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Author Topic: Is infinity an illusion?  (Read 68329 times)

Offline Bill S

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Re: Is infinity an illusion?
« Reply #275 on: 11/10/2013 23:11:31 »
Quote from: JP
there isn't a reason to assume the universe didn't start off infinite

I’m delighted that you mentioned that, JP, its something I have come across in discussions on other forums.  I always ask for an explanation as to how some infinite object can come into existence; especially something that is often described as infinitesimally small.

Those who don’t just ignore the question have so far failed to produce a convincing answer.  Perhaps its just that I don’t understand the answers.  However, I usually find that your explanations make sense, so perhaps I’m in luck at last.
 

Offline JP

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Re: Is infinity an illusion?
« Reply #276 on: 12/10/2013 03:53:01 »
I don't think you'll like the answer.  ;)  There's a couple of parts to it, and I'm not an expert--someone who deals with "theories of everything" could probably tell you more, but I don't think there's someone like that on this forum. 

The first part is that you're basically asking for the answer to "how does a universe come to be?"  The problem with that is that there are very few ways to approach that question--all our scientific measurements take place within the universe and all our models deal with measurements within the universe.  One hope is that if we can come up with a theory that describes everything in the universe in simple terms (string theory being one candidate) that it would tell us about the allowed structure of the universe or universes and perhaps how they came to be.  String theory does indeed do this to an extent--predicting that an infinite number of universes exist all with different parameters.  (I don't know what it says about finite vs. infinite universes, but if I had to guess, it would allow both.)  Is this useful?  Is this even science?  I'm doubtful.  It may explain our universe very well, but can we ever test its predictions about other universes? 

The second part is to ask yourself why you prefer a finite universe or why you feel an infinite universe is impossible and check if there's a scientific reason to think so.  The usual reason is that nothing we can measure of starts off infinite, so why should the universe?  And everything that we know of that starts off finite and grows does so at a finite rate, and so can never become infinite in any of our measurements.  That's a logical reason to say that nothing can be infinite, including the universe.  That would also be an erroneous conclusion.  Why?  Everything we measure is within the universe.  In fact, everything we measure is within the observable universe, which is certainly smaller than the entire universe.  So we can apply this logic only to the class of objects "things within the (observable) universe."  Since that class does not include the universe itself, it's flawed reasoning to try to apply these limitations to the whole universe.  This doesn't help us come up with a plausible reason why the universe could be infinite, but it demonstrates that there's no plausible reason why it couldn't be and that the usual arguments are flawed.

So what is a model that might work?  One that I've heard of and that makes some sense to me is that all possible universes at all possible times exist as a set of states.  We say there is time and space because our brains and bodies work in a certain way to put ordering to these states.  We process information by moving "forward" in time (converting energy to entropy) so we see an arrow of time.  Various parameters of our particular universe define what we can interact with as we move in time, so we experience causality, etc. 

So what might we see if we could step outside our human brains and look at the set of states making up our "universe"?  It might just be that each universe is completely generated from a small set of parameters.  From those parameters, you can imagine generating an entire set of states of the universe, which when placed in order by things living within the universe, form the entire universe from start to finish.  From the outside however, you'd just have a list of parameter values for each potential universe from which you can generate an infinite set of states.  Some of these values might make observers within the universe measure it as infinite and some might make them measure it as finite.

One last comment: theories of everything are pretty far out there and I take them with a huge grain of salt--I view most of them as philosophy with a lot of math rather than physics, since they don't make testable predictions.  They also veer alarmingly close to what we see in New Theories where promoters of crackpot ideas will say "you have to free your mind for a paradigm shift" or somesuch nonsense.  But the important difference is that while you do have to be willing to consider "really out there ideas" when thinking about the origin of the universe, all ideas are going to be about as far out there, since they all deal with the creation of the universe, which is something we don't have a good way of scientifically probing.  As I mentioned at the start, you have just as much scientific evidence and justification to back up your "common sense" ideas as you do to back up the idea that the universe started off infinite or even that there's an infinite number of universes, some of which are finite and some of which are infinite.
 

Offline Pmb

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Re: Is infinity an illusion?
« Reply #277 on: 12/10/2013 07:05:03 »
Quote from: JP
there isn't a reason to assume the universe didn't start off infinite

I’m delighted that you mentioned that, JP, its something I have come across in discussions on other forums.  I always ask for an explanation as to how some infinite object can come into existence; especially something that is often described as infinitesimally small.

Those who don’t just ignore the question have so far failed to produce a convincing answer.  Perhaps its just that I don’t understand the answers.  However, I usually find that your explanations make sense, so perhaps I’m in luck at last.

This would make an excellant FAQ question. Don't you think?
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #278 on: 12/10/2013 14:03:45 »
JP, thanks for that response.  There's a lot there to think about, and I shall have to come back to it a few times to get the most out of it.

I may have missed it, but so far I have not found the much sought after answer to the question: How can something that did not previously exist come into being in an infinite state?

There are other things to come back to when time permits, but, for now, thanks again.
 

lean bean

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Re: Is infinity an illusion?
« Reply #279 on: 12/10/2013 15:57:58 »
Quote from: JP
there isn't a reason to assume the universe didn't start off infinite
I always ask for an explanation as to how some infinite object can come into existence; especially something that is often described as infinitesimally small.
Bill, I don’t know why you assume the universe was  infinitesimally small to begin with?  Just because the equations of running the observable universe backwards ends with those equations breaking down/singularity, Why do you assume that means the whole of the universe was once infinitesimally small?

I may have missed it, but so far I have not found the much sought after answer to the question: How can something that did not previously exist come into being in an infinite state?
Answering from what JP has already said, the processes of the origins of a universe or universes maybe a unique process with no comparison processes/laws within a universe. Smacks of philosophy... but I like it.
How can something that did not previously exist come into being in an infinite state?
the bb was the beginning of a determinable space and time, and as such, could be a regional happening following from the density of matter/energy within that region. In other words, our understanding of spacetime (determinable) may be a regional property not happening at the 'same' time everywhere in an infinite universe.
« Last Edit: 12/10/2013 16:24:53 by lean bean »
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #280 on: 12/10/2013 16:18:55 »
Quote from: LB
Bill, I don’t know why you assume the universe was  infinitesimally small to begin with?

That is not an assumption at which I just arrived.  As a hitch-hiker, I have to place some reliance on what scientists say when they write books for the edification of non-scientists.

Quote
Answering from what JP has already said, the processes of the origins of a universe or universes maybe a unique process with no comparison processes/laws within a universe.

Isn't that a bit like saying "God created the Universe, so there is no point in even thinking beyond that"?
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #281 on: 12/10/2013 16:35:09 »
Quote from: JP
So what is a model that might work?  One that I've heard of and that makes some sense to me is that all possible universes at all possible times exist as a set of states.  We say there is time and space because our brains and bodies work in a certain way to put ordering to these states.  We process information by moving "forward" in time (converting energy to entropy) so we see an arrow of time.  Various parameters of our particular universe define what we can interact with as we move in time, so we experience causality, etc.


Apart, perhaps, from some of Barbour’s work, this is the closest I have seen to the basic outline of what I have in mind.  However, it does seem to make one assumption that I would consider has an alternative.  It appears to assume that existence necessarily takes the form of universes.  Such an assumption robs the idea of much of its potential explanatory power.
 

lean bean

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Re: Is infinity an illusion?
« Reply #282 on: 12/10/2013 16:47:47 »
Cor Bill, that was quick.
Quote from: LB
Bill, I don’t know why you assume the universe was  infinitesimally small to begin with?
That is not an assumption at which I just arrived.  As a hitch-hiker, I have to place some reliance on what scientists say when they write books for the edification of non-scientists.
Where does it say for sure the 'whole' universe was infinitesimally small at 'a' beginning. Remember the bb was a beginning of determinable space and time. That could be a regional state (because of mass/energy density) in an infinite universe.
Quote
Isn't that a bit like saying "God created the Universe, so there is no point in even thinking beyond that"?
True, but if you want to go beyond, you have to remember things that can't happen within our universe can happen with 'objects' like universes, faster than light inflation for instance.

« Last Edit: 12/10/2013 16:54:58 by lean bean »
 

Offline dlorde

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Re: Is infinity an illusion?
« Reply #283 on: 13/10/2013 13:17:52 »
dlorde, as fascinating as this discussion is, I think we should stop now because we are way off topic and must be trying the patience of the mods.
As I said, if you wish to continue it, start a new thread :)
 

Offline dlorde

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Re: Is infinity an illusion?
« Reply #284 on: 13/10/2013 13:32:06 »
Quote from: LB
Bill, I don’t know why you assume the universe was  infinitesimally small to begin with?
That is not an assumption at which I just arrived.  As a hitch-hiker, I have to place some reliance on what scientists say when they write books for the edification of non-scientists.
I'd be surprised if a knowledgeable scientist would describe it in those terms. I suspect it's a misinterpretation or misunderstanding. The 'initial' (earliest we can describe) state is generally described as very hot and very dense and expanding very rapidly. Intuition would suggest that the currently observable universe would then have been infinitesimally small, but the observable universe is (almost certainly) not the whole universe, so could conceivably have started as an infinitesimally small part of an infinitely large, hot, dense, expanding universe.
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #285 on: 13/10/2013 18:49:37 »
Quote from: LB
Where does it say for sure the 'whole' universe was infinitesimally small at 'a' beginning. Remember the bb was a beginning of determinable space and time.


 Once again we run into difficulties arising from the use of “universe” in various ways.  This is why I prefer to reserve “Universe” what we can observe, or to which we can reasonably extrapolate our observations; and use “cosmos” for the bigger picture.

Quote
That could be a regional state (because of mass/energy density) in an infinite universe.

Or a finite Universe in an infinite cosmos.  It seems very much to be a matter of terminology.
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #286 on: 13/10/2013 19:00:44 »
Quote from: dlorde
Intuition would suggest that the currently observable universe would then have been infinitesimally small, but the observable universe is (almost certainly) not the whole universe, so could conceivably have started as an infinitesimally small part of an infinitely large, hot, dense, expanding universe.

To avoid falling into the “misinterpretation trap” I must ask for more clarification before responding to this. 

Do you mean that the “infinitely large, hot, dense, expanding universe” came into being at the BB, or was it just the “infinitesimally small part”?

If the former, what is the relationship/difference between the infinite part and the infinitesimally small bit?

If the latter, is the infinitely large part eternal?

 What are your grounds for thinking that the infinitely large part is expanding?
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #287 on: 13/10/2013 19:30:04 »
JP, although this is a (part) response to your last post, it is very general, so I am not starting with a quote. 

I am aware that intuition is a poor guide where modern scientific concepts are concerned, but if an idea seemed to provide some insight into aspects that were poorly understood, or not really understood at all, might it not be worth investigating? 

I am certainly not saying “Look, I have the answer”.  I lack both the scientific background and the maths to make such a claim, but I have some (crackpot?) ideas in my head.  Obviously, it would be gratifying if they turned out to be well founded, but I’m not really that naïve, so having them laid to rest would be quite acceptable, and much more likely.

Basically, the idea is that a re-think of the concept of infinity could explain much of the weirdness of quantum theory.  That would include things like wave/particle duality, the ability of quons (sensu Herbert) to appear to be in more than one place at a time, entanglement and action at a distance.     
 

Offline Pmb

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Re: Is infinity an illusion?
« Reply #288 on: 13/10/2013 22:28:32 »
Quote from: lean bean
Bill, I don't know why you assume the universe was  infinitesimally small to begin with?  Just because the equations of running the observable universe backwards ends with those equations breaking down/singularity, Why do you assume that means the whole of the universe was once infinitesimally small?
That's what modern cosmology says so its no surprise that Bill accepts that as it is. I do. Cosmologists and most physicists know that the big bang theory is an extrapolation running back wards. But it works that way. Only when we run things back to 10-34s or so do we see things working out to what we observe today.
« Last Edit: 13/10/2013 22:30:22 by Pmb »
 

Offline Pmb

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Re: Is infinity an illusion?
« Reply #289 on: 13/10/2013 22:42:02 »
Quote from: webplodder
But what caused the BB?
Nobody knows.
 

Offline dlorde

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Re: Is infinity an illusion?
« Reply #290 on: 14/10/2013 00:30:28 »
Do you mean that the “infinitely large, hot, dense, expanding universe” came into being at the BB, or was it just the “infinitesimally small part”?
As far as I'm aware, it's not known whether anything 'came into being' at the BB, just that the earliest state we can infer was a hot, dense, expanding one. This may have been finite or infinite in extent. If it was infinite, the observable universe would be a part of it.

Quote
If the former, what is the relationship/difference between the infinite part and the infinitesimally small bit?
Not sure I understand what you're asking - it would be the same as for any finite part of something infinite. 

Quote
If the latter, is the infinitely large part eternal?
I have no idea. Pace concerns about the meaning of eternity and whether time began at the BB, how could we possibly know or guess? (and what difference would it make?).

Quote
What are your grounds for thinking that the infinitely large part is expanding?
The Cosmological Principle (homogeneity) & Ockham's Razor. The observable universe is expanding; if it is part of a larger universe, the simplest assumption is that it too is expanding. Otherwise we'd have to find some explanation for why the observable universe is not representative of the greater whole.
 

Offline Pmb

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Re: Is infinity an illusion?
« Reply #291 on: 14/10/2013 17:23:18 »
Quote from: dlorde
Intuition would suggest that the currently observable universe would then have been infinitesimally small, but the observable universe is (almost certainly) not the whole universe, so could conceivably have started as an infinitesimally small part of an infinitely large, hot, dense, expanding universe.

To avoid falling into the “misinterpretation trap” I must ask for more clarification before responding to this. 

Do you mean that the “infinitely large, hot, dense, expanding universe” came into being at the BB, or was it just the “infinitesimally small part”?

If the former, what is the relationship/difference between the infinite part and the infinitesimally small bit?

If the latter, is the infinitely large part eternal?

 What are your grounds for thinking that the infinitely large part is expanding?

Bill, You might find some of the answers to your questions here
http://superstringtheory.com/cosmo/
 

lean bean

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Re: Is infinity an illusion?
« Reply #292 on: 14/10/2013 17:25:08 »
Quote from: LB
Where does it say for sure the 'whole' universe was infinitesimally small at 'a' beginning. Remember the bb was a beginning of determinable space and time.

 Once again we run into difficulties arising from the use of “universe” in various ways.  This is why I prefer to reserve “Universe” what we can observe, or to which we can reasonably extrapolate our observations; and use “cosmos” for the bigger picture.

I prefer to reserve "observable universe" to that which we observe... it's in the name :)  If I have been using the term infinite universe, then I would guess that's what you call the Cosmos and for what we can 'conjecture' about ,as you say, the bigger picture...Mulitverse ideas and infinite Universe.

bill
Quote
Or a finite Universe in an infinite cosmos.  It seems very much to be a matter of terminology.
Yes, our observable universe as part of a larger infinite Universe.
Quote from: lean bean
Bill, I don't know why you assume the universe was  infinitesimally small to begin with?  Just because the equations of running the observable universe backwards ends with those equations breaking down/singularity, Why do you assume that means the whole of the universe was once infinitesimally small?

That's what modern cosmology says so its no surprise that Bill accepts that as it is. I do.
So who is it  coming up with ideas like mulitverse and eternal inflationary Universe, If not cosmologists ?  And can you rule out the idea of an infinite Universe?
 
Quote
Cosmologists and most physicists know that the big bang theory is an extrapolation running back wards. But it works that way. Only when we run things back to 10-34s or so do we see things working out to what we observe today.
Yes, that’s why I said a determinable space and time began at the bb, If you want to be precise then 10-34s after the bb a determinable space and time arose.
« Last Edit: 14/10/2013 17:29:53 by lean bean »
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #293 on: 14/10/2013 21:23:36 »
Quote from: LB
you have to remember things that can't happen within our universe can happen with 'objects' like universes

Do you mean there may be other universes in which things could happen that cannot happen in our Universe, or do you have concrete examples?
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #294 on: 14/10/2013 21:29:00 »
Quote from: dlorde
The Cosmological Principle (homogeneity) & Ockham's Razor. The observable universe is expanding; if it is part of a larger universe, the simplest assumption is that it too is expanding. Otherwise we'd have to find some explanation for why the observable universe is not representative of the greater whole.

Delightfully put.  I hope you won't mind if I hang on to that, and quote it later.  :) 
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #295 on: 14/10/2013 21:44:50 »
Quote from: LB
This is why I prefer to reserve “Universe” what we can observe, or to which we can reasonably extrapolate our observations

What I said was:
"This is why I prefer to reserve “Universe” what we can observe, or to which we can reasonably extrapolate our observations"
Obviously there should be "for" between "Universe" and what, but even allowing for any confusion that might have arisen from that omission, your addition of bold type is tantamount to miss-quoting me. 

"Universe", as I defined it, and "observable universe" are not quite synonymous.

I guess discussions would be less fun if we all used a rigidly defined terminology.  :)
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #296 on: 14/10/2013 22:55:16 »
LB, its not going anywhere other than to note that "the Universe we can observe, or to which we can reasonably extrapolate our observations" is not quite the same as the "observable universe". Just an observation.  :)
 

Offline Bill S

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Re: Is infinity an illusion?
« Reply #297 on: 14/10/2013 23:00:17 »
Quote from: LB
Cor Bill, that was quick.

I'm working on getting responses in before the questions are posted, but my time machine is being difficult.
 

lean bean

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Re: Is infinity an illusion?
« Reply #298 on: 14/10/2013 23:11:54 »
LB, its not going anywhere other than to note that "the Universe we can observe, or to which we can reasonably extrapolate our observations" is not quite the same as the "observable universe". Just an observation.  :)
Bill, my last post. I can't get the quote boxes looking right?? It seems the whole post is from you..I have given up trying to get it right..

Quote
LB, its not going anywhere other than to note that "the Universe we can observe, or to which we can reasonably extrapolate our observations" is not quite the same as the "observable universe". Just an observation.  :)
what's not going where? I'm usually asleep by now...I have had me milk and biscuits and teddy's tucked in

Ps late add on. if you mean the galaxy is going nowhere, yes I know it's expanding spacetime taking it for a ride. did you mean something esle?

« Last Edit: 14/10/2013 23:26:32 by lean bean »
 

Offline dlorde

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Re: Is infinity an illusion?
« Reply #299 on: 14/10/2013 23:46:54 »
Delightfully put.  I hope you won't mind if I hang on to that, and quote it later.  :) 
Thank you; you're welcome to quote it any time.
 

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Re: Is infinity an illusion?
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