Fuddland
My theory is based on a widely-known fact: the longer you wait for a bus [at a stop which a number of buses travelling different routes coincide], the more chance there is that the next one to arrive will be the one you want.
When the first one pulls up, you hardly expect it to be your bus. If it’s not, then when the next one arrives, you think it’s more likely to be yours. When ten buses have passed, none of which were the one you wanted, then the next one must almost certainly be for you. And so on… [Until you realise you’re at the wrong stop. But let’s assume you are at the right one.]
The logic governing these thought processes is the assumption that, as time goes on, the probability of an event occurring approaches a certainty; it has to happen eventually, if you just wait long enough. [In mathematical terms, an event which is certain to occur has probability equal to 1; one which can never happen has probability 0. For example, the chances of this entry receiving any comments supporting my theory is close to 0.]
So now let’s apply this rule to the following event:
Time travel is going to be discovered by a human, and it will be used to travel backwards to a time earlier than our present day, and its secret revealed to another human, providing them with all the technology required, who will then demonstrate the discovery to the whole world.
Clearly, this has not happened [unless I missed the report on last night’s news]. Therefore time travel will never be discovered by a human being for as long as we exist.
Ta da!
Comments
Ade | 2005 / 06 / 20 – 11:22
Kav and myself have already come up with a similar proof, at least proof that we ourselves will never get to time travel. We simply stated that, if either of us do ever get to time travel, we will travel back in time to the time at which we made this pact and introduce us to ourselves. We gave ourselves 5 minutes but we didn’t show.
David | 2005 / 06 / 20 – 11:34
Re #1: Perhaps you accidentally told yourselves the wrong bar to meet yourselves in…
Cathy | 2005 / 06 / 20 – 15:03
Hmm. Am I wrong, or doesn’t this contradict your previous theory - ie, that if someone does discover time travel, go into the past and change it to such an extent that time travel has now been (wioll haven be) discovered in our past, it would all have happened in an alternate universe, and not this one?
In which case, it only looks as though the past is immutable, because changes can’t have any effect in this universe.
For the record, my jury’s still out on time travel, but I do like the many-worlds theory :-)
David | 2005 / 06 / 20 – 15:12
Re #3: Absolutely. But then they’re two different theories. No-one said I couldn’t have more than one, did they? ;)
For a genuine hole in this theory, consider the event, “Time travel is going to be discovered by a human, but they don’t travel backwards to a time earlier than our present day and reveal its secret to another human”. [Does that mean that the probability of an event, or at least events which have an “opposite” event that makes sense, should only approach 1/2 as time goes on?]
Cathy | 2005 / 06 / 20 – 17:58
I’m going to say “hmm” again. Hmm. Would the probability only approach ½ if the “opposite” event was equally as likely as the primary event?
My brain’s melted in the heat…
Mark | 2005 / 06 / 20 – 18:27
Similar to this (from a post of mine last August: Time Travel Story):
“Time travel is impossible now and that will always be the case but as technology and understanding improve over time the possibility of time travel being possible in the future increases. Would you agree so far?” I chewed on my lip for a second and nodded. It sounded reasonable. “Okay, given that, we can say that the probability of time travel being possible now is very small indeed but each day that passes that probability rises. It’s a very small rise but the important thing is that it’s a rise. Now, we know the universe is infinite or, if it’s not, then it’s doing a good impersonation so we can easily see that our very small probability tends towards certainty as you approach the end of everything. Following this?”
In my mind I pictured a little graph with a slope representing probability of time travel being possible rising as the axis increased over time. I thought I followed it well enough and nodded again.
“Excellent. Finally, the universe is quantum in nature and obeys probability at the various quanta energy levels so, knowing that, we can see that while time travel is clearly impossible now, no matter when now is, because it will be possible in the future it is possible now even though it isn’t!”
Richard | 2005 / 06 / 20 – 23:13
If someone arrived from the future and told me they were a time traveller, I would keep very quiet about it. My sanity is doubted enough as it is.
David | 2005 / 06 / 20 – 23:39
Re #5: Yes, that was my assumption: the event and its opposite are mutually exclusive.
Re #6: The reason I say “by a human” in my statement of the [ridiculous] idea is specifically because [a] I don’t believe the universe [by which I suppose we mean, time itself] to be infinite and [b] I didn’t want to exclude the possibility of extra-terrestrial life interfering. Entropy rules supreme!
Re #7: Wibble.
Brown | 2005 / 06 / 21 – 10:25
Re #8: Entropy isn’t what it used to be.
[Edited by commenter — 09:26]
Cathy | 2005 / 06 / 21 – 11:02
Re: #8 (and apologies for more inconvenient questions ;-) ): Events being mutually exclusive doesn’t imply that they have equal probability of happening, surely? I could have event A = I roll a 6 with a die; event B = I don’t roll a 6. But the probabilities aren’t equal.
In which case, what we really need to think about is the probability that time travel could be discovered, and not one person would travel back in time, show off the discovery and claim all the credit? I’m pretty sure that’s practically 0, in which case the chances of someone doing so is practically 1, in which case it’s practically certain that you’re correct and time travel is impossible :-)
David | 2005 / 06 / 21 – 11:31
Re #10: You’re right of course, I was just being rather lazy with my definitions of events and their opposites. :)
[What] we really need to think about is the probability that time travel could be discovered, and not one person would travel back in time, show off the discovery and claim all the credit. I’m pretty sure that’s practically 0, in which case the chances of someone doing so is practically 1, in which case it’s practically certain that you’re correct and time travel is impossible.
Isn’t that what I said in the original entry? It’s certainly what I meant!
Don’t you have exams to revise for? :P
Cathy | 2005 / 06 / 21 – 13:35
Isn’t that what I said in the original entry? It’s certainly what I meant!
Aha. Aha ha ha. If I’m not mistaken, that was before the possibility of the opposite event was considered, and therefore the answer you arrived at was absolute certainty of the fact rather than almost absolute certainty.
Or else I was just reading it too quickly. Ahem.
Anyway, exams have been over for two weeks, whoo! And this week therefore concludes my three weeks of sitting-around-ness with nothing to do. For the moment though, I can still bug you in your comments ;-)
Sarah | 2005 / 06 / 21 – 16:03
Right well I did promise David that I would read this and make a comment cos no one else had responded, but it seems that lots of people now have, and they have far more interesting things to say… So, I shall respond to Cathy and say merely ‘Hmmm’. There, that’s my contribution. And I realise it’s probably in danger of contravening the commenting policy by being ‘off-topic’ so I’ll stop now. And after this ramble you will never ask me to comment again. Victory is mine.
“Yay David!”
David | 2005 / 06 / 21 – 17:33
Re #13: Any comment which contains the phrase “Yay David!” is immune from the commenting policy. ;)
mrtn | 2005 / 06 / 23 – 19:19
re #8(re #6): placement of square brackets meant at first glance i read this as “[a] i don’t believe the universe.”
which sounds about right.
David | 2005 / 06 / 24 – 07:43
Re #15: Sounds about right to me too. :)
Commenting Closed
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