Recognitions:
Gold Member

## Why Stephen Hawking says universe can create itself from nothing?

Ah thank you for that clarification. I had originally thought Guth was one of the originators but when I did a wiki search it mislead me. I was also having trouble in regards to the others Mukhanov Chibisov etc.
Thanks for also clarifying the distinction.
Its still something I'm currently studying in a self taught manner. Along with a variety of virtual particle models. I have also kept copies that Marcus posted on loop quantm gravity. That I will probably try to figure out next.

=sigh=
i noticed you avoided the question i asked.

oh well. it's tiresome to repeat, and my experience with you is that (repetition) is what has to happen to keep you on topic. or at least, on the narrow topic of the question asked.

 Quote by Chalnoth But when you say something is impossible, that requires a mathematical proof.
i wouldn't confuse the disciplines of "logic" and "mathematics". they're closely related disciplines but not the same. i would say that logic is a more primary discipline (i.e. mathematics necessarily employs logic but not the other way around). logic doesn't require quantitative foundation except for the boolean. i hope we don't get into a dispute of semantics.

and i've seen very goofy claims of "mathematical proofs" both from theists (like Stephen Unwin) who claim to "mathematically prove" God exists and atheists (like Richard Dawkins) who "mathematically prove" the opposite. both are goofy, so be careful with that semantic, Noth. you could be heading for a very unimpressive crash.

the question regarding what is possible is directed toward physical reality. so we're not talking about what is possible for Middle Earth and wizards like Gandalf the White vs. Gandalf the Gray. so, even though mathematics is necessary to describe physics (logic isn't enough, there are quantitative relationships involved), mathematics isn't sufficient. there are also the physical axioms.

i have a glimpse of the concept of a quantum fluctuation. i have a crude electrical engineer's concept of QM and understand what the quantity $\Psi$ is about. and regarding that, i understand that a particle like a subatomic particle can pop into existence at some place and time. or at least appear to when we measure things. the probabilities of such are reasonable for particles so small. but it seems like a fantastic stretch to apply that to entire universes. especially coming from people who reject the supernatural, it's as if they're just choosing a different supernatural, one more to their liking. i'm thinking of Dawkins, so please don't take this as directed toward you, Noth.

 Now, it is conceivable that somebody might come up with a way to describe a universe's beginning without there being anything before (no space-time, no matter, nothing), but that comes with a significant problem: how do you describe 'nothing' mathematically?
empty set. i know, it's still a set. but that's why i am not on board with your semantic to begin with.

 This doesn't mean it's impossible, but it does mean that we can't really start to examine the possibility without a coherent description of what 'nothing' actually means.
real "nothing" would be no physical quantity (what i like to call "stuff") and no relationships or law of interaction either. and no one around to behold it.
 Recognitions: Gold Member Science Advisor I notice you go to great lengths to avoid addressing real science issues by imposing logical constraints amenable with your world view, rbj.

 Quote by MathematicalPhysicist That's really simple. If you create something from nothing then that nothing becomes something, cause if it were nothing then how did we got something? As I said it's not logical, and we might as well start believe in witches and fairies if that's what we come to believe.
I don’t agree. I explained it and you ignored my argument. What’s wrong with it?

To repeat:
Creation is going on all the time in so called empty space, with matter and antimatter particles annihilating each other, as a natural process.
If a similar process occurred at the start of the BB without a perfect annihilation, we would be left with separate amounts of matter and antimatter, adding to zero.

By the division of an original nothing into two positive and negative parts, there is a creation, but it doesn’t have to offend any laws of physics or logic, does it?

I agree that two separate and opposite quantities equating to zero are not nothing, but my explanation answers your question of how we got something from nothing, does it not?

 Quote by Chronos I notice you go to great lengths to avoid addressing real science issues by imposing logical constraints amenable with your world view, rbj.
I don’t know if the logical constraints which you say rbj seeks to impose are biased by his world view.

However, I do think that it is very necessary that we impose rational and logical constraints when we are addressing science issues, otherwise we get these accusations of witches and fairies.
Scientific theories and hypotheses have to stand the test of logic as well as mathematics.

.

Mentor
Blog Entries: 8
 Quote by Johninch Scientific theories and hypotheses have to stand the test of logic as well as mathematics.
Not at all. Scientific theories must only stand the test of experiment. If it turns out that experiment is incompatible with logic and mathematics, then logic and mathematics will have to change.

 Quote by micromass Not at all. Scientific theories must only stand the test of experiment. If it turns out that experiment is incompatible with logic and mathematics, then logic and mathematics will have to change.
It's difficult to make experiments in cosmology, particularly concerning the BB, so we have to fall back on observations and mathematics. Ideally all the information should match. But I don't see how we can exclude logic - you mean we don't have to think straight?

The main problem with your argument is that you seem to be ignoring the necessity to interpret the results of experiments, as if they all lead to obvious conclusions. Quite apart from quality problems in the execution in some cases.

.

Mentor
Blog Entries: 8
 Quote by Johninch It's difficult to make experiments in cosmology, particularly concerning the BB, so we have to fall back on observations and mathematics. Ideally all the information should match. But I don't see how we can exclude logic - you mean we don't have to think straight?
You seem to be equation logic with thinking straight. Logic is a mathematical discipline with a very specific meaning.Furthermore, the current accepted logical system in mathematics is classical logic. This has already been shown not to model reality. So we already had to abandon (classical) logic and find a new kind of logic.

 The main problem with your argument is that you seem to be ignoring the necessity to interpret the results of experiments, as if they all lead to obvious conclusions. Quite apart from quality problems in the execution in some cases.
I don't see how I ignored anything. In science, you make experiments and observations to test your theories. If eventually they seem to contradict the established theory (and if there are no errors), then the theory is wrong. This includes logic and mathematics. I see no a priori reasons why mathematics should be able to model this world. In fact, I speculate that it probably doesn't (but this is just a guess, I have no single shred of proof or evidence for it).

Recognitions:
Gold Member
 Quote by marcus When inflation was first proposed, folks couldn't think of what might have caused it so they came up with all sorts of ideas like "quantum fluctuation" and "eternal" and "anthropic" (to explain why a quantum fluctuation would produce the right amount of inflation which would then conveniently stop). It was a large exercise of the imagination, which is certainly fine up to a point. Guth strikes me as coming from an earlier era. But maybe he defines inflation for the general pubic. A lot has changed though. Guth, Hawking, Vilenkin, Linde don't write so much any more, or their papers don't get quite the same amount of attention. Here are some recent papers where inflation comes from *something*. There's growing interest in this (which again does not prove it's right.)
As stated I went and looked into the history of developments on the various inflationary/expansion models. After some extensive searching I realize what your saying in your previous post.

Here is what I've found out.

false vacuum became old inflation later replaced by new inflation. Due to problems in new inflation it later became chaotic eternal inflation. There are other models that derived from the original false vaccuum. However all these models failed to solve one key problem that of pocket/multi universe formation.
As far as I can tell string theory is currently working with Guth I can't recall what string theory model is representative in this line of research DQ something lol. I don't follow string theory it makes my teeth ache.

This paper is the latest I could find that involved false vacuum
http://arxiv.org/abs/1112.3005

At first I thought of starting a new thread on it however I quickly realized that there are aspects in it that I don't quite agree with. However thats another topic.

 Quote by Chronos I notice you go to great lengths to avoid addressing real science issues by imposing logical constraints amenable with your world view, rbj.
 Quote by Johninch I don’t know if the logical constraints which you say rbj seeks to impose are biased by his world view.
besides that, i would like to know what real science issues i am going to great lengths to avoid. what are they? certainly not that "science" is about what is material and empirical. that real science issue is something that i push relentlessly.

perhaps it's that i don't afford "science" the totality of reality in my worldview. (i.e. i do not subscribe to the belief system of "Materialism" or "Physicalism". and, BTW, neither do John Polkinghorne, Freeman Dyson, or Owen Gingerich as best as i understand what they say and write.) is that it, Chronos?

 However, I do think that it is very necessary that we impose rational and logical constraints when we are addressing science issues, otherwise we get these accusations of witches and fairies. Scientific theories and hypotheses have to stand the test of logic as well as mathematics.
it looks like PF Mentor micromass has weighed in on this issue on the other side. and, from previous experience, i have to be careful not to say something that whoever admin doesn't like (Greg seems to be fine, but it's the captains under him).

anyway, having done work in science (only in acoustics - totally classical physics), engineering mathematics, and in logic, i must dispute a few things said here:

logic is not a sub-discipline of mathematics but it is the other way around.

i would disagree with this:

 Quote by micromass Scientific theories must only stand the test of experiment. If it turns out that experiment is incompatible with logic and mathematics, then logic and mathematics will have to change.
even when the experimenter is hallucinating? when the astronomer is peaking into his telescope and sees teapots or spaghetti monsters or even the same guy with a beard in Michelangelo's Sistine Chapel painting, he might need to question the empirical outcome of the experiment.

 Quote by micromass You seem to be equati[ng] logic with thinking straight.
he's not the only one. so did Aristotle (and quite a few others of his descent). might want to look up "logic" and "term logic" in wikipedia. (again, not to say that wikipedia is accurate in all things, but this looks reasonably decent.)

these formal rules of logic are solely about thinking straight. it's about applying consistency and about being clear about what a premise says and what it does not say.

 Logic is a mathematical discipline with a very specific meaning.
perhaps logic in mathematics is a mathematical discipline, but otherwise that statement is false in that it is not sufficiently broad.

mathematics is about quantity (among other things like structure, but mainly about quantity). except in the boolean sense, logic need not be. and although quantity can be assigned boolean variables, it need not be. "value" is not exactly the same thing as "quantity".

logic, as a discipline, contains mathematics (when quantity is introduced to the discussion), and science (when the empirical and material are introduced to the discussion), and sociology, politics, and law (when human beings and human behavior are brought into the discussion), and, if i dare say so, religion (when notions of God and the metaphysical are brought into the discussion). and even this statement from me is also not sufficiently broad.

 Quote by rbj real "nothing" would be no physical quantity (what i like to call "stuff") and no relationships or law of interaction either. and no one around to behold it.
The link below is including so many physical quantities that exist in universe .
Can you prove these quantities came from energy ? or came from another quantity ?
If you can not , that mean they came from real "nothing" .

http://en.wikipedia.org/wiki/List_of...cal_quantities
 Recognitions: Gold Member Science Advisor This is what happens when you abandon a mathematical discussion and start arguing metaphysics and philosophy which are disciplines that go nowhere and terminate in pointless non mathematical / non empirical arguments and frankly Chalnoth hit the nail on the head many posts ago when he said "We don't know" as of now.

Recognitions:
 Quote by big_bounce The link below is including so many physical quantities that exist in universe . Can you prove these quantities came from energy ?
This statement makes no sense whatsoever. Energy is a physical property of matter (pedantically, it is a property of every quantum-mechanical field).

 Quote by big_bounce or came from another quantity ? If you can not , that mean they came from real "nothing" .
This is also incorrect. Just because we don't know how these physical quantities arose, that doesn't mean that you get to automatically substitute your favored explanation in its absence.

Recognitions:
Gold Member
 Quote by WannabeNewton This is what happens when you abandon a mathematical discussion and start arguing metaphysics and philosophy which are disciplines that go nowhere and terminate in pointless non mathematical / non empirical arguments and frankly Chalnoth hit the nail on the head many posts ago when he said "We don't know" as of now.
Well said I for one, like many others have gotten tired of the pointless bickering going on.
Debating is one thing, provided supporting articles, mathematics or reasonable analysis is included is one thing.
Personal based arguments is quite another.
If you have a problem with a model, then take the time to provide supporting evidence or problems with THAT given model.
If you look at this thread carefully enough some of the problems of false energy has been stated. The one that stands out the most is the problem of stopping the inflation.
That lead to a multiple of alternate modifications. Some of which I listed.
If I as NON scientist can spend the time looking for problems in a given model AND supply supporting material. Then so can anyone else.

Recognitions:
Gold Member
Chalnoth posted:

 ...These fluctuations are the ones that started the initial density perturbations which eventually grew to be the galaxy clusters and voids in our universe today. These are not the fluctuations which might have gotten inflation started, but rather the ones that were occurring as inflation was progressing.....
Are these necessarily different perturbations....??

In a very new series of papers from Ashtekar, et al, [recently discussed here] it seemed the authors had found consistent inflationary perturbations all the way back in the Planck regime.....

 Using LQG ideas and techniques, we have extended the inﬂationary paradigm all the way to the deep Planck regime. At the big bounce, one can specify natural initial conditions for the quantum state Ψo that encodes the background homogeneous quantum geometry, as well as for ψ that describes the quantum state of perturbations. There is a precise sense in which generic initial conditions for the background lead to a slow roll phase compatible with the 7 year WMAP data....
[I think Marcus had started a thread referencing these papers, but I did not record the thread link..]

A Quantum Gravity Extension of the Inflationary Scenario
Ivan Agullo, Abhay Ashtekar, William Nelson
(Submitted on 7 Sep 2012)
http://arxiv.org/abs/1209.1609

The pre-inﬂationary dynamics of loop quantum cosmology:

Confronting quantum gravity with observations
Ivan Agullo, Abhay Ashtekar, and William Nelson

 ...Using techniques from loop quantum gravity, the standard theory of cosmological perturbations was recently generalized to encompass the Planck era. We now apply this framework to explore pre-inﬂationary dynamics. The framework enables us to isolate and resolve the true trans-Planckian diﬃculties, with interesting lessons both for theory and observations. Speciﬁcally, for a large class of initial conditions at the bounce, we are led to a self consistent extension of the inﬂationary paradigm over the 11 orders of magnitude in density and curvature, from the big bounce to the onset of slow roll.
 Certainly. Anything with "Nothing/create" are good catch phrases. Zero/uncertainty to entropy to universe. Might wanna check "The information as absolute" by S.V. Shevchenko, V.V. Tokarevsky. http://arxiv.org/abs/1004.3712. In informational conception the unique fundamental essence that exists is absolutely infinite Set “Information”, which include, for example, subset “Matter”; all what one sees is/are “words”. Any element of the Set contains the Set totally because of to define the element is necessary to point out all differences of given element from every other element in the Set. The element “nothing” is only one of the Set’s elements –i.e. dynamical null set. 'Nothing' is fairly complicated stuff. You have to define nothing in specific way. The idea of "nothing" stems from this notion of a collection and analogous to empty set. So we can think of "nothing" as a term describing the set itself and not a necessity of zero in mathematical language. The universe might came from uncertainty. Nothing can only make sense if given limitations but can be use in both accounts. Nothing is our imaginative construct to make sense of specific order in a specific task. It is associated with the mathematicians new concept of "zero" (as a number without any magnitude). It is a formal "nothing", like zero, but made up of +1 and -1, or equal amounts of positive and negative charges, or even completely balanced forces which give the appearance of zero activity, and, of course, many others of similar ilk. To say that the universe came from nothing is a "fair assumption" relative to what we 'currently' know to a certain (v) degree of confidence.

 Quote by WannabeNewton ... and frankly Chalnoth hit the nail on the head many posts ago when he said "We don't know" as of now.
it hadn't been the instances when Chalnoth says "We don't know" that i had ever disputed what he/she said.

it was, in fact, the instances when he should have said "We don't know", and said something quite different (and virtually diametrically opposite) that i took issue with what he said. at least in the other multiverse thread.
 Recognitions: Gold Member I read that article before the other thread you mentioned. I ran into the problem of finding references to Bunch-Davies vacuum. As a result I've been having trouble understanding it. Anyone have a good reference link? Edit a couple of posts occired while I wad typing I am referring to the last post by Naty

 Similar discussions for: Why Stephen Hawking says universe can create itself from nothing? Thread Forum Replies Cosmology 45 General Physics 12 Science Textbook Discussion 0 General Discussion 6 General Physics 4