Can the Universe Cause Itself to Exist from a Physics Perspective?

[Chalnoth]

1. Yes, in OUR universe stars are important, I know. But imagine Universe where energy is not conserved. Observers there can develop on isolated blobs of matter, they won't need a central star. Now say heavier elements in their chemistry are developed during thir BB (like some part of our helium) - et voila, they don't need stars

Albrecht and Iglesias looked at the implications of the fact that the time coordinate can be chosen arbitrarily on the laws of physics here:
http://arxiv.org/abs/0805.4452

They found that if you take a random Hamiltonian as input (which is the equivalent of taking the laws of physics as being random and changing in time), then you can simply make a change to the time coordinate to get a Hamiltonian that is constant in time. And if you have a Hamiltonian that is constant in time, then you have conservation of energy (by Noether's theorem).

Basically the upshot is that you can't have a universe where energy isn't, in some sense, conserved.

As for big bang nucleosynthesis, the problem there is that the production of carbon is so obscenely slow compared to the production of lighter elements that it effectively can't happen in the early universe.

2. unlikely? or difficult to imagine? :)

Like the BBN stuff, I'd have to look up the issues again, but I'm pretty sure that the existence of closed timelike curves leads to either contradictions or instabilities that make such a scenario impossible.

 

[Dmitry67]

They found that if you take a random Hamiltonian as input (which is the equivalent of taking the laws of physics as being random and changing in time), then you can simply make a change to the time coordinate to get a Hamiltonian that is constant in time. And if you have a Hamiltonian that is constant in time, then you have conservation of energy (by Noether's theorem).

As for big bang nucleosynthesis, the problem there is that the production of carbon is so obscenely slow compared to the production of lighter elements that it effectively can't happen in the early universe.

At first, why Hamiltonian?
Alternative Universe can be so different so the laws are absolutely different.

Regarding the article, it is interesting. So there is time coordinate where Hamiltonian is constant, but why that coordinate IS time? (direction where entropy increases?)

Finally, regading the carbon production, what carbon? The laws can be so different that there are 2747 stable elements made of blahblarks Q, U, T, L, A and B :)

 

[Chalnoth]

At first, why Hamiltonian?

It's just one particularly way to write down arbitrary laws of physics.

Alternative Universe can be so different so the laws are absolutely different.

That was why they considered a random Hamiltonian.

Regarding the article, it is interesting. So there is time coordinate where Hamiltonian is constant, but why that coordinate IS time? (direction where entropy increases?)

I believe they chose the one where the Hamiltonian was constant.

Finally, regading the carbon production, what carbon? The laws can be so different that there are 2747 stable elements made of blahblarks Q, U, T, L, A and B :)

You might be surprised.

 

[Dmitry67]

1 It's just one particularly way to write down arbitrary laws of physics.

2 I believe they chose the one where the Hamiltonian was constant.

2 then the direction of such time can be different from thermodynamic arrow.

1 hamiltonian can be used only in the narrow subset of all mathematical systems (=universes).

 

[Chalnoth]

1 hamiltonian can be used only in the narrow subset of all mathematical systems (=universes).

Why?

 

[Dmitry67]

Can you write a Hamiltonian for the Boolean Logic universe? (it is just an example)
Universe (in general) is not necesserily based on real/complex numbers.

 

[Chalnoth]

Can you write a Hamiltonian for the Boolean Logic universe? (it is just an example)
Universe (in general) is not necesserily based on real/complex numbers.

Since you can represent an arbitrary mathematical function in boolean logic, it would just be a matter of writing one down in computer code. Not that difficult.

 

[DevilsAvocado]

Chalnoth & Dmitry67, your latest talk about 'islands' and Hamiltonian is way above my 'horizon', but I have been thinking some more about the Mathematical Universe Hypothesis.

Dmitry67, when you mentioned "7. Can we somehow transfer our consciousness into such universes?", I started thinking about 'brains' and mathematics. If MUH is correct, our brain is 'just' a mathematical formula, right? Then we must have the 'mother lode' of formulas inside our heads, if we are going to explain 'ourselves', AND the universe, AND 'everything else', right?

Then I started thinking about something else, which is so 'simple', that Tegmark just couldn’t have missed it: Gödel's incompleteness theorems

I know this must be wrong, but I can’t find the error myself... (I also have to live up to my username hehe )

Second incompleteness theorem
For any formal effectively generated theory T including basic arithmetical truths and also certain truths about formal provability, T includes a statement of its own consistency if and only if T is inconsistent.

To me, this must mean we already know that your (Chalnoth) 1-2-3 boiling down of Tegmark’s arguments is inconsistent in the very first sentence:

1. A mathematical structure is just a fully-consistent set of rules.
2. If our universe is fully consistent, then it is isomorphic to some mathematical structure (which we don't yet know). This would indicate that at least some mathematical structures have real existence.
3. It is generally easier for all things of a class to exist than for only some of them to, so it is simpler to propose that all mathematical structures exist.

If our universe is fully consistent and thus isomorphic to a mathematical structure, then TOE must be inconsistent to be able to prove the consistency of the universe!? Therefore the universe (=TOE) also must be inconsistent!? And if the universe is inconsistent, it cannot be a mathematical structure, therefore TOE can never be found (from 'inside')!?

Que? What am I missing...

 

[baywax]

What created (caused) number 7?

Numbers 6 and 8...

I would like to weigh in and say that the universe has been evolving since long before the BB. The BB is just one symptom of whatever started the whole process. This universe building process probably started in response to an overwhelming imbalance of nothing to something... as in a ratio of 0 to 1... 1 being "nothing" (in an abstract manner of course).

 

[DevilsAvocado]

Numbers 6 and 8...

11 + 100 = 111

 

[Chalnoth]

If our universe is fully consistent and thus isomorphic to a mathematical structure, then TOE must be inconsistent to be able to prove the consistency of the universe!? Therefore the universe (=TOE) also must be inconsistent!? And if the universe is inconsistent, it cannot be a mathematical structure, therefore TOE can never be found (from 'inside')!?

Que? What am I missing...

Just because you can't prove from within the mathematical structure that the structure is consistent doesn't mean it isn't consistent. It just means you can't demonstrate it within said structure.

 

[Dmitry67]

Chalnoth had already replied...

DavilsAdvocado, do you know the Game of Life? The one you can play on the inlimited chess board? That Universe is degterministic and very simple. What is quite contreintuitive, is that both Goedels theorems are applicable to such universe: there are some statements regarding the configurations of dots which can not be proved or dismissed.

Also, not that Goedels theorem is not applicable to ANY mathematical structure, but to some subset of such structures.

 

[baywax]

11 + 100 = 111

actually, in visual terms 11 + 100 is equal to 11100

in this instance there are more ones than zeros and an imbalance continues to occur.

this might lead to expansion or inflation... but the ratio here between 1s (which now represent "something") and 0s... (which represent "nothing") is much less of an imbalance than 0 to 1. So... the dominance of nothing... or some other equally homologous medium, causes a violent reaction within itself that produces an opposite, balancing medium or condition. The sum of the metaphoric parts is a universe. Just guessing!

 

[Chronos]

Mathematics and the origins of the universe have a great deal in common - both rely on fundamental assumptions that, by definition, are unprovable. Logic allows us to delve a bit deeper, but also ultimately fails. There is no reasonable explanation why this, or any other universe exists, imo. For that reason, I favor the God hypothesis. It provides a reasonable, albeit incomplete, explanation.

 

[Chalnoth]

For that reason, I favor the God hypothesis. It provides a reasonable, albeit incomplete, explanation.

No, it really doesn't. The problem is that there's a tension between different definitions of the word, and neither class of definition comes close to solving the problem. The more specific your definition gets, the more complex your God gets, and thus the less it becomes an explanation. The less specific your definition gets, the more meaningless the term God even becomes, and thus it fails as an explanation in the other direction.

Because of this vague slipperiness of the very definition of the word "god", it is an impossibility to ever bring up any evidence for or against, and for that reason the hypothesis simply fails as being too poorly-defined.

 

[DevilsAvocado]

Just because you can't prove from within the mathematical structure that the structure is consistent doesn't mean it isn't consistent. It just means you can't demonstrate it within said structure.

So how do we prove your second statement?

"2. If our universe is fully consistent, then it is isomorphic to some mathematical structure ..."

If the universe = mathematical structure, then how can we ever use mathematics to prove it fully consistent?

 

[DevilsAvocado]

... Also, not that Goedels theorem is not applicable to ANY mathematical structure, but to some subset of such structures.

Agree. Many weak systems of arithmetic do not satisfy the hypotheses of the second incompleteness theorem. But now we are talking about the whole enchilada... things that do apply to Gödel's incompleteness theorems, and things that don’t...

The problem is, as I see it, that we cannot 'pick and chose'; everything (in the universe) has to be fully consistent!?

The liar paradox seems hard to get out of - "The next sentence is false. The previous sentence is true."

 

[DevilsAvocado]

actually, in visual terms 11 + 100 is equal to 11100

Maybe...?

All I wanted to say is that number 7 is totally irrelevant, and created by humans (of course!). We can do perfectly well with 1/0, On/Off, black/white, light/dark, etc, to any calculation possible.

So the correct question maybe is - What created (caused) number light light light!?

 

[DevilsAvocado]

... I favor the God hypothesis. It provides a reasonable, albeit incomplete, explanation.

I don’t agree. The 'designer hypothesis' immediately raises the larger problem - Who designed the designer!?

Furthermore, the 'designer' has exactly the same problem as quantum fluctuations – how to choose a moment for BB – in a 'period' where there was no time and no moments to choose...

And Occam's razor prefers simpler explanations, as 'nothingness', than an extremely complicated 'designer', to do the same thing.

 

[Chalnoth]

So how do we prove your second statement?

My point is that you simply define a mathematical structure as being a fully-consistent set of axioms. This definition means that there may be things which we call mathematical structures which actually aren't. And there are certainly many things which are mathematical structures which we are unaware of.

Our inability to be absolutely 100% certain whether or not everything we call a mathematical structure actually is one is basically irrelevant to the point.

If the universe = mathematical structure, then how can we ever use mathematics to prove it fully consistent?

An inconsistency is an impossibility. We may not be able to prove the mathematical structure which we think is isomorphic to our universe is consistent (and thus an actual mathematical structure). But we know that if it turns out not to be consistent, it can't describe our universe.

 

[DevilsAvocado]

... An inconsistency is an impossibility. ...

Thanks a lot for the explanation. I think I see the light now...

We already know that the universe is fully consistent, otherwise we wouldn’t be here, right? Or we would be here, but a lot of people would get killed on the 'inconsistent highway' everyday – by Boltzmann Brains popping out of nowhere and smashing into their windshields...

So, if we can find a mathematical structure that describes this fully consistent universe, it is okay. And then we would know that the universe is isomorphic to that mathematical structure.

Correct?

 

[Newai]

I don't see why the universe has to have been created at all. The perception of time we have is perhaps something we should not pin to the nature of the universe. Slice time out of the mystery, and it might be easier to grasp.

 

[DaveC426913]

I don't see why the universe has to have been created at all.

Well, our current evidence seems to suggest it was.

Or more to-the-point: our current evidence seems to suggest that, at one time, it wasn't.

 

[Chalnoth]

Thanks a lot for the explanation. I think I see the light now...

We already know that the universe is fully consistent, otherwise we wouldn’t be here, right? Or we would be here, but a lot of people would get killed on the 'inconsistent highway' everyday – by Boltzmann Brains popping out of nowhere and smashing into their windshields...

So, if we can find a mathematical structure that describes this fully consistent universe, it is okay. And then we would know that the universe is isomorphic to that mathematical structure.

Correct?

Well, just bear in mind that we may never be certain as to which mathematical structure it is (this would basically be a theory of everything).

As of right now, we don't even have a fully-developed mathematical structure that might conceivably be a theory of everything.

 

[Chalnoth]

Well, our current evidence seems to suggest it was.

Or more to-the-point: our current evidence seems to suggest that, at one time, it wasn't.

That's not true. All that our current evidence shows is that our region of the universe had a beginning. This may have been a transition from some previous state, or it may have been started from nothing. We just don't know.

 

[DaveC426913]

That's not true. All that our current evidence shows is that our region of the universe had a beginning. This may have been a transition from some previous state, or it may have been started from nothing. We just don't know.

That changes absolutely nothing about Newai's comment or my response.

 

[Chalnoth]

That changes absolutely nothing about Newai's comment or my response.

But what I'm saying is that evidence about the status of our own region says nothing about the status of what lies outside our region, pro or con. So we can't honestly say we have evidence for a beginning of The Universe. Just our observable part.

 

[DaveC426913]

But what I'm saying is that evidence about the status of our own region says nothing about the status of what lies outside our region, pro or con. So we can't honestly say we have evidence for a beginning of The Universe. Just our observable part.

I got that. It still changes nothing.

Go back to newai's post and insert whichever one suits you.

 

[Chalnoth]

I got that. It still changes nothing.

Go back to newai's post and insert whichever one suits you.

So are you saying that our evidence doesn't suggest that the universe was created? Because it doesn't.

 

[DevilsAvocado]

Well, just bear in mind that we may never be certain as to which mathematical structure it is (this would basically be a theory of everything).

As of right now, we don't even have a fully-developed mathematical structure that might conceivably be a theory of everything.

Thanks, that’s cool. I’m just happy that Gödel doesn’t mess all things up and that the universe is fully consistent.

 

[DevilsAvocado]

I don't see why the universe has to have been created at all.

If you’re thinking of "Steady State" – forget it. We can rewind the (observable) universe and 'something' definitely happen 13.8 billion years ago – and we can prove it. If it was a Big Bounce, colliding Branes, or a new bubble in the Multiverse, or the beginning of everything from nothing – that we can’t prove, yet.

The perception of time we have is perhaps something we should not pin to the nature of the universe. Slice time out of the mystery, and it might be easier to grasp.

Time is a fundamental part of space-time in our (observable) universe and cannot be sliced out that simple. It’s like trying to explain life and slice out the parents of a newborn...

 

[DaveC426913]

So are you saying that our evidence doesn't suggest that the universe was created? Because it doesn't.

Our evidence does suggest that our portion of it was created.

 

[Chalnoth]

Our evidence does suggest that our portion of it was created.

But that language is highly misleading. Our evidence suggests that our portion of it had a beginning. But "was created" implies intent behind said creation. Simple formation out of a random event is far more likely.

 

[DaveC426913]

But that language is highly misleading. Our evidence suggests that our portion of it had a beginning. But "was created" implies intent behind said creation. Simple formation out of a random event is far more likely.

Well, you are making that inference; I am not. Nor did I think anyone else was.

If we are talking about intent that is a whole 'nother ball of worms.

 

[Chalnoth]

Well, you are making that inference; I am not. Nor did I think anyone else was.

If we are talking about intent that is a whole 'nother ball of worms.

Yes, it is, which is why I prefer to use words which carry no such implication. Because whether you like it or not, "was created," does carry the implication of intent to many readers. So I simply opt to use neutral language, such as "began" or "had a beginning."

 

[DaveC426913]

Yes, it is, which is why I prefer to use words which carry no such implication. Because whether you like it or not, "was created," does carry the implication of intent to many readers. So I simply opt to use neutral language, such as "began" or "had a beginning."

Context. This has not been a discussion about intent. You are broadening the scope of the discussion. In fact, you are the only one so far who has fallen victim to the apparent ambiguity that you warn against.

 

[Chalnoth]

Context. This has not been a discussion about intent. You are broadening the scope of the discussion. In fact, you are the only one so far who has fallen victim to the apparent ambiguity that you warn against.

I think you need to review the discussion again.

 

[DevilsAvocado]

Gentlemen DaveC426913 & Chalnoth, couldn’t we settle all by (this layman logic):

If you’re thinking of "Steady State" – forget it. We can rewind the (observable) universe and 'something' definitely happen 13.8 billion years ago – and we can prove it. If it was a Big Bounce, colliding Branes, or a new bubble in the Multiverse, or the beginning of everything from nothing – that we can’t prove, yet.

 

[DaveC426913]

I think you need to review the discussion again.

OK, granted. In the larger discussion, there is talk about Creation.

However, the three of us (including you an newai) had been discussing creation as an effect of time, starting in https://www.physicsforums.com/showthread.php?p=2554971#post2554971", which really had nothing at all to do with intent, nor had either of us used the "creation" word until you introduced it.

 

[Dmitry67]

If the universe = mathematical structure, then how can we ever use mathematics to prove it fully consistent?

This is impossible
To prove that any mathematical theory is self-consistent, you always need to use more powerful/more complicated theory.
So the whole mathematics is based on the pure belief.

The self-consistency of Peano arithmetics is proven in ZF set theory. And I believe there are no proofs that ZF (or other set theory, there are many different :) ) are self-consistent.

 

[DevilsAvocado]

This is impossible
To prove that any mathematical theory is self-consistent, you always need to use more powerful/more complicated theory.
So the whole mathematics is based on the pure belief.
...

Thanks Dmitry67, I realize this now and that we already know that the universe is fully consistent, otherwise lot of weird stuff would happen to us... and the math describing this must therefore be fully consistent.

... An inconsistency is an impossibility. ...

Thanks a lot for the explanation. I think I see the light now...

We already know that the universe is fully consistent, otherwise we wouldn’t be here, right? Or we would be here, but a lot of people would get killed on the 'inconsistent highway' everyday – by Boltzmann Brains popping out of nowhere and smashing into their windshields...

So, if we can find a mathematical structure that describes this fully consistent universe, it is okay. And then we would know that the universe is isomorphic to that mathematical structure.

 

[celebrei]

No, it really doesn't. The problem is that there's a tension between different definitions of the word, and neither class of definition comes close to solving the problem. The more specific your definition gets, the more complex your God gets, and thus the less it becomes an explanation. The less specific your definition gets, the more meaningless the term God even becomes, and thus it fails as an explanation in the other direction.

Because of this vague slipperiness of the very definition of the word "god", it is an impossibility to ever bring up any evidence for or against, and for that reason the hypothesis simply fails as being too poorly-defined.

Well, we shouldn't be too dismissive of Chronos' view or the "God Hypothesis" since "God" is more of a metaphysical assertion rather than a scientific theory, others who have a naturalistic world view would think God and most metaphysical statements are meaningless, yet as Karl Popper said, they are not meaningless but rather not falsifiable, hence metaphysical statements implies something about the universe that are not empirically testable, but remain epistemically plausible.

 

[DevilsAvocado]

... as Karl Popper said, they are not meaningless but rather not falsifiable, hence metaphysical statements implies something about the universe that are not empirically testable, but remain epistemically plausible.

I don’t agree, because scientifically this statement:

"I favor the God hypothesis. It provides a reasonable, albeit incomplete, explanation."

Has the exactly the same significance as this statement:

"I favor the Santa Claus hypothesis. It provides a reasonable, albeit incomplete, explanation."

For those who believe in Santa Claus, even if not empirically testable, Santa remains epistemically plausible.
For science, and those who don’t believe in Santa Claus, this means absolutely nothing.

 

[marcus]

I don't see why the universe has to have been created at all...

Well, our current evidence seems to suggest it was.

Or more to-the-point: our current evidence seems to suggest that, at one time, it wasn't.

I believe that statement is out of line with current expert opinion. There is no scientific reason to believe that the universe did not exist before, say, 13.7 billion years ago, according to the relevant research community.

For example, according to Einstein-Online, a Max Planck Institute public outreach site, most scientists would be surprised if it actually turned out that there was a singularity at the start of expansion. By a singularity I mean a point where time stops as you work back, where there is no "before". The expectation is that time and existence go back before the start of expansion. If you want a non-technical pubic outreach discussion as of 2006, try the E-O essay called "A tale of two big bangs". It is the top google hit if you say "tale of two big bangs". Or use this link:
http://www.aei.mpg.de/einsteinOnline/en/spotlights/big_bangs/index.html

If you want a technical sample of what the research community is actually studying these days ( non-singular models of conditions leading up to the start of expansion) just do a spires search with keyword "quantum cosmology" for papers from 2006 and later.
You can use this link:
http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=dk+quantum+cosmology+and+date%3E2005&FORMAT=WWW&SEQUENCE=citecount%28d%29
or just go to Spires and ask for keyword "quantum cosmology" and date > 2005.

You will see 374 papers, after 2005, studying several different non-singular models of what can have led up to the start of expansion, pursuing several ideas. Some papers proposing ways to test nonsingular models by astrophysical observation--primarily features of the microwave background.

Roger Penrose pointed out in 2005 that there had been a change in conventional scientific opinion, among the relevant expert community. According to a talk he gave at Cambridge, before 2005 it was generally considered meaningless to talk about before-BB (like "what is north of the north pole?") but according to him 2005 was a watershed year when the prevailing scientific opinion changed. Of course some had been working on nonsingular models already for quite some time, but he picked out 2005 as the year that dominant opinion shifted. For what it's worth---just one person's take on a change of fashion in scientific thought.

I set up the Spires search to list in order of citation-count so you get the most cited papers first. All or virtually all of the first hundred or so treat non-singular models----where time and existence go back before the start of expansion.

 

[cristo]

This thread's really slipped under the radar: theological or philosophical discussions are not permitted in the cosmology forum. Thus, this thread is closed.