The Instigator
MrMarkP37
Pro (for)
Losing
14 Points
The Contender
Lexicaholic
Con (against)
Winning
17 Points

Time Travel to the Past will never be possible

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Post Voting Period
The voting period for this debate has ended.
after 5 votes the winner is...
Lexicaholic
Voting Style: Open Point System: 7 Point
Started: 6/24/2009 Category: Science
Updated: 7 years ago Status: Post Voting Period
Viewed: 3,578 times Debate No: 8762
Debate Rounds (4)
Comments (6)
Votes (5)

 

MrMarkP37

Pro

Lexicaholic has stated that there is a lack of interesting debate topics, so I decided to challenge him to this debate, which I hope he will find interesting.

It is my belief that time travel to the past is not only impossible at this time, but will never be possible. I will explain in round two and look forward to my opponent's opening round.
Lexicaholic

Con

Thank you for the debate Mr. Mark!
My opponent has stated that:

"It is my belief that time travel to the past is not only impossible at this time, but will never be possible. I will explain in round two and look forward to my opponent's opening round"

I propose that my opponent is wrong, for the following reasons:

1. Time travel to the past is already possible.

Conceptual time travel to the past already occurs whenever you remember a past event. While it may not be actual time travel, you can think backwards in sequences of time to a past state. Therefore, one form of time travel, a conceptual one, already exists.

2. Wormholes offer a possiblity
http://en.wikipedia.org...

Wormholes may allow travel to the past. It wouldn't be travel through time (more like around it) but if you have a way to survive a trip through a wormhole you probably have a way to wrap a bubble of your own space time around you, which means that you can bring a watch with you ... to time* travel to the past. Zing!

* as in, keep track of time for

3. Cosmic Strings offer a possibility
http://www.livescience.com...

If we bend it, we can break it. If we break it, we've bought it ... a ticket to the past that is!Through time, too.

4. Science says it's possible! Unlikely ... but still possible!
http://www.pbs.org...

Scientists can't make claims unless there is evidence to empirically support the claim. No one can say if time travel to the past is possible, though they might qualify that some methods don't work. Spinning around in a box, for example, may make you feel like you're time traveling when you're six, but clearly it doesn't work. For time travel to the past to be precluded as a possibility, every possibility would have to be tested with negative results. That hasn't happened yet.

5. If my opponent would like to argue the grandfather paradox, remember that the debate is "time travel to the past is not possible" not that interaction in the past is impossible. If you reach the past and instantly vanish (because you would otherwise interfere with causality, then you've still traveled to the past ... you just didn't enjoy it very much.

That's all for now. I look forward to my opponent's response!
Debate Round No. 1
MrMarkP37

Pro

Very clever, I have to think harder when I word these things.

Of course, I meant the ability to physically travel backward in time to a previous date.

My first argument as to why this would never be possible is because it presupposes that the past is in constant existance as a physical thing (as opposed to a memory) which is not logical. When things move into the past they are no longer there physically. This lack of a physical realm makes it impossible for people to physically go there because it no longer exists.
As Stephen Hawking questioned, if time travel to the past is possible then why have we not experienced time-traveling tourists to our time? Why were there not reports of out of place observers at different historical moments?
My opponent has already conceded that effecting past events is impossible (by his admission that the grandfather clause does exist) so were time travel possible interaction with the past would be impossible.

Your article on cosmic strings is from an article that asserts that most scientists think that time travel is impossible. What would happen if we bent time with cosmic strings? Just because we bend space time does not mean that we would travel back into time. We might simply fold space onto itself, it could lead to the destruction of an area of space.
The main point is that once the past becomes the past it ceases to exist as a physical thing. It becomes a mere memory and that is the only way to experience the past. To believe otherwise would be to believe that versions of ourselves live on forever in the past but this is not possible as one thing cannot occupy two points in space at the same time. Since space and time are connected in spacetime, it is not possible for a version of ourselves to exist in the past as well as exist in our present.
Lexicaholic

Con

"Very clever"

Thank you. :)

Re: Point 1

"Of course, I meant the ability to physically travel backward in time to a previous date."

For now I will merely note that my opponent has conceded the semantics arguments. Rather than belabor the point, however, I will proceed to arguments of substance.

Re: Point 2

"My first argument as to why this would never be possible is because it presupposes that the past is in constant existance as a physical thing (as opposed to a memory) which is not logical. When things move into the past they are no longer there physically. This lack of a physical realm makes it impossible for people to physically go there because it no longer exists."

My opponent makes a valid point. He assumes that time is a measurement of a state of transitions, from one point to the next … that the universe is like a puzzle, that is rearranged, and that the period of the shift between each rearrangement is the measure of time. Of course, if this is the case, then the past is, in theory, just one particularly complex arrangement … one that is unlikely, but that could possibly, come again. In addition, there is the possibility that the universe expands, collapses, and then expands again, like an entropy ridden rubber band. [1] If that is the case, then everyone could find themselves traveling to the past at some point in the collapse towards re-expansion. [2]

"As Stephen Hawking questioned, if time travel to the past is possible then why have we not experienced time-traveling tourists to our time? Why were there not reports of out of place observers at different historical moments?"

Maybe there are, or maybe fears of altering causality have prevented them from visiting in an interactive form. Perhaps they would ‘visit' using self-created temporary micro-universes, existing in a parallel state outside of any sense of dimensions, and of which we are unaware. [3] Who knows? The technology would clearly have to be enormously advanced. Because it is impossible to say that we have been visited, it is best to say that evidence suggests that time travel is impossible. It does not, however, preclude it.

"My opponent has already conceded that effecting past events is impossible (by his admission that the grandfather clause does exist)"

Careful now – I never stated that the grandfather clause exists, just that even if you use it, it would be irrelevant to the debate.

Re: Point 4
"To believe otherwise would be to believe that versions of ourselves live on forever in the past but this is not possible as one thing cannot occupy two points in space at the same time. Since space and time are connected in spacetime, it is not possible for a version of ourselves to exist in the past as well as exist in our present."

While it is not possible for two things to occupy the same point in space-time, it is possible for another thing to displace an object in space, as we do whenever we move. Assuming that this displacement occurs as a consequence of our movement through time (albeit forward) there would seem little reason to expect a different result if we went backward. Therefore it is possible for a time traveler to displace, say, past air molecules, but, of course, in doing so we would change the pattern of the past and affect causality. This being the case, we would only experience the past for an infinitesimally small moment before either it branched off into a parallel universe or was altered to a different state than the ‘original' past.

[1] http://en.wikipedia.org...
[2] http://en.wikipedia.org...
[3] http://www.npr.org...
Debate Round No. 2
MrMarkP37

Pro

In order to avoid paradoxes and the destruction of causality one of three things must be true. Either if time travel to the past is possible then whenever someone has traveled to the past, they always existed there and anything they did became part of history. The problem with this is that it negates free will, by making everything that happens "fate".
Another possibility (as you pointed out) is that your mere existance in the past causes the branching off of another dimension. If this is the case then a "time-traveler" would never be able to return to his present in his own dimension.
The problem with this is because he wouldn't be able to travel back to his dimensional present, it could never be confirmed that his time-travel experiement was successful.
The third option is that time travel will never be possible.

If people are able to travel back in time at some point, why weren't there many people there to witness the birth of Christ? Or the battle of Gettsyburg, or the assassination of Lincoln, or the bombing of Pearl Harbor or any of a host of historic events. If time travel were possible we should notice in history that whenever an historic event occured there were a great deal more people there than there should have been. This lack of extra observers proves that time travel is not possible.

If time travel to the past is possible why doesn't the scientist who invented it come back to an earlier time and share his findings with the past?

We could conduct an experiment. We could create a monument in Washington and etched a message to the future on it. We could ask any scientist that invents time-travel to the past to arrive at the dedication ceremony for the building. If someone shows up then time travel to the past is possible, if not then it isn't.
Lexicaholic

Con

"The problem with this is that it negates free will, by making everything that happens "fate"."

Arguably any number of theories would negate free will. The big bang could make all of existence one big inevitable mechanical process. If the concept of past is an illusion then certainly free will could be as well.

"The problem with this is because he wouldn't be able to travel back to his dimensional present, it could never be confirmed that his time-travel experiement was successful."

Confirmation does not equal success however. We're arguing whether or not someone could possibly travel back in time, not whether or not someone could verify such an accomplishment.

"This lack of extra observers proves that time travel is not possible."

Once again, not so. For one thing, many historical events are full of people, which would make it difficult to discern if a time traveler was there or not. Also, there is the possibility that the past could be observed in a state outside of the universe, in which case causality could be preserved. Finally, there is nothing to say that what people perceive to be ghosts, aliens and so forth are actually time travelers. If that is the case, history is replete with instances of such things before the occurrence of a historical event. [1]

"If time travel to the past is possible why doesn't the scientist who invented it come back to an earlier time and share his findings with the past?"

I would assume causality would have something to do with that. If you tell people about how they might obtain the marvels of the future, then they will make the marvels of the future, and then the original inventor of said marvel will have no need to invent it, creating a paradox.

"We could conduct an experiment. We could create a monument in Washington and etched a message to the future on it. We could ask any scientist that invents time-travel to the past to arrive at the dedication ceremony for the building. If someone shows up then time travel to the past is possible, if not then it isn't."

We could, but then we would have to assume that the monument lasted through the ages so that it would be recognized as significant when time travel finally became available. The problem with the question "why don't we see them at important event X" is that the civilization that exists when time travel is possible could potentially have an entirely different way of valuing important events. Similarly, a 21st century monument may not be something that historians of the era keep track of, any more than people today keep track of time capsules.

[1] http://www.space-2001.net...
Debate Round No. 3
MrMarkP37

Pro

There are two basic problems with time travel, one is possible to overcome, the other is not.

The energy needed (10 to the 19 billion electron volts, a quadrillion times larger than that produced by our most powerful machine on Earth) is so enormous that it is nearly impossible for our brains to comprehend. However, I will admit that it is theoretically possible to generate such energies for a sophisticated enough society.
However, the second problem is the radiation that this causes. The radiation is so great that it would vaporize anyone who comes near it.
Lexicaholic

Con

Well, it might vaporize them, but only if they were in the same physical plane ... like you've said, a future society would have to be very advanced to pull it off, to the point where we could scarcely imagine the forces involved. It is possible that in the future mankind will have evolved to a state unrecognizable as the crude material it once was. Assuming abiogenesis, we started as chemicals and minerals, became simple organisms, then became more complex organisms, and are now organisms that transform chemicals and minerals around ourselves. Who knows what we could become in the far future? Perhaps we will be a form of radiation, or energy, or pure information imprinted in some unimaginable medium ... the possibilities are endless.

While it may be true that people of the future can not travel to the past, it is certainly true that people of the present can not accurately predict people of a far enough removed future. How strange would our society seem to the ancients, the Ur-people who thought that we had animist spirits that were borne to the east or west depending on how well we fought, and saw a little god in every thing around them? Comprehension of a certain degree of divergence is impossible, because people simply do not contemplate it. So long as this is so, time travel to the past is possible, just very unlikely within that understanding provided us by the knowledge we presently possess.
Debate Round No. 4
6 comments have been posted on this debate. Showing 1 through 6 records.
Posted by Maikuru 7 years ago
Maikuru
Very enjoyable debate.

C: Tie
S&G: Tie
A: Con - Pro provided the standard fair but Con came prepared and then some. He addressed all arguments thoughtfully and proposed a number of possibilities.
S: Con - His sources were numerous and relevant.
Posted by Lexicaholic 7 years ago
Lexicaholic
Thanks for the debate!
Posted by Lexicaholic 7 years ago
Lexicaholic
My response is going to be a little late, just because I want to approach your substantive claims on their own merits. Also, I've gotten kind of busy this weekend. :/
Posted by Lexicaholic 7 years ago
Lexicaholic
Sweet. It's on!
Posted by MrMarkP37 7 years ago
MrMarkP37
Nope, just a straight debate. You can say anything you want.
Posted by Lexicaholic 7 years ago
Lexicaholic
Any special rules or restrictions I should know about before accepting?
5 votes have been placed for this debate. Showing 1 through 5 records.
Vote Placed by Maikuru 7 years ago
Maikuru
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Vote Placed by MrMarkP37 7 years ago
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Vote Placed by Lexicaholic 7 years ago
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