because it is incredibly expensive, those who can afford it just don’t want to waste a journey through time returning to school to prove a point to an old philosophy teacher when they could be off killing Hitler or placing a massive bet back in 2019 that no one would win the Olympics or Wimbledon in 2020 because all sport would be cancelled.

3) we forget the exact time and date we’re supposed to return. I will be honest, having done the experiment countless times, were time travel to be offered to me right now I myself would have no clear memory of which time or date to return to in order to demonstrate time travel’s possibility to my class. Because no one did appear at the classroom door with a message from the future, the moment passes with little importance. The time and date, important for a few breathless minutes, becomes forgotten by the day’s final bell.

4) there might be certain rules about what can and can’t be done. As the countless movies about time travel have shown us, there seem to be dangers involved with meddling in the past. Maybe, as Back to the Future would have it, you can’t meet yourself when time travelling. If so, then returning to your classroom to tell you that time travel is possible would be a big no-no. Or perhaps one can only travel forward in time but not backward, for fear of inadvertently changing the course of history (killing our own grandfather, etc.) While my experiment does ensure forward time travel from the point of view of us not time travelling (because the time is in our future), unless time travel becomes possible one minute from the challenge being set, that moment two minutes ahead in our future will be long in the past for the person actually time travelling, and therefore forbidden by such a rule.

5) we wouldn’t recognise a time traveller even if we saw one. Many times during these experiments either a random person enters the classroom around the predicted time to great applause and laughter - bewildered colleagues or pupils returning from the toilet. In one case an entire touring party for an Open Morning. Or sometimes a student in the class stands up and claims to be from the future all along. We laugh because we recognise these people as being from our present. But perhaps that’s how time travel would work - to ensure there are no inconsistencies and weirdnesses in present time caused by those travelling non-linearly, maybe the only way you can go back in time is a way which inserts you coherently into the narrative of the present? The teacher who enters the classroom to laughter is actually one of the very children laughing at him…but his time travelling form disallows any way of communicating the paradox and all our feeble minds can grasp is a familiar face and a shared backstory?

There are many other objections to the experiment, but these are my favourites (feel free to add any more below in the comments).

What I like about the experiment is that it feels like it is proving something, even as it isn’t. And the replies it generates feel like they are disproving something, but actually, once you unpack the thinking, you see that even they are based on speculation and hypotheses. We spend a good few minutes believing we have logically argued to some sort of conclusion - time travel is or isn’t possible - only to, on reflection, discover we know just as much about time travel following the discussion as we did before it. Very little.

Though, of course, if one day we did the experiment and someone did walk through that door…

Would we really have proven time travel exists then?

Or would we be more likely to dismiss the whole thing as something set up by me in advance - a paid actor given the name of someone in the room? A big practical joke? A strange, but non-time travel related coincidence? Don’t Hume’s objections to testimony of miracles apply equally here?

And if we all believed it - those of us who saw it - would our story convince anyone else who wasn’t there?

I have called this thing an “experiment” for this entire post, but I’m not sure many scientists would be happy with that terminology. Does a person entering a specific room at a pre-agree point in time really prove or disprove the hypothesis “time-travel is possible”?

There will be an inference to the best explanation in either outcome, but the best explanation is merely that: an explanation, not proof.

Which is why I was so delighted to hear that episode of The Panpsycast and discover that there are people like Olivia Coombes out there doing the heavy lifting with this stuff philosophically alongside all the physicists and other scientists looking at possibilities beyond the merely logical. It was a great reminder of the spirit of Philosophy Unleashed - take your philosophical thinking beyond the arbitrary bounds of what is being taught or what is historically considered “serious” philosophy and take more deep looks into the things that truly fascinate you. Until such a time as time travel ever is possible, you only have one life to examine and make, in Socrates’ words, worth living. Makes sure you spend at least some of it asking the questions that nobody else is.

Author: D. McKee

(My new book, AUTHENTIC DEMOCRACY: AN ETHICAL JUSTIFICATION OF ANARCHISM, is available now from Tippermuir Books and Amazon)