Philosophy Discussion Forums

So this is just something that I'm wondering, I have no idea if these assumptions are true/false!

Time travel has been something that you know people always wanted to do. But you know how in like TV shows or movies where the person goes back in time, they some how change the present time (time where they came from) and the future. The people who lives have changed, well we can assume they didn't actually experience the immediate change right? Wouldn't it be that their life in that time change has always been like that [change]?

Example: Jack goes back in time a couple of years. His friend John originally was super rich. When Jack returns back to his (present) time John is poor. But John doesn't just go from rich to poor all of a sudden in his reality right?

So wouldn't this mean that time exists based on someone's reality? Because isn't there still that "time" or "dimension" where John continues to live his life being rich?

I'm just wondering if time is really this one "line" that we all follow. Assuming Past, Present, and Future is exists at the same time, there could be people from the future going back and forth through time, changing events that happened. Say that effected us (or has), we didn't notice it. Life has been the same everyday, no one lives have been drastically changed.

Idk if this even made sense or how stupid this sounds. I'm not a physicist or a time expert this just a question that's been on my mind, and if you have any thoughts/answers I would definitely be glad to view them.

OnlybutteredPopcorn wrote:The people who lives have changed, well we can assume they didn't actually experience the immediate change right? Wouldn't it be that their life in that time change has always been like that [change]?

Yes, I would agree with that. That sounds like a reasonable assumption. The one thing I am pretty sure of is that if our circumstances were being manipulated and our reality was being changed through trips from the future to the past, we would not notice the changes in that whatever changes were happening, they would be a seamless transition from one reality to the next since our reality, by nature, is as we experience it and would be the normal experience as we remembered it. The memory changes as the changes happen and thus become normal memories.

OnlybutteredPopcorn wrote:I'm just wondering if time is really this one "line" that we all follow.

Going backward in time would presumably require the traveller to follow the same timeline. Traveling back on another timeline would be useless if we wanted to affect a particular timeline. If multiple timelines do exist, I don't see how timelines would be crossed, even with time travel. If we could travel through time, I would assume we would have to follow the same timeline, otherwise we would displace all people, places and everything else, possibly even the laws of physics in the process.

Thank you for the interesting topic.

The first thing to consider {besides 'Dr. Who', an interesting SciFy series about time travel} is Quantum Mechanics {physics} which to date has not been disproven and still has scientific validity. In the Quantum world alternative universes {and time lines for that matter} are not only possible but are in fact likely. There is no reason to believe that this world here and now that we are communicating in in this forum is happening as a one time event in one way as it could be happening, and the results can be different in a parallel universe - Another words we exist in a multi-dimensional universe where not only is anything possible but also more than one interpretation and existent potential exists for all things that are happening. As you can see this will have great appeal to ScyFy writers and lunatics who love chaos - And in my opinion will become more refined in meaning as time progresses {i know that is an assumption that time is progressing, but I'll go out on a limb and make the assumption that progress is real, though what is may mean is relative}.

Now if you think about it you will remember we had this conversation a long time ago and if you really think hard enough you will remember when we had this conversation in the future - or is that now the past?

And yes even Einstein could be wrong - God does indeed play dice with the Universe.

UniversalAlien wrote:There is no reason to believe that this world here and now that we are communicating in in this forum is happening as a one time event in one way as it could be happening, and the results can be different in a parallel universe.

Light travels in a straight line.

The Truth wrote: (Nested quote removed.)

Light travels in a straight line.

Are you sure? How do you define an exact straight line in a universe which curves. In fact straight lines are illusional and do not exist. That humans measure light as it appears to be following a so-called straight line is a defect of human comprehension and is one reason humanoids are at least temporarily condemned to their limited dimension.

Prove that straight lines exist in real time in a real universe.

UniversalAlien wrote:Prove that straight lines exist in real time in a real universe.

What constitutes a straight line is irrelevant as it regards the relationship between why light travels in a straight line, and why time travel is impossible. The relevant factor is that light always follows a predictable path (Which we rightly or wrongly define as straight) from the point of origin to the point of detection. (Although for the sake of accuracy its path can vary ever so slightly)

Even though light is free to take any path it chooses, theoretically even forward and backward through time, you never ever see it take any other path than the straight one. If you understand why this is true, then you will also understand why time travel is impossible.

To disprove time travel, only one piece of evidence is necessary. Light travels in a straight line.

Even if we were to grant light traveling in an apparent straight line this does not mean that time travels in a straight line. Time in fact does not travel at all. Time measures rate of occurrences in a limited paradigm and only has validity in a limited dimension. In reality time is always relative and has no absolute direction or absolute rate of occurrence. Many humans do not accept time travel because it does not fit in with their conscious perception of reality and they find it disturbing to the frame of reference they cling to and to the limited nature of their biological being which decays within the biological paradigm of their existence. It is an unfortunate commentary on humans that they feel obligated to their biological selves. As much as some might not like it quantum physics trumps the limited viewpoint of a self'-limiting mind. There is no question that time travel is not only possible but what is impossible is the stopping of time travel as time travel goes on incessantly - Aristotle's mythical 'Unmoved Mover' is well aware of the paradox - you are not as you are caught up in your limited time line and allow a limited knowledge of physics to control you thinking- think Quantum Universe and you can open the doors of closed time lines.

UniversalAlien wrote:Even if we were to grant light traveling in an apparent straight line this does not mean that time travels in a straight line. Time in fact does not travel at all. Time measures rate of occurrences in a limited paradigm and only has validity in a limited dimension. In reality time is always relative and has no absolute direction or absolute rate of occurrence. Many humans do not accept time travel because it does not fit in with their conscious perception of reality and they find it disturbing to the frame of reference they cling to and to the limited nature of their biological being which decays within the biological paradigm of their existence. It is an unfortunate commentary on humans that they feel obligated to their biological selves. As much as some might not like it quantum physics trumps the limited viewpoint of a self'-limiting mind. There is no question that time travel is not only possible but what is impossible is the stopping of time travel as time travel goes on incessantly - Aristotle's mythical 'Unmoved Mover' is well aware of the paradox - you are not as you are caught up in your limited time line and allow a limited knowledge of physics to control you thinking- think Quantum Universe and you can open the doors of closed time lines.

And you have some evidence to support this POV?

On the other hand the fact that light travels in a straight line is well established and does indeed prove that time travel (As people generally understand the term) is impossible.

The Truth wrote: Light travels in a straight line.

Light follows a geodesic. You have to redefine the term "straight line" rather drastically to say that light follows one.

OnlybutteredPopcorn wrote: I'm just wondering if time is really this one "line" that we all follow. Assuming Past, Present, and Future is exists at the same time, there could be people from the future going back and forth through time, changing events that happened. Say that effected us (or has), we didn't notice it. Life has been the same everyday, no one lives have been drastically changed.

There is a sense in which everything, past, present and future, might exist "simultaneously" - although not really at the same time. The way that relativity works hints at there being a link between time and space, as if they were sort of the same thing, or "made of the same stuff". It could be that if one were able to view the universe from *outside* (I know you can't, it's a mind experiment), then one would all the moments in the universe "simultaneously". One possible version of this would have the expansion of the universe being time itself. If you want to know more about that try searching for "A Little Expansion on the Lightness of Fine-Tuning" and also look for the article titled "On Time" at the same location.

UniversalAlien wrote:There is no reason to believe that this world here and now that we are communicating in in this forum is happening as a one time event in one way as it could be happening, and the results can be different in a parallel universe - Another words we exist in a multi-dimensional universe where not only is anything possible but also more than one interpretation and existent potential exists for all things that are happening.

'

In regards to what you said, wouldn't that mean that there would have to be some amount of dimensions to fit how many times people have traveled through time?

There is no reason to believe that this world here and now that we are communicating in in this forum is happening as a one time event in one way as it could be happening, and the results can be different in a parallel universe - Another words we exist in a multi-dimensional universe where not only is anything possible but also more than one interpretation and existent potential exists for all things that are happening.

OnlybutteredPopcorn wrote:
In regards to what you said, wouldn't that mean that there would have to be some amount of dimensions to fit how many times people have traveled through time?

If you do some research you many come up with concepts/ideas such as:

The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternative histories and futures are real, each representing an actual "world" (or "universe"). It is also referred to as MWI, the relative state formulation, the Everett interpretation, the theory of the universal wavefunction, many-universes interpretation, or just many-worlds. The original relative state formulation is due to Hugh Everett in 1957. Later, this formulation was popularized and renamed many-worlds by Bryce Seligman DeWitt in the 1960s and 1970s. The decoherence approaches to interpreting quantum theory have been further explored and developed, becoming quite popular. MWI is one of many multiverse hypotheses in physics and philosophy. It is currently considered a mainstream interpretation along with the other decoherence interpretations and the Copenhagen interpretation.

Do you remember when we had this discussion next year?

UniversalAlien wrote:If you do some research you many come up with concepts/ideas such as: MWI

UniversalAlien, one must be very careful when attempting to use MWI to support time travel. It doesn't matter whether you believe in collapse or decoherence, in either model light always travels in a straight line. This holds true even at the quantum level. In the famous double slit experiment, constructive and destructive interface occur even before collapse or decoherence occurs. It is this simple fact, that interference occurs before collapse, that proves that time travel even under MWI is not possible. One simple fact holds true in every possible world in the MWI theory, light travels in a straight line. Just as light travels in a straight line, so does time, and for the very same reason, interference.

I really like your post OnlyButteredPopcorn, and your name as well:) I agree with what you said, and it can be easier for processing if you take in consideration of the fifth dimension, which is infinite possibilities of time that's like a tree stem (time plot) with branches (possibilities influenced by our actions, chance, and other people's actions). So to use the same example, Jack goes back in time and does something that results in John becoming a poor is actually a false statement. What Jack really did was taking action to change HIS OWN "present time" from one branch to another. (In the fifth dimension, this looks a lot like a railway switch.) This raises another question, where did the rich John go? Well, the rich John is no longer in the went-back-in-time Jack's present but another present (it's almost impossible to determine which present the rich John is now in for there are infinite presents and every single thing Jack does can have certain unknown effect).

I'm sorry if I made it more confusing, I kinda get the feeling that I did. But think about this, it's actually not worthwhile to think about this issue. If you know the Mobius Circle, you know that a incident in a higher dimension is almost always imperceptible by beings in the lower dimension. So, let the problem go, I'm sure at some point you will get a epiphany regarding time travelling.

What a coincidence. My friend and I were talking about this, because I brought up a similar topic as the OP. If someone travels back in time, and changes the present, isn't he or she in a different time than the past or the present? My friend point out that time is moving backwards because the Big Bang is accelerating back to its origin. The example of a vase breaking down and then rewinding back to its original structure is the model of time.

This raised the question of cause and effect: that really the future causes the past. Like someone already said, that the past, present, and future, exist simultaneously, so something in the future possibly could effect what happened years ago, on a different perceptual level. I really don't know the physics of it.

As far as light is concerned, isn't light twofold: waveform and particles. The particles move in all sorts of directions. And Einstein proved that when light passes a heavy mass, such as a planet, it bends. So a light doesn't necessarily move in a straight line.

Stein Von Spitzheit wrote:I really like your post OnlyButteredPopcorn, and your name as well:) I agree with what you said, and it can be easier for processing if you take in consideration of the fifth dimension, which is infinite possibilities of time that's like a tree stem (time plot) with branches (possibilities influenced by our actions, chance, and other people's actions). So to use the same example, Jack goes back in time and does something that results in John becoming a poor is actually a false statement. What Jack really did was taking action to change HIS OWN "present time" from one branch to another. (In the fifth dimension, this looks a lot like a railway switch.) This raises another question, where did the rich John go? Well, the rich John is no longer in the went-back-in-time Jack's present but another present (it's almost impossible to determine which present the rich John is now in for there are infinite presents and every single thing Jack does can have certain unknown effect).

Haha thank you! And this is actually what I've been thinking (and I tried to explain), I just didn't know if it was really true.

And also The Truth, what does light have to do with time?