Falsification of eternal inflation

[Chalnoth]

Well, obviously this discussion is going nowhere. You absolutely refuse to pay attention.

The point I have been making all along is that uniqueness is an assumption, where as proliferation is not. Once you have fully-defined something, you automatically get more of that sort of thing unless you explicitly exclude more than one. I wash my hands of further discussion, because you absolutely refuse to accept this very simple point.

 

[Calrid]

Well, obviously this discussion is going nowhere. You absolutely refuse to pay attention.

The point I have been making all along is that uniqueness is an assumption, where as proliferation is not. Once you have fully-defined something, you automatically get more of that sort of thing unless you explicitly exclude more than one. I wash my hands of further discussion, because you absolutely refuse to accept this very simple point.

No I am I just don't get how proliferation is not and you have done nothing to explain that.

I refuse to accept it because it is nonsense, you insist that more than one universe is the standard on no basis whatsoever.

Fine storm off but your philosophy here is just plain wrong. Maybe you should contact Smolin et al and explain in depth how they are just wrong if you feel this strongly. I think they will probably just ignore you though if you insist on axioms that are not robust and cannot be accepted as a matter of course.

Reality doesn't conform to linguistic form it is linguistic form that conforms to reality, if it doesn't this is not science it is sophistry.

Simply any trite phrase (that itself can be seen as difficult to precisely manage in definite terms) like this has no bearing on the evidence that will reveal itself and it never will. The accuracy of anything cannot be established by any of what you have said and no one has and hopefully ever will ever of claimed it can.

Let me put it even more simply: reality does not give a crap what you think or for opinions.

You might not like that but this is the philosophy of science, the rules are slightly different from the philosophy of general practice. Hence why science is a discreet area of thought from philosophy and religion.

 

[Fra]

Hello, I just stumbled upon this thread, I didn't follow it at all, so forgive me for inserting a random comment.

The question is what do we mean by multiple universes?

If the objection is against a unique universe, then flexibility can exist also in the evolving universe where you have evolving laws, a little bit in line with Smolins thinking. So there is still no uniqueness as it's constantly evolving.

Just because you reject the notion of multiple, non observable universes, doesn't mean you assume uniqueness. I don't.

I think all necessary flexiblity can be accounted for by evolution of law within the universe we live in.

So we rephrase what calnoth said
"that uniqueness is an assumption, where as proliferation is not"

this is very close to this

"assuming fixed eternal laws is an assumption, but allowing for evolution is not"

Paradoxally this is pretty much the argument Smoling uses to REJECT the multiverse idea.

Ie. just because the universe evolves, and laws change, doesn't mean there is a whole ensemble of different universes. It could well be the same one that just evolves. The latter seems to contain less assumtpions that assuming some state space of possible universes that can't be described anyway. It's the existence of unobservable ensembles of different universes that smolin object to.

His argument is never that the one universe is unique, or having static laws.

There is a thine line between "proliferation" and "evolution", isn't it?

/Fredrik

 

[Chalnoth]

Hello, I just stumbled upon this thread, I didn't follow it at all, so forgive me for inserting a random comment.

The question is what do we mean by multiple universes?

If the objection is against a unique universe, then flexibility can exist also in the evolving universe where you have evolving laws, a little bit in line with Smolins thinking. So there is still no uniqueness as it's constantly evolving.

Just because you reject the notion of multiple, non observable universes, doesn't mean you assume uniqueness. I don't.

I think all necessary flexiblity can be accounted for by evolution of law within the universe we live in.

So we rephrase what calnoth said
"that uniqueness is an assumption, where as proliferation is not"

this is very close to this

"assuming fixed eternal laws is an assumption, but allowing for evolution is not"

Paradoxally this is pretty much the argument Smoling uses to REJECT the multiverse idea.

Ie. just because the universe evolves, and laws change, doesn't mean there is a whole ensemble of different universes. It could well be the same one that just evolves. The latter seems to contain less assumtpions that assuming some state space of possible universes that can't be described anyway. It's the existence of unobservable ensembles of different universes that smolin object to.

His argument is never that the one universe is unique, or having static laws.

There is a thine line between "proliferation" and "evolution", isn't it?

/Fredrik

I don't see how that makes a difference. You'd just be adding the assumption that there is only one unbroken chain of universes, instead of adding the assumption that the birth of a universe happens only once. It's still an added assumption.

 

[Fra]

I don't see how that makes a difference. You'd just be adding the assumption that there is only one unbroken chain of universes, instead of adding the assumption that the birth of a universe happens only once. It's still an added assumption.

You seem to focus on the chain, rather than each step I think this is the point of disagreement.

There is no objective expectation of this chain. One can even say that the chain is broken or recreated at each instant of time in evolution.

As I see it, there is indeeed an "minimum assumption argument" motivating the evolutionary picture, in the very sense that evolution takes one step at a time, guided by the current expectations. But each step is constantly updated as feedback is arrived.

If we consider from the perspective of rational inference and learning (science).

I think it would be completely irrational, to expect that a systems actions at any instant of time or evolution, would depend on anything else than it's current expectation/state. This is to say that the minimally speculative action (way of placing ets) is the evolutionary one.

My issue with multiverse thinking is not that it's impossible that there are worlds beyond this where there is stuff that is causally isolated from me. OF course that's sort of posisble. But the question is in what sense is it rational to list possibilities, to which my rational action is invariant anway?

So I am definitely not BANNING or excluding possbilities, all I'm suggesting is that it's irrational to suggest that decision problems in this universe should have to account for completely imaginary possibilities. I find that irrational; and thus speculative in the sense of pondering about possibilities that make no difference.

So, I care only about the universe I live in and see, not because it's the only logical possibility, but because it's the only rational choice. (or so goes my reasoning)

/Fredrik

 

[Chalnoth]

You seem to focus on the chain, rather than each step I think this is the point of disagreement.

There is no objective expectation of this chain. One can even say that the chain is broken or recreated at each instant of time in evolution.

As I see it, there is indeeed an "minimum assumption argument" motivating the evolutionary picture, in the very sense that evolution takes one step at a time, guided by the current expectations. But each step is constantly updated as feedback is arrived.

If we consider from the perspective of rational inference and learning (science).

I think it would be completely irrational, to expect that a systems actions at any instant of time or evolution, would depend on anything else than it's current expectation/state. This is to say that the minimally speculative action (way of placing ets) is the evolutionary one.

My issue with multiverse thinking is not that it's impossible that there are worlds beyond this where there is stuff that is causally isolated from me. OF course that's sort of posisble. But the question is in what sense is it rational to list possibilities, to which my rational action is invariant anway?

So I am definitely not BANNING or excluding possbilities, all I'm suggesting is that it's irrational to suggest that decision problems in this universe should have to account for completely imaginary possibilities. I find that irrational; and thus speculative in the sense of pondering about possibilities that make no difference.

So, I care only about the universe I live in and see, not because it's the only logical possibility, but because it's the only rational choice. (or so goes my reasoning)

/Fredrik

I really don't understand what you're trying to say here. But the idea of some sort of unbroken chain of universes is incompatible, for instance, with a universe which expands forever, because such a universe would never become a new universe, in this view. And that view is at odds with the minimal cosmological model for our observable universe.

 

[Fra]

I really don't understand what you're trying to say here. But the idea of some sort of unbroken chain of universes is incompatible, for instance, with a universe which expands forever, because such a universe would never become a new universe, in this view. And that view is at odds with the minimal cosmological model for our observable universe.

I really don't understand your objection either. Maybe it's becaus I was the one jumping in the middle of this.

What I mean with an "evolving universe" in the sense of evolving law, is something much more weird than just expanding or inflating universe (like classical cosmology).

My view is rooted from an inference or measurement perspective, not classical cosmology. Each obsever merely has an observable window of something unkonwn. The idea that there is some gigantic system in where are these observers exists and evolve in a way that can be described from an inside observer does not make sense to me.

This is why, I suppose maybe it would make more sense to say that each observer constantly recreates the inferred IMAGE of the universe. Then these obsevers itneract and exert selective pressure on each other. There is no external or objective picture on this event chain. Rather each observer has it's own, incomplete and distorted picture of the event chain, and this is what determines the action of the observers in interaction with thet environment,

About the cosmological constant comment, it seems to me you are thinking of a classically expanding single universe. Then we'ere talking pass each other. My fault.

I am envisoning something different. I'm thinking an evolving relational model of observers that responds to other observers. This entire game has evolving rules. And the only descriptive contexts are inside observers, but none of them can make a complete (ie. classical deterministic description, not even probabilistic). This is why MAYBE it makes more sense to you do say that each inside observer deifnes one universe (one observer = one world). But that use of the world makes not sense to me as they obviously interact.

I assume that the the meaning of decomposing into universes is that they are not interacting?

So I replace the "multiple universes" that are interacting, with multiple observers that are interacting. And in this picture each observer encodes an inside view of the universe. And the laws of that universe is a matter of negotiation among constitutients. No needto spawn new universes in black holes to revise the laws(like smolins CNS). There are different options to explain the laws and paramters. (that said it's still en open question of course)

Edit: the advantage of this thinking, is that there is an idea that this can lead to prediuctions. In particular can it infer the action we usually hardcode (EH action, SM action) as a form of inferential "rational action" that simply follows from a principle of minimum speculation.

I'm sorry we're drifting away now but in explaining this has everything to do with at least my argument.
See some loose thinking here https://www.physicsforums.com/showthread.php?t=239414

/Fredrik

 

[Chronos]

The mulitverse concept is scientifically unappealing absent observational evidence favoring the existence of other universes. Reliance on intrinsically unobservable universes to explain 'fine tuning', or any other properties of our universe, is tantamount to theology.

 

[Fra]

The mulitverse concept is scientifically unappealing absent observational evidence favoring the existence of other universes. Reliance on intrinsically unobservable universes to explain 'fine tuning', or any other properties of our universe, is tantamount to theology.

I fully agree, this is exactly my point.

/Fredrik

 

[Calrid]

The mulitverse concept is scientifically unappealing absent observational evidence favoring the existence of other universes. Reliance on intrinsically unobservable universes to explain 'fine tuning', or any other properties of our universe, is tantamount to theology.

It's probably true that the opposite is the case also ie the insistence on a single universe as being the only set up because we just have no idea and nothing to base such a theological belief on.

It would be wise to be agnostic on this issue at least scientifically as both the theists and atheists aren't provably correct.

That was my point. Apparently this is contentious, why I still have no fricking clue.

 

[Chalnoth]

The mulitverse concept is scientifically unappealing absent observational evidence favoring the existence of other universes. Reliance on intrinsically unobservable universes to explain 'fine tuning', or any other properties of our universe, is tantamount to theology.

a) The logical consequences of the weak anthropic principle apply whether or not you have any sort of multiverse. The weak anthropic principle is only a selection effect, after all, and is undeniably true no matter what the overall universe looks like (it is a tautology, so it has to be true). It therefore has to be considered for any theory which is to talk about the origins of the physical laws we observe. To call the use of a logical tautology a strike against multiverse ideas is absurd in the extreme.
b) Multiverse ideas are strongly preferred from a wide number of directions, from particle physics, to inflation, to simple logic (as I mentioned earlier, if the physical process that started our region of space-time happened once, chances are it happened many times). The multiverse, therefore, should be the default, and people claiming that there is only one universe should have to explain why their assumption of uniqueness is accurate.

 

[Calrid]

a) The logical consequences of the weak anthropic principle apply whether or not you have any sort of multiverse. The weak anthropic principle is only a selection effect, after all, and is undeniably true no matter what the overall universe looks like (it is a tautology, so it has to be true). It therefore has to be considered for any theory which is to talk about the origins of the physical laws we observe. To call the use of a logical tautology a strike against multiverse ideas is absurd in the extreme.
b) Multiverse ideas are strongly preferred from a wide number of directions, from particle physics, to inflation, to simple logic (as I mentioned earlier, if the physical process that started our region of space-time happened once, chances are it happened many times). The multiverse, therefore, should be the default, and people claiming that there is only one universe should have to explain why their assumption of uniqueness is accurate.

Again this is riddled with assumptions that are purely philosophical.

You still don't get what I mean by reality not giving a crap what you think. These trite little rules and principles are subservient to evidence. No amount of principle or speculation will change that. You have no evidence so no matter what principle your highly biased mind wants to invent you cannot prove God does not exist or even that he is more or less likely to exist because of an opinion.

I fear you study physics not philosophy which is probably why your ontology is so weak.

I study physics, I just happen to be interested in the philosophy of physics too.

Your argument has axioms which not everyone will accept because they have no predictive power in this question.

I still don't see how the weak anthropic principle even matters here. There are either more than one universe or just one. Nothing rests on your predicates or axioms, they are just speculative arm waving.

How about instead of getting annoyed you start with explaining something simple like why they are preferred in particle physics. Its all very well stating that but I don't understand why that is the case? Hence I cannot agree with your axiom of choice, that the Universe has multiple versions by default.

Chances are that the universe happens many times, I agree we just differ on the number of Universes it takes or rather to be precise I disagree either concern as yet distinguishes itself. But for sake of argument let me take the position of being in favour of one universe theories: in yours all universes could of been created at the same time. In mine they were endlessly recycling. rather worryingly so far according to your occams razor God is wining the argument with just 1 once because it's simpler and requires no further assumptions than God did it. I'm not religious so you can see why this concerns me. :tongue:

 

[Chalnoth]

I study physics, I just happen to be interested in the philosophy of physics too.

Clearly not interested enough that you care to actually understand any of it.

How about instead of getting annoyed you start with explaining something simple like why they are preferred in particle physics.

Particle physics, as we know it today, depends on the concept of spontaneous symmetry breaking, which indicates that at least some parts of the way in which physics behaves at low energy depends critically upon the outcome of random events in the past history of our universe. The expectation is that far away, the outcomes of these random events will have been different, and therefore the low-energy laws of physics are likely to be different far away.

More speculative theories, such as supersymmetry, predict even more aspects of physical law depend on such spontaneous symmetry breaking events.

 

[Calrid]

Clearly not interested enough that you care to actually understand any of it.Particle physics, as we know it today, depends on the concept of spontaneous symmetry breaking, which indicates that at least some parts of the way in which physics behaves at low energy depends critically upon the outcome of random events in the past history of our universe. The expectation is that far away, the outcomes of these random events will have been different, and therefore the low-energy laws of physics are likely to be different far away.

More speculative theories, such as supersymmetry, predict even more aspects of physical law depend on such spontaneous symmetry breaking events.

That doesn't say why we need 1 universe or infinite or x universes. Does it, it doesn't relate to the weak anthropic principle at all. Smolins proposal caters for the observable evidence equally as well as the others that Susskind appears to prefer. Again the contentions with weak or strong anthropic principles only come about if we have just 1 universe ever. We don't so semantically they are identical. Eternal universes is on paper identical to infinite universes or multiple universes. They both contain the same potential number of universes we only differ on form. I still can't see how any of this makes any scientific impact without evidence. Actually why it makes any impact without evidence either particularly since this is where we stand now.

Clearly I am interested enough because unlike you I don't think this is an answered question in physics, where as you seem to be labouring under the delusion it is. That's not healthy, I can assure you it is not. The reason you do believe that can only because of biased teaching or biased assumptions on your part. you need to distinguish between the probabilities of both here. As far as I can see both have equal probability of being correct hence both are valid hypotheses.

Actually Smolin I think has some more whacky theories about black holes and universe creation so he appears to also have some universe within universe theories too, but I'm not savvy on these so I can't comment.

I'm not sure why you find the idea that there are still some great unanswered questions in physics disturbing or even controversial? It seems odd that you do?

I think what you need to do is relate the strong and weak anthropic principles to a particular theory then construct a reason why multiple universes is favoured over eternal but singular universes using each theory and giving points for and against for both using whatever symmetry parameters or particle elements you think are relevant. Good luck that is a PhD in itself. Probably more of philosophy of science than science but meh, it's all good.

CPT violations won't help you here either btw. I have already stated that entropy isn't reversable and yes also the weak force isn't if anything that helps both theories not just one. I don't see the issue there, I don't also see why distance matters or you use the term far away as if somehow that is relevant?

SuSy is of course hypothetical, but relating theory to hypotheticals or hypotheticals to hypotheticals still produce hypotheticals I'm afraid.

Purely inductive reasoning will tell us nothing about reality unless it has a soupçon of deductive reasoning or what we like to call evidence based theory.

 

[Chalnoth]

That doesn't say why we need 1 universe or infinite universes. Does it, it doesn't relate to the weak anthropic principle at all.

You asked a question, I gave an answer.

But yes, it absolutely does relate to the weak anthropic principle, because any time we're talking about the variability of natural law, the weak anthropic principle has a part to play as a selection effect in determining how we interpret how the theory relates to observation. Now, it's usually very very difficult to carefully make use of the selection effect that is the weak anthropic principle, but it's still something that has to be done to interpret such ideas.

Again the contentions with weak or strong anthropic principles only come about if we have just 1 universe ever. We don't so semantically they are identical.

What? The strong anthropic principle states that the laws of the universe must be such that life is possible. It's an absolute statement about the nature of physical law with no justification whatsoever. The weak anthropic principle, on the other hand, is purely a tautology: observers can only observe a universe where they can possibly exist.

Clearly I am interested enough because unlike you I don't think this is an answered question in physics, where as you seem to be labouring under the illusion it is. That's not healthy I can assure you it is not.

Answered? I never said that. I said that the default assumption should be proliferation. There's a difference.

It is heartening, of course, that evidence from cosmology and high energy physics appears to provide tacit support for the idea of a prolific universe, an idea which can be arrived at through very simple logical argument: it is mathematically more difficult to define a single element of a set than the whole set.

You, on the other hand, seem to be laboring under the delusion that old, unevidenced ideas about the universe should be given preference just because they're old ideas. I'm saying that an idea should be judged based upon its merits, not the number of people who have believed it in the past. And before even looking at the evidence, the broad, general concept of a multiverse is far far more likely than a single universe (that is, the entire universe being a simple, causal extension of our observable region with no change in physical law from place to place). The questions that remain are exactly how prolific is the universe, how much does the character of physical law vary, and, perhaps most importantly, which specific multiverse proposals, if any, are accurate.

 

[Calrid]

You asked a question, I gave an answer.

But yes, it absolutely does relate to the weak anthropic principle, because any time we're talking about the variability of natural law, the weak anthropic principle has a part to play as a selection effect in determining how we interpret how the theory relates to observation. Now, it's usually very very difficult to carefully make use of the selection effect that is the weak anthropic principle, but it's still something that has to be done to interpret such ideas.What? The strong anthropic principle states that the laws of the universe must be such that life is possible. It's an absolute statement about the nature of physical law with no justification whatsoever. The weak anthropic principle, on the other hand, is purely a tautology: observers can only observe a universe where they can possibly exist.

Neither say anything about reality though do they, they just say that certain ideas like God done it seem more unlikely than there are an infinite number of possible universes eternal or outside of each other.

Actually weak or strong anthropic principles are both tautologies, just in different ways.

They both assume the antecedent. It's how they go about it that is interesting.

I find the idea that you think tautologies are logically consistent rather odd though. This kind of tells me that you're relying on conclusions that are based on conclusions. Which is bad philosophy.

This question is also up in the air too, because the axioms cannot find distinction. So it highlights why we are still at the philosophy stage.

Answered? I never said that. I said that the default assumption should be proliferation. There's a difference.

Why though?

You keep stating this but it is hedged with non sequiturs. Am I to take it it is true because you say so or can you relate your idea to reality in a deductive fashion that proves that one "theory" is preferred?

It is heartening, of course, that evidence from cosmology and high energy physics appears to provide tacit support for the idea of a prolific universe, an idea which can be arrived at through very simple logical argument: it is mathematically more difficult to define a single element of a set than the whole set.

Maths does not denote science, you have been infected by the verve of String Theorists. What denotes a theory is evidence not arm waving.

Set theory is riddled with its own inconsistencies, such that its difficult to really make a completely coherent set theory without applying axioms that are not reliant on proofs by definition. You will get no help there either. The philosophy of maths is a completely different subject than the philosophy of science. One which you would do well to avoid comparing.

You can take my word on this as well, nothing will get a thread closed faster than challenging mathematical axioms or using them to explain scientific ones.

I'm afraid maths underlies reality not the other way around or vise-a-versa will not be indulged in a thread in this area of the forum so I'd avoid it.

Hell it would probably get locked in philosophy since everything always does.

This forum has a rather odd fear of philosophy no matter how interesting it is. But meh it is a science forum. There are plenty of places for arm waving. It just seems string theory is indulged being purely philosophical and other philosophical concerns are not so I question the standards here?

I was rather annoyed that a thread that moved into an area like NDEs which was being discussed on a scientific basis was closed, IMO it should of been moved to Skepticism & Debunking, hopefully it will be..? Or at least we can continue the debate there. Anyway beside the point.

You, on the other hand, seem to be laboring under the delusion that old, unevidenced ideas about the universe should be given preference just because they're old ideas. I'm saying that an idea should be judged based upon its merits, not the number of people who have believed it in the past. And before even looking at the evidence, the broad, general concept of a multiverse is far far more likely than a single universe (that is, the entire universe being a simple, causal extension of our observable region with no change in physical law from place to place). The questions that remain are exactly how prolific is the universe, how much does the character of physical law vary, and, perhaps most importantly, which specific multiverse proposals, if any, are accurate.

Old? Bounce theory is at the cutting edge? it's newer than Susskinds ideas or others. Another qualitative assumption that old is worse than new as well. You seem to like that. That's a philosophical maxim, it could be that the Big Bang endlessly recycling at heat death, an older idea is better than the big bounce.

Again if any are accurate has not been established in any way beyond mathematical masturbation, that is not science.

This is still deeply entrenched in philosophical debate, just like interpretations are; would you like to tell me which of the quantum interpretations is more likely to be true also?

 

[Fra]

I'll just note that the evolving law I referred to is not at all the same as the weak anthropic principle. The "observer" I'm talking about has nothing at all to do with biological or carbon based life. This is starting to sound like the misconception realists always make in QM, confusing observers with consciousness.

The antrophic principle has nothing to do with the evolution of law I'm envisioning.

The predictive value in the picture I suggested lies in the conjecture that all actions are rational. This means that the laws automatically negotiate the laws that sustain the observers. It does not mean that the laws of the universe are created first - by a constraint that it must support life. It rather mans that the form of life and the laws are related. The mechanism of evolution is small variation and selection by environement.

I think the environment and laws is NOT pre-tuned to support life at all as per antrophic arguments at all, the environment and the laws of the universe AND observers emerge together, because the environment consists of other obserers. And the laws of the universe are whatever the compoents negotiate. Those obsever that are inconsistent with the laws are never banned in any way - they are just unstable.

/Fredrik

 

[Calrid]

I'll just note that the evolving law I referred to is not at all the same as the weak anthropic principle. The "observer" I'm talking about has nothing at all to do with biological or carbon based life. This is starting to sound like the misconception realists always make in QM, confusing observers with consciousness.

The antrophic principle has nothing to do with the evolution of law I'm envisioning.

The predictive value in the picture I suggested lies in the conjecture that all actions are rational. This means that the laws automatically negotiate the laws that sustain the observers. It does not mean that the laws of the universe are created first - by a constraint that it must support life. It rather mans that the form of life and the laws are related. The mechanism of evolution is small variation and selection by environement.

I think the environment and laws is NOT pre-tuned to support life at all as per antrophic arguments at all, the environment and the laws of the universe AND observers emerge together, because the environment consists of other obserers. And the laws of the universe are whatever the compoents negotiate. Those obsever that are inconsistent with the laws are never banned in any way - they are just unstable.

/Fredrik

Let me some up: reality doesn't give a damn what you think.



I agree anthropic principle is a red herring in discussions like this, it always muddies what is a simple issue does something happen like this and if so how? Consciousness issues always seem to devolve into why questions which are by their nature doomed to end in philosophy and ..?

Start from the most easy to prove assertion, consciousness has evolved in the universe, but don't use that consciousness as a basis for your ideas it is likely to come with all sorts of biases. They caused the problem in the first place with all that damned God stuff.

There may be a gas cloud of ionic particles arranged "organically" with sentience in the universe that finds our ruminations rather quaint and old fashioned.

 

[Chronos]

a) The logical consequences of the weak anthropic principle apply whether or not you have any sort of multiverse. The weak anthropic principle is only a selection effect, after all, and is undeniably true no matter what the overall universe looks like (it is a tautology, so it has to be true). It therefore has to be considered for any theory which is to talk about the origins of the physical laws we observe. To call the use of a logical tautology a strike against multiverse ideas is absurd in the extreme.
b) Multiverse ideas are strongly preferred from a wide number of directions, from particle physics, to inflation, to simple logic (as I mentioned earlier, if the physical process that started our region of space-time happened once, chances are it happened many times). The multiverse, therefore, should be the default, and people claiming that there is only one universe should have to explain why their assumption of uniqueness is accurate.

Perhaps you missed my point - where is the observational evidence? I like pink fairies as well as anyone, but, resist accepting them as reality without a picture of one in action.

 

[Chalnoth]

Perhaps you missed my point - where is the observational evidence? I like pink fairies as well as anyone, but, resist accepting them as reality without a picture of one in action.

My entire point here is that there isn't evidence for a unique universe, or for a multiverse. And we shouldn't just think that a multiverse requires evidence when a unique universe does not merely because people have thought our universe unique for longer.

And when we look at the actual merits of the two ideas, the multiverse wins hands down. Now, obviously, without strong evidence we can't say with any tremendous degree of confidence that a multiverse is true. But we can say it is more likely.

Note, also, that the same arguments that lead one to the conclusion that some sort of multiverse is likely also leads one to the conclusion that any specific multiverse proposal is unlikely.

 

[Calrid]

My entire point here is that there isn't evidence for a unique universe, or for a multiverse. And we shouldn't just think that a multiverse requires evidence when a unique universe does not merely because people have thought our universe unique for longer.

And when we look at the actual merits of the two ideas, the multiverse wins hands down. Now, obviously, without strong evidence we can't say with any tremendous degree of confidence that a multiverse is true. But we can say it is more likely.

Note, also, that the same arguments that lead one to the conclusion that some sort of multiverse is likely also leads one to the conclusion that any specific multiverse proposal is unlikely.

Correct neither has any more validity because of age or any other quality you can imagine they are both equally valid and since they are mutually exclusive either one must be true or the other, which is about all we can say atm.

No it does not win hands down. You have again just proceeded straight to the conclusion without making an argument.

I'm not sure what you are saying any more tbh.

The fact still remains that neither a multiple universe or eternal multiple universe hypothesis distinguishes itself in any form, philosophically or otherwise. If you don't believe me you probably should try stepping out of your comfort zone and reading "theories" other than those who recommend multiverses. There is nothing wrong with any of them on philosophical grounds, apart from the fact none of them are scientific yet. You might say its easier to test for bounces than multiverses but again ease of testing does not = likelihood of correctness.

 

[Fra]

My entire point here is that there isn't evidence for a unique universe, or for a multiverse.

I do not see where the idea of uniquness comes from? I don't recognise mylself here.

My point is also exactly this: The action of any observer, depends only upong the evidence at hand. Which happens to be incomplete uncertain evidence of the observable universe she lives in. And this "picture" is constantly evolving.

There is no assumption of uniquenss here, on the contrary, the lack of definitivess is exactly what the single universe evolves. Evolves doesn't just mean classical cosmologial expansion, I mean that the laws of physics a re constatly challages and renegotiated as previously inferred symmetries are broken, and new symmetries are inferred.

My point is exactly that:

The rational action of any obsever, depends only upon the evidence at hand. But this evidence and action are evolving as things evolve. And there is not external description of this evolution, only inside views. Ie. a rational observer has not incentive to focus on anything by the evidence at hand, relating to the universe he lives in.

There is no uniqueness about this?

/Fredrik

 

[Fra]

The evidence at hand; is what FORMS the picture of the universe the observer lives in.

Ie. the "observable universe" as inferred from any inside observer is just due to the actual evidence it has. The only decision problem existing in this picture, is what action to take. The generalized locality principle then suggest that it's irrational to think that information that is not at hand would influence this decision.

This doesn't imply the assumption that there the future can't reveal things that will come to challage the current state. It just means that it's rational to place your bets according to your eviedence and nothing else. So it's like a game, without absolute rules. The rules are a matter of negotiation and evolution in an undecidable way from the point of view of the single player.

/Fredrik

 

[Calrid]

I do not see where the idea of uniquness comes from? I don't recognise mylself here.

My point is also exactly this: The action of any observer, depends only upong the evidence at hand. Which happens to be incomplete uncertain evidence of the observable universe she lives in. And this "picture" is constantly evolving.

There is no assumption of uniquenss here, on the contrary, the lack of definitivess is exactly what the single universe evolves. Evolves doesn't just mean classical cosmologial expansion, I mean that the laws of physics a re constatly challages and renegotiated as previously inferred symmetries are broken, and new symmetries are inferred.

My point is exactly that:

The rational action of any obsever, depends only upon the evidence at hand. But this evidence and action are evolving as things evolve. And there is not external description of this evolution, only inside views. Ie. a rational observer has not incentive to focus on anything by the evidence at hand, relating to the universe he lives in.

There is no uniqueness about this?

/Fredrik

Well he was talking to me. I see no issue with saying that both uniqueness and multiverse theories are pretty much on a par as hypotheses go, although I'd agree that the God did it hypothesis seems unlikely given it requires a divine and infinite being, but I cannot argue likelihoods all that strongly or with any conviction, because frankly nothing is preferred by what I think or anyone thinks. or any observer alien or human thinks which would be a stronger anthropic principle. And true your argument needs neither probably because it isn't some sort of religion driven argument it is completely secular as far as I can tell.

 

[Fra]

Well he was talking to me.

Ah Ok. I guess part of the confusion was due to me jumping into the middle of dicussion.

/Fredrik

 

[Chalnoth]

The fact still remains that neither a multiple universe or eternal multiple universe hypothesis distinguishes itself in any form, philosophically or otherwise.

Again, the number of assumptions is different. A singular universe (one big bang event, where the low-energy laws of physics are the same everywhere) requires additional assumptions. It is therefore highly unlikely.

 

[Calrid]

Again, the number of assumptions is different. A singular universe (one big bang event, where the low-energy laws of physics are the same everywhere) requires additional assumptions. It is therefore highly unlikely.

Why though?

If MWI contains less assumptions does it make it more likely to be true. Also does MWI really contain less assumptions or is it just another way of describing Copenhagen? The same can be said of both theories that really the only difference is how the universes are arranged, they are actually on paper identical with the same number of assumptions, the same number of potential variables; the issue of assumptions is semantic and has little to do with science. Also I don't think that the laws have to be the same everywhere in one universe at all, that is an added assumption that is entirely superfluous. Plus of course with every new universe then the laws are different because of the quantum starting conditions, depending on which theory you are talking about. Given enough monkeys and enough type writers and enough time, and given monkeys of infinite diversity that all type infinitely fast is a semantic way of saying the same thing.

Again you will have to explain this default thing to me again because I don't think you have even attempted to explain why x no of alternative universes are actually any different from x no of eternal universes. I've seen philosophical papers on both and to be honest they appear to be different ways of saying the same thing just like physics interpretations are.

You're not making a case here your just proceeding from a conclusion to a conclusion it's definitely a tautology.

The assumption issue to me all seems to be in how you want to apply language and nothing to do with science. Neither maths nor language underlie reality the reverse is true.

 

[Chalnoth]

Why though?

Why what? Why are fewer assumptions more likely to lead to the truth? Or why does a unique universe require more assumptions (same low-energy physical laws everywhere, one singular big bang event)?

Well, I've already given arguments to both. So instead I'll just give an example for the second: the standard model of particle physics. The standard model of particle physics contains within it spontaneous symmetry breaking. This well-tested theory unambiguously predicts that far enough away, the low-energy laws of physics will be different. To get a unique universe, you have to add assumptions to the theory: you need some new physical process to transform the spontaneous symmetry breaking into explicit symmetry breaking.

If MWI contains less assumptions does it make it more likely to be true.

Yes.

Also does MWI really contain less assumptions or is it just another way of describing Copenhagen?

It's not another way of describing the Copenhagen interpretation, because it actually describes what happens at the boundary of collapse, while the Copenhagen interpretation does not. Despite the use of the word "interpretation", the two are not the same theory, because MWI drops the assumption of collapse. Its predictions about the boundary of collapse have also been experimentally verified:
http://prl.aps.org/abstract/PRL/v77/i24/p4887_1

So here the intuition about fewer assumptions has worked fantastically.

 

[Calrid]

Why what? Why are fewer assumptions more likely to lead to the truth? Or why does a unique universe require more assumptions (same low-energy physical laws everywhere, one singular big bang event)?

Why indeed, do fewer assumptions always lead to truth or is that just your bias talking? Clearly many theories have far more assumptions than others and clearly are much better. The theory of the four elements and the theory of atoms for example.

Well, I've already given arguments to both. So instead I'll just give an example for the second: the standard model of particle physics. The standard model of particle physics contains within it spontaneous symmetry breaking. This well-tested theory unambiguously predicts that far enough away, the low-energy laws of physics will be different. To get a unique universe, you have to add assumptions to the theory: you need some new physical process to transform the spontaneous symmetry breaking into explicit symmetry breaking.

I disagree and so does Smolin et al.

Symmetry breaking can occur in both theories given time in one and given multiple universes in the other. This has yet to be established as a reason to favour one over the other. If it has I will be all ears.

It's not another way of describing the Copenhagen interpretation, because it actually describes what happens at the boundary of collapse, while the Copenhagen interpretation does not. Despite the use of the word "interpretation", the two are not the same theory, because MWI drops the assumption of collapse. Its predictions about the boundary of collapse have also been experimentally verified:
http://prl.aps.org/abstract/PRL/v77/i24/p4887_1

So here the intuition about fewer assumptions has worked fantastically.

So intuition working in one case dictates reality? That's not a very solid basis for an axiom is it. There are no black swans just because one person has never seen any? In this case we have. Clearly some people believe that all the posits remain consistent between the two ideas. If you think that one interpretation is favoured you are clearly not in the same ball park as the rest of science. If that were the case then these interpretations would not still be growing at a pace.

MWI describes what happens if the wave function is real, it has only moved the goal posts to a different area. We know nothing at all about the wavefunctions mapping onto the reality. Hence MWI is merely just the same way of stating the same thing, neither is more likely to be true. Tell me is the wave function real ie a pictorial representation of the wave or is it a purely inductive statement based on unknowable variables?

"If a tree falls in the woods and no one is around to hear it does it make a sound?"

Intuition is no substitute for science and evidence. Conjecture is no substitute for the facts of where we stand atm nor is philosophical blather about occams razor. If philosophy cannot distinguish two competing hypotheses then it must remain ignostic. Evidence will out.

http://www.world-science.net/exclusives/060330_multiversefrm.htm

<<quoted article deleted - go to the link above>>

The debate is still very much alive and kicking. Choosing a side seems premature to me.

I might buy it too, but arm waving is seldom convincing in science.

I can't read your paper by the way sadly. So I cannot comment on it. I doubt it has resolved this speculative issue though. Atm one can always question the interpretation of results.

 

[Chalnoth]

Why indeed, do fewer assumptions always lead to truth or is that just your bias talking? Clearly many theories have far more assumptions than others and clearly are much better. The theory of the four elements and the theory of atoms for example.

I never said that fewer assumptions always lead to the truth. What I said was that fewer assumptions usually lead to the truth. And it's obviously only a valid statement as long as the theories in question aren't already falsified.

And that's a terrible, terrible example anyway because not only was the old theory of four elements falsified long ago, it wasn't all that well-defined in the first place.

I disagree and so does Smolin et al.

And yet, you haven't been able to come up with a single coherent argument to support a unique universe, regardless of the fact that a unique universe requires more justification.

MWI describes what happens if the wave function is real, it has only moved the goal posts to a different area. We know nothing at all about the wavefunctions mapping onto the reality. Hence MWI is merely just the same way of stating the same thing, neither is more likely to be true. Tell me is the wave function real ie a pictorial representation of the wave or is it a purely inductive statement based on unknowable variables?

No, they are materially different theories. Wave function collapse is never absolute in MWI, whereas Copenhagen Interpretation assumes that under unspecified conditions, the wave function collapses. The problem with testing the Copenhagen Interpretation is precisely the fact that the theory is ill-defined: this means that any time what you're testing looks like MWI, you can just shift the boundary of collapse in CI to save CI from being falsified. Collapse in CI, in other words, is just a "god of the gaps". MWI, on the other hand, is exactly specified and can, in principle, be falsified (whereas the wavefunction collapse postulate of CI cannot be falsified).

The debate is still very much alive and kicking. Choosing a side seems premature to me.

It's reasonable to have some debate. What is unreasonable is people insisting that their ideas hold special status such that any other ideas must have evidence to be considered reasonable, without any justification for making such a claim.

The paper, by the way, basically shows two things:
1. The boundary of collapse is gradual, as predicted by MWI.
2. The wavefunction collapse occurs even though no measurement of the wavefunction is performed (an interaction is turned on, the results of which are not recorded).

 

[Calrid]

I never said that fewer assumptions always lead to the truth. What I said was that fewer assumptions usually lead to the truth. And it's obviously only a valid statement as long as the theories in question aren't already falsified.

And that's a terrible, terrible example anyway because not only was the old theory of four elements falsified long ago, it wasn't all that well-defined in the first place.

Which is a qualitative claim that has nothing to do with science.

I don't think any example is going to satisfy you with such premises as you have so meh.

It's reasonable to have some debate. What is unreasonable is people insisting that their ideas hold special status such that any other ideas must have evidence to be considered reasonable, without any justification for making such a claim.

Ironically that is precisely what you are doing.

I'm not making any claims, quite the opposite, I am saying we cannot make any claims atm both are equally likely to be true.

No, they are materially different theories. Wave function collapse is never absolute in MWI, whereas Copenhagen Interpretation assumes that under unspecified conditions, the wave function collapses. The problem with testing the Copenhagen Interpretation is precisely the fact that the theory is ill-defined: this means that any time what you're testing looks like MWI, you can just shift the boundary of collapse in CI to save CI from being falsified. Collapse in CI, in other words, is just a "god of the gaps". MWI, on the other hand, is exactly specified and can, in principle, be falsified (whereas the wavefunction collapse postulate of CI cannot be falsified).

No they are not materially different, ie the wave function has been shown to exist in all possible states by experiment, they are conceptually different.

It's not a "god of the gaps" because CI makes no judgement about what exists in those gaps it can only say that what happens between emission and measurement is undefined, ie it is agnostic about an entity before measurement. The wave may exist as a definite entity but such a contention cannot be known. Hence we say that it's description is a figurative one not a pictorial one.

The paper, by the way, basically shows two things:
1. The boundary of collapse is gradual, as predicted by MWI.
2. The wavefunction collapse occurs even though no measurement of the wavefunction is performed (an interaction is turned on, the results of which are not recorded).

Have they shown that there really is gradual collapse? I Wouldn't know I can't read the paper. AFAIK anyway Copenhagen is agnostic on what measurably happens at collapse anyway as it has to be by definition.

Doesn't MWI contend that collapse doesn't happen anyway because the wave function is real and the wave function actually exists as a complete description of physical reality before measurement? Hence it is deterministic.

The results are not recorded and never can be. This isn't even philosophy it's pure arm waving.

It is kind of pointless discussing that paper since I can't read it, but I bet plenty of people have contended that its results do not prove CI is wrong, or I would of heard about it. I suspect your conclusions are arguable and a matter of interpretation.

 

[Chalnoth]

Ironically that is precisely what you are doing.



Your conclusions are arguable and a matter of interpretation.

Uh, what? No they aren't. That's what the experiment shows. There is a measurement of the resulting wavefunction, obviously. That is how the progressive decoherence is observed. It is the interaction in the middle that involves no measurement.

 

[Calrid]

Uh, what? No they aren't. That's what the experiment shows. There is a measurement of the resulting wavefunction, obviously. That is how the progressive decoherence is observed. It is the interaction in the middle that involves no measurement.

So we still don't know what exactly happens at measurement, but we'll claim we do anyway? it still sounds inductive to me?

Kind of a pointless contention anyway because I can't read what you are talking about. An interesting analogy to the wave but ultimately a pointless discussion.

 

[dm4b]

Well, the main issue here is that we don't know how to sensibly talk about a universe without a spacetime. But even if you want to consider a universe starting literally out of nothing, the default expectation would be for it to start in a generic state, not in a very special one. And a generic state is, by definition, a high-entropy state. So even with a universe beginning out of nothing, you run into the exact same entropy considerations.

Looks like I missed a few pages of activity on this thread!

The human mind has the tendency to feel that what it cannot imagine, is not there. Just because spacetime could have been "created" at the moment of the Big Bang, does not mean the Universe was created out of nothing.

And, if we understand so little about how the Universe could have come about in this way, as to say it was created out of nothing, we surely can't say what the default expectation would be. Also, is entropy going to exist outside time/space? I would think a more highly ordered state would be just as likely, which might make a lower entropy beginning to the Universe more likely.

So, I disagree, I don't think we necessarily would have the exact same entropy considerations.

But, you're right, we do lack the ability at this point and time to talk sensibly (in physics terms anyhow) about a reality (NOT our Universe, which wouldn't be around anyhow) without space and time. But, then again, I'm not so sure reality is restricted by what we humans can talk about, let alone imagine.

I am reminded of an Alan Watts saying when I see some of the challenges in physics today: "A persistently insolvable problem should always be considered to perhaps be a question being asked the wrong way".

 

[Calrid]

And, if we understand so little about how the Universe could have come about in this way, as to say it was created out of nothing, we surely can't say what the default expectation would be.

I think it's rather arrogant to assume we have as yet any concrete answers.

Also, is entropy going to exist outside time/space? I would think a more highly ordered state would be just as likely, which might make a lower entropy beginning to the Universe more likely.

Entropy is such a contentious term, it only really makes sense in very specific situations we can measure with any consistency, when it comes to commenting on overarching reality it is such an ill defined term. Hell I don't recall the name, but one scientist went mad trying to pin it down to a system specifically.

For a start define ordered? Isn't that a human conceit? What is more ordered about a human being and the chemicals that make up his structure in whatever state they happen to be in. Or a diffuse mostly hydrogen gas cloud and a star? Think about it?

But, then again, I'm not so sure reality is restricted by what we humans can talk about, let alone imagine.

Quite we tend to be very anthropocentric. As I said before I'm not sure reality gives a toss about our speculations on it, or the conditions we try to force on it because of our biases.

I think Bohr had it right we might not have the language or maths to describe reality, that I hope will not always be the case.

I am reminded of an Alan Watts saying when I see some of the challenges in physics today: "A persistently insolvable problem should always be considered to perhaps be a question being asked the wrong way".

Nice way of putting it, I'm sure Bohr would of approved.