I have a theory that I believe proves it is impossible to travel backward in time. The theory is based purely in practicality and requires no mathematical or physical calculation whatsoever (although I throw a bit of bullshit math in for good measure).

It should be noted that I have no understanding of formal time travel theory or even basic physics so this is surely full of holes. Still, it has been fun to ponder and so I feel an urge to record it here.

If you've heard of this particular theory, please let me know as I've done some research (okay, only a little googling) and have come up with nothing.

If at any point in the future1, a method for backward time travel becomes possible, all points in time (both past and future points) will immediately have evidence of backward time travel. In other words, we would know backward time travel is possible today if it is ever discovered in the future.

Let us call the point in time when backward time travel is first exercised, the fulcrum point. It is easy to explain how all points in time occurring after the fulcrum point will have evidence of backward time travel, as we now have evidence of everything that has occurred in the past. But how would all points in the past (including this point right here) have evidence of backward time travel if it happens after that point? Simple - people are stupid and greedy.

I propose that if backward time travel ever becomes possible, it would eventually become available to the wrong kind of people2. This would create a race for the past.

In order to capitalize on backward time travel, one would have to travel to a time where no one believed backward time travel was possible. There they could use their knowledge of the future as a competitive advantage.

Given an infinite number of time and an infinite number of stupid and greedy people, one will eventually get caught, exposing backward time travel to that point in time and all future points in time. The result of this is that the fulcrum point moves backward in time as people get caught.

The consequences of a single fulcrum move is two fold:

  • INF-1 people are now looking further backward in time for the next point where backward time travel is not yet known. The -1 assumes that the dumb-ass who got caught was fried or put in jail for life or otherwise removed from the infinite pool of people capable of traveling backward in time.

  • n new people now have knowledge of backward time travel. Where n is the number of people who exist between the new fulcrum point and the old fulcrum point but not after the old fulcrum point. These people join the race for the past.

The net result is INF+n-1 people jumping backward in time looking for the next point at which an opportunity awaits to screw people over.

This cycle continues for a long time3, the fulcrum point moves further and further backward until the space-time plane balancing on the fulcrum falls down and all time has the exact same knowledge of backward time travel (and possibly the exact same knowledge of everything).

We can therefore assume that backward travel will never be discovered as we have no evidence for backward time travel today.

Footnotes

  1. Ever - that's a long time

  2. like Bif.

  3. Actually, this would take zero time because traveling in time is moving around in existing time, not creating new time. Or is it? How much time does it take to travel 100 years into the past? It takes 100 years!

Comments:

Craig S. Cottingham points to Niven's Law of Time Travel:

was the best reference I could find to Niven's Law of Time Travel, which IIRC says something like if time travel is ever invented, people will go back and mess with the past such that time travel was never invented.

Note that even if you travel forward in time, when you return to the "now", you're travelling backward in time. The only way to avoid that is to travel forward and never return -- which is what each of us is doing, continuously....

Excellent!