The geometry of BGV theorem is not difficult to understand. One must turn to the “verbal/written language” because people like Sean Carroll obfuscate the clear meaning of the geometry.
“The inflationary period began at approximately 10⁻³⁶ seconds after the Big Bang.” Source: Alan H. Guth, The Inflationary Universe: The Quest for a New Theory of Cosmic Origins, Basic Books, 1997, p. 186.
This science writer describes Guth’s position correctly in this quote:
“Guth is best known for pioneering the theory of cosmic inflation, a model that explains the exponential growth of the universe mere fractions of a second after the Big Bang, and its continued expansion today.”
“10 Questions for Alan Guth, Pioneer of the Inflationary Model of the Universe” by Christina Couch.
The geometry of BGV theorem shows there is a boundary so that any expanding universe (like ours) cannot be eternal to the past. Einstein’s GR shows that space and time are integral to each other. Both came into existence at the same moment in time. This is a direct implication of the theory. Vilenkin acknowledges the initial conditions were “no spacetime.”
See Vilenkin, Alexander. “Birth of inflationary universes.” Physical Review D 27.12 (1983): 2848.
Thank you for sharing your Grok conversations. I gave it some additional prompts. Grok writes:
"The criticisms you raise are valid:
An eternal, hot, dense static state is highly fine-tuned and unstable in classical general relativity, making it seem miraculous without exotic physics.
The sudden transition to expansion appears arbitrary without a clear mechanism, resembling a second fine-tuning issue, and the onset of expansion marks a thermodynamic beginning in the sense of initiating entropy evolution."
When I asked “Isn’t it true that we have no empirical evidence our universe was ever in a nonexpanding state?”
Grok replied, “Yes, no direct empirical evidence suggests our universe was ever in a non-expanding state.”
I also asked Grok if my comment about our standard cosmology is completely noncontroversial. Grok replied:
“In the context of standard cosmology—excluding speculative models like Aguirre-Gratton or non-expanding scenarios—your comment is noncontroversial. All multiverse models in this framework (e.g., eternal inflation) involve expanding spacetimes, and the BGV theorem implies they have a past boundary, consistent with an ultimate beginning. This view is widely accepted among cosmologists working within empirically supported models.” https://grok.com/share/c2hhcmQtMg%3D%3D_d9decdd2-4306-475f-9f62-85c8ad55565c
It isn’t a matter of what I want. This point is what does the science say. The only way to avoid a Creator is to embrace some speculative cosmology without any empirical support. Einstein’s GR implies space and time came into existence at the same point. Many observations support the concept our universe is a spacetime. Since this is true, the initial conditions were “no spacetime”. In that case, Nature did not exist and the beginning of the universe cannot be caused by any Natural process. See the book God and the Astronomers by NASA scientist Robert Jastrow or this paper by Vilenkin.
Vilenkin, Alexander. “Birth of inflationary universes.” Physical Review D 27.12 (1983): 2848.
Really? Sean Carroll, of all people, you’re accusing of obfuscating the clear meaning of the physics of the BVG theorem?
That suggestion can’t be entertained by a thinking person who has ever spent any amount of time listening to the man.
If anything Sean Carroll is one of the most down to Earth people who do the most to try to bring everyone on board and understand the ideas they speak about. It is clear to anyone who listens to him that he’s as much of a teacher as he is a theoretical physicist.
Just as readily, the only way to avoid some speculative cosmology is to embrace a Creator without any empirical support.
This point has been raised repeatedly. Throughout you refuse to acknowledge or even discuss that divine creation does not enjoy some privileged position as a hypothesis.
There lies your mistake. In bold. A detail you didn’t bother adding previously. You can’t just pretend like all multiverse models involve or are products of inflationary cosmology.
So no, I was in fact correct. It is not standard cosmology, nor uncontroversial, to claim that all multiverse models involve an absolute beginning. Grok again agrees.
Indeed. In fact, it’s rather hard to understand the point of this argument. There is a 900-foot tall looming non sequitur right in the center of it: the idea that the universe having a beginning means that a creator-god exists. That simply doesn’t follow. Not only does it not follow, but it makes so little sense that it is damned near impossible to imagine how anyone could think that it COULD follow. It’s very much in the “horses have four legs, therefore, communism is the best system of economic organization” class of non sequiturs. Two things that have utterly zero to do with each other and no known relationship to one another; yet one of them is said to follow from the other.
I’ve seen this time and again: despite the core problem with the argument, someone will point to some particular set of scientific or quasi-scientific facts, observations or speculations, and say, “well, gawrsh, that shows that the universe DID have a beginning, so, you know, case closed.” The difficulty is that no matter how strong your evidence is that horses have four legs, communism still doesn’t follow. Emphasizing the four-legs point is just a distraction from the unresolvable problem.
That Inference article is worth a read. The bit you quoted “It probably did,” follows a section explaining that …
Modern physics can describe the emergence of the universe as a physical process that does not require a cause.
… and a bit later …
If all the conserved numbers of a closed universe are equal to zero, then there is nothing to prevent such a universe from being spontaneously created out of nothing. And according to quantum mechanics, any process which is not strictly forbidden by the conservation laws will happen with some probability.
Nothing to prevent is not the same as proof, and Vilenkin is correct to point out that theories of Quantum Creation are not yet testable. Occam’s Razor makes this a reasonable position, at least, and there is no need to follow the rabbit don’t the “Who Created God” rabbit hole. One CAN jump down that rabbit hole if so inclined, but we have a plausible idea for the origin of the universe that does not require chasing philosophical rabbits.
“More importantly, the BGV theorem was published in 2003. This is a mathematical proof that any cosmological model which is expanding on average over its history must have a beginning. Because all multiverse models contain a universe generator of some kind, all multiverse models are expanding. Therefore all multiverse models have an ultimate beginning.”
It never dawned on me that you thought you were correcting me. I thought you were agreeing with me and so I did not see any reason to comment on the fact BGV applies to expanding universes.
Hello Ron!
Not true. You cannot say the Creator has no empirical support when we can observe his effects in the universe. The scientific evidence for God is very like the scientific evidence for dark matter. We cannot directly detect dark matter with our instruments or our eyes, but we can observe its effects in the universe.
For good measure I again asked Grok whether my views here are correct, and it agreed. The multiverses emergent from various distinct physical theories were NOT invented to try to provide answers to fine-tuning problems, nor to try to “naturalize” the big bang. That claim is a historical falsehood.
I’ve never seen an equation in the bible that predicts things like physical constants, the rate of expansion of space, rate of star formation in the early universe, the temperature of the CMB, or anything of that sort.
Simply put God is not a scientific hypothesis that predicts anything. Every time science discovers something new, rather, apologists come along and declare after the fact that they knew it all along and it’s totally what God would have done. To consider anything in cosmology to be evidence for the God hypothesis you need an actual hypothesis that generates quantifiably testable predictions. And why would you expect a particular world on the God hypothesis?
Obviously since God is supposed to be a supernatural omnipotent mind with the ability to bend reality to his will, there’s no reason in the first place to expect the physical universe to exhibit any particular attribute since God could simply will for life to be able to exist no matter the conditions inside the universe. Everything everywhere could be like the core of a blue supergiant, a hundred million degree kelvin roiling plasma, or the surface of a neutron star, or innumerable other possiblities, and God could just want life to be able to exist regardless. There isn’t a reason to think there had to be any sort of physical reality at all in the first place.
Another issue here is that religious apologists often also propose that the mind and consciousness are the product of an immaterial soul, so it’s not clear what value or purpose the physical universe holds if God’s ultimate aims for human life is the afterlife. Since in your religious conceptions the human mind, emotions, morality, and all the rest don’t require physical organs such as human brains to exist in the first place, theism ultimately does not predict a physical universe at all. God could assign souls to massless photons living on a 2 dimensional plane. Or numbers on a number line. Or vertices in a purely geometric realm.
You don’t have a scientific hypothesis and you never will.
The point is that the universe is not entirely natural. We know that because the ultimate beginning happened in the absence of Nature. Therefore, a natural process is precluded.
Nothing else you wrote is relevant to the conversation.
On the contrary, it is exactly relevant; it’s what makes the difference between a scientific argument and apologetics. You complained that no one here would discuss “the science” with you, but here you are, refusing to discuss the science. If you cannot answers those criticisms as an apologist, that is no shame on you - No one really expects that you should be able to answer such questions scientifically.
Again, what you are trying to do is no different from the many who have come before you, trying to refine things in such a way as to “prove” the existence of God. The only thing new is obfuscating the question with AI, and that has been tried here before too.
