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

  • Thread starter Mentat
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In summary, backward time travel is impossible because it would create paradoxes. Some people have suggested the "Pretzel Time" idea, where the future is already in the past, but this is not supported by logic. Others have proposed the idea of multiple time dimensions, but this is also not supported by evidence. The concept of antimatter and its behavior in time supports the idea that traveling backwards is not possible. Additionally, the existence of an infinite number of "Mentats" in a non-Mentat perspective is inconsistent with the idea of time travel. Therefore, the idea of going back in time is not feasible.
  • #141
Originally posted by MajinVegeta
In order for us to travel to the past, would the future already need to exist?

In a manner of speaking. Let's say a man decided to bring a cell phone back with him to 1900. For the people in 1900, their future has been predicted. The same holds true for the man in 2003 who encounters a time traveler from 2100.

The bottom line is traveling to the past in the same universe is impossible. Time progresses in a linear fashion. It may progress at different speeds and intervals, but still in the same direction.

Many Worlds theory, on the other hand, allows time travel into the past of an alternate universe, identical to your own at the instant you time travel. Then, you are free to kill your parents, as it does not contradict your existence because you are from another universe. This is all just theory, of course, but it seems to be the most practical way of time travel to the past (or possibly wormholes but those would cause paradoxes as well).
 
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  • #142
But there is still a paradox. If the man goes back to 1900, before he was born, that contradicts the very first law of thermodynamics. Even with the multiple hisotry theory.
The man going back to 1900 would cause a closed time loop to occur. That is, the same thing will continue to happen again and again, infinitely. in 2003, the man decides to go to 1900, and when 1900 proceeds into the future, (say the guy was born in 1980) the man is born again, and then he decides to go back to 1900 hundered...

so, the question remains, are closed time loops paradoxical?
 
  • #143
Originally posted by MajinVegeta
But there is still a paradox. If the man goes back to 1900, before he was born, that contradicts the very first law of thermodynamics. Even with the multiple hisotry theory.
The man going back to 1900 would cause a closed time loop to occur. That is, the same thing will continue to happen again and again, infinitely. in 2003, the man decides to go to 1900, and when 1900 proceeds into the future, (say the guy was born in 1980) the man is born again, and then he decides to go back to 1900 hundered...

so, the question remains, are closed time loops paradoxical?

Are saying this is all happening in the same universe?? I don't understand, because in my post I was saying the same thing--that time travel in the same universe creates paradoxes.

When a man travels to a different universe, however, he escapes the paradox of a closed time loop because he involves himself with the timeline of another universe.

Can you please clarify your last post because I think we are agreeing on the same thing here, just saying it differently.
 
  • #144
Originally posted by Locutus
Yes, but this is also true for space. If you remove all spatial dimensions, there is no existence either. If you remove one spatial dimension, things can still exist, but not if you remove all of them. The fact that the universe can't exist without its time dimension stems from the fact that time is one-dimensional. If there were multiple time dimensions, we could add/subtract them the same way we could add/subtract spatial dimensions.
No existence in our familiar form. That does not warrant idea that no existence is possible. Notice yourself, you can remove or add spatial dimensions freely, given that at least 1 remains, but as soon as you remove time, all spatial dimensions loose sense. Therefore time is more fundamental than spatial dimensions.

Besides spatial dimensions, you can imagine arbitrary number of any other dimensions, like imagine computer program - its in its own "space", in this case space is freedom of states, possibilities. And computing steps are interactions that can be assigned notion of particles or forces, and they exist in that computer time. Dimensionality of such computer can be made arbitrariliy large, and it has not even close resemblence to our spatial dimensions. When you stop that computer time, these particle cease to exist, and only single state remains. You can't think of all possible states as existing simultaneously, given constraints of computer program, there is only 1 way to proceed from given state - via causal interaction. And that's possible only when computer clock is restarted. And for particle inside computer program, there is no way to detect whether time runs or is stopped. The only thing what particle can detect is interaction _when_ time runs. For it, to exist is to have computer time running. Same for us, to exist _requires_ concept of time and interaction. For computer program, to jump in time means skipping series of cause/effect interactions and start interacting with something that doesn't exist yet or anymore. Not only does this scrap causality, it simply doesn't make sense.

Multiple time dimensions is as meaningless as multiple lengths. You can introduce as many as you like, it does not change essence of the concept, it remains unique.
Originally posted by Mentat
Possibilities exist, here and now, otherwise how could I be conceiving of them, here and now?
Possiblity: I imagine that I'm god and destroy that universe. Do you feel anything? Is that possibility "real"? Why is it not possible? Because we live in _real_ world? What makes it real? Constraints to possibilities? Okay, is there such a law of nature that forbids wimms to destroy universe? No, but there are laws of nature that states that to do that, you'd need to spend energy - interact. And they state that wimms has not even pion's chance in myuon's ass to kick the universe. Therefore we safely conclude, that this imagination is not real. But I conceive it, perfectly vividly. Its here, it exists! So what? It has no capacity to interact with real world. Therefore, it does not exist. There exist my braincells, that fired this way for duration of this post, they are real, but not the imagination. When I'm finished, horrible image of wimms destroying universe ceases to exist even in my imagination. And definitely its not something that could exist separately from my delusion.

See? To exist requires interaction. And interaction creates form. You might imply that now that I've written that delusion down, it exists on this forum in electronic shape. But its not what I imagined. What you perceive is delusion crap of somebody who'd better be drunk. And that's what it is - useless crap not end of world. But if you'd truly perceive sky crushing down on you, it would be real. Thing is what it appears to other thing to be.

There is a difference between imaginary delusions and real world out there. Imaginary delusions are limited by your own constraints only, real world limits you with requirement to interact in frame of laws we are trying to find out. As long as this universe is causal and logical, there is no room for "all possible universes", there is only one, here and now, constrained by only one possible direction of time - from past to future by means of cause/effect interactions.

To add here, consider abstract ideas, like geometric point, or line. Are they real? Do they exist? In our delusions, yes, but in universe out there - no, they don't exist. We can model world around us by using our imaginary shapes, but that doesn't make our imagination real, its merely description of something out there.
Time as coordinate dimension is of that kind - its is convenient to use it as spatial dimension, because this allows us to compute formulas, but it doesn't mean you can move on it the same way as you move in space.

As to multiple histories, they can't exist concurrently. To exist means to interact, if they don't interact they don't exist. You can shape the world around you, if you have free will, and this way decide which way your history develops, but there is no way you could swap your reality, much the same way as wimms cannot destroy universe, or how single value of variable in computer program cannot arbitrarily and acausally change whole state or even structure and program of the supercomputer. The only way how you could escape into other universe is via imagination. This is apparently perfectly possible, as we can learn from institutions with soft walls.
 
  • #145
We can't prove that time has always existed. At the instant of The Big Bang nothing existed but energy at infinite temperature and density. No matter or mass existed and there was no dimention to the singularity, just a mathematical point. Did spacetime exist? I don't think so. I don't think that spacetime existed until after inflation and matter or mass started to form out of the expanding and thus cooling singularity. I believe that only then did space, time, dimension, location and direction come into existence.
Also remember that we are 3 dimensional beings and cannot preceive nor conceive of four or more dimensional spacetime. Things pop into and out of our 3 dimensional universe without our being able to "see" where they came from or where they went and though a photon may be seen by us to take a billion years to reach us from a distant galaxy, to the photon it took no time at all. The trip was instantaneous and it existed everywhere along it's path at the same time. Not only can it be two places at once but it can and is everywhere at once. It doesn't make sense to us 3D beings, but it is. I like to think of it as "Instantaneous travels at 300,000 k/sec or c to us. That is our limit and constant not the cosmos's.
 
  • #146
mentat
"The true test of another man's intelligence is how much he agrees with you."
royce:wink:
 
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  • #147
Originally posted by wimms
Notice yourself, you can remove or add spatial dimensions freely, given that at least 1 remains, but as soon as you remove time, all spatial dimensions loose sense. Therefore time is more fundamental than spatial dimensions.

Okay, but as soon as you remove time, 1 time dimension no longer remains. The best example is to imagine a universe with one time and one space dimension. If you remove either dimension, existence as we know it disappears. What makes time unique is that we can't remove any time dimensions because (according to you) there must be one that always remains. We can remove some spatial dimensions (as there are three of them), but not all of them. It seems like you are trying to say that time dimensions are somehow more fundamental to existence than space dimensions, where as I am saying this only seems this way because we have 1 time dimension and 3 space...


You can't think of all possible states as existing simultaneously, given constraints of computer program, there is only 1 way to proceed from given state - via causal interaction. And that's possible only when computer clock is restarted.

However, running that program on two different computers may yield two different results, meaning that multiple outcomes are possible. If you hadn't observed the results of the program, all outcomes would exist simultaneously as they would be in a state of quantum flux, until of course they are observed, the wave function breaks down, and a definite outcome emerges (Schrodinger's cat again).


To exist requires interaction. And interaction creates form.

Now we're speaking the same language! You said in a previous post that detection is interaction, and I was saying that something must be detected to definitely exist. So we finally agree.
 
  • #148
Originally posted by Royce
We can't prove that time has always existed. At the instant of The Big Bang nothing existed but energy at infinite temperature and density. No matter or mass existed and there was no dimention to the singularity, just a mathematical point. Did spacetime exist? I don't think so. I don't think that spacetime existed until after inflation and matter or mass started to form out of the expanding and thus cooling singularity. I believe that only then did space, time, dimension, location and direction come into existence.
Sigh. I know its hard to talk about time. Especially talking about not time. Let's see how well did you manage to get away without time.

At BB instant - temporal, ok zeropoint. Existed nothing but energy - so, energy already existed? temporal concept. Energy - concept requires interaction to have meaning. Temperature - concept requires motion. Density - spatial concept. No "spacetime existed until after inflation" - until after is temporal concept. existed is temporal concept. Not exist until - contradiction. Inflation - verb, requires time. "matter started to form", expansion, cooling - all verbs requiring concept of time. And only then did time come into existence? hmm...

Imho, best you can, is start like this: First, nothing existed. (It sucked.) So, Time began. (..and it was good) Then singularity appeared. Then dimensions appeared. Then bang, it diversified into holy universe. Concept of energy and temperature appeared. Local density, cooling, inflation. (damn, almost like bible.)

Note that density of universe is still infinity, its still perhaps singularity, temperature is still infinite, etc. Its just we happen to exist in some arbitrary range of all of this, and perceive some local fluctuations as our reality, maybe falling down some entropy gradient perceiving phase shifts ala cooling and lumping of matter.

So here we are. If there ever was beginning, then it had to begin with time. Then there was 1 thing - singularity that existed (omm). Then it split into parts. Problem with this: its a creation. Hastalavista energy conservation laws.

Also remember that we are 3 dimensional beings and cannot preceive nor conceive of four or more dimensional spacetime. Things pop into and out of our 3 dimensional universe without our being able to "see" where they came from or where they went and though a photon may be seen by us to take a billion years to reach us from a distant galaxy, to the photon it took no time at all. The trip was instantaneous and it existed everywhere along it's path at the same time. Not only can it be two places at once but it can and is everywhere at once. It doesn't make sense to us 3D beings, but it is. I like to think of it as "Instantaneous travels at 300,000 k/sec or c to us. That is our limit and constant not the cosmos's. [/B]
Why you think we can't conceive 4th dimension? Have you ever played 3D games on your computer? Had a sensation of depth? You played it on 2D monitor. Technique called projection. In 3D world, you can happily watch 4D movie and it'll actually make sense. What would you think, why any string theory of the week has all those upper dimensions curled into Planck size? They are not here.

Well, I can perfectly understand and even agree, that photon with 0 time feels like it travels at infinite speed. Problem with that photon being everywhere at once is that its enough to have single one for the whole universe. God maybe, the overseer?
 
  • #149
Originally posted by Locutus
It seems like you are trying to say that time dimensions are somehow more fundamental to existence than space dimensions

However, running that program on two different computers may yield two different results, meaning that multiple outcomes are possible. If you hadn't observed the results of the program, all outcomes would exist simultaneously as they would be in a state of quantum flux, until of course they are observed, the wave function breaks down, and a definite outcome emerges (Schrodinger's cat again).

Now we're speaking the same language! You said in a previous post that detection is interaction, and I was saying that something must be detected to definitely exist. So we finally agree.
But of course detection is interaction. How else can you detect anything? I don't even see now where the disagreement was..

Yes I'm trying to say that time is more fundamental. It actually creates all other spatial dimensions (And 3 are sufficient, but that's opinion). If you think of 1D line as of mathmatical concept, then its possible abstraction, but it cannot exist as reality. There is no way to detect any distinguishable points on it without concept of time. As soon as concept of time emerges, its minimal "planck" time creates distinguishable points, and arbitrary "lightspeed" to detect them.

I don't understand why are you fascinated by that poor cat. Computer program is not quantum flux, its perfectly and completely deterministic system whose outcome can be reproduced indefinitely with completely predictable results. What I was talking about is program, algoritm, and its execution steps as concept of time. objects inside the program are those that "exist". Think of your favourite 3D game.
 
  • #150
Originally posted by wimms
No existence in our familiar form. That does not warrant idea that no existence is possible. Notice yourself, you can remove or add spatial dimensions freely, given that at least 1 remains, but as soon as you remove time, all spatial dimensions loose sense. Therefore time is more fundamental than spatial dimensions.

Besides spatial dimensions, you can imagine arbitrary number of any other dimensions, like imagine computer program - its in its own "space", in this case space is freedom of states, possibilities. And computing steps are interactions that can be assigned notion of particles or forces, and they exist in that computer time. Dimensionality of such computer can be made arbitrariliy large, and it has not even close resemblence to our spatial dimensions. When you stop that computer time, these particle cease to exist, and only single state remains. You can't think of all possible states as existing simultaneously, given constraints of computer program, there is only 1 way to proceed from given state - via causal interaction. And that's possible only when computer clock is restarted. And for particle inside computer program, there is no way to detect whether time runs or is stopped. The only thing what particle can detect is interaction _when_ time runs. For it, to exist is to have computer time running. Same for us, to exist _requires_ concept of time and interaction. For computer program, to jump in time means skipping series of cause/effect interactions and start interacting with something that doesn't exist yet or anymore. Not only does this scrap causality, it simply doesn't make sense.

Multiple time dimensions is as meaningless as multiple lengths. You can introduce as many as you like, it does not change essence of the concept, it remains unique.
Possiblity: I imagine that I'm god and destroy that universe. Do you feel anything? Is that possibility "real"? Why is it not possible? Because we live in _real_ world? What makes it real? Constraints to possibilities? Okay, is there such a law of nature that forbids wimms to destroy universe? No, but there are laws of nature that states that to do that, you'd need to spend energy - interact. And they state that wimms has not even pion's chance in myuon's ass to kick the universe. Therefore we safely conclude, that this imagination is not real. But I conceive it, perfectly vividly. Its here, it exists! So what? It has no capacity to interact with real world. Therefore, it does not exist. There exist my braincells, that fired this way for duration of this post, they are real, but not the imagination. When I'm finished, horrible image of wimms destroying universe ceases to exist even in my imagination. And definitely its not something that could exist separately from my delusion.

See? To exist requires interaction. And interaction creates form. You might imply that now that I've written that delusion down, it exists on this forum in electronic shape. But its not what I imagined. What you perceive is delusion crap of somebody who'd better be drunk. And that's what it is - useless crap not end of world. But if you'd truly perceive sky crushing down on you, it would be real. Thing is what it appears to other thing to be.

There is a difference between imaginary delusions and real world out there. Imaginary delusions are limited by your own constraints only, real world limits you with requirement to interact in frame of laws we are trying to find out. As long as this universe is causal and logical, there is no room for "all possible universes", there is only one, here and now, constrained by only one possible direction of time - from past to future by means of cause/effect interactions.

To add here, consider abstract ideas, like geometric point, or line. Are they real? Do they exist? In our delusions, yes, but in universe out there - no, they don't exist. We can model world around us by using our imaginary shapes, but that doesn't make our imagination real, its merely description of something out there.
Time as coordinate dimension is of that kind - its is convenient to use it as spatial dimension, because this allows us to compute formulas, but it doesn't mean you can move on it the same way as you move in space.

As to multiple histories, they can't exist concurrently. To exist means to interact, if they don't interact they don't exist. You can shape the world around you, if you have free will, and this way decide which way your history develops, but there is no way you could swap your reality, much the same way as wimms cannot destroy universe, or how single value of variable in computer program cannot arbitrarily and acausally change whole state or even structure and program of the supercomputer. The only way how you could escape into other universe is via imagination. This is apparently perfectly possible, as we can learn from institutions with soft walls.

You are wrong here. Concepts that exist within my mind, right now, do exist. They are not physical, but they do require physical interaction (of neurons) to be produced. They don't exist in the past or future, because nothing "exists" in the past or future. For something to be said "to exist", it has to exist in the present.
 
  • #151
Originally posted by Royce
mentat
"The true test of another man's intelligence is how much he agrees with you."
royce:wink:

LOL

Not always. Sometimes the true test of another man's intelligence is how well he can argue with you.
 
  • #152
Originally posted by wimms
Yes I'm trying to say that time is more fundamental.

Time and space are each definite properties of the universe. To say one is "more fundamental" than the other is just irrelevant. They are both fundamental and crucial to existence.

If you think of 1D line as of mathmatical concept, then its possible abstraction, but it cannot exist as reality. There is no way to detect any distinguishable points on it without concept of time.

You are not looking at the flip side of things. If there was no space, there would be no points to detect in the first place! The bottom line is: BOTH TIME AND SPACE ARE EQUALLY FUNDAMENTAL TO EXISTENCE!

As far as the computer program analogy goes, if you meant to describe a program in which the same outcome is arrived at each time, this is not an accurate analogy because the universe cannot be predicted in the same way that a computer program can. Maybe I just don't see your message behind the example of the computer program in the first place.
 
  • #153
Originally posted by Locutus
Time and space are each definite properties of the universe. To say one is "more fundamental" than the other is just irrelevant. They are both fundamental and crucial to existence.

You are not looking at the flip side of things. If there was no space, there would be no points to detect in the first place! The bottom line is: BOTH TIME AND SPACE ARE EQUALLY FUNDAMENTAL TO EXISTENCE!
Of course I am looking for both sides. Its not irrelevant, because you can have concept of time without geometric spatial dimensions, but spatial dimensions cannot exist without time. Spatial dimensions can only be _imagined_ without time, and even that is illusion, because "to continue to be" (definition of "exist") you need time.

There is another aspect. 1D line has no distinguishable points. Its continuum, and it has infinite number of points between any two you pick, or nothing, ie same point. You need distinguishing criteria, you need detection means. Zero time make no sense, infinite time makes no sense, this leaves finite timestep as the only meaningful concept, and this finite timestep is what quantifies space into distinguishable points. Only after that can you speak of space as of usable reality. Whats more important, if you try to quantify 1D line into points with uniform spacing, you can't do that without uniform time. But even if time is not uniform you have no means to detect that, for you space is uniform, as the only criteria for you is time.
This leads to suspicion that space is perception, not real. But oh well.
I do agree that both are fundamental for existence, but I tend to put time in higher rank of importance.

As far as the computer program analogy goes, if you meant to describe a program in which the same outcome is arrived at each time, this is not an accurate analogy because the universe cannot be predicted in the same way that a computer program can. Maybe I just don't see your message behind the example of the computer program in the first place.
Not predictability is important. Concept of time and existence is what I tried to explain. Think of this computer as of universe, and yourself as of creature inside the program. There is no outside. Creature inside cannot know anything about predictability, even uncertainty principle applies to it, because any interaction it makes with other creatures change states of both. But yeah, if it didn't help, then it wasn't a good example. Still, there is notion of space in that program, there is notion of time. But space isn't geometric as in 3D. How it is perceived by creatures inside, is matter of interactions, they might even perceive it as our 3d space.

Originally posted by Mentat
You are wrong here. Concepts that exist within my mind, right now, do exist. They are not physical, but they do require physical interaction (of neurons) to be produced. They don't exist in the past or future, because nothing "exists" in the past or future. For something to be said "to exist", it has to exist in the present.
Well, I think you have confusion about concept of exist. What exists, is your neurons, and their state, that both requires energy and generates energy. Concepts you are imagining, have no capacity to generate energy, consume energy, interact with anything, or even sustain their existence on their own.

Its something like arguing about concept of water. Does water exist? sure. So where is fundamental particle of water? ah, its not water that exist, its our abstraction of molecules.

When we talk about existence in universe, we are not talking about all possible abstractions we can arrange from quantums of existence, like when 3 photons for Planckscale moment of time happen to be in triangular arrangement, we don't say that triangle exists. Even less can we say that this triangle can interact with square in the future. When you look deeper, you see that the only way to exist is to interact.

And although I agree with your second part about "exist", I suggest to make further distinction between abstract concepts and reality.

ps. no need to quote long posts in full.
 
  • #154
Wimms,
You argue semantics and our inability and the limits of our language to speak or write about events that we think happened outside of our normal spacetime. While your logic may be impeccable, it is simply not relevant. Logic, Mathematics, Relativity and probably Quantum Mechanics blow up and become meaningless and incomprehensible inside the event horizon of a black hole much less the singularity itself. Events that must have happened sequentially but outside of normal time and normal space, i.e. 0 time and 0 space. While matter may not be able to exist outside of spacetime energy and gravity apparently can and do.
There are a number of very good books on black holes, singularities and The Big Bang. I just finished one by John Gribbin "In The Beginning" written for laymen like me who are facinated by science but don't have the math or background to understand highly technical and mathematical writing.
 
  • #155
Originally posted by wimms
Well, I think you have confusion about concept of exist. What exists, is your neurons, and their state, that both requires energy and generates energy. Concepts you are imagining, have no capacity to generate energy, consume energy, interact with anything, or even sustain their existence on their own.

This may be the materialist's viewpoint, but it is not necessarily true. Think of this, why does our brain create new synapses, and "fire" neurons, if not to produce "thought"? Thought is not a physical entity, but it is the metaphysical product of the physical action of the brain.

Its something like arguing about concept of water. Does water exist? sure. So where is fundamental particle of water? ah, its not water that exist, its our abstraction of molecules.

But water does exist, and that's the point. As far as matter goes, there are no real molecules either, there are just quark and gluons (or just strings, in my preferred viewpoint). However, the fact that they interact, in a certain matter, produces "water".

When we talk about existence in universe, we are not talking about all possible abstractions we can arrange from quantums of existence, like when 3 photons for Planckscale moment of time happen to be in triangular arrangement, we don't say that triangle exists. Even less can we say that this triangle can interact with square in the future. When you look deeper, you see that the only way to exist is to interact.

Yes, and unless concepts interact with physics, such as occurs in the brain, they don't exist either. But the fact that there is an interaction (within the brain) proves that there is [at least conceptual] existence.

And although I agree with your second part about "exist", I suggest to make further distinction between abstract concepts and reality.

I do believe in a distinction between abstract concepts and physical reality. However, I also believe that I'm "really" thinking right now.

ps. no need to quote long posts in full.

I know, I was just in a hurry.
 
  • #156
Originally posted by Mentat
This may be the materialist's viewpoint, but it is not necessarily true. Think of this, why does our brain create new synapses, and "fire" neurons, if not to produce "thought"? Thought is not a physical entity, but it is the metaphysical product of the physical action of the brain.
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.

But water does exist, and that's the point. As far as matter goes, there are no real molecules either, there are just quark and gluons (or just strings, in my preferred viewpoint). However, the fact that they interact, in a certain matter, produces "water".
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.

Human thought is extremely unstable "thing", process rather than a product, and needs constant "refreshing" by additional energy shaped to interact in specific manner, constraint by design of our brain.

Yes, and unless concepts interact with physics, such as occurs in the brain, they don't exist either. But the fact that there is an interaction (within the brain) proves that there is [at least conceptual] existence
I do believe in a distinction between abstract concepts and physical reality. However, I also believe that I'm "really" thinking right now.
Absolutely. You are thinking. But not concepts you use. They don't think. They don't exist. Its stuff that makes up the concepts that exists. Take for eg. concept of infinite line. It can't exist even in your mind, as your finite number of neurons simply can't represent it. You imagine line by few samples and few properties it would have if it existed. Even here you imagine actually not the concept itself but ingredients of it.

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

Originally posted by Royce
Wimms, You argue semantics and our inability and the limits of our language to speak or write about events that we think happened outside of our normal spacetime. While your logic may be impeccable, it is simply not relevant. Logic, Mathematics, Relativity and probably Quantum Mechanics blow up and become meaningless and incomprehensible inside the event horizon of a black hole much less the singularity itself. Events that must have happened sequentially but outside of normal time and normal space, i.e. 0 time and 0 space. While matter may not be able to exist outside of spacetime energy and gravity apparently can and do.
Royce, your attitude hurts the spirit. Its essentially giving up before even trying. I really didn't mean to play games with language, although its educating to notice that not even single sentence can be meaningful if it doesn't include concept of time, explicit or implicit.

Theories don't produce understanding, not even explanation. They produce models, internally consistent models, refutable and testable by experiment. Interpretation is done by using philosophy of age, paradigm. Models are round, circular, pretty much indifferent to what is anterior vs posterior. They simply interrelate bunch of simplicities into consistent complexity. Take this simplest formula: v=l/t. There is not even hope to decide which is fundamental of the 3, velocity, distance or time. For this model it is irrelevant. Possibly for any model. But when you move deeper into the hierarchy of abstractions, closer to fundamentals, importance of such ordering becomes relevant. Not too long ago timeflow was considered constant. SR was revolution, and not even now does it go down easily. Back then, it didn't go down at all. After it was proved unrefutable, it started process of paradigm shift, philosophy changed. And its still not done yet - time has lost its respect and is reduced to 4th dimension, even though its still always assumed that timeflow is uniform and even within a reference frame.

Most complex theories produce sideeffects, results that have no sense. There is whole set of rules how to decide when to discard such results as "physically meaningless". When stripped off from all the complex hitech talk, its essentially what is called "common sense". Basically stuff that doesn't fit into framework gets discarded as meaningless. Criteria for decision is existing paradigm. The more beautiful is model of prevailing theory, the harder it is to get paradigm shifted. It takes mad scientist or mad philosopher to do that, and in our times only scientist can possibly do that. But scientist can't do that if he hasn't philosophy ground to think different. So, philosophical and scientific evolution need to progress together.

Models use equations. Equations by their very nature equalize concepts, even if they are in hierarchical relationship. One example of this happening is concept of time that has been equated to dimension. Within framework of model, its irrelevant, and it is useful to think so for sake of computations within layer of abstraction. But meaning to such irrelevance gives human, and here we are, thinking of time as of dimension for travel.

"Events that must have happened sequentially but outside of normal time and normal space, i.e. 0 time and 0 space." You know, this is pretty much definition of time. You can't get rid of it. Its fundamental.
There is something wrong with our current models. Its a fact. These same models predict such incomprehensible things. I'd say we should accept such predictions with caution. Accept, but don't trust. New paradigm shift is around the corner.
 
  • #157
Wimms,
The whole point of modern Physics is the common sense doesn't apply anymore nor does it make sense. Relativity whether general or special and Quantum Mechanics are beyoun and outside of everday experience and therefore do not make common sense. The more crazy an idea is the more its is probably right. If it is crazy enough.
Time is not constant nor even flowing but relative and local to the given reference set. That was one of the major features of GR. Time is relative to the observer. Time does not flow smooth at the quantum level just as spacetime is not smooth at the quantum level but is quantumized.( I still don't know if that's a word or not.)
I believe that spacetime is a function or characteristic of mass/matter based somewhat on what little I know and understand of string theory. Until matter begins to form out of the expanding and thus cooling energy inside a, the, singularity there is no spacetime within the singularity. As mass/matter forms it also forms dimensions. What is the number now, 11+? Of these dimenions are the four that we experience directly and know as spacetime. If a void contains no matter then it is my beleif that it contains no space, no time, no spacetime and is total infinity without constraints or limits and as they pointed out in "MenIn Black" "Size doesn't matter." It is totally irrelevent.
Once again Common Sense does not and cannot apply because such conditions are forever totally outside human experience and human experience is what Common Sense is bases on.
I cannot write or talk without words that have time/duration connotation; but, that connotation does not apply in this context.
 
  • #158
Mentat,
To get back to the your original point, "Why we can't go back." If we were really 4-D beings and could see time just as we see east or west or up or down and you, traveling forward in time, watched me traveling backward in time; you would see me NOW at point A, then I would also appear at point B somewhere in your past, being both places, A, NOW and B,PAST at the same time. I would then disappear
from point A, NOW and continue on from B, PAST. Impossible and incomprehensible to you, of course. However to me, traveling backward it time in reference to your time and place, it would be perfectly normal and natural, an orderly and timely progression from A, my NOW to B, my FUTURE.
Time, like space is relative to the observer. I'm not saying that it is physically possible, I don't know but I believe it would involve have an intrinsic velocity greated the C. Fortunatly or perhaps unfortunately, again depending on your point of view or mind set, we are not truly 4-D being but only 3-D beings and while we live in TIME and know we live in TIME we can only see NOW which is the spacetime point that Time coincides or intersects our spacetime 3-D plane.
PS I'm not even sure I understand what I just said/wrote. Your thoughts and comments, please!
 
  • #159
Originally posted by Royce
Mentat,
To get back to the your original point, "Why we can't go back." If we were really 4-D beings and could see time just as we see east or west or up or down and you, traveling forward in time, watched me traveling backward in time; you would see me NOW at point A, then I would also appear at point B somewhere in your past, being both places, A, NOW and B,PAST at the same time. I would then disappear
from point A, NOW and continue on from B, PAST. Impossible and incomprehensible to you, of course. However to me, traveling backward it time in reference to your time and place, it would be perfectly normal and natural, an orderly and timely progression from A, my NOW to B, my FUTURE.


Exactly. "Your future". This means that you are not traveling to the past, but to the future.

Time, like space is relative to the observer. I'm not saying that it is physically possible, I don't know but I believe it would involve have an intrinsic velocity greated the C. Fortunatly or perhaps unfortunately, again depending on your point of view or mind set, we are not truly 4-D being but only 3-D beings and while we live in TIME and know we live in TIME we can only see NOW which is the spacetime point that Time coincides or intersects our spacetime 3-D plane.
PS I'm not even sure I understand what I just said/wrote. Your thoughts and comments, please!

I don't really know the point you are trying to get at either. First you seem to deny that time is a dimension. Then you say that "we can only see NOW which is the spacetime point that Time coincides or intersects our spacetime 3-D plane". I'm just confused. We call it "spacetime" because we are including time (obviously). Thus is must be four-dimensional, unless you think there are only two dimensions of space.
 
  • #160
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.
 
  • #161
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.
 
  • #162
i went back in time the other day mutha****a
 
  • #163
**** you nerds, get the computer and get some pussy
 
  • #164
i mean subtracting myself from this time
 
  • #165
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.
 
  • #166
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 [Broken]
 
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  • #167
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.
 
  • #168
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.
 
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  • #169
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!
 
  • #170
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.
 
  • #171
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.
 
  • #172
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.
 
  • #173
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?
 
  • #174
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.
 
  • #175
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 :wink:.


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' :smile:.
 
<h2>1. What is the paradox of backward time travel?</h2><p>The paradox of backward time travel refers to the logical inconsistency that arises when considering the possibility of traveling back in time. It raises questions about the nature of causality and the possibility of changing the past.</p><h2>2. Why can't we go back in time?</h2><p>According to current scientific understanding, time travel to the past is not possible. This is because it would violate the laws of physics, specifically the law of causality which states that an effect cannot occur before its cause. Additionally, the concept of time as a linear progression makes it impossible to physically travel backwards.</p><h2>3. Is backward time travel theoretically possible?</h2><p>While backward time travel is not possible according to our current understanding of physics, some theories, such as Einstein's theory of general relativity, allow for the possibility of time travel. However, these theories also propose that certain conditions, such as the existence of wormholes or the manipulation of black holes, would be necessary for such travel to occur.</p><h2>4. Are there any real-life examples of backward time travel?</h2><p>There is currently no evidence of any real-life examples of backward time travel. While some scientists have theorized about the possibility of time travel, there is no concrete evidence to support its existence. The concept is largely confined to science fiction.</p><h2>5. Can we ever hope to understand the paradox of backward time travel?</h2><p>As our understanding of physics and the nature of time continues to evolve, it is possible that we may one day gain a better understanding of the paradox of backward time travel. However, it is also possible that it may remain a philosophical and theoretical concept that is beyond our current scientific capabilities to fully comprehend.</p>

1. What is the paradox of backward time travel?

The paradox of backward time travel refers to the logical inconsistency that arises when considering the possibility of traveling back in time. It raises questions about the nature of causality and the possibility of changing the past.

2. Why can't we go back in time?

According to current scientific understanding, time travel to the past is not possible. This is because it would violate the laws of physics, specifically the law of causality which states that an effect cannot occur before its cause. Additionally, the concept of time as a linear progression makes it impossible to physically travel backwards.

3. Is backward time travel theoretically possible?

While backward time travel is not possible according to our current understanding of physics, some theories, such as Einstein's theory of general relativity, allow for the possibility of time travel. However, these theories also propose that certain conditions, such as the existence of wormholes or the manipulation of black holes, would be necessary for such travel to occur.

4. Are there any real-life examples of backward time travel?

There is currently no evidence of any real-life examples of backward time travel. While some scientists have theorized about the possibility of time travel, there is no concrete evidence to support its existence. The concept is largely confined to science fiction.

5. Can we ever hope to understand the paradox of backward time travel?

As our understanding of physics and the nature of time continues to evolve, it is possible that we may one day gain a better understanding of the paradox of backward time travel. However, it is also possible that it may remain a philosophical and theoretical concept that is beyond our current scientific capabilities to fully comprehend.

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