Boltzmannbrain

We know a lot of properties that time has.  Importantly, we can use this knowledge to make almost any prediction that we need.  In this sense, it really don't think time is very mysterious.

And I think one thing that seems mysterious to people, is that we can't see into the past or future like we can with space (it is spacetime, but I will call it space to be less confusing).  But general relativity came along and showed us a geometry of spacetime that is very accurate.  In this geometry, the photons have such angles that only carry information from space, not time.  It is kind of like being partially blind, and you can only see in certain directions.  

However, I think that there is a very big mystery to be solved about time.  It is a dimension that we are automatically travelling through at the speed of light instead of having various speeds in the spatial directions.  How is this happening?  

22 minutes ago, MigL said:

You cannot 'see' an extension along the time axis, as that implies an 'outside' PoV.
If you understand the concept of the block universe, you must realize that you are embedded in it. 
There is no outside.

Where did I say you can?  

4 hours ago, swansont said:

The object exists at t=0 and at t= t1, the current time. It is likely to exist at some time t2>t1

One can speak of its past and future, though those are colloquial expressions.

That's not how this works.

I wasn't sure what you knew.  That is why I simplified it to spatial distance.  However, I did add that it is a different kind of metric than Euclidean. 

The idea is practically the same.  The spacetime interval for the coffee cup is s^2 = - (ct)^2, x^2, y^2, z^2 = - (3x10^8m/s*1s)^2, 0, 0 , 0.  

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Which is why we don't speak of present except in relation to our own frame. And my objection has nothing to do with the present. It's the assertion that relativity says that the future already exists. No additional conditions were specified.

I am just trying to explain it to you the best I can.

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You've introduced other frames into the discussion, but that's just a distraction. We have an observer, who has a frame of reference. There are events that happened in the past, and some will (presumably) happen in the future. Relativity tells us that clocks in different frames will disagree as to when an event occurred, or the order in which events occurred. But regardless of your frame, there will be a time where the coffee had not yet been spilled.

The only reason why the coffee hadn't spilled in your present is because of the angle that your present occupies in spacetime.  It is in the present of other frames because their presents in spacetime are at a different angle.  

1 minute ago, swansont said:

If there’s no past, present or future, because they are human constructs, how is it that “relativity implies a block universe, which is to say that the future already exists”? If future is a human construct, not part of relativity. These statements are inconsistent.

Imagine you are looking at a typical coffee table.  It's measurements are not important, but let's say it's 2 meters long, 1 meter wide and 1/2 meter high.  Does this object have a past, future or present?  Of course not, it is just an object. 

In one second, this coffee table extends through the 4th dimension. 

Now let's isolate this coffee table again.  It is now an object measuring 2m x 1m x 0.5m x 300,000,000m (remember the coffee table went through 1 second of time). *this is of course uses the Minkowski metric which is different metric than Euclidean metric, but the idea is the same. 

At the beginning of the second, the coffee table was in our present.  But for someone or something else travelling at a certain speed, the coffee table at the end of the second is in their present.  We are all correct GR.   

The reason why the coffee table had a past, present and future is because we say it does; that's it.

Imagine that someone spills a coffee at the end of that second.  If we are at the beginning of that second, there will be other frames of reference where the coffee was already spilled.  Of course they can't communicate to us that this will happen, but it happens in their present nonetheless.  

So if the coffee spills at what may be an infinite number of "presents" in the universe, what or who is to say that it should have a present at all.  Or a past or a future.  It (along with the rest of the universe) just exists eternally in GR. 

12 hours ago, MigL said:

The 'block' universe is an interpretation.
One of many, and the one you are choosing to use is called 'eternalism' and has many counter-arguments.
See here for other interpretations 

 

If you watched the video or truly understand GR, you would know that there is really only one option.

11 hours ago, MigL said:

i) GR is not a 'complete' theory; while extremely accurate where applicable, it fails to make valid predictions in many cases, as it fails miserably when dealing with hi mass/energy and extremely short separations.

I didn't say it was a complete theory.  This thread is about my claim that time travel is not possible with GR.  

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ii) Gr does allow for closed timelike loops, which would enable time travel through the use of 'wormholes'.
However, keeping those wormholes open requires the use of 'exotic' matter ( negative mass/energy ), which, as far as I know, can be harvested from immediately inside the event horizon of a Black Hole ( the 'counterpart' to Hawking radiation ), and may not exist or be realizable. 
See K Thorne's work.

What does that tell you about my knowledge of the subject ?

 

It tells me that you agree with me that time machines are possible, at least theoretically.  But I am not only saying that it is unknown whether or not they are possible, I am flat out saying that they are impossible.  I gave my reasons in the OP.  It makes no sense to even talk about them in GR (except to say that they make no sense).

4 hours ago, swansont said:

I don’t think this is a true statement. How does it imply a block universe, where “the future” already exists?

What future? 

Take a 1 dimensional particle that lasts for 5 seconds for example.  Assume there is no force applied to it so that its worldline looks like a long straight 2 dimensional line on a spacetime diagram.  In GR, this line doesn't have a past, present or future; it just simply exists.  Past, present and future are human constructs.  They are concepts in the mind.  Since everything is made up of these eternal particles, so is the universe.

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IIRC the possibility of time travel is limited, it’s not arbitrary. You can only go back to a time after you built a time travel device.

edit: #8

https://www.preposterousuniverse.com/blog/2009/05/14/rules-for-time-travelers/

 

What if advanced aliens built a time everyday for the past 10,000 years, and they have them, oh I don't know, under some mountains?  It allows a lot of opportunity to do illogical things like change the past.  

9 hours ago, exchemist said:

That article is an elaborate way of saying time travel is not possible. What does it mean to say you can "carve" spacetime? It's bullshit. 

12 minutes ago, exchemist said:

Nobody claims it is, apart from Dr. Who.

Can you provide a reference to show who thinks it possible?

I took the first reference that came up because this is not what I had expected to have to defend.  

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Dr. Ana Alonso-Serrano, a postdoctoral researcher at the Max Planck Institute for Gravitational Physics in Germany, explained the possibility of time travel and how researchers test theories. 

Space and time are not absolute values, Alonso-Serrano said. And what makes this all more complex is that you are able to carve space-time.

“In the moment that you carve the space-time, you can play with that curvature to make the time come in a circle and make a time machine,” Alonso-Serrano told USA TODAY. 

She explained how, theoretically, time travel is possible. The mathematics behind creating curvature of space-time are solid, but trying to re-create the strict physical conditions needed to prove these theories can be challenging. 

 

from https://www.usatoday.com/story/tech/science/2022/09/10/time-travel-possible-science/7847346001/

53 minutes ago, MigL said:

Not that I have high regard for the 'logic' used in your argument, ...

So your response is that my logic isn't good, but you don't say why.  Okay, you have my ear, so please tell me what part of my logic is not up to your standards.

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but I don't recall anyone saying that it was possible.

And this just tells me that you don't know much about this topic.  

Time travel is not logically possible if we assume Einstein's theory of relativity is more or less the true explanation of the universe.

Einstein's theory of relativity implies a block universe, which is to say that the future already exists, and the past still exists.  Ultimately, the universe is a 4d structure that doesn't change. 

And as far as we know, this entire structure doesn't age in another temporal dimension, and it doesn't exist inside of another spacial dimension either - it simply just exists.

Now for an example of the illogical idea of time travel.  Imagine that it is the 3rd of January at 11:00pm.  You are alone in your house.   A week later you have the opportunity to travel back in time (somehow).  You decide to visit yourself on the 3rd of January at 11:00pm.

Structurally speaking, what happened here, how did this static 4d structure (the universe) change?  How can a nonmechanical structure just change itself from being A to being B? 

Moreover how is it logical that the universe has only you in your house and also has two of you in your house? 

From what I understand, the universe is made up of events that have their set x,y,z,t locations in spacetime.  None of these events move, and none of them appear or disappear.  Everything just is the way it is.  In general, nothing physical actually changes or moves (I put "physical" because you could argue that a nonphysical consciousness moves through the human parts of this structure, but that's a whole other discussion).

How is time travel logically possible?

Yes, I would definitely think that the detector would read a dilation of time.  A precise clock should breifly slow *slightly* as the wave passes.

A gravitational wave comes from the acceleration of mass.  This would seem to mean that a gravitational wave would cause a very brief moment of gravitational increase and decrease to the detector.  So depending on how strong the wave is, it would be just like a mass existing for a brief period and then disappearinas at the detector.  And I would think that this must cause a brief time dilation as well.

A question I find interesting is what is the trough of a gravitational wave?  If the crest is a brief pull with time dilation, is the trough a push with time "expansion"?  Is it a sort of moment of anti gravity or dark energy? 

I am very much open to critique by anyone if what I said is nonsense.  

1 hour ago, zapatos said:

Precisely how fast is 'fast enough'?

I already posted it.  It's a simple equation of many to choose from.  Something like 1/(1 - t) would work.  

4 hours ago, Genady said:

As an illustration to the Markus' explanation above, consider this example from Gravitation by Misner, Thorn, and Wheeler:

This is interesting, but I have no idea how this is an example of Markus' explanation.  Please explain.

5 hours ago, Luc Turpin said:

Tell me more about 'evidence and lack of evidence pointing to'! Are you talking about the points that I raised, or you have others?

The evidence points to the consciousness constrained to being just a property of the brain.  We know this because of the correlations found so far between mind and brain.  And there is practically no evidence (that I am aware of) suggesting otherwise.

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'This subjective conscousness is a property in of itself', but it needs the physical to express itself! Right? So its not onto itself! Right? Or are you saying that its does not need the physical to express itself?

My post was defending the idea that the mind is an immaterial property of the brain and not a physical one.  I was reading your discussion with the other poster, and it seemed you both thought an immaterial mind was a bad idea.  This is why I made my post.

To answer your question, no, I definitely was not saying that the mind has the ability to do otherwise than what the brain does.  So far, there only seems to be a one-to-one correlation between mind and body. 

My personal opinion is that I am still not sure, but I am leaning towards epiphenomenalism (mind-body being fully correlated).  But I don't think we know enough for me to make a hard claim yet. 

The mind being an immaterial property of the brain might not be as woo as it sounds.  I personally think this is where the evidence and lack of evidence is pointing to.  It also explains philosophical zombies.

If there were two identical people each living on identical planets doing identical things and one had a mind and the other didn't; the one that doesn't is the "zombie".  We would never know which has the mind, even by looking at every particle in both people.  The physical makeup is identical.  The mind would not have any autonomy in the person versus the zombie.  


Then you may say, well maybe in reality there is something physically different about life with minds versus life without minds.  So assume we narrow it down to some biochemical process that every living thing with a mind has.

But now what?  We still haven't detected the mind.  There would still be the mind-body problem simply because the subjective consciousness can experience and have its physical properties.  This subjective consciousness is a property in of itself.  This makes the mind something entirely different from physical, but a immaterial property of the physical nonetheless. 


The mind would simply be something directly correlated with what the chemical process does.  The mind couldn't escape or have any autonomy.  It is said that the mind would be like smoke coming out of a train, or a passenger taking ride in a boat.

19 minutes ago, Airbrush said:

My next question is, can something finite in mass (or size) expand to an infinite size?  And please explain for me without advanced math.  Thank you.

Yes, if it expands fast enough.

9 hours ago, Genady said:

The domain of the function 11−t excludes 1 , as the domain of the function 1x excludes 0 :

(Domain of a function - Wikipedia) 

From Division by zero - Wikipedia

Extended real line[edit]

The extended real number line is obtained from the real number system  by adding two infinity elements:  and  read as "positive infinity" and "negative infinity" respectively, which are treated as actual numbers. By adjoining the elements  and  to  it enables a formulation of a "limit at infinity" that works like a limit at any real number. When dealing with both positive and negative extended real numbers, the expression  is usually left undefined. However, in contexts where only non-negative values are considered, it is often convenient to define .

3 hours ago, Genady said:

Mathematically speaking, it cannot reach infinite size, but it rather increases unboundedly as t→1  from below. At t=1 , the formula is undetermined: mathematically speaking, 10 is undefined.

But that's what we were taught in high school.  It turns out there are ways it is allowed.  

15 minutes ago, Genady said:

I did not miss that point, but my counterpoint was that it does not work mathematically. It reaches the infinity and momentarily changes to −∞ and stays negative after that. Distance cannot do this.

P.S. You want the size to reach infinity and to stay infinite. Try another formula.

Okay, now I am certain you missed the point.  I will tell you it a second time.  The universe can reach infinite size in a finite amount of time, mathematically speaking. 

P.S. Try to understand the point that the poster is trying to make instead of looking for an irrelevant issue that only sidetracks the discussion.  Don't worry, you are by far not only the one that does this on discussion forums like this one.

33 minutes ago, Genady said:

and becomes negative after that.

I think you missed the point.  I was trying to show how you can reach infinite size in a finite amount of time, whatever the formula has to be to reach 14 billion years.

On 11/25/2023 at 10:55 AM, Airbrush said:

We always hear that the big bang started from a tiny point, smaller than a proton, that experienced cosmic inflation and expanded many times the speed of light for a tiny fraction of a second.  Oh, I see, that was only the observable portion of the entire universe.  Considering that anything finite can never expand to an infinite size, does that not indicate that the region of the universe we live in is probably not indicative of our universe out to a distance of, for example, a googol light years?  Or Graham's number of light years?  It would appear that our universe probably has a finite size.  Or maybe it has reached infinity through some means we don't understand?  Was the beginning of the entire universe not a tiny point, smaller than a proton, but for the universe to be infinite in size, the beginning had to be infinite in size, which doesn't make

Why would it have had to be infinity in the beginning g?  If distance is a function of time, the equation 1/(1 - t) reaches infinity in 1 second.  I don't know if something like this rate of expansion is considered in mainstream physics, but it at least works mathematically.

5 hours ago, joigus said:

It can't happen. If a particle is at rest for just the shortest of times, the uncertainty in position becomes zero for just that time, so the uncertainty in momentum goes to infinity in every direction, and the particle immediately flies away. 

Isn't there always a frame where the particle is at rest (unless it is going the speed of light of course).

10 minutes ago, Luc Turpin said:

So, my imperfect understanding of it is this: consciousness is not needed to explain quantum mechanics. It, (QM) stands alone not needing consciousness. Its not part of it, so says most physicists. However, Penrose uses quantum mechanics to explain consciousness. I too feel that there might be a role for consciousness in QM, but this statement has not validity, because it is just a hunch and that does not count for anything.

 

Okay, I understand now.  Physicists can be a funny bunch (they are very smart; don't get me wrong).  But they seem to automatically take on a hardcore physicalism approach - at first!  I notice that the physicists that are well versed in philosophy too, have a much much more "open" approach to mind-body possibilities.  

7 minutes ago, Luc Turpin said:

My position at this stage, based on evidence, is that brains are not always needed to produce consciousness, but living matter is required.  My position could move backward or forward depending on evidence.

Well that seems like a very reasonable position. 

My position takes it a step further which is just based on my reasoning.  I think that it is more likely than not that the consciousness is more fundamental to matter than a living organism (yes I am a *type* panpsychist).  Unfortunately, I don't think we will ever be able to gather evidence of whether or not something is consciousness (has a mind).  I just don't see how we could detect something so evasive like a conscious mind.

2 hours ago, DrmDoc said:

My view of consciousness regards the most basic form of awareness as suggested by an organism's observed behavioral reactions.  Truly, we cannot determine whether an organism has even the smallest measure of consciousness without observable behavioral responses to its environment.  From my perspective, consciousness doesn't necessarily confer intelligence.  Intelligence is a subjective measure based on observable behaviors suggesting a thought process and having a thought process is exclusive to having a mind.  A mind, from my view, is that mental matrix arising from brain function that give rise to behaviors we perceive as thought and intelligent.  Nevertheless, I agree that consciousness in its most basic form is not exclusive to having a brain; however, for human equivalent consciousness, some form of brain or neural function is essential. 

Thought, in my view, arises from a matrix of biological processes within the brain involving a recipracol metabolic system of checks and balances (homeostasis).  I would prefer not to speak too much about this system as it's basic implications are most unsettling.  However, if we agree that basic consciousness is the progenitor of the mind and the mind the progenitor of thought, then none of these are observable without responses to stimuli. Indeed, there are responses to stimuli that appear mindless, which we confer as instinct; however, mindful responses confer a thought process, which is a quality that appears contrary to instinctive and reactive behaviors.  If the behaviors we observe in other living things are contrary to those we confer as instinctive, then it's most likely that their behaviors doesn't confer thinking.  But most living things are complex and function through a combination of instinct and thought.  A bird, for example, may be instinctively driven to build a nest while its seemingly thoughtful behaviors in choosing the materials to build that nest suggest otherwise--indeed, there is more than mindless reactiveness occurring.

In the early days of my study of the dreaming brain, the RAS was a focal in understanding of the sleep process and its association with atonia amid that process.  IMO, there's so little regards given in science to the brainstem and particularly its crown, the thalamus.  There is more than considerable research suggesting that thalamic function is sufficient to viably sustain life in the absence of major cortical structures.

You seem well versed on this subject.  I am interested to know if you are a epiphenomenalist (just means that the mind is only a property of brain functions and has no influence at all) or something else.   

4 hours ago, Luc Turpin said:

I too sense (not very scientific) that QM may have something to do about it, but, again, most physicists, I believe, do not. Most that do appear to be on the fringe of QM. One noted exception is Roger Penrose a mathematician, mathematical physicist, philosopher of science and Nobel Laureate. He does not involve consciousness to explain quantum mechanics, but rather tries to involve quantum mechanics to explain consciousness. E.g. uses the theory to explain consciousness, but does not say that it is part of it. 

 

I don't know what you mean when you say that it is not "part of it".