Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: AndroidNeox on 12/05/2013 21:17:02
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I don't understand why it seems that things happen.
Relativity requires that all events (points in spacetime) must be fixed and immutable. But, if every event 'is', then why does it seem they happen? Why does our perspective seem to change?
It seems clear that we MUST exist in some sort of multiverse, if we assume both relativity and quantum mechanics are correct. QM has shown that outcomes are not pre-determined by hidden variables and that a perfect coin toss can really be observed to have either outcome. Also, relativity requires (non-simultaneity & causality) that events are fixed, both in the future and the past.
But, that doesn't really change the problem. If relativity is correct then, why does it seem that things happen?
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I don't understand why it seems that things happen.
Given that we exist in a world of which we have to make sense, how could it be otherwise?
If we live in a cosmos which is truly infinite, then there can be no change, no time and no motion, and every part must be the whole. Only our limited 3 + 1 dimensional view of the cosmos must give rise to the illusion of movement and change.
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Relativity requires that all events (points in spacetime) must be fixed and immutable.
Not really. Events in spacetime are measured relative to an observer. Different observers won't necessarily agree on the timing or ordering of events, so they are clearly not fixed and immutable in spacetime. I don't think relativity requires that spacetime be viewed as a 4D Parminidean block, either. You can view it that way if you wish, but it's not a requirement.
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Yes, events in spacetime must be fixed and immutable. While different observers might not agree on time, they must agree on sequence and causality requires that each event exist for any observer. This is a requirement of Relativity because it's a requirement of causality.
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I think I can give a clear argument why events in spacetime must exist in an unchangeable form. It's a consequence of 'non-simultaneity'... the fact that, for observers in different reference frames, the time associated with some events will not be the same. For some observers, the event will be in the past. For other observers, the event will be in the future. However, causality requires that the event exist for all observers.
Einstein was bothered by this because it seemed that, because all future events must already exist, for some observers, there seemed to be no possibility of 'free will'.
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... causality requires that the event exist for all observers.
... for some observers, there seemed to be no possibility of 'free will'.
If the event must exist for all observers, doesn't that preclude free will for all observers? if not, why not?
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I don't understand why it seems that things happen.
I promise all of you that it merely appears to seem that way, that is all.
Relativity requires that all events (points in spacetime) must be fixed and immutable.
That is incorrect. Relativity requires no such thing.
Please go back to the basics and study spacetime diagrams. I created a webpage for this and this alone for just this purpose such. It's at http://home.comcast.net/~peter.m.brown/sr/spacetime.htm
Einstein thought Relativity requires it and he was right. I agree, there are many misconceptions about Relativity, such as that it allows for the formation of event horizons.
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Please ignore everything I posted before now. I was a bit confused about something and wish to start from scratch.
You wrote
I don't understand why it seems that things happen.
What is it that's bothering you?
Relativity requires that all events (points in spacetime) must be fixed and immutable.
Relativity requires no such thing. Where on Earth did you get that idea from?
Einstein thought Relativity requires it and he was right.
Where on Earth did get the idea that Relativity requires it from? That is completely wrong.
I agree, there are many misconceptions about Relativity, such as that it allows for the formation of event horizons.
There most certaily are event horizons in relativity. I don't know where you got the idea that there wasn't but they most certaintly do exist.
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While different observers might not agree on time, they must agree on sequence and causality requires that each event exist for any observer.
Different observers can indeed disagree on sequence so long as causality is preserved in the process.
Imagine that you are standing at a train station and a passenger car comes by. There is a light in the center of this car which switches on just as it reaches you. When light reaches the rear of the car, we will call that Event A. When it reaches the front, we will call that Event B. Light travels at the same speed regardless of the observer, so light is traveling at the same speed towards both the front of the car and the rear. However, the car is moving forward in your reference frame, so the rear is advancing towards the light whereas the front is retreating from it. For this reason, you see light strike the rear before the front: Event A precedes Event B.
Now imagine the same scenario from the point of view of a person who is on board the car. In their frame of reference, the car is at rest. The front and rear do no appear to be moving relative to the light which has been emitted. This means that Event A and Event B happen simultaneously in the frame of reference for this second person.
We can extend this further if we consider a third observer which is travelling in another passenger car on a second track which is moving in the same direction but at a higher velocity. From the point of view of the third observer, the first passenger car will appear to be moving rearward relative to his position. This means the person will see the light strike the front before the rear. Event B has preceded Event A for this third person.
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First, hidden variables have not been ruled out and secondly, absolute instantaneity has not been ruled out either!
Don't swallow everything that comes near your mouth...
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First, hidden variables have not been ruled out and secondly, absolute instantaneity has not been ruled out either!
Explanation?
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Entanglement seems to show non-local hidden variables. What seems to be ruled out is locality and there are still loopholes to investigate. About instantaneity, it is Einstein's theory that says there is only relative instantaneities. Entanglement, again, seems to show the contrary. Relativity is incomplete. Show me a proof of the existence of "spacetime" and I will show you the contrary proof. The first proof is: no one knows what it is... The others are just too long to explain for now, but you can find some in my earlier posts, including the true explanation of frame dragging, it is very simple in fact.
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Don't swallow everything that comes near your mouth...
Yeah, but what if I'm really hungry? :D
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Fixed nature of spacetime: This is a consequence of causality combined with non-simultaneity. Causality requires that all events be mutually-observable by different observers and that causal sequences (like falling dominoes) must appear in the same sequence for all observers. Non-simultaneity is the fact that observers in different reference frames cannot necessarily agree on the time of any particular event(s).
Brian Greene had a good example in one of his books. As I recall, he posited two aliens 10 billion light years away, one stationary and the other moving at 30 miles per hour. Their clocks read the same time as they pass. However, each has a different perspective of what time is ‘now’ on Earth… differing by centuries. For one observer, Abraham Lincoln would still be alive while for the other he would be long dead. The fact that he hadn’t died, yet, for one observer doesn’t mean that the event might not happen. All of the events in spacetime are fixed and observable for any observer, independent of when they perceive the events to happen.
This bothered Einstein and, as I understand it, he was never able to reconcile this with his belief in free will.
Non-existence of event horizons: The reason Einstein insisted that event horizons cannot form is that they are infinitely far away from all observers. Mass stretches spacetime. As matter falls into a collapsar, spacetime stretching approaches infinite. An external observer would see the infalling object (or observer) slow down and never reach the event horizon. The infalling observer would see the external universe speed up.
The relationship between time for an external, inertial observer and the infalling observer is exponential. As the distance between the infalling observer and the (hypothetical) event horizon approaches zero, the difference between time rates of the two observers approaches infinite. There hasn’t been enough time, yet (13.8 billion years) for any matter to have fallen to an event horizon… not even the matter that would nucleate the event horizon in the first place. In 100 trillion years there still won’t have been enough time.
People often get confused because the ‘proper time’ of the infalling observer is finite. But, this is just an aspect of exponential curves which might have only a finite distance to travel along one axis of a graph but, before reaching zero, will have to extend infinitely far out along the other axis.
Einstein did analyze models of event horizons but they were always independent of time. They existed at time = zero and were unchanged until time = infinity.
Einstein probably understood Relativity better than anyone and I’m baffled why physicists so cavalierly ignore his conclusions.
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... causality requires that the event exist for all observers.
... for some observers, there seemed to be no possibility of 'free will'.
If the event must exist for all observers, doesn't that preclude free will for all observers? if not, why not?
Exactly, dlorde! That is exactly what bothered Einstein about this. He was never able to reconcile this requirement of Relativity with free will.
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First, hidden variables have not been ruled out and secondly, absolute instantaneity has not been ruled out either!
Don't swallow everything that comes near your mouth...
Actually, hidden variables were ruled out by Bell's Inequality and absolute instantaneity cannot exist because Einstein proved 'non-simultaneity'.
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Entanglement seems to show non-local hidden variables. What seems to be ruled out is locality and there are still loopholes to investigate. About instantaneity, it is Einstein's theory that says there is only relative instantaneities. Entanglement, again, seems to show the contrary. Relativity is incomplete. Show me a proof of the existence of "spacetime" and I will show you the contrary proof. The first proof is: no one knows what it is... The others are just too long to explain for now, but you can find some in my earlier posts, including the true explanation of frame dragging, it is very simple in fact.
Entanglement is required in all causal systems. Action at a distance is not possible unless Relativity is entirely wrong. I am not willing to toss out Relativity.
There are purely local (nothing going faster than light) explanations for what we see as 'action at a distance', but none that work in the classical 'universe' model of reality. They require a multiverse. Multiverse cosmologies allow quantum mechanics to be consistent with Relativity and provide purely causal explanations for the 'weirdness' of quantum mechanics.
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... causality requires that the event exist for all observers.
... for some observers, there seemed to be no possibility of 'free will'.
If the event must exist for all observers, doesn't that preclude free will for all observers? if not, why not?
Exactly, dlorde! That is exactly what bothered Einstein about this. He was never able to reconcile this requirement of Relativity with free will.
You missed my point, despite the highlights and the italics; I was curious to know why you first said free will is precluded for some observers. You now seem to agree it must be all observers.
What bothered Einstein outside of physics is really only of incidental interest, whether it was wearing socks or free will.
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... causality requires that the event exist for all observers.
... for some observers, there seemed to be no possibility of 'free will'.
If the event must exist for all observers, doesn't that preclude free will for all observers? if not, why not?
Exactly, dlorde! That is exactly what bothered Einstein about this. He was never able to reconcile this requirement of Relativity with free will.
You missed my point, despite the highlights and the italics; I was curious to know why you first said free will is precluded for some observers. You now seem to agree it must be all observers.
What bothered Einstein outside of physics is really only of incidental interest, whether it was wearing socks or free will.
I'm sorry if I said free will would be precluded for 'some' observers. I don't see where I typed that. Certainly, if it can't exist for some observers it can't exist for any.
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... causality requires that the event exist for all observers.
... for some observers, there seemed to be no possibility of 'free will'.
I'm sorry if I said free will would be precluded for 'some' observers.
No problem, I guess it was just a typo. It just seemed to imply there was some way that some observers could, somehow, still have free will - glad to know it's all or nothing ;) I don't see where I typed that...
?? It's in your post that I've quoted a few times now (e.g. above).
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I don't understand why it seems that things happen.
Which things?
Relativity requires that all events (points in spacetime) must be fixed and immutable.
That an event is fixed can been seen through what it means to be an event. I.e. consider the event defined as
E = “pebble hits Rock at R = (x, y, z) at T = T”
The position 4-vector has components r = (ct, R).
Question: What would it mean for event E to not be fixed (aka immutable)?
Answer: Such a thing is meaningless.
But, if every event 'is', then why does it seem they happen? Why does our perspective seem to change?
The existence of an event is a result of the laws of nature and causality, i.e. what nature does with initial conditions.
For example; Event A exists as a result of Newton’s laws and initial conditions.
It seems clear that we MUST exist in some sort of multiverse, if we assume both relativity and quantum mechanics are correct.
You’re attempting to read way to much into events than what is really there.
Do you understand that spacetime is not a product of special relativity? It exists in non-relativistic Newtonian dynamics? All spacetime is, is the collection of places and locations. I.e. the set of all pairs of times and places r = (ct, x, y, z) = (ct, R) where R = (x, y, z), is given the name “spacetime.”
Consider an inertial frame S. Then in S the motion of a particle is defined by y = vt + k. Then this particle moves in a straight line with constant speed v. What Newton called a trajectory in 3D “space” is what Minkowski called a “worldline” in spacetime. In this case the spacetime is 2D, one coordinate for time and one for space.
Nothing about this hints at a multiverse.
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Pmb, you can't have both Relativity and Quantum Mechanics be correct except in a multiverse. Relativity requires that spacetime be fixed and unchanging. QM requires that multiple outcomes are possible for events. That means, multiple outcomes must exist in fixed spacetime. However, multiple outcomes cannot be observed (it would violate physical laws... conservation symmetries).
This can be explained in purely local terms (nothing going faster than light).
"Action at a distance" depends upon the existence of universal time... it must be possible to define an instant so that it's agreeable to all observers. Relativity has proven no such thing exists ("non-simultaneity"). Any physicist that believes in "action at a distance" should have their school credits for Relativity revoked because they obviously don't understand it.
The logic is simple and each premise is backed by experiment. The only plausible cosmologies are purely local, multiverse theories.
Quantum mechanics provides a rule that satisfies these requirements. If any observation would be inconsistent with even a single quantum within the observer, the outcome's state would be non-Hermitian. Schrödinger described such states as unobservable.
The idea that observation alters the universe is a hold-over from classical physics' interpretation of "the universe". If we discard that outdated concept and accept that observation alters the observer, then we end up with purely local and physically-consistent observable reality.
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If we live in a cosmos which is truly infinite, then there can be no change, no time and no motion, and every part must be the whole. Only our limited 3 + 1 dimensional view of the cosmos must give rise to the illusion of movement and change.
As far as I understand it, this argument could only be true if you assume that the universe is isotropic and homogeneous.
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If we live in a cosmos which is truly infinite, then there can be no change, no time and no motion, and every part must be the whole. Only our limited 3 + 1 dimensional view of the cosmos must give rise to the illusion of movement and change.
As far as I understand it, this argument could only be true if you assume that the universe is isotropic and homogeneous.
Yes, but at which scale? This is the question... Maybe there is multiple bigbangs in the universe...
(there is a bug in the "quote" function, remove one "quote" for double quote)
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First, hidden variables have not been ruled out and secondly, absolute instantaneity has not been ruled out either!
Don't swallow everything that comes near your mouth...
Actually, hidden variables were ruled out by Bell's Inequality and absolute instantaneity cannot exist because Einstein proved 'non-simultaneity'.
You are entirely wrong and Einstein didn't proved anything, experiments and observations prove things to some extent... This is local hidden variables which seem to have been ruled out, leaving us with non local hidden variables...
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Why does it seem that things happen?
If we assume that events not only occur in the present, but continue to exist in what we perceive as the past, and may already exist in our future, this does seem to preclude free will.
Consider this (crackpot?) possibility. The Cosmos is infinite, timeless and changeless. Even saying that everything that can happen has already happened is misleading because the concept of “happening” involves the process of change. The best we can say is that in the cosmos, “everything is”.
The question now becomes: Why do we perceive things as happening? It must be because we have to make sense of the world in which we exist, or we would not be able to exist in it. We have evolved to perceive time and change. Thus, time and change are essential to us, but ultimately they are illusions. They are what we perceive in our 3 + 1 D spacetime, so they are as real as anything else in our Universe. The same can be said of free will; it operates in our Universe, so it is real in our Universe. That is all we can say about it in a scientific context.
I acknowledge that it seems I am saying that in the context of the cosmos, there is no free will. However, it is so nearly impossible for us to imagine a timeless and changeless state that we have to ask if we could be sure that, in the infinite cosmos, things are not as they are because of the things we perceive ourselves as doing, from choice, in our communal frame of reference. That, of course, is a question too far for a science forum, but I contend that anything up to that point has a right to a place in the sort of speculative science that asks what came before the Big Bang, or if there could be multiple universes.
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These things can have you scratching your block sometimes. :)
According to the growing block universe theory of time (or simply the growing block view), the past and present exist and the future does not exist. The present is an objective property, to be compared with a moving spotlight. By the passage of time more of the world comes into being, therefore the block universe is said to be growing. The present is supposed to be the place where this is supposed to happen, a very thin slice of spacetime, where more of spacetime is coming into being.
From http://en.wikipedia.org/wiki/Growing_block_universe (http://en.wikipedia.org/wiki/Growing_block_universe)
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Pmb, you can't have both Relativity and Quantum Mechanics be correct except in a multiverse.
I don't know where you got that idea from but you're alone in that assumption. That is by no means assumed to be the case in the wonderful world of quantum mechanics and relativity. One does not imply the other by ay means.
Relativity requires that spacetime be fixed and unchanging. QM requires that multiple outcomes are possible for events. That means, multiple outcomes must exist in fixed spacetime.
That is a false conclusion. You took "are possible" and took that to mean "must happen" which certainly doesn't follow. I believe that this is the root of your mistake.
Quantum mechanics provides a rule that satisfies these requirements. If any observation would be inconsistent with even a single quantum within the observer, the outcome's state would be non-Hermitian. Schrödinger described such states as unobservable.
The idea that observation alters the universe is a hold-over from classical physics' interpretation of "the universe". If we discard that outdated concept and accept that observation alters the observer, then we end up with purely local and physically-consistent observable reality.
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These things can have you scratching your block sometimes. :)
According to the growing block universe theory of time (or simply the growing block view), the past and present exist and the future does not exist. The present is an objective property, to be compared with a moving spotlight. By the passage of time more of the world comes into being, therefore the block universe is said to be growing. The present is supposed to be the place where this is supposed to happen, a very thin slice of spacetime, where more of spacetime is coming into being.
From http://en.wikipedia.org/wiki/Growing_block_universe (http://en.wikipedia.org/wiki/Growing_block_universe)
I agree with this totally. The is only one present that exits for the whole universe. The galaxies we see from past light are doing something "now" just as we are. Because the speed of light precludes us from seeing it immediately means little in the cosmic scheme of things. Einstein needn't have worried. We usually over think the details and the whole picture becomes as remote as the furthest galaxy.
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Some interesting stuff on time here (http://www.iep.utm.edu/time/).