I've one story where the grandfather paradox is not addressed, but rather is there to explore the character's past and how he ended up the way he did. This is soft SF, thus the time travel is just a plot device, rather like QL or ST, not an end to itself. There is a group, the Forcers (aka Timeline Enforcement), who investigate temporal anomolies and correct the timestream. And they do.

I had another idea churning that I've never written more than a few paragraphs. I keep getting blocked. Basically, a change to the past puts the present and future into a dreamlike limbo. There's a emerging alternative timeline and a fading one. A handful of characters from the old timeline have a limited window of oppurtunity to go back and change it back. Of course, that has nothing to do with science, more to do with science fantasy.

You might want to check out Balancer in the latest WOTF anthology. It handles the idea not too disimilarly, albiet much better than I concieved.

One straight fantasy I'm working on (actaully I just piddle with it on and off), takes the tact, that in essence, causality can't be voliated. Then again, that won't be stated explicitly (if I do finish it). The time travel is there as a plot device.

Some speculate that you could move around in the past, but you have an inability to do anything or interact with the reality. A variation on this says that the things set in time are like stone objects to us. We might travel to the office of our boss ten years ago, but we wouldn't be able to muster the astronomical energy needed to alter one molecule of ink - let alone lift a pen. Another variation puts you in a different "phase" which makes you unable to make solid contact with anything. (They are like a ghost to you, and you are like a ghost to them.) Other variations of this abound. Paradoxes aren't very common in these scenarios.

Then there is the "multiple universe" scenario. I personally think that these are generally very carelessly done. I have never, ever read or seen an example of it that was truly well thought out and satisfactory to me. However, the thing that is convenient about the multiple universes is that you can escape many of the paradoxes.

For example, J's future self can come back and prevent him from finding his muse, but that would not paradoxically make the future J cease to exist because the future J would come from an entirely different parallel universe. Therefore, when the future J returned to his own time, he would not see any of the changes he made **unless** he actually returned to the new parallel universe that he just caused.

This becomes unsatisfactory to me for a number of reasons. 1) Wouldn't that make *two* Js in one universe, while the original one is missing a J? 2) Doesn't that mean that he did not actually rectify his problems, but simply **abandoned** them to the other universe? 3) From a Theistic and teleological standpoint - are these souls multiplying every time there is a split of universes? Are they the same soul experiencing the same things, or are they different souls entirely? If they are different - who was the originating soul?

These are the biggest problems that I see most works of fiction ignoring when they use the parallel universe explanation. Personally, I think they would be more interesting stories if they didn't ignore them - but that would take time to think it through, and a lot of these guys are TV writers who are under pressure to produce *now*. For the purpose of character and dealing with what is real to the character I like the idea of exploring number 2 above. (The real spouse in one reality that he left as opposed to the new one that he technically never married. And if #1 is also true, he would have to kill his parallel self off to enjoy the benefits of that parallel universe.)

SLIGHT SPOILER FOR MOVIES LAKE HOUSE AND DeJavu IN THE FOLLOWING PARAGRAPH.

The most popular approach to it seems to be to ignore any thoughts of a coherent reality and simply let the timeline be changed. Most of these simply leave it a mystery how the paradox can work. I generally don't like these unless they are - for lack of a better description - poetic. For example, I really enjoyed Lake House with Keanu Reeves and Sandra Bullock. It was a self-negating plot, but I didn't mind it because it was more of a poetic fantasy than a science fiction movie. DeJavu with Denzel Washington was another one I liked because of the way the paradox revealed the sacrifice and commitment of the character and had a poetic/miraculous quality to it. Each of these plots built me up to expect a miracle - and that is what I got: A true *miracle*. And there is no other way to explain these paradoxes, but through a miraculous act of God. (Although, some of them are simply nonsense and completely incoherent, so - in C.S.Lewis style - I simply reject them as nonsense and would not attribute them to God - fictional or otherwise.)

There are hybrids of these speculations, too. My story "Does this Count?" has one scientist who theorizes that you can affect the past, but if you do, it was something you already did in the current timeline, because you cannot change what has already happened. If you try to change something that already happened, you will somehow be prevented - because you clearly didn't succeed in the present timeline. This scenario is a hybrid of the first one that said you cannot change anything, but it combines it with the last one that says you can go back in time and interact with your own timeline. This variation avoids the incoherence of the latter because any "change" made is a "change" that already existed in the previous timeline.

I am certain there are many, many more ways of looking at time travel, and I think the trick is finding the scenario that best challenges the beliefs and desires of your characters. Which scenario stretches them best the way you want to stretch them?

Fun stuff.

Another is that my time travelers enter the bodies of people of the time. I like to have their host's head bumped so the personality change is explainable. I use this most when the main character is learning old technologies.

One I did was where a group goes back in time to save Benedict Arnold's future reputation. They try to kill him while he is still considered good, and ends up being the ones that wound him, which he actually did. The time travelers cause the history we know, to happen.

There is the idea where people go back in time, and slip things into the "cornerstones" of buildings as they are constructed, and then the valuable objects or documents are retrieved after they get back when the building is torn down. Again, they are not really changing history, just finding out what the history will tell them a bit later.

The final favorite is where their effects are not recorded in history. They effect a few people or even a large group of people, but as long as it is not recorded, it does not matter.

I find it a bit silly that if we could travel through time that nothing could be altered. As I see it one of two possibilities would exits. Everything we do is part of history, so you couldn't change anything, or once you changed it, the future changes accordingly. I like the concept that everything changes, if you want to go messing with time and kill yourself inadvertently...so what? We make mistakes now, and if we are bold enough to go back and mess with the past, deal with the consequences.

Now how you go about traveling through time...that is the trick.

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I find it a bit silly that if we could travel through time that nothing could be altered.

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Many thought the theory of relativity was silly when it was proposed. The question is, though - what is plausibly true? There are many possibilities, and at the moment the answer is a complete mystery. So why is it "silly" to consider that nothing could be altered in the past? Certainly for the sake of story it can be entertained without being "silly."

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As I see it one of two possibilities would exits.

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Then I don't think you have really considered it at length. Do you have any background in Physics? Philosophy? I think if you explored these areas as they relate to time travel, you might find many, many more possibilities.

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I like the concept that everything changes, if you want to go messing with time and kill yourself inadvertently...so what? We make mistakes now, and if we are bold enough to go back and mess with the past, deal with the consequences.

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I think that is a remarkable thing to say. The possible complete annihilation of everyone you love merits a "so what?"

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Now how you go about traveling through time...that is the trick.

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With thoughts like the one above, I doubt God would ever grant us the ability if the past could, indeed, be changed.

ciao,
Mark

As for understanding the how's and why's, lets see. Time and space are go hand in hand. One of the reasons Einstein used the term "spacetime" to signify that they are a matched pair. One way time travel could theoretically be achieved is by moving from one point in space and time to another point in space and time. Once you have relocated yourself, you would then join the normal flow...if not, then I guess you wouldn't be able to interact with anything, but then you would also not be part of the flow and would probably be stuck in that moment.

So, if you rejoin the space and time you could interact, and even change the events happening there. The question would then be, are the events you try and change things that have already happened and you are only fulfilling history? Or do changes change the future? Or, being in the past, are you now immune from the changes you make to the past?

One way or the other, once you join a past timestream, you become part of it and you can change it. While the outcome is still heavily speculative.

As for my lack of concern for someone being stupid...well, I've come to the conclusion people do dumb things on a regular basis. Even intelligent people do highly unintelligent things. Many of them repeat the same mistakes over and over. I have long since removed myself from feeling any responsibility for other peoples poor choices. I've made my own, I deal with them. You make your own, you deal with them. If someone invented a time machine and the first person that went back killed one of their relatives, should I be upset that someone lacked the foresight to think through what killing their ancestor would do? No, I would not, and since they would have never existed, neither would anyone else.

I've seen many movies that have used time travel, some good, some bad. It always seems to be about how to make it right, when the real answer would be more along the lines of how not to screw it up. Time cops hunting down the rouge time traveler who is messing up the grand scheme of things. One question, if there is a grand scheme, then why would God, or any other entity that created this grand scheme, allow some little human to make a mess of it? One aspect of writing is believability, and I have a hard time swallowing the very overused time cop story.

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I like the concept that everything changes, if you want to go messing with time and kill yourself inadvertently...so what?

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In order to be helpful to MartinV, let's take this as a case study. How would you deal with this paradox?

If LD traveled to the past and inadvertently aligned his seeming nihilistic attitude with a physical nothingness by ending his life, then the change that takes place includes his nonexistence in the future. So in the future time, he is not available to go back and kill himself, which means he will live. Which means he will live to go back and kill himself, which means he will not exist in the future to go back and kill himself, which means he will not get killed and will go back...yaddah-yaddah-yaddah.

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As for my lack of concern for someone being stupid...

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Well, I sort of understand your meaning a little better, now. (It related more to other's stupidity than to your own carelessness.) However, if I take what you are saying seriously, then I guess you wouldn't care too much about someone driving stupidly and killing innocent people? (I have a hunch you don't believe this, but I would like to see how that reconciles with your thoughts on time travel.)

I think you are right when you say:

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Time travel has all the makings of disaster on a grand scale.

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Probably far more than people realize. A significant event (probably a very, very small one could be significant enough) could change the timing of conception for every baby from that time forward, which would mean the entirety of humanity would be erased and replaced with different people.

As far as your interpretation of Einstein goes, I don't think it tells us as much as you think it does. We really don't know what time *is*. We simply experience it. So to predict how you would or would not slide into a particular time line is dicey business - and from a *scientific* perspective, it is enshrouded in mystery. We know so little about it, the speculations need not be limited by your personal preferences.

Especially for good fiction.

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One question, if there is a grand scheme, then why would God, or any other entity that created this grand scheme, allow some little human to make a mess of it?

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I think I made that point. If the past can be changed, I doubt God will ever allow time travel. (I doubt he will anyway, but that reasoning isn't relevant to the point at hand.)

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However, if I take what you are saying seriously, then I guess you wouldn't care too much about someone driving stupidly and killing innocent people?

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Actually I do. If someone wants to kill themselves, and they succeed, so be it. I would call that a stupid decision. If someone wants to kill themselves and take a few hundred people with them, then no, now someones stupidity is branching out to harm others. We even have a special word for that type of person.

Time travel in any form would be dangerous, and since I do have a story in the works which does include time travel (although humans are not the inventors), nothing about the time travel is beneficial to the main character. Every time he tries to manipulate the outcome of events...they end up worse, which prompts him to continue trying, and makes things even worse each time.

I'm not just preaching here, either. It translates into writing, as well. I think the strongest writers are the ones who really care about their characters - even the bad ones. When you don't care about the evil characters, they are flatter. But if you pity them, and are hoping and looking for something redeeming in them (even if it doesn't surface in the story), the writer treats them more as real, complex human beings. In other words, they resist treating their characters in a simple minded way. It also makes the characters more dynamic because they, too, go through transformations of a sort.

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Every time he tries to manipulate the outcome of events...they end up worse, which prompts him to continue trying, and makes things even worse each time.

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I think the strongest writers are the ones who really care about their characters

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Looking up the word paradox and all the definitions mention contradiction. So when one travels through time and changes something in the past that had not happened before, it contradicts the time travelers view of the past. I still think that a change in the past would change the future. So the future someone came from would no longer be the future they returned too. The Butterfly Effect wasn't bad, but after each change the new history of time was dumped on him. For the movie that worked, but I like the idea that the time traveler doesn't know what the changes are until they go see for themselves.

OSC's own Pastwatch, does a wonderful job of how paradox and future interference in past events.

Though I agree I've rarely seen the multi-verse all things at all times approach done well (Sliders Tv show being a particularly abyssmal example). It is the easiest to work with since basically anything that can happen has happened somewhere at sometime. I wish I could think of a good example of this but none come to mind.

Time splits and parallel time lines are another method you can use. Bob goes back and initiates events that radically diverge from his own timeline, at the moment of divergence the timeline splits and they stay split. Travellers from both timelines can now go back and make additional changes. As these changed compound you basically end up with the all things have happened at some point as the time stream fractures more and more.

Another is a fixed time line where the traveller exists outside the line, i.e. once they travel outside of there own relative time they are outside and no longer affected, so you go back and kill your grandpa, your timeline ceases to exist, but the traveller continues to exist because they are outside the original continuum.

Another is nature abhores a paradox, just as it does a vacuum and events will transpire to prevent anything from significantly altering the timeline and small changes are absorbed into the whole.

What if we assume that all human souls exist before a given person is born, and they are "waiting" for a body to enter and thus begin their life. This is assuming the age old question of nature vs. nurture is a resounding "NATURE" and various other things, but go with it for the sake of argument. What if, say I go back in time and kill my mother before I was born, or any descendent, and thus disrupt my eventual birth. Instead of this producing a paradox, what if all the necessary changes to the timeline took effect, only instead of me being born from that family, my same soul was then born into some other child. The immediate effect of changing my past might alter my physical body but leave my soul and personality and the core of who I am unchanged.

It still doesn't give an answer for if I go back in time and kill *myslef* but maybe if you hand-wave some explanation that the timeline cannot accomodate 2 instances of the same soul, and thus no person can travel back to a point in time (or into the future either) where they already exist.