Is time travel to the past impossible?

[yahooyoda]

If causality is an ultimate law then time travel to the past would be absolutely impossible.

[Locke]

Yes, I agree time travel to the past is impossible. My viewpoint though doesn't stem from a causal relationship; rather that time is just a construct. All measurements seem to follow this idea. Take a ruler for example; it is not a meter per say. Rather it is a close approximation to our idealized meter. Time is just the measurement of the duration between one event or position or another event or position.

[Dennis Mahar]

Locke,

My viewpoint though doesn't stem from a causal relationship; rather that time is just a construct. All measurements seem to follow this idea.

If time is just a construct.
Who constructed the construct?
Who constructed the constructor of the construct?

[Locke]

If time is just a construct.
Who constructed the construct?
Who constructed the constructor of the construct?

This is a very interesting question set of questions.

Well, in my view man is the constructor of time in the sense of how we view it. Objects move throughout the universe but with no observer the duration of movement is meaningless; things just flow. Rivers flowed for millennia without any observation from man; but, it took man to observe the river and divide that flow into increments such as gallons. Again, and I hope that I'm not wearing out the analogy; A 127 ft tall building doesn't mean that there are physically 127 ft in it, rather the height of the building corresponds to 127 of our idealized notion of a foot. I can't remove a ft from the building; I can remove the material of the building that in length matches our ideal ft. Gallons, ft, and any other measurements are extremely useful for us; but, they are never the things they measure; nor, are the objects measured in turn the idealized increment of measurement. Wow, I am long winded. I hope that makes some sense. :-)

" Who constructed the constructor of the construct?" Now that is the ultimate question. I don't know. We are still seeking this. That's why certain religions survive. They answer, for their believers, these questions. The simple gods have fallen by the wayside. Why is there lightning? " Zeus".... well, actually. Why does the sun cross the sky. " Apollo"..... wellllll, actually.

[Dennis Mahar]

Locke, have we noticed a causal relationship here?

construct, constructor of construct, constructor of constructor of construct

[Locke]

Dennis,

I can't deny that cause and effect are a truism of the universe. But, I'm afraid that in my present mode of thought; this is no more insightful to me then saying all matter is composed of energy. The statement is true. I could lose myself in this statement. I could say that since all energy in the universe is presumed to have come from the Big Bang; then, all things in the universe are exactly the same; just put together in different forms. If this answer satisfied me then would I ask about butterflies, whales, quasars? I could just look at them and say they are me and I am them.

If a meteorite strikes the earth. I could look at causal effects at any number of levels. The interaction of force through the atomic structure due to the strike. I could try to map the force distribution. I could look at it at the molecular level. Force and reaction through clusters of atoms. I could look at it through normal human perceived levels. How large was the displacement of earth when it hit the ground? I could look at the reaction at the planetary scale. The earth hardly noticed the strike at all; no deviation of orbit nor rotation. I could look at the same reaction on the galactic scale. Not even noticeable with all the energy of the fusion fires of stars in our galaxy. The micro and the macro. The forest for the trees and all that.

Perhaps in the future I will embrace this idea. All things are possible.

[Dennis Mahar]

Locke,

Perhaps in the future I will embrace this idea. All things are possible.

Because the existence of Locke is temporary.
Subject to change...infant, child,youth, man, old man.
Because Locke will cease to exist.
Because Locke is 'thrown' into the World and 'thrown' out of it.


Would Locke be better occupied in trying to fathom quasars.
or
Would Locke be better occupied in investigating 'who am I'.

Possibilities.

[Locke]

:-) Pretty good.

Locke,

Perhaps in the future I will embrace this idea. All things are possible.

Because the existence of Locke is temporary.
Subject to change...infant, child,youth, man, old man.
Because Locke will cease to exist.
Because Locke is 'thrown' into the World and 'thrown' out of it.


Would Locke be better occupied in trying to fathom quasars.
or
Would Locke be better occupied in investigating 'who am I'.

Possibilities.

Why limit me to one or the other :-)

[Dennis Mahar]

Why limit me to one or the other :-)

It's more about the assumption being made that everything is split by Western thinking...
Science and philosophy being structured around a prior decision, and being bound to that decision...the splitting of the World in order to grasp the World.

It's possible to hold split World/unified World pictures together..
but mostly there's a forgetting of unified World....

[Dragonspirit]

Of course it is... one basic method is to do deep trance, and image a tube cutting its way into the past at ten times the speed of light.. Maintain the velocity for a few minutes, then let it drift on its own.. regroup back home, and take the dominant molecule in your Being, and send it into the tube, creating its own tube slightly ahead of itself, as it progresses.. Any time stop velocity, and exit the tube.. Have a pardy.. tell me about it...

..In my first TT experiment, I exited in prehistoric times where forests were tiny clumps of trees... In my "dream" a young TRex attacked.. I just stood my ground knowing it was just a dream.. but where the beast slashed my arm, at home there was a bright red throbbing stinging mark on my arm same as the gash in the dream...
This item needs more research.. It could even be dangerous...

[Blair]

Dragonspirit, bong-toking...... know-it-all...... noob.... of the..... week.

[Dragonspirit]

I don't know how to take your post..? Does this mean you're insulting me..? I'm straight.. This is all truth.. Are you telling me I'm not welcome here..? I don't know..? I been through hell and back, and worse.. I have a lot of data and incites... I ain't gonna play where it ain't fun.. I'm searching for a forum where people are good folks, only!.. Did I make a mistake in coming here?.. I thinks I did...

[DHodges]

If causality is an ultimate law then time travel to the past would be absolutely impossible.

You should understand that time is a mental construct, not something that exists in some absolute sense on its own. It is defined relationally.

In my opinion, time travel to the past is not possible on the macroscopic scale (a person can not travel back in time) but there may be exceptions at the quantum level. E.g., a photon traveling forward is the same as an anti-photon traveling backward, and it turns out that an anti-photon is just a photon, so which way is it really going?

[Blair]

I don't know how to take your post..? Does this mean you're insulting me..? I'm straight.. This is all truth.. Are you telling me I'm not welcome here..? I don't know..? I been through hell and back, and worse.. I have a lot of data and incites... I ain't gonna play where it ain't fun.. I'm searching for a forum where people are good folks, only!.. Did I make a mistake in coming here?.. I thinks I did...

Oh sorry! I didn't realize I was allowed to my own opinion. I thought someone else decided that.

[cousinbasil]

I have a lot of data and incites...

By all means, do not let prince keep you from sharing your incites.

[David Quinn]

Time is a relative thing. If a person were to somehow go back to a previous point in history, from his point of view time would still be flowing forward. And he has no way of knowing whether he has really gone back, or whether he has just continued forward to another realm which merely resembles the past.

Not that it really matters either way. It's all just appearances in the end.

-

[jupiviv]

Travel means motion, so it can only occur in space. Time and space are different things.

[cousinbasil]

Travel means motion, so it can only occur in space. Time and space are different things.

Different, but intricately bound together.

The following is a quote from Brian Greene's The Fabric of the Cosmos. I find that this one paragraph encapsulates the connection between space and time, according to Special relativity, better than any other brief description I have yet encountered. It tells why time slows down for moving objects:

Special relativity declares a similar law for all motion: the combined speed of any object's motion through space and its motion through time is always precisely equal to the speed of light. At first, you may instinctively recoil from this statement since we are all used to the idea that nothing but light can travel at light speed. But that familiar idea refers solely to motion through space. We are now talking about something related, yet richer: an object's combined motion through space and time. The key fact, Einstein discovered, is that these two kinds of motion are always complementary. When the parked car you were looking at speeds away, what really happens is that some of its light-speed motion is diverted from motion through time into motion through space, keeping their combined total unchanged. Such diversion unassailably means that the car's motion through time slows down.

[jupiviv]

The "time" talked about in the theory of relativity is not the same as the time I'm talking about. The former is strictly limited within the context of the theory itself, and must be understood in that context. The time I am talking about is simply the appearance of change.

[chikoka]

Time travel must be caught up with the concept of the identity of the fundamental particles.
Traveling to the past by someone would mean that there will be a duplication of the fundumental particles he is made from, unless their (the particles) identity involves location in space.
This is tied intimatly to whether time and space realy exist or even if they dont exist and only ordering does then does their idenitity change when they are orderd differntly with respect to other particles.
Causality aside , one way of moving back in time would to create a "hole" by shifting all identical particles back "at the same time" atemporaly.
This would allow you to move back in time depending on how deep (time shifted) the hole you create was.

[cousinbasil]

The "time" talked about in the theory of relativity is not the same as the time I'm talking about. The former is strictly limited within the context of the theory itself, and must be understood in that context. The time I am talking about is simply the appearance of change.

You are missing the actual point of relativity, then. Another quote from Green's book suffices to corroborate this crucial point: "Time and space are in the eye of the beholder." The appearance of change remains the same for a person within a moving reference frame; however, to a person at rest with respect to the moving reference frame, all changes within the moving frame appear to slow down.

It should be noted here that things do not appear to change - things actually do change. How fast they seem to change gives us our experience of time.

But time and space are intimately connected, such that travel through space slows down travel through time.

Say you had two identical accurate watches, worn by two different people. Let's put them on a space station, although this doesn't really matter. If one of them boards a spacecraft and takes off for a ride that has him moving at great speed relative to the station, then eventually returns, his watch will show less time has elapsed than the watch of the person who remained on the station.

In other words, time is the appearance of change on the face of the watch. If one watch appearers to change less, then less time has actually elapsed for the person wearing it. There is no other thing that is time for him and his watch but how things change. To him, it will seem as if the watch worn by the person who remained on the station has somehow sped up, but that his own watch is accurate.

Now let's say you are the person that remained on the station, and I took off on the ship. Assume I was gone for fifty years. All this time I was moving at great speed relative to you, either receding from you or approaching you on the way back. When I finally return to the space station, you will be old and gray, and I will not. Our watches have calendar functions: yours says fifty years have gone by, while mine says one year has elapsed. Again, the changes in the watches appear to be different. But this time, we also can notice the changes in ourselves.

Obviously, you felt 50 years go by. It's not as if I felt 50 years go by and my body just did not age - I only felt one year go by. Time itself is the appearance of change - how fast they appear to change is relative to the observer; these appearances will be different if one observer is moving with respect to the other. Moving with respect to means traversing space as well as time, while the reference fram has only traversed time.

Thus, it does not matter how you define time. Time and sapce are different, yet by their very nature connected in the manner I have described.

[m4tt_666]

a super accurate atomic watch!

[cousinbasil]

a super accurate atomic watch!

The watch can be a $9.98 Timex. It doesn't matter in the scenario I just gave.

The thought experiment I have described above has in fact been carried out with "super accurate" atomic clocks, one kept on the ground and the other loaded onto a 747. The results verified the theory very precisely, even though the time lapse differential was necessarily small due to the relatively tame, subsonic speeds a 747 can achieve.

[jupiviv]

@Cousinbasil - in the theory of relativity, time is defined as the reading on a measuring device(clocks). That is not "change" in the sense I'm talking about. The change I'm talking about is simply the appearance of different things. When things appear, there appears to be change. This change doesn't lie in an individual thing. It's a certain kind of connection we create between two things. The appearance of permanence too is a connection created between two things. In reality, this connection is an illusion, because the connection is really our own consciousness of those things. There is no change and no permanence.

[Carmel]

jupiviv - in the theory of relativity, time is defined as the reading on a measuring device(clocks).

Carmel:
This is woefully incorrect. cb is right, time and space lie on the same continuum and can't be separated. When scientists look deep into space, they are literally looking back in time.