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If time travel was to happen what would it mean? Where are the travels from the future? There are three kinds of processes that we can easily understand, causal, non causal and anti causal. Non causal means event happen not only based on passed events but future events. A perfect low pass filter is a non causal filter. If there we people or particles traveling back in time it is well beyond our comprehension today how that could result in one reality. Of course do we have one reality. With special relativity two observers cannot agree on the order of events anyway.
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If time travel was to happen what would it mean? Where are the travels from the future? There are three kinds of processes that we can easily understand, causal, non causal and anti causal. Non causal means event happen not only based on passed events but future events. A perfect low pass filter is a non causal filter. If there we people or particles traveling back in time it is well beyond our comprehension today how that could result in one reality. Of course do we have one reality. With special relativity two observers cannot agree on the order of events anyway.
What if there were 10^100 different realities splitting off from a single point in time and just one of them happened to involved a time traveler arriving from the future at just that precise moment. What would the chances be of our reality being the same one with that time traveller in it? Maybe history is always splitting off anyway, whether time travel is involved or not and if someone goes back in time, the point where the traveler reenters the timeline occurs in just one of those realities.
The Time traveller would arrive in some point that appears to be the past, but would then find events unfolding differently from the moment he arrived. This model of time travel preserves free will and everything is random even if you travel back in time.
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If time travel was to happen what would it mean? Where are the travels from the future? There are three kinds of processes that we can easily understand, causal, non causal and anti causal. Non causal means event happen not only based on passed events but future events. A perfect low pass filter is a non causal filter. If there we people or particles traveling back in time it is well beyond our comprehension today how that could result in one reality. Of course do we have one reality. With special relativity two observers cannot agree on the order of events anyway.
What if there were 10^100 different realities splitting off from a single point in time and just one of them happened to involved a time traveler arriving from the future at just that precise moment. What would the chances be of our reality being the same one with that time traveller in it? Maybe history is always splitting off anyway, whether time travel is involved or not and if someone goes back in time, the point where the traveler reenters the timeline occurs in just one of those realities.
The Time traveller would arrive in some point that appears to be the past, but would then find events unfolding differently from the moment he arrived. This model of time travel preserves free will and everything is random even if you travel back in time.
Perhaps time travel is such that all people that arrived from the future arrived from a different reality. Thus if a new reality is born from a person travailing back in time it is not essential for the same person to travel back to the same point in time within the new reality. In fact it is not even necessary of the person who traveled back in time that created this new reality to even be born in the time line of this new reality.
It is an interesting question if it is possible to have realities that are completely consistent in that the person who travels back in time to create the reality is born again in this new reality travels back in time and all events unfold in exactly the same way. Another thing to think about is if time travel is possible one might expect infinite realities and thus the probability of being born in a reality where there are no visitors from the future is zero. Of course lots of things happen which are probabilistically impossible. For instance the probability of us being born an any sufficiently small interval of time is vanishingly small.
Another question is if you travel back to the past how well can you use knowledge of the future to your advantage since each action you take to change the future can have dramatic effects on the future. Perhaps our reality is unstable and any perturbations of that reality lead to destruction. As a consequence all other realities are death sentences and that is why we exist in a reality where no one has visited us from the future.
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You heard of the "many universe" model of reality. Everytime you flip a coin there is one universe where the result is heads and another universe where the result is tails. You get split in two along with the Universe as you flip the coin and each you is unaware of the other and each observes only on outcome of the coin toss and not the other. I'd say the probability of someone arriving from the future must be minutely small, since we don't seem people arrive from the future all the time. From the point of view of the time traveller, traveling back in time is simply winding back history and rerolling all the random "dice" of everything that occurs after you reenter the timeline. Even if the time traveller does absolutely nothing and makes no contact with the world, and even if he is light years away and cannot possible effect anyting on Earth, events may still transpire differently, since different atoms may decay at different times from what happend before, the random atoms will travel in different directions as a result, different weather patterns will arise out of this, and on days that were previously sunny in the original history may experience rain in the new timeline. A time traveller who went back in time could never return to his future.
Time Travellers can use their knowledge to their own benefit, certainly the short term plans of the major political actors will be know to them and their actions anticipated from that over the short term. Superior technology would be great help. If the time traveller were to take a series of short hops back in time frequently, he could literally create a timeline where there was no wars, simply by the expedient of going back in time and eliminating those who would have started them.
You could go back in time and get rid of Hitler, and go back in time and eliminate those who would have filled the power vacuum and would have done bad things. The easiest thing to do is just send Adolf back in time and thuis into another reality where in the one he left he is never seen again.
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