Where does relativity allow for non-determinism and free will?

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In summary, the conversation discusses the concept of free will in relation to the theories of classical mechanics, general relativity, and quantum mechanics. It is argued that in a deterministic universe, free will is not possible as all actions can be predicted and determined by the laws of physics. The idea of a "block universe" is also mentioned, where the passage of time is seen as an illusion and consciousness is associated with the 4-dimensional structure of the brain. The conversation also touches on the concept of non-determinism in physics and the role of free will in decision making.
  • #1
Dmitry67
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I am orbiting a neutron star on an edge of stability. If I drop a rock on it, it collapses and I get a Black Hole. If I don’t do it, I can fly away, leaving it as is. It is my choice, and both options are compatible with GR, both are valid GR solutions.

I wonder, where exactly (mathematically) GR have a room for non-determinism? Is it because any free-will choices initially occur on the microscopic level, where they don’t emit G-waves, and only then are amplified to the macroscopic level, where they do affect the rest of the Universe?
 
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  • #2
You can set up similar conditions for EM, chemistry, thermodynamics, Newtonian mechanics, etc. This is not unique to GR, but is a feature of all classical mechanics.
 
  • #3
Dmitry67 said:
I am orbiting a neutron star on an edge of stability. If I drop a rock on it, it collapses and I get a Black Hole. If I don’t do it, I can fly away, leaving it as is.
Are you assuming it cannot be determined you drop it or not? Our minds may convince ourselves we have free will but is that really so?
 
  • #4
Well, you can forget about free will and think about just QM 'random' events. Neutron decays and proton and electron fly into different directions, while the total momentum is conserved. If heavy proton hits neutron star, it collapses. Somehow all different solutions (where electron and proton are ejected in different directions) are compatible with GR, even the initial conditions (neutron at rest) are the same.
 
  • #5
Quantum is probabilistic, GR is deterministic. What's the problem exactly?
 
  • #6
Dmitry67 said:
Well, you can forget about free will and think about just QM 'random' events. Neutron decays and proton and electron fly into different directions, while the total momentum is conserved. If heavy proton hits neutron star, it collapses. Somehow all different solutions (where electron and proton are ejected in different directions) are compatible with GR, even the initial conditions (neutron at rest) are the same.
Again, the same is true of all classical physics.
 
  • #7
Dmitry67 said:
I am orbiting a neutron star on an edge of stability. If I drop a rock on it, it collapses and I get a Black Hole. If I don’t do it, I can fly away, leaving it as is. It is my choice, and both options are compatible with GR, both are valid GR solutions.

I wonder, where exactly (mathematically) GR have a room for non-determinism? Is it because any free-will choices initially occur on the microscopic level, where they don’t emit G-waves, and only then are amplified to the macroscopic level, where they do affect the rest of the Universe?
Mathematically, this is a consequence of the fact that GR determines geometry for given matter, but that GR itself does not determine matter. To determine matter, you must go beyond GR, such as classical electrodynamics, Standard Model of elementary particles, string theory, free will, God, or whatever you like ...
 
  • #8
If you ASSUME non-deterministic free-will then any previously deterministic theory becomes non-deterministic.
 
  • #9
Passionflower said:
Are you assuming it cannot be determined you drop it or not? Our minds may convince ourselves we have free will but is that really so?

Very provocative thought, Passionflower. How would you answer your own question?
 
  • #10
DaleSpam said:
If you ASSUME non-deterministic free-will then any previously deterministic theory becomes non-deterministic.

No,
free will is not consistent with some deterministic theories (for example, classical mechanics)
 
  • #12
bobc2 said:
Very provocative thought, Passionflower. How would you answer your own question?
I believe we have no free will.
 
  • #13
Dmitry67 said:
I am orbiting a neutron star on an edge of stability. If I drop a rock on it, it collapses and I get a Black Hole. If I don’t do it, I can fly away, leaving it as is. It is my choice, and both options are compatible with GR, both are valid GR solutions.
Your "choice" would depend on non-gravitational interactions in your brain (especially electromagnetic ones), and as Demystifier said GR does not uniquely specify the behavior of matter which is acting under other forces. In a deterministic universe it might be that if you specified all laws of physics, then given a set of initial conditions only one outcome (either dropping the rock or not) would be compatible with those laws and initial conditions.
 
  • #14
Passionflower said:
I believe we have no free will.

Wow. What a refreshingly straight-forward answer. That would appear to be consistent with the "block universe" model, i.e., 4-D universe populated by 4-D objects (including our bodies). Some aspect of the observers seem to be moving at the speed of light along their respective world lines.

Would that model be consistent with your no-free will concept? If so, what is the nature of--or what aspect of the observer is it that observes and developes the impression that he is is making decisions and causing things to happen? Observer 4-dimensional physical structure could not be moving in this model (including the 4-D spaghetti-like bundle of neurons stretched along the world line for billions of miles), so what does the moving?
 
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  • #15
Passionflower said:
I believe we have no free will.


And then there is the possibility that nothing actually moves along the worldline at the speed of light (consciousness, or whatever). In the same way you regard free will as an illusion, it could be that the passage of time is an illusion.

I think JesseM made a comment in passing about Julian Barbour's book, "The End of Time" (not sure I got the title right). I've read the book as well. He talks about the "End of Time" in the context that we should put an end to the concept of time itself--passage of time is an illusion. At one point he references Eingstein's comforting letter to the wife of Besso at the time of his very close friend Besso's death. Barbour seems to regard that letter as an indication that Einstein embraced the Kurt Godel block universe concept with consciousness associated with the 4-dimensional brain-neuron structure simultaneously all along its world line (this is different than another view with a 3-D consciousness doing the moving along the worldline at light speed, implying passage of time). Of course Einstein and Godel must have had conversations about this during their many walks home together at the end of the day at Princeton. The passing of time illusion develops from the sequential order of the structure along the worldline.

I was not convinced about Barbour's eradication of time--how does consciousness operate without time? He may logically affirm the aspect of illusion of conscious stream of events being in sync with some more fundamental time passage, but I don't think he made a strong argument for throwing time out the window completely.

(Hope this hasn't veered too far into the metaphysics that we normally try to avoid here)
 
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  • #16
Passionflower said:
I believe we have no free will.


My mom said "everything happens for a reason". I don't think she meant that in a deterministic sense, however it is absoulutely true.

I never have, and suspect I never will see something that happened for no reason.

I would also never confuse that for a lack of free will. The beauty of me being me and only me and not you is I do what I want when I want, and you or anybody else can't do anything about it.

To say it differently, I have faith in the illusion of "me". :)


Oh and sorry for the metaphysics stuff.
 
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  • #17
bobc2 said:
Wow. What a refreshingly straight-forward answer. That would appear to be consistent with the "block universe" model, i.e., 4-D universe populated by 4-D objects (including our bodies). Some aspect of the observers seem to be moving at the speed of light along their respective world lines.
Not really, that whole "moving at the speed of light" notion is just a cute mathematical trick, it doesn't really make sense to interpret it as "motion" in a literal sense since it isn't change in something with respect to time. See [post=430613]this post[/post] for details.
bobc2 said:
Would that model be consistent with your no-free will concept? If so, what is the nature of--or what aspect of the observer is it that observes and developes the impression that he is is making decisions and causing things to happen? Observer 4-dimensional physical structure could not be moving in this model (including the 4-D spaghetti-like bundle of neurons stretched along the world line for billions of miles), so what does the moving?
The actual events in your brain (and consequent behaviors like talking) are exactly the same in the "block universe" picture as they are in the "flowing time" picture, so you should have the same thoughts and feelings either way, I don't see why it would make a difference.

edit: and to get more philosophical, even if you think of spacetime itself in the "block universe" picture, if you take the stance that subjective qualia are not completely equivalent to physical brain states (even if they are completely determined by them, as some philosophers like David Chalmers believe), then if you're worried about the subjective sense of time you could always adopt a picture where there's a sort of subjective "spotlight" of consciousness moving in a sort of nonphysical "mental time" along the worldline of some brain, successively experiencing different brain states. Perhaps an advocate of the many-minds interpretation of quantum mechanics might also be likely to take a view like this...
 
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  • #18
Folks,

GR is an emergent phenomena, i.e. it emerges from more basic quantum phenomena, so you can't argue from the macroscopic the microscopic (i.e. quantum level). GR theory breaks down at the singularity because the mathematics no longer models the physics, but QT, I expect, when it is fully understood (unlikely) will not break down.
 
  • #19
JesseM said:
Not really, that whole "moving at the speed of light" notion is just a cute mathematical trick, it doesn't really make sense to interpret it as "motion" in a literal sense since it isn't change in something with respect to time. See [post=430613]this post[/post] for details.

Not really, JesseM. We may not be on the same page here. First, I am simply trying to represent a particular interpretation of Special Relativity (not my own) in which you first regard the universe as a 4-dimensional space with time as a parameter that provides a description of motion using parametric equations (just like you would do it for projectile motion in ordinary 3-space). So, now we have a 4-dimensional space populated by 4-dimensional static material objects. These objects typically are very small in X1, X2, and X3 but string out for millions or billions of miles along their worldline.

Consider the 4-D observer object shown in the sketch below. A 4-D photon extends out to a position of 186000 mi along X1 and 186000 mi along X4. Keep in mind that the 4-D objects are frozen into the "block universe" and do not move. For the sake of making progress with the concept we assume some "aspect" of the observer moves along the observers vertical worldline to get to the point at 186000 mi along X4. From the sketch it is obvious that "aspect" (consciousness, ..., whatever...) had to move at speed c (although we can easily bring in an illusion concept ala Godel, because otherwise you have a 3-D consciousness moving, and given simultainaeity issues of SR, that leads inevitably to zombies and Solipsm (Einstein insisted on avoiding a concept that would lead to Solipsism).

Now, this is definitely not a mathematical trick--it is strictly 4-D geometry. You are just operating on an interpretation of a 4-D universe populated with 4-D objects which is at least consistent with the situation described. I personally don't see that this is a proven concept--but it at least seems consistent with SR.

Two_4-D_Objects.jpg


JesseM said:
The actual events in your brain (and consequent behaviors like talking) are exactly the same in the "block universe" picture as they are in the "flowing time" picture, so you should have the same thoughts and feelings either way, I don't see why it would make a difference.

I think I would agree with you. However, the "flowing time" should be given a sharper description. I take it that the "flowing time" still persists in conjunction with 4-D space populated by 4-D objects. Otherwise how is it that different observers can have the different cross-section "views" of the universe if there is not a 4-D space or 4-D objects for which cross-sections can be "viewed."

JesseM said:
edit: and to get more philosophical, even if you think of spacetime itself in the "block universe" picture, if you take the stance that subjective qualia are not completely equivalent to physical brain states (even if they are completely determined by them, as some philosophers like David Chalmers believe), then if you're worried about the subjective sense of time you could always adopt a picture where there's a sort of subjective "spotlight" of consciousness moving in a sort of nonphysical "mental time" along the worldline of some brain, successively experiencing different brain states. Perhaps an advocate of the many-minds interpretation of quantum mechanics might also be likely to take a view like this...

Of course you are right here. I think the subjective "spotlight" is essentially consistent with the Godel consciousness spanning the entire worldline, possibly even randomly focusing attention on various locations along the worldine. How would you know you hadn't already focused on a given spot on the worldline before--as you point out, the neuron information informs the consciousness with memories of past and the present state, etc. In the same way we experience our consciousness changing focus among the various parts of our brains (picturing food one moment, remembering some distant memory the next, etc.), the 4-D concousness can roam the entire worldline sampling sections of neurons evoking various illusions (I think this was the upshot of Godel's concept, but I could be very wrong here and someone might be able to give a more accurate representation of Godel). And I think Julian Barbour (and others) have implied that Einstein was thinking in terms of his departed Besso has getting along just fine--still living a good life along his earlier worldline (I appologize for this kind of remark without solid reference--but Einstein's letter has been discussed in a number of references that I don't have in front of me at the moment).

Then, we enter a whole new arena when Q.M. starts weighing in. It has been a while since I've read Chalmers, but it seems I came away feeling he had good rationale for his concepts but actually did not remove the 4-D objects but instead made them infinitely more complex.

Finally, to close the loop, all of this commentary is just to demonstrate that there is some major thinking that would fully support Passionflower's earlier comment about free will.

(I'm afraid we've outlived our metaphysical/philosophical license here--sorry)
 
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  • #20
I thought I'd provide at least one reference to the Einstein letter that has been analyzed by so many biographers and other authors. This one is from Michael Lockwood's "The Labrinth of Time." First, here is a passage from the book (Chpt 3, pg 52) where Lockwood quotes a couple of sentences from Einstein's letter to Besso's wife:

...In his letter, written less than a month before his own death, Einstein says of his friend (writing to Besso's wife), "He is now a little ahead of me in bidding this strange world farewell. That means nothing. For us devout physicists, the distinction between past, present, and future likewise has no significance beyond that of an illusion, albeit a tenacious one."

Lockwood then goes on for over a page presenting his interpretation of Einstein's words. After identifying a couple of sources of distress for someone losing a loved one he continues with, "...Einstein's words are hence addressed to a different, and more basic, source of distress in the bereaved. This is the thought that the person no longer exists, is simply not there any more. It is the thought, so to speak, that the deceased individual has been swallowed up by non-being: that a living, breathing, human being has been supplanted by a void. ..."

A couple of sentences later: "...Natural though it is, to be sad on these grounds, Einstein would argue, makes sense only if we think of time in a way that physics shows to be mistaken. Relativity as Einstein saw it, supports a tenseless conception of time. From this perspective, a person who is not living now, but did or will live at other times, exists in just as substantial a sense as someone who does not live here, but only at some other place. If Einstein is right, the terms 'past', 'present', and 'future' do not express objective differences between times, any more than 'to the west', 'here', and 'to the east' express objective differences between places..."

And later: "...Regarded in this light, death is not the deletion of a person's existence. It is an event, merely, that marks the outer limit of that person's extension in one (timelike) spatio-temporal direction, just as the person's skin marks out the limit in other (spacelike) directions." (my bobc2 note: This is of course just a statement of the concept of a 4-dimensional universe populated by 4-dimensional static objects)

And finally, "...Einstein is urging us to regard those living in times past, like those living in foreign parts, as equally out there in spacetime, enjoying the same flesh-and-blood existence as ourselves. It is simply that they and we inhabit different regions of the continuum."
 
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1. Why is General Relativity considered non-deterministic?

General Relativity (GR) is considered non-deterministic because it does not adhere to the principles of causality and determinism that are fundamental to classical physics. According to GR, the laws of physics are not fixed and the universe is not fully predictable. Instead, it allows for the possibility of multiple outcomes for a given set of initial conditions.

2. How does GR challenge the concept of determinism?

GR challenges the concept of determinism by proposing that the curvature of spacetime is influenced by the distribution of matter and energy, rather than being a fixed and unchanging entity. This means that the behavior of objects and events in the universe cannot be predicted with absolute certainty, as they are affected by the constantly changing structure of spacetime.

3. What evidence supports the non-deterministic nature of GR?

One of the key pieces of evidence for GR's non-deterministic nature is the phenomenon of gravitational lensing, where the path of light is bent by massive objects in its path. This effect is not fully predictable and can result in distorted or multiple images of the same object. Additionally, the observed expansion of the universe and the existence of black holes also support the non-deterministic nature of GR.

4. Can GR coexist with determinism?

While GR challenges the concept of determinism, it is possible for the two to coexist in certain ways. For example, at a macroscopic level, the laws of classical physics and determinism can still be applied to explain the behavior of objects in the universe. However, at a microscopic level, the probabilistic and non-deterministic nature of quantum mechanics must be taken into account.

5. Are there any implications of GR's non-deterministic nature?

The non-deterministic nature of GR has significant implications for our understanding of the universe. It suggests that the universe is constantly in a state of flux and that the future is not fixed, but rather shaped by the interactions of matter and energy. This also challenges the idea of free will, as all events in the universe are influenced by the ever-changing structure of spacetime.

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