Understanding the Paradox of Backward Time Travel: Why We Can't Go Back

[Mentat]

Originally posted by wimms
Chemistry. Try smoke some good stuff and you'll see. Metaphysics is quite an area of its own. While discussing fundamental physics, its hard to mix them comfortably. It will lead to pure beliefs and philosophical running circles with strong force. Thought is state or process, and brain is machine that works by its own rules to compare those states. But that'll go too far off topic.
That thought is not physical entity is exactly my point. In same way any abstract concept, like 1D line, can not be physical entity.

Says who? A 1-d line can be a physical entity, and must be for string theory to be correct.

You say that Chemistry is the reason that synapses connect, and neurons "fire". However, you still have yet to explain why, when I think of something, a change occurs in my brain. Unless the change is an interaction between my thought and the physical brain, then I don't see any explanation.

Exactly, produces abstraction we call water. But its not fundamental. Whole universe we can talk about consists of abstractions we put into hierarchy. While digging into fundamentals, we are trying to dismantle abstractions into anteriority/posteriority relations so we can see what is made of what. While we do so, we continuously find that there is no such "thing" as what we call by our abstraction. But we always, always see that something interacts, and at times forms stable systems we can assign abstract ideas to.

OK, so you are a fundamentalist, right? I can respect that. However, that doesn't mean that "thought" doesn't exist, any more than it means that "water" doesn't exist. Yes, I am the same (at the subatomic level) as a piece of would, except that the interaction is different. That is also the difference between a subconscious process of the brain, and a conscious "thought". The interaction is different. That's what separates one "thing" from another.

Absolutely. You are thinking. But not concepts you use. They don't think. They don't exist.

Then water doesn't exist either? Think about it. You are the one who said that water must be an abstract concept, if your reasoning is taken as true.

But ok, at least we both agree that to exist something needs to interact.

Yes, and thoughts interact.

 

[chosenone]

If you were able to build a time machine to go back in time.what would happen even if you could turn back time,would be that the time machine will function as it travels back in time,until it was turned on or even build.then it would stop going back,every time you turn it on,it would turn off.no matter what that's all that would happen.

 

[killacali]

i went back in time the other day mutha****a

 

[killacali]

**** you nerds, get the computer and get some kitty

 

[killacali]

i mean subtracting myself from this time

 

[chosenone]

well if were going to go there.then let's define what we mean by going back in time.do we mean tuning everything back at once,or do we mean pulling your self,or subtracting your self from this time line,and dropping in on another.if your turning back time in reference to everything at once.every time you turn the time machine on,it would go back until it was turned on.so it would turn off every time you turned it on.but if you want to subtract yourself from this time line and drop in on another.then that's where paradoxes come in.you and the time machine did'nt exist in that time,and would change the whole universe by putting matter into play,colliding with events that would send the universe in a new direction.you would'nt even have to change a event to do it.you would breath air.those atoms were meant to go somewhere else.the energy you used from food would be burning,giving off heat,tranferring it to the air,thus changing the momentum.would the universe allow such a thing,and if it did why would you do it?there would be nothing left of the world you came from,even if you did'nt change something that brought your life into being.

 

[Mentat]

Welcome to the PFs, killacali. Perhaps you haven't yet read the rules for posting. I suggest that you read them soon. They are here: https://www.physicsforums.com/misc/guidelines.html

 

[wimms]

Originally posted by Mentat
Says who? A 1-d line can be a physical entity, and must be for string theory to be correct. .

I express my opinion. 1D line is infinite continuum of size=zero points with specific geometric shape - straight. Anything to be found in real world will be necessarily consisting from finite stuff.

You say that Chemistry is the reason that synapses connect, and neurons "fire". However, you still have yet to explain why, when I think of something, a change occurs in my brain. Unless the change is an interaction between my thought and the physical brain, then I don't see any explanation.

This is metaphysics. If you like, we can start new thread on that. But have it ever crossed your mind that change might occur first in your brain, and only then do you feel that excitationg as "thought"? That you might be just complex machine?

OK, so you are a fundamentalist, right? I can respect that. However, that doesn't mean that "thought" doesn't exist, any more than it means that "water" doesn't exist. Yes, I am the same (at the subatomic level) as a piece of would, except that the interaction is different. That is also the difference between a subconscious process of the brain, and a conscious "thought". The interaction is different. That's what separates one "thing" from another.

Not sure what you mean by fundamentalist. I like to think I'm openminded person. Like to ponder about fundamental questions.
One must make distinction between process of thought, and subject of thought.
Yes, now you approach it. Stuff is all same, interactions work out different. Your brain is all same, but excitations are different, and so your thoughts. Stable conglomerates of interactions that can be destroyed and built by means of interaction, is what we call objects. We perceive them through interaction, assign them properties and call them names, notice repeating number of such objects, and generalise them into abstract ideas. We say they exist, to talk about them, to have mental pictures of them. What infact exists, is stuff in permanent interaction supporting ongoing existence of that conglomerate we call names. Then, we go on and imagine mental picture of whatever weird stuff mathmaticians can ever come up with, that picture being mostly flawed, and work backwards, saying that if we have such abstraction, then it must exist. When we find something that produces even remotely comparable perception and can be called with same name as our imagination, we say bingo. Sometimes, we continue to search for impossible images, sometimes, after bingo, what we imagine and what is out there have nothing in common except similar perception.

Then water doesn't exist either? Think about it. You are the one who said that water must be an abstract concept, if your reasoning is taken as true.

But of course water as concept alone does not exist. There is a fluid, h20 that consists of molecules and hell knows what, that we call for short - water. What we call water, might be perceived more like air to some (fish), snow, ice, vapour, plasma, empty space, field, sound, whatelse. But not that is important how we call it or how we perceive it. Important is that we observe it by interacting. Which water? seawater, peewater, lakewater, rainwater? What is concept of water? Any water? how can you interact with any water? You need the thing, you look, sniff, taste, touch it to make sure you are not going to drink gasoline. You interact with the real thing that exists, and then say yeah, huh, its just water. There is a direct correspondance between what we both think of water and what we can go an touch. When you tell me that you've got 1D infinite line and thus infinite amount of 0D points, then geez, can I taste some?

Why need that splitting hair? To have criteria for decision what is possible in nature and what is not. To exist means to physically interact somehow. And perhaps be dismantable to finite ingredients. At least when we talk about sub-object levels.

 

[Royce]

Mentat,
First of all let me say that I agree completely with you that we can't go back time time, nor forward for that matter faster than our normal procession but for different reasons. We can't go back not because doing so would create paradoxes or is illogical but because it is physically impossible so far as I know and understand. It is not allowed. It's against the rules or would violate the laws of physics as we know them.
Second, Though I may not have been clear in what I wrote; I do think that time is the forth dimension and is a dimenion in spacetime the same as the other three spatial dimentions. The point that I was trying to make is that while we all have three degees of freedom in the spatial dimensions we do not have any degee of freedom in the temporal dimension.
We can all move and see and effect anything and everything in the "normal" 3 dimensions of space. Standing still in one spot I have only to turn my head to see anywhere in all the other dimensions and I can move in any direction as far and as fast as it want within the physical limits of my ability and the limit of C. Within this 3-D space I can and do effect or influence and change other objects. This is what I mean by three degrees of freedom.
However, in the 4th dimension we do not have any freedom of movement, sight or effect what so ever. We are constrained to move in only on direction smoothly at a constant velocity along the time dimension. We cannot see into the past or future. We cannot move into the past or future nor can we have any effect on anything in the past or future. This is what I me when I say we are 3-D beings living existing in a 4-D universe. Persumably or theoretically a truly 4-d object or being would be able to see and move in all four dimensions as freely as we move in three.
To make it easier to understand, for the sake of discussion, let's condense our 3 dimensions into 2 so that we are 2-D beings existing in a 2-d plane, a sheet of paper, if you will. We can move, see, effect anything on the plane but can never move, see or effect anything not on that plane. The 4th dimension, time, is of course perpendicular to the plane and every point on the plane. The plane and we and everything else on the plane are moving smoothly in one direction at constant velocity along the time dimension, setting aside relativity for the moment. The only place that we can see of effect anything of that dimension is at the point that it intersects and coinsides with the plane that we are on, the plane of our existence. Anything and everything else along the time axis is off of the plane therefore beyound our sight, experience and effect.
Now back to the real 4-D world. Anything and everything all the time axis is off, outside, beyound our 3-D plane of existence except where the time axis intersects and coinsides with our 3-D plane of existence. That intersection is what we call NOW and is the only place that we can exist, see, touch or effect. This is what I mean by saying the we are 3-D beings living in a 4-D universe.
I hope that this makes the point that I'm trying to make clearer. We cannot move in time in ether direction faster or slower than we are without moving out of or off of our only plane of existence. It isn't allowed. It's against the rules and would violated the Laws of Physics and existence.
I apologize for this being so long but I could think of no other way of saying it to make it hopefully clearer.

 

[chosenone]

if you were to try to turn back time.when you get atoms to move backwards,you need to get the electromagnetic fields to be re absorbed by the atoms,even if you can do that,you have to make the universe that is expanding,shrink back down to what it was,at the time you wants to stop at was.since we can't know what's making the universe boundries expand.you can't be sure you could get it to.just so you could travel back!gravity is'nt even doing it!

 

[Mentat]

Originally posted by wimms
I express my opinion. 1D line is infinite continuum of size=zero points with specific geometric shape - straight. Anything to be found in real world will be necessarily consisting from finite stuff.

An infinite line is composed of "finite stuff". It's composed of infinite spaces (each of which are finite). Besides, there is no empircal or logical reason to assume that all physical things must be finite.

This is metaphysics. If you like, we can start new thread on that. But have it ever crossed your mind that change might occur first in your brain, and only then do you feel that excitationg as "thought"? That you might be just complex machine?

I am just a complex machine (I don't approve of the word "just" in there, but I agree otherwise). That doesn't mean that the physical interaction within my brain doesn't produce thought (any less than Oxygen and Hydrogen interactions can produce water).

Not sure what you mean by fundamentalist. I like to think I'm openminded person. Like to ponder about fundamental questions.
One must make distinction between process of thought, and subject of thought.

When I said "fundamentalist" I meant someone who believes that all theories should describe things at the smallest level. The actual word is "reductionist", and that's the kind of theory that QM (for example) is. However, there are other kinds of theory, such as Relativity (which - I think - is considered a holositic theory).

Yes, now you approach it. Stuff is all same, interactions work out different. Your brain is all same, but excitations are different, and so your thoughts.

Then why in the world do you disagree that "thoughts" exist?

Stable conglomerates of interactions that can be destroyed and built by means of interaction, is what we call objects. We perceive them through interaction, assign them properties and call them names, notice repeating number of such objects, and generalise them into abstract ideas. We say they exist, to talk about them, to have mental pictures of them. What infact exists, is stuff in permanent interaction supporting ongoing existence of that conglomerate we call names. Then, we go on and imagine mental picture of whatever weird stuff mathmaticians can ever come up with, that picture being mostly flawed, and work backwards, saying that if we have such abstraction, then it must exist. When we find something that produces even remotely comparable perception and can be called with same name as our imagination, we say bingo. Sometimes, we continue to search for impossible images, sometimes, after bingo, what we imagine and what is out there have nothing in common except similar perception.

Now remember, I'm not saying that all of the things that we imagine can exist physically. I'm saying that they already exist, as concepts. I'm saying that a concept exists in exactly the same way as any other compound, caused by the interaction of subatomic particles.

When you tell me that you've got 1D infinite line and thus infinite amount of 0D points, then geez, can I taste some?

I didn't say it consisted of 0d points.

Why need that splitting hair? To have criteria for decision what is possible in nature and what is not. To exist means to physically interact somehow. And perhaps be dismantable to finite ingredients. At least when we talk about sub-object levels.

Exactly. And "thoughts" fit all of the criteria quoted above.

 

[Mentat]

Originally posted by Royce
Mentat,
First of all let me say that I agree completely with you that we can't go back time time, nor forward for that matter faster than our normal procession but for different reasons. We can't go back not because doing so would create paradoxes or is illogical but because it is physically impossible so far as I know and understand. It is not allowed. It's against the rules or would violate the laws of physics as we know them.

I agree. I don't see the point in speculating about the paradoxes that it causes, when it's not physically possible anyway. However, there are those that believe that it is physically possible, so I'm making a case for why it is illogical.

Second, Though I may not have been clear in what I wrote; I do think that time is the forth dimension and is a dimenion in spacetime the same as the other three spatial dimentions. The point that I was trying to make is that while we all have three degees of freedom in the spatial dimensions we do not have any degee of freedom in the temporal dimension.

We can all move and see and effect anything and everything in the "normal" 3 dimensions of space. Standing still in one spot I have only to turn my head to see anywhere in all the other dimensions and I can move in any direction as far and as fast as it want within the physical limits of my ability and the limit of C. Within this 3-D space I can and do effect or influence and change other objects. This is what I mean by three degrees of freedom.
However, in the 4th dimension we do not have any freedom of movement, sight or effect what so ever. We are constrained to move in only on direction smoothly at a constant velocity along the time dimension. We cannot see into the past or future. We cannot move into the past or future nor can we have any effect on anything in the past or future. This is what I me when I say we are 3-D beings living existing in a 4-D universe. Persumably or theoretically a truly 4-d object or being would be able to see and move in all four dimensions as freely as we move in three.

Not necessarily. Provided the dimension serves the purpose of defining our position, it is one of "our" dimensions.

To make it easier to understand, for the sake of discussion, let's condense our 3 dimensions into 2 so that we are 2-D beings existing in a 2-d plane, a sheet of paper, if you will. We can move, see, effect anything on the plane but can never move, see or effect anything not on that plane. The 4th dimension, time, is of course perpendicular to the plane and every point on the plane. The plane and we and everything else on the plane are moving smoothly in one direction at constant velocity along the time dimension, setting aside relativity for the moment. The only place that we can see of effect anything of that dimension is at the point that it intersects and coinsides with the plane that we are on, the plane of our existence. Anything and everything else along the time axis is off of the plane therefore beyound our sight, experience and effect.
Now back to the real 4-D world. Anything and everything all the time axis is off, outside, beyound our 3-D plane of existence except where the time axis intersects and coinsides with our 3-D plane of existence. That intersection is what we call NOW and is the only place that we can exist, see, touch or effect. This is what I mean by saying the we are 3-D beings living in a 4-D universe.

But think of this. We don't exist in the spatial dimensions, except for the part that currently intersects our position, do we?

I hope that this makes the point that I'm trying to make clearer. We cannot move in time in ether direction faster or slower than we are without moving out of or off of our only plane of existence. It isn't allowed. It's against the rules and would violated the Laws of Physics and existence.

I thought General Relativity said that our movement in time changes, inversely proportional to our movement in space.

 

[Royce]

And a very good one in my opinion. I just want to be sure that you realize that I'm not arguing with you. We can't argue; we agree!

Yes, it defines our poosition but we have no freedom of movement in or on it nor can we see anywhere along it except at that defined position, that instant in time.

Yes again. At any given moment, T axis intersection, we can only be one place, Z, Y, and Z axis intersection; but, that is living within the dimensions. The dimensions are real at least as I think of them not just sets of ordinates that define our position.

I had set aside relativity for this discussion and at any normal velocity the effects are not noticeable and insignificant. However and speeds any significant appoaching C time does change and is relative. Again, if I were in a spaceship traveling somewhere near the speed of light I would not notice the difference but you and observer back on eart would see my clocks and me too slowdown. I would not realize any thing different until I returned to Earth and found out it was much later and you were much older than I could accound for, the famous twin paradox.

 

[wimms]

Originally posted by Mentat
An infinite line is composed of "finite stuff". It's composed of infinite spaces (each of which are finite). Besides, there is no empircal or logical reason to assume that all physical things must be finite.

I think there is reason. Why do you need finite "spaces" to construct a line? Is point at position Pi finite?

When I said "fundamentalist" I meant someone who believes that all theories should describe things at the smallest level. The actual word is "reductionist", and that's the kind of theory that QM (for example) is. However, there are other kinds of theory, such as Relativity (which - I think - is considered a holositic theory).

No, then I'm not "(dogmatic) reductionist". I believe in Newton, I believe in GR, they all model, approximate reality to a reasonable degree of accuracy, within the limits/range of applicability in the hierarchy of abstractions. Theory that would describe all things at smallest levels would be needless for casual application. But it would be closest to understanding what is really out there. All else is just behavioural models that do not touch meanings of their components. Such meaning is given them by man. And it may change every time we find new level of abstraction deeper.
For eg. concept of energy, concept of movement, inertia, mass, vacuum, all may disappear eventually. But there are some concepts that cannot disappear at any level of abstraction. They are known, and they are fundamental.

Then why in the world do you disagree that "thoughts" exist?

Because I define "exist" as requirement to interact, physically.

Now remember, I'm not saying that all of the things that we imagine can exist physically. I'm saying that they already exist, as concepts. I'm saying that a concept exists in exactly the same way as any other compound, caused by the interaction of subatomic particles.

Ok, maybe we can settle, if we define this:
- To exist physically means to interact with physical entity.
- To exist imaginarily means to interact with imaginary entity.
- Physical entity and imaginary entity cannot interact. They are incompatible.
- Imaginary entities at different levels of abstraction cannot interact.
Would this clarify my position? I'm interested in physical existence. It necessarily underlies any imaginary concept. Imaginary concept without underlying physical existence is not real. If you like, we may talk about "inner space", but keep it separate from universe.

Concept of triangle cannot interact with concept of water.
Concept of size cannot interact with concept of taste.
Concept of point cannot interact with concept of quantum.
Concept of thought cannot interact with neuron. They are at different levels of abstraction and thus incompatible.
I think that even imaginary thoughts at same level can't really interact, because there are only that many ways to communicate your thoughts. Intellects without common perception of world cannot communicate.

Concept of quantum may BEHAVE like concept of point at certain degree of approximation (formal model), but that does not mean that quantum IS point. Assertion that imaginary 1D line is interacting with physical quantums is thus flawed to even start with, for eg. To interact, physical entity must have more properties than definition of 1D line can possibly offer. Fluently such line gets properties like tension, intensity, vibration, volume, etc..
Afaik real theoretics have long ago dropped idea of equating their concepts with reality, instead, they just say that this set of equations best approximates what can be tested by experiment. Assigning physical meaning to these equations is just meant to tease our imagination (which is needed to generate new ideas).

At times, its extremely difficult to see whether concepts are compatible. Thats the art and area where breakthoughs happen - to see ingredients and order them in right hierarchy from most fundamental to most abstract. Most of the time, we are chasing our tail.

Some say that we already long ago had all required ingredients to form TOE, its just that we can't put them together. It will most probably require bend of our beliefs, and that's the most difficult one. "Its not the spoon that you should try to bend, Neo, its you"

As laymen we can't speak formally, shooting equations at each other, thus we are limited to talk at conceptual levels, and its too easy to get into crazy logical flaws. Its even more difficult to avoid than for Phds who can check their reasoning with math (Phds might say: impossible), so we can't really avoid keeping track of what is more fundamental than other. Phds can avoid that, because for them its just equation.

I didn't say it consisted of 0d points.

I assumed that. What is definition of line then? Would you construct 3D objects with such lines? How about 3D "line" with finite quants of finite 3D size? how about forgetting that line abstraction and talk about quants?

 

[Mentat]

Originally posted by Royce
And a very good one in my opinion. I just want to be sure that you realize that I'm not arguing with you. We can't argue; we agree!

That's right. I wouldn't argue with my good buddy, would I?

Yes, it defines our poosition but we have no freedom of movement in or on it nor can we see anywhere along it except at that defined position, that instant in time.

Very true.

Yes again. At any given moment, T axis intersection, we can only be one place, Z, Y, and Z axis intersection; but, that is living within the dimensions. The dimensions are real at least as I think of them not just sets of ordinates that define our position.

Also correct.

I had set aside relativity for this discussion

Then I will do so also. Sorry for bringing it up.

 

[Mentat]

Originally posted by wimms
Because I define "exist" as requirement to interact, physically.

So do I (for the time being).

Ok, maybe we can settle, if we define this:
- To exist physically means to interact with physical entity.

Sure, I can agree with that.

- To exist imaginarily means to interact with imaginary entity.

... and the physical entity of the brain, right?

- Physical entity and imaginary entity cannot interact. They are incompatible.

Why?! You cannot have an imaginary entity, without there first having been a physical interation in the brain.

- Imaginary entities at different levels of abstraction cannot interact.

Why not? I also really don't get what "different levels of abstraction" means.

Would this clarify my position? I'm interested in physical existence. It necessarily underlies any imaginary concept. Imaginary concept without underlying physical existence is not real. If you like, we may talk about "inner space", but keep it separate from universe.

But why? Without the physical (brain) interacting with the conceptual (mind), science could not exist, because we would be unable to ponder anything.

Concept of triangle cannot interact with concept of water.

It can in my (conceptual) mind. Besides, water isn't a concept - it is a physical entity. Subatomic physical things interact a certain way, to produce more advanced physical entities.

Another thing I wonder about: Why is it that you include theoretical particles, such as photons, in your list of "real physical things"?

Concept of size cannot interact with concept of taste.
Concept of point cannot interact with concept of quantum.
Concept of thought cannot interact with neuron. They are at different levels of abstraction and thus incompatible.

Again, why? You haven't given any reason to believe this, and I think I have presented a case toward my opinion (above).

Also, why do you call a neuron a concept?

I think that even imaginary thoughts at same level can't really interact, because there are only that many ways to communicate your thoughts. Intellects without common perception of world cannot communicate.

Yes they can, they just won't know what the other is talking about .


BTW, we could discuss equations if you wanted to, but I don't see how it clears much up, except for the fact that 1D entities can be physical. Actually, the math behind string theory is quite a bit beyond me, so I am rather confined to conceptual speech. But, I'm learnin' .

 

[wimms]

-- Physical entity and imaginary entity cannot interact. They are incompatible.

Why?! You cannot have an imaginary entity, without there first having been a physical interation in the brain.

Maybe its not clear what interaction is? Its what we observe as mutual exchange of energy, within all of the conservation laws.
When you try to imagine nuclear explosion in your head, I'm sure you can get the image. But when you get that image, I'm sure you hometown will not get blown away.. Your imagination does not have influence to not a single atom in your body, its a shadow. Its not even clear what we perceive as thought. But one thing is clear, our thought image can be larger than our brain, it exists in our mind for short time, and is recycled into other thought that engages same amount of neurons, but is magnitudes smaller in any conceptual respect (yet may have more influence on our body, like reverting from concept of infinities to a concept of tits).

-- Imaginary entities at different levels of abstraction cannot interact.
Why not? I also really don't get what "different levels of abstraction" means.

something forms what we know as quants. Quants form what we know as atoms, atoms form molecules, molecules form chemistry, materials, that form solid and other bodies, bodies form celestrial bodies, they form star systems, galaxies, etc. These examples of abstractions. But they have corresponding physical systems. To say that 1 hydrogen atom interacts with what you call car is nonsense. Or that your car interacts with galaxy. Atom can interact at atom level only, and car at mechanical level.

But why? Without the physical (brain) interacting with the conceptual (mind), science could not exist, because we would be unable to ponder anything.

Yes, but not the opposite. Our brain can perfectly exist without our marvellous conceptual mind. Concepts you imagine do not exchange energy with your neurons. Its only neurons that exchange energy.
Shadow of an object does not exchange energy with that object, they don't interact. Shadow is not physical entity, its something else, illusion perhaps. Our mind is able to create those shadows and observe them. That does not make shadows physical.

It can in my (conceptual) mind. Besides, water isn't a concept - it is a physical entity. Subatomic physical things interact a certain way, to produce more advanced physical entities.

Water is concept, that has corresponding physical entity. Triangle is concept, that does NOT have corresponding physical entity. Bermuda triangle does have physical entity. How would you make abstract idea to exchange energy with physical entity??

Another thing I wonder about: Why is it that you include theoretical particles, such as photons, in your list of "real physical things"?

Did I mention photons? I include all that can exchange energy within laws of conservation. I try to see them in anterior-posterior hierarchy, and judge what are compatible concepts for interaction. Trying to forcibly mate incompatible concepts can lead to weird results, and getting stuck with progress.

There is something wrong at quantum level with our theories. If not anything else, then they are way too complex for levels more fundamental than molecules. Maybe its result of mating incompatible concepts, and missing some intermediate abstractions.

BTW, we could discuss equations if you wanted to, but I don't see how it clears much up, except for the fact that 1D entities can be physical.

No, I don't want equations unless they seem important. But I'd like to understand how 1D lines can be physical. I can understand ropes, but 1D lines?

 

[The_Lance]

You people wrote a lot on this topic, it was difficult reading all of it. Though, it was the correct thing to do because a good portion of my view points have already been cleared up by wimms.

Except, wimms, you claim that physical entities can not interact with imaginary entities. If so, then I was wondering why it is that when some people on a perfecly warm day think of the artic, they shiver? Is this not an example of the thought of the artic weather interacting with their physical body?

If you can clarify this maybe I can fully see your perspective of the subject.

I must admit that this forum has made me think of time in new ways, but what I think of as time is something that mimics the properties of a dimension without actully being one. I think that we are being carried though time by means of something like inertia. Once we were set in motion and now we are holding to that tendency to keep going forward. And inertia can't be manipulated (yet ).

 

[Mentat]

Originally posted by wimms
Maybe its not clear what interaction is? Its what we observe as mutual exchange of energy, within all of the conservation laws.
When you try to imagine nuclear explosion in your head, I'm sure you can get the image. But when you get that image, I'm sure you hometown will not get blown away.. Your imagination does not have influence to not a single atom in your body, its a shadow. Its not even clear what we perceive as thought. But one thing is clear, our thought image can be larger than our brain, it exists in our mind for short time, and is recycled into other thought that engages same amount of neurons, but is magnitudes smaller in any conceptual respect (yet may have more influence on our body, like reverting from concept of infinities to a concept of tits).

Alrighty then. I'll disregard that last sentence.

You are still not seeing my point. A concept interacts with the physical brain, and vice versa. This is evident in the fact that a concept causes an energy/matter reaction to occur in the brain (and possibly other reactions, due to neural stimulus, such as the feeling of anxiety. Think about it.).

something forms what we know as quants. Quants form what we know as atoms, atoms form molecules, molecules form chemistry, materials, that form solid and other bodies, bodies form celestrial bodies, they form star systems, galaxies, etc. These examples of abstractions. But they have corresponding physical systems. To say that 1 hydrogen atom interacts with what you call car is nonsense. Or that your car interacts with galaxy. Atom can interact at atom level only, and car at mechanical level.

Why is it that you accept that atoms form these other "concepts" - such as a car - but won't accept that the atoms in the brain form concepts as well?

Yes, but not the opposite. Our brain can perfectly exist without our marvellous conceptual mind. Concepts you imagine do not exchange energy with your neurons. Its only neurons that exchange energy.
Shadow of an object does not exchange energy with that object, they don't interact. Shadow is not physical entity, its something else, illusion perhaps. Our mind is able to create those shadows and observe them. That does not make shadows physical.

Shadows are not physical entities. In fact, they are the absence of the physical entity, light. However, I don't see the relevance of this to your argument.

Water is concept, that has corresponding physical entity. Triangle is concept, that does NOT have corresponding physical entity. Bermuda triangle does have physical entity. How would you make abstract idea to exchange energy with physical entity??

I could make the physical entities in my head (called neurons) exchange energy, merely by thinking about such "concepts". How does that allow for these thoughts to be any less "real" then acual water?

Did I mention photons? I include all that can exchange energy within laws of conservation. I try to see them in anterior-posterior hierarchy, and judge what are compatible concepts for interaction. Trying to forcibly mate incompatible concepts can lead to weird results, and getting stuck with progress.

But photons are energy, and thus they are part of the exchange of energy as well. And yet, they are theoretical, and will remain such forever.

No, I don't want equations unless they seem important. But I'd like to understand how 1D lines can be physical. I can understand ropes, but 1D lines?

Yes, I don't see how that's any harder to believe in than 0d points.

 

[LaplaceOperator]

Let's get this discussion back to physics:

[*Slaps self on head* now I remember why I disagreed with Zefram, when he made (sort of) the same point as Hurkyl is making. It's all in the way we think of time. You see, you can think of time as being like the spatial dimensions, in the sense that if I put something in a certain place (in space), it will still be there when I look away. But this is not how I view time. As I see it, when you continue down the T dimension, everything that you "have done" (past tense) "disappears" (or ceases existing). I say this because, if it were "still happening", then it would be happening in the present, not the past. The past is compose of things that "have happened", it does not contain things that "will happen" or "are happening".

But according to relativity, the thing you call "the T dimension" depends on your frame of reference.

Take the following example from special relativity:

Consider the following two events-
EVENT A - My phone rings at my house, at 9:30 AM.
EVENT B - A meteorite hits Jupiter, at 9:40 AM.

According to an observer on earth, EVENT A occurred 10 minutes before EVENT B. But what about an observer traveling at 0.9c from Earth to Jupiter?

You can use the Lorentz Transformation to show that for such an observer, EVENT B would occur over 20 minutes before EVENT A! The order of events is reversed!

How is this possible? Because even in special relativity, two different observers measure time along a different "T dimension". Just like two people who are facing different directions would mean different things when they say "left" and "right".

Of-course, in the narrow framework of special relativity, you can't violate causality. The speed-of-light speed limit prevents you from doing so. But in GENERAL relativity, there are no such limits. By altering the metric of spacetime in just the correct way, you can - in theory - create a reference frame by which some effects preceed their causes. You can - in theory - create a reference frame by which 2005 (on earth) occurred before 1980 (on earth).

 

[michael_selway]

I explained the paradox of backward time travel, in the old PFs, and I would like to do so again.

Here is why it is impossible to travel backwards in time (and it doesn't matter how far backwards):

As soon as you travel to a time that is before the exact time when you started traveling, you create paradox. If I start traveling at 5:00 A.M. (I know that using minutes, as a way of measuring exact time, is crude, but it should get the point across), and I travel back to 4:59, I have yet to start traveling. But, if I have yet to start traveling, how did I get to 4:59? The answer: I didn't, it's impossible. Unless someone can prove me wrong, it makes no sense to imply that I can start traveling, after having already arrived at my destination.

Have u guy watched Bak to the future?

when u go back in time there is another u, a younger one

------------------------------------

http://www.putfile.com/media.php?n=StarWarsEpisode3Clip

btw here's a clip from the movie that i found!

great movie!

 

[Nomy-the wanderer]

To apply the special relativity, u need to be close to the speed of light...IF u r fast enough u can travel through some years of future, i'll state the same example again, i u r on a spaceship traveling thrpough space in a high speed close to the speed of light for a certain amount fo time, u'll be back on Earth after uhumm 5 years for ex. (that's according to u) while probably more than 30 years have passed on earth(i didn't calculate it, depends on the speed of course)

There's a 25 years difference between u and the other people who remained on earth, this means that if it was the eyar 2005 when u did so, then u've traveled to the year 2035 while mit was supposed to be the year 2010 for u..

But u can't go back, u've no way of slowing down, or gettin back in time, because the clock only ticks more seconds and there's no way to make it tick backwards..

 

[hershal]

I have not gone thru all the posts in the thread, except the first one and the last one. Accidently I came across a bit of information on BBC, just have a look about wht kind of backwards time travel can be possible.

http://news.bbc.co.uk/2/hi/science/nature/4097258.stm

 

[PRyckman]

only way to go back without paradoxes

No matter where you are in the universe due to relativity compared to energy you are always in the middle. That being said, If you could teleport halfway to the edge of the galaxy, since you'd still be in the middle the universe would only be half as old. The reason this does not create a paradox is because the amount of time you travel back is equal to the time it would take light to travel that distance. Therefor if you teleported one light year away from here you would be one year in the past. It doesn't create any paradoxes because there is no possible way to interact with your past self since you cannot travel faster than light.

Note that teleporting to Earth again from your new point in history would put you even farther back in time and you still couldn't get there any sooner because space would be more condense, and it's speed of expansion greater, it would balance the equation so that you could not get there any faster. I'd love to hear back from some of you on this, I think I found proof of it in E=mc2, a shortword on that
E=mc2 could also be an equation for pi, with c2 being radius

I've thought a lot about what we're missing in that equation, and I think that it is the Grand Unified theory that we all look for. And that there may only be 2 dimensions. Time and direction. Atleast at a sub atomic level. The only reason we perceive 3 dimensions is because of the uncertainty principle. As more and more forms of energy circle around each other there is increased certainty in they're position and decreased in their momentum, a balance of these two un/certainties allows us to see them as a point and not a direction.
Please feel free to email me, I might not remember to check this site and thread again. Patrick_ryckman@hotmail.com