"The current understanding of science holds that spacetime began to exist
when the universe began to exist. It is meaningless to ask what came before
the Big Bang, in the same sense that it is meaningless to ask
what is south of the South Pole." ~ Dave Muscato
“More than half of our neighbors believe that the entire universe was created
six thousand years ago. This is, incidentally, about a thousand years
after the Sumerians invented glue.” ~ Sam Harris [less than half by now]
This discussion will briefly address why creationists are so excited about the Big Bang as evidence for a creator and why they often believe that the multiverse concept is just an attempt by many scientists to avoid the contention that the Big Bang logically points to a creator. A disclaimer - I have no educational background in cosmology but have been following this aspect of creationism and apologetics for many years and hope that I at least understand the main issues.
A. The Big Bang
Most physicists and cosmologists in the 19th and 20th centuries, including Einstein, viewed the universe in a static state or steady state condition. Although it had been observed since 1912 that galaxies (at that time called nebula because telescopes were not strong enough to reveal they were really galaxies and not globs of gas/dust) were receding from earth, the importance of this observation was not appreciated. In 1924 Hubble observed that these nebula were actually other galaxies outside our own and by 1927 he had formulated a law to describe how fast they were moving away from us. A Belgian Roman Catholic priest and physicist, Georges Lemaître, working with mathematical equations showed that the universe was actually expanding. Fred Hoyle, who was a proponent of the steady state model, described during a BBC interview in 1949 this expansion theory as “The Big Bang” and the name stuck. Gradually over the decades observations such as the Cosmic Microwave Background Radiation (CMB) in 1964 , galaxy formations, and mathematical models supporting the Big Bang all coalesced into convincing support for the theory. It is now accepted that the Big Bang occurred 13.8 billion years ago. A major advancement was the development of inflation by Guth from theoretical mathematics that solved some problems with the Big Bang Theory(1).
There are several major misconceptions about the Big Bang. First, it was not an explosion like we experience explosions on earth. Rather, the observable universe is expanding and carrying galaxies with it. This very brief expansion period is known as inflation and is integral to the Big Bang Theory but also as we will see is critical in the Multiverse idea. This is also why the galaxies are not only moving away from us but counterintuitively, accelerating. Another misconception is that the Big Bang explains the origin of the universe. However, it does not explain the origin of energy, space and time. Current calculations place the observable universe with a diameter of 93 billion light years and age of 13.8 billion years. Note this is not what we can observe but rather what is the physical limit the speed of light produces for the theory (2).
The reason apologists love the Big Bang is they think it points to a beginning, not an infinite state, and that this confirms the Biblical Genesis. This expectation is summarized in the Cosmological Argument for God but more specifically the Kalam Cosmological Argument for God where since everything is said to have a cause the universe must have been caused (3). My simplified rendition:
Things are always caused by something
The Universe began at the Big Bang
The Universe was thus caused by something
The best explanation must be God
But as I will now show, it’s not at all clear that the Big Bang was the start of the universe. An infinite universe is also possible. Questions then arise. What is the universe expanding into? Furthermore, what caused inflation? Well, it turns out that it is entirely possible that our universe could be infinite and the Cosmological Arguments for God must now be suspended. “Our current cosmological model does an excellent job describing the universe down to the first fraction of a second. It is only a tiny fraction of a second where our theoretical models break down: physics becomes very different from anything we could build an experiment for here on earth and we also struggle to look back this far since our view is obscured by things like the Cosmic Microwave Background. But just because a tiny fraction of a second seems small on a human timescale that doesn't mean there isn't a lot of room for a lot to have happened back then that we don't yet know about: maybe our universe started from nothing, maybe it bounced back from a previous universe or started from within another. We don't even know if our universe is a finite size or infinite. All we are pretty confident about so far is that our universe has been expanding for many billions of years. When we extrapolate backward the entire part of the universe that we can observe today was converged to a single point around 14 billion years ago.
Time is a concept that works great in our daily life but there are limits to it… So when we say before the big bang, we can not just assume that something like "a second before the big bang happened" has to make sense. For example, the future can be infinite, a clock ticking forever, I don't need to imagine anything beyond that. In the same way in the early universe density diverges and the concept of time can stop existing as we reach time zero, there does not have to be a before.” (4)
From Karen Masters: “We can define the universe as everything there is, so in that case there is nothing outside of it. We also say that space and time both started at the Big Bang and therefore there was nothing before it. Another definition for the universe is the observable universe - which is the part of it that we can technically see. We cannot know what is outside of that (since we can't observe it), but we think that physics works the same everywhere and so we think that it should be very similar to the observable universe. We actually think that the universe might be infinite in extent, and so goes on forever, even though we can only see a finite part of it.
We can speculate in meta-physics or in religion about what was before the Big Bang, but again, we cannot use science to tell anything about it as physics as we understand it breaks down at that point.” (5).
As Pandian writes, things in theoretical physics can become very strange and as the video below by Physics Girl also explains:
“As to where everything came from, there is no conclusive opinion. One idea was that the Universe was created from vacuum. This is because according to quantum theory, the apparently quiescent vacuum is not really empty at all… Such [quantum] vacuum fluctuations cannot be observed directly as they typically last for only about 10-21 seconds and the separation between the electron and positron is typically no longer than 10-10 cm. However, through indirect measurements, physicists are convinced that these fluctuations are real… In 1982, Alexander Vilenkin proposed an extension of Tyron's idea and suggested that the Universe was created by quantum processes starting from "literally nothing", meaning not only the absence of matter, but the absence of space and time as well.” “Another idea is from Stephen Hawking and James Hartle. Hawking proposed a description of the Universe in its entirety, viewed as a self-contained entity, with no reference to anything that might have come before it. The description is timeless, in the sense that one set of equations delineates the Universe for all time… In Hawking's words, the Universe "would neither be created nor destroyed. It would just BE”… So, the origin of mass in the Universe and the Universe itself is quite speculative at this point.” (6)
Important short fun 10 min. video to update us on cosmological understandings - and misunderstandings. Please watch! And you may never look at raisin bread the same way again.
Very probably no singularity - https://bigthink.com/starts-with-a-bang/big-bang-beginning-universe/
The start of our universe - 2 interpretations
Either the Big Bang was the start of the universe or it was not but was preceded by a period of inflation. It turns out there is a way to test which origin explantion is true.
"As you can clearly see, there can be no doubt that there truly are super-horizon fluctuations within the Universe, as the significance of this signal is overwhelming. The fact that we see super-horizon fluctuations, and that we see them not merely from reionization but as they are predicted to exist from inflation, is a slam dunk: the non-inflationary, singular Big Bang model does not match up with the Universe we observe. Instead, we learn that we can only extrapolate the Universe back to a certain cutoff point in the context of the hot Big Bang, and that prior to that, an inflationary state must have preceded the hot Big Bang."
There was a universe before the Big Bang. And has been noted above, an infinite universe cannot be ruled out. The Cosmological Argument for God thus rests on an unproven premise and should be discarded at this time.
Ethan Siegel - what is the universe expanding into?
How vs. What and Einstein?
Scientist : Einstein's theory of general relativity has been validated and corroborated by evidence.
Critic : Einstein's theory of relativity cannot be valid until you explain the origin of space-time.
Scientist : Listen, there is evidence for this theory, let's talk about that.
Critic : If you cannot explain the origin of space-time, your theory is false, because where did the space-time needed by general relativity come from ? It's a religion because you can't explain the origin of space-time
~Adeleke Emmanuel Oluwasegun
Summary
My point is that we don’t know if the universe is finite or infinite. We don’t know what came before the Big Bang and neither do the theologians nor philosophers. And to suggest that it must be God is just another example of a God of the Gaps Argument (logical fallacy) which has a terrible track record with science, forever shrinking in the face of ongoing scientific research and discoveries. Apologists are no longer justified in making this inference. If they were honest the Cosmological Argument for God and it’s offspring the Kalam Cosmological Argument should be put in a box to be discussed later if an infinite universe is someday ruled out. If it is finite there still may be natural explanations. Even IF somehow the Big Bang pointed to a deity, which it does not necessarily, the theist would only have a deistic god and in no way a personal one, let alone the God of the Bible. Indeed, considering how we find the universe, the earth, and life on our planet, this deity should be tried for indifference, incompetence or malevolence.
Does Modern Cosmology Prove the Existence of God? https://bigthink.com/starts-with-a-bang/modern-cosmology-god/?fbclid=IwAR0vJFo9njQs28lKAcilguAnhjdye8gN3SFrR_YUa2tRbdft3BqSoqf0jx0
Citations and References for section A
2. Misconceptions. https://en.wikipedia.org/wiki/Observable_universe
3. Cosmological Arguments for God.
4. What was there before the Big Bang? http://curious.astro.cornell.edu/the-universe/cosmology-and-the-big-bang/101-the-universe/cosmology-and-the-big-bang/general-questions/1098-but-seriously-what-was-there-before-the-big-bang-beginner
5. What was there before the Big Bang?
6. Where did the universe come from? http://curious.astro.cornell.edu/the-universe/cosmology-and-the-big-bang/101-the-universe/cosmology-and-the-big-bang/general-questions/572-where-did-the-universe-come-from-intermediate
7. How small was the universe at the start of the Big Bang? [never was a singularity] https://www.forbes.com/sites/startswithabang/2021/08/25/how-small-was-the-universe-at-the-start-of-the-big-bang/?sh=35a8618e5f79
8. Yes, the universe is really 100% reductionist in nature. https://bigthink.com/starts-with-a-bang/universe-reductionist/#Echobox=1690577002
9. The Strongest Evidence for a Universe Before the Big Bang (March, 2023)
10. Our Universe Wasn't Empty, Even Before the Big Bang (September, 2023)
B. The Multiverse
The apologists I have interacted with often think that scientists desire to never admit the existence of a deity and that the multiverse is a way for science to deny that the Big Bang is a beginning; the multiverse then amounts to an excuse for atheists to move past the Cosmological Argument for God according to them. Never mind that in America at least, a significant percentage of scientists are theists. My limited reading however is that the multiverse falls out of equations for inflation, which was briefly detailed in part A of this posting which is supported and integral to the Big Bang Theory. It is not just something science imagined to avoid the Big Bang as an origin to the universe. As Ethan Siegel writes : “One of the most successful theories of 20th century science is cosmic inflation, which preceded and set up the hot Big Bang. We also know how quantum fields generally work, and if inflation is a quantum field (which we strongly suspect it is), then there will always be more "still-inflating" space out there. Whenever and wherever inflation ends, you get a hot Big Bang. If inflation and quantum field theory are both correct, a Multiverse is a must.”
“That’s what the multiverse is, and why scientists accept its existence as the default position. We have overwhelming evidence for the hot Big Bang, and also that the Big Bang began with a set of conditions that don’t come with a de facto explanation. If we add in an explanation for it — cosmic inflation — then that inflating spacetime that set up and gave rise to the Big Bang makes its own set of novel predictions. Many of those predictions are borne out by observation, but other predictions also arise as consequences of inflation.”(7)
“This picture, of huge Universes, far bigger than the meager part that's observable to us, constantly being created across this exponentially inflating space, is what the Multiverse is all about. It's important to recognize that the Multiverse is not a scientific theory on its own. It makes no predictions for any observable phenomena that we can access from within our own pocket of existence. Rather, the Multiverse is a theoretical prediction that comes out of the laws of physics as they’re best understood today. It’s perhaps even an inevitable consequence of those laws: if you have an inflationary Universe governed by quantum physics, this is something you’re pretty much destined to wind up with.”
“It's possible that our understanding of the state before the hot Big Bang is incorrect, and that our ideas about inflation are completely wrong for this application. If that's the case, then the existence of a Multiverse isn't a foregone conclusion. But the prediction of an eternally inflating state, where an uncountably large number of pocket Universes are continuously born and driven inextricably apart from one another, is a direct consequence of our best current theories, if they're correct.” (8)
Brian Cox discusses the Big Bang and the Multiverse concept here:
Conclusion
Our universe may indeed by infinite or finite. If infinite the Cosmological Argument for God fails. The Big Bang is strongly supported by science but says nothing about what came before or why it started. These unknowns negate the arguments for God through logical inferences because the premises are not established as theists claim, or are falsified. The Big Bang does not by default support deism, let alone theism. If the Multiverse is true, then again the Big Bang Theory fails to automatically support the existence of God.
An important observation from Sabine Hossenfelder is that the Multiverse is not a scientific theory and it’s also not even a scientific hypothesis because to date there is no way to test it. It is a theoretical prediction from inflation where inflation is integral to the Big Bang Theory. It is beyond irony that theists run to embrace the Big Bang which depends on inflation while trying to diminish the multiverse idea which is a direct consequence of that same inflation.
Citations for section B
7. Why the multiverse is suspected
8. The Multiverse is Inevitable https://www.forbes.com/sites/startswithabang/2017/10/12/the-multiverse-is-inevitable-and-were-living-in-it/?sh=55fc36f016c9