Physics, the study of nature, is grounded not just in precise facts, but also a loose form of logic called mathematics, and in even more general reasonings we know as “philosophy”. For example, the rise of Quantum Field Theory required massive Effective Ontology: define things by their effects. The reigning philosophy of physics became “shut-up and calculate”. But it’s not that simple. Even the simplest Quantum Mechanics, although computable, is rife with mind numbing mysteries (about the nature of matter, time and non-locality).
Recently the (increasing) wild wackiness of the Foundations of Physics, combined with the fact that physics, as it presently officially exists, cannot under-stand Dark Energy and Dark Matter, most of the mass-energy out there, has led some Europeans to organize conferences where physicists meet with reputable philosophers.
[Bell, CERN theory director, discovered a now famous inequality expressing locality, which Quantum physics violate. Unfortunately he died of a heart attack thereafter.]
Something funny happened in these conferences: many physicists came out of them, persuaded, more than ever, or so they claimed, that they were on the right track. Like little rodents scampering out in the daylight, now sure that there was nothing like a big philosophical eagle to swoop down on them. They made many of these little reasonings in the back of their minds official (thus offering now juicy targets).
Coel Hellier below thus wrote clearly what has been in the back of the minds of the Multiverse Partisans. I show “his” argument in full below. Coel’s (rehashing of what has become the conventional Multiverse) argument is neat, cogent, powerful.
However I claim that it is not as plausible, not as likely, as the alternative, which I will present. Coel’s argument rests on a view of cosmology which I claim is neither mathematically necessary, nor physically tenable (in light of the physics we know).
To understand what I say, it’s better to read Coel first. Especially as I believe famous partisans of the Multiverse have been thinking along the same lines (maybe not as clearly). However, to make it fast, those interested by my demolition of it can jump directly to my counter, at the end: NO POINTS, And Thus No Multiverse.
Multiverses Everywhere: Coel Hellier’s Argument:
“Prompted by reading about the recent Munich conference on the philosophy of science, I am reminded that many people regard the idea of a multiverse as so wild and wacky that talking about it brings science into disrepute.”
Well, being guided by non-thinking physicists will do that. As fundamental physicist Mermin put it, decades ago:
Coel, claiming to have invented something which has been around for quite a while, probably decades: “My argument here is the reverse: that the idea of multiple Big Bangs, and thus of a multiverse, is actually more mundane and prosaic than the suggestion that there has only ever been one Big Bang. I’m calling this a “philosophical” argument since I’m going to argue on very general grounds rather than get into the details of particular cosmological models.
First, let me clarify that several different ideas can be called a “multiverse”, and here I am concerned with only one. That “cosmological multiverse” is the idea that our Big Bang was not unique, but rather is one of many, and that the different “universes” created by each Big Bang are simply separated by vast amounts of space.
Should we regard our Big Bang as a normal, physical event, being the result of physical processes, or was it a one-off event unlike anything else, perhaps the origin of all things? It is tempting to regard it as the latter, but there is no evidence for that idea. The Big Bang might be the furthest back thing we have evidence of, but there will always be a furthest-back thing we have evidence of. That doesn’t mean its occurrence was anything other than a normal physical process.
If you want to regard it as a one-off special event, unlike any other physical event, then ok. But that seems to me a rather outlandish idea. When physics encounters a phenomenon, the normal reaction is to try to understand it in terms of physical processes.”
Then Coel exposes some of the basic conclusions of the Standard Big Bang model:
“So what does the evidence say? We know that our “observable” universe is a region of roughly 13.8 billion light years in radius, that being the distance light can have traveled since our Big Bang. (Actually, that’s how we see it, but it is now bigger than that, at about 90 billion light years across, since the distant parts have moved away since they emitted the light we now see.) We also know that over that time our observable universe has been steadily expanding.”
Then astrophysicist Coel start to consider necessary something about the geometry of the universe which is not so, in my opinion. Coel:
“At about 1 second after the Big Bang, what is now our observable universe was only a few light years across, and so would have fitted into (what is now) the space between us and the nearest star beyond our Sun. Before that it would have been yet smaller.”
What’s wrong? Coel assumes implicitly that the universe started from a POINT. But that does not have to be the case. Suppose the universe started as an elastic table. As we go back in time, the table shrinks, distances diminish. Coel:
“We can have good confidence in our models back to the first seconds and minutes, since the physics at that time led to consequences that are directly observable in the universe today, such as the abundance of helium-4 relative to hydrogen, and of trace elements such as helium-3, deuterium, and lithium-7. Before that time, though, our knowledge gets increasingly uncertain and speculative the further back we push.”
These arguments about how elements were generated, have a long history. They could actually be generated in stars (I guess, following Hoyle and company). Star physics is not that well-known that we can be sure they can’t (stars as massive as 600 Suns seem to have been discovered; usual astrophysics says they are impossible; such stars would be hotter than the hottest stars known for sure).
Big Bangists insist that there would have been no time to generate these elements in stars, because the universe is 13.8 billion years old. But that 13.8 billion is from their Big Bang model. So their argument is circular: it explodes if the universe is, actually 100 billion years old.
But back to Coel’s Multiverses All Over. At that point, Coel makes a serious mistake, the one he was drifting towards above:
“One could, if one likes, try to extrapolate backwards to a “time = zero” event at which all scales go to zero and everything is thus in the same place. But trying to consider that is not very sensible since we have no evidence that such an event occurred (from any finite time or length scale, extrapolating back to exactly zero is an infinite extrapolation in logarithmic space, and making an infinite extrapolation guided by zero data is not sensible). Further, we have no physics that would be remotely workable or reliable if applied to such a scenario. “
…”all scales go to zero and everything is thus in the same place.” is not true, in the sense that it does not have to be. Never mind, Coel excludes it, although he claims “extrapolating back in time” leads there. It does not.
Instead, Coel invites us to Voodoo (Quantum) Physics:
“So what is it sensible to consider? Well, as the length scale decreases, quantum mechanics becomes increasingly important. And quantum mechanics is all about quantum fluctuations which occur with given probabilities. In particular, we can predict that at about the Planck scale of 10−35 metres, quantum-gravity effects would have dominated. We don’t yet have a working theory of quantum gravity, but our best guess would be that our Big Bang originated as a quantum-gravity fluctuation at about that Planck-length scale.”
Well, this is conventional pata-physics. Maybe it’s true, maybe not. I have an excellent reason why it should not (details another time). At this point, Coel is firmly in the conventional Multiverse argument (come to think of it, he did not invent it). The universe originated in a Quantum fluctuation at a point, thus:
“So, we can either regard our Big Bang as an un-natural and un-physical one-off event that perhaps originated absolutely everything (un-natural and un-physical because it would not have been a natural and physical process arising from a pre-existing state), or we can suppose that our Big Bang started as something like a quantum-gravity fluctuation in pre-existing stuff. Any physicist is surely going to explore the latter option (and only be forced to the former if there is no way of making the latter work).
At times in our human past we regarded our Solar System as unique, with our Earth, Sun and Moon being unique objects, perhaps uniquely created. But the scientific approach was to look for a physical process that creates stars and planets. And, given a physical process that creates stars, it creates not just one star, but oodles of them strewn across the galaxy. Similarly, given a physical process that creates Earth-like planets, we get not just one planet, but planets around nearly every star.”
Coel then gets into the famous all-is-relative mood, rendered famous by “French Theory”:
“It was quite wrong to regard the Sun and Earth as unique; they are simply mundane examples of common physical objects created by normal physical processes that occur all over the galaxy and indeed the universe.
But humans have a bias to a highly anthropocentric view, and so we tend to regard ourselves and what we see around us as special, and generally we need to be dragged kicking and screaming to the realisation that we’re normal and natural products of a universe that is much the same everywhere — and thus is strewn with stars like our Sun, with most of them being orbited by planets much like ours.
Similarly, when astronomers first realised that we are in a galaxy, they anthropocentrically assumed that there was only one galaxy. Again, it took a beating over the head with evidence to convince us that our galaxy is just one of many.”
Well, it’s not because things we thought were special turned out not to be that nothing is special. The jury is still out about how special Earth, or, for that matter, the Solar System, are. I have argued Earth is what it is, because of the Moon and the powerful nuclear fission reactor inside Earth. The special twist being that radioactive elements tend to gather close to the star, and not in the habitable zone. So Earth maybe, after all special.
At this point, Coel is on a roll: multiverses all over. Says he:
“ So, if we have a physical process that produces a Big Bang then likely we don’t get just one Big Bang, we get oodles of them. No physical process that we’re aware of happens once and only once, and any restriction to one occurrence only would be weird and unnatural. In the same way, any physical process that creates sand grains tends to create lots of them, not just one; and any physical process that creates snowflakes tends to create lots of them, not just one.
So, we have three choices: (1) regard the Big Bang as an unnatural, unphysical and unexplained event that had no cause or precursor; (2) regard the Big Bang as a natural and physical process, but add the rider that it happened only once, with absolutely no good reason for adding that rider other than human parochial insularity; or (3) regard the Big Bang as a natural and physical event, and conclude that, most likely, such events have occurred oodles of times.
Thus Big Bangs would be strewn across space just as galaxies, stars and planets are — the only difference being that the separation between Big Bangs is much greater, such that we can see only one of them within our observable horizon.
Well, I don’t know about you, but it seems to me that those opting for (3) are the ones being sensible and scientifically minded, and those going for (1) or (2) are not, and need to re-tune their intuition to make it less parochial.”
To make sure you get it, professor Coel repeats the argument in more detail, and I will quote him there, because as I say, the Multiverse partisans have exactly that argument in the back of their mind:
“So, let’s assume we have a Big Bang originating as a quantum-gravity fluctuation in a pre-existing “stuff”. That gives it a specific length scale and time scale, and presumably it would have, as all quantum fluctuations do, a particular probability of occurring. Lacking a theory of quantum gravity we can’t calculate that probability, but we can presume (on the evidence of our own Big Bang) that it is not zero.
Thus the number of Big Bangs would simply be a product of that probability times the number of opportunities to occur. The likelihood is that the pre-existing “stuff” was large compared to the quantum-gravity fluctuation, and thus, if there was one fluctuation, then there would have been multiple fluctuations across that space. Hence it would likely lead to multiple Big Bangs.
The only way that would not be the case is if the size of the pre-existing “stuff” had been small enough (in both space and time) that only one quantum fluctuation could have ever occurred. Boy, talk about fine tuning! There really is no good reason to suppose that.
Any such quantum fluctuation would start as a localised event at the Planck scale, and thus have a finite — and quite small — spatial extent. Its influence on other regions would spread outwards, but that rate of spreading would be limited by the finite speed of light. Given a finite amount of time, any product of such a fluctuation must then be finite in spatial extent.
Thus our expectation would be of a pre-existing space, in which there have occurred multiple Big Bangs, separated in space and time, and with each of these leading to a spatially finite (though perhaps very large) universe.
The pre-existing space might be supposed to be infinite (since we have no evidence or reason for there being any “edge” to it), but my argument depends only on it being significantly larger than the scale of the original quantum fluctuation.
One could, of course, counter that since the initial quantum fluctuation was a quantum-gravity event, and thus involved both space and time, then space and time themselves might have originated in that fluctuation, which might then be self-contained, and not originate out of any pre-existing “stuff”. Then there might not have been any pre-existing “stuff” to argue about. But if quantum-gravity fluctuations are a process that can do that, then why would it happen only once? The natural supposition would be, again, that if that can happen once, then — given the probabilistic nature of physics — it would happen many times producing multiple different universes (though these might be self-contained and entirely causally disconnected from each other).”
Then, lest you don’t feel Multiversal enough, professor Coel rolls out the famous argument which brings the Multiverse out of Cosmic Inflation. Indeed, the universe-out of nothing Quantum fluctuation is basically the same as that of Cosmic Inflation. It’s the same general mindset: I fluctuate, therefore I am (that’s close to Paris motto, Fluctuat Nec Mergitur…). Coel:
“In order to explain various aspects of our observed universe, current cosmological models suggest that the initial quantum fluctuation led — early in the first second of its existence — to an inflationary episode. As a result the “bubble” of space that arose from the original quantum-fluctuation would have grown hugely, by a factor of perhaps 1030. Indeed, one can envisage some quantum-gravity fluctuations leading to inflationary episodes, but others not doing so.
The inflationary scenario also more or less requires a multiverse, and for a similar reason to that given above. One needs the region that will become our universe to drop out of the inflationary state into the “normal” state, doing so again by a quantum fluctuation. Such a quantum fluctuation will again be localised, and so can only have a spatially finite influence in a finite time.
Yet, the inflationary-state bubble continues to expand so rapidly, much more rapidly than the pocket of normal-state stuff within it, that its extent does not decrease, but only increases further. Therefore whatever process caused our universe to drop out of the inflationary state will cause other regions of that bubble to do the same, leading to multiple different “pocket universes” within the inflationary-state bubble.
Cosmologists are finding it difficult to construct any model that successfully transitions from the inflationary state to the normal state, that does not automatically produce multiple pocket universes. Again, this follows from basic principles: the probabilistic nature of quantum mechanics, the spatial localisation of quantum fluctuations, and the finite speed at which influence can travel from one region to another.”
The driver of the entire Multiverse thinking is alleged Quantum Fluctuations in a realm we know f anything. Those who are obsessed by fluctuations may have the wrong obsession. And professor Coel to conclude with more fluctuations:
“The dropping out of the inflationary state is what produces all of the energy and matter that we now have in our universe, and so effectively that dropping-out event is what we “see” as our Big Bang. This process therefore produces what is effectively a multiverse of Big Bangs strewn across that inflationary bubble. Thus we have a multiverse of multiverses! Each of the (very large number of?) quantum-gravity fluctuations (that undergo an inflationary state) then itself produces a whole multiverse of pocket universes.
The point I am trying to emphasize is that any process that is at all along the lines of current known physics involves the probabilistic nature of quantum mechanics, and that means that more or less any conceivable process for creating one Big Bang is going to produce not just a single event, but almost inevitably a vast number of such events. You’d really have to try hard to fine-tune and rig the model to get only one Big Bang.
As with any other physical process, producing multiple Big Bangs is far more natural and in-line with known physics than trying to find a model that produces only one. Trying to find such a model — while totally lacking any good reason to do so — would be akin to looking for a process that could create one snowflake or one sand grain or one star or galaxy, but not more than one.”
Patrice Says: NO POINTS, AND THUS NO MULTIVERSE(s):
Did the universe expand from one point? Not necessarily. It could have been from a line, a plane, a volume, even something with a crazy topology. The Big Bang is the time zero limit of the FLRW metric. Then the spacing between every point in the universe becomes zero and the density goes to infinity.
Did the Universe expand from Quantum Gravity? Beats me, I don’t have a theory of Quantum Gravity.
What I know is that, expanding from what’s known of gravity, if the universe expanded from a “point”, that would be smaller than the Planck volume, thus the universe would be within a Black Hole. From what we know about those, no expansion.
Once we don’t have the universe expanding from a point, we cannot argue that it expanded from one point in some sort of “stuff”. If the universe is the “stuff” itself, and it’s everywhere, and expanding from everywhere, exit the argument about a “point”.
The argument about a “point” was that: why this particular point? Why not another “Quantum Fluctuation” from another “point” in the “stuff”. Why should our “point” be special? Is it not scientific to believe in the equality of points? Except points have measure zero in three dimensional space, and thus it’s more “scientific”, “mathematical” to suppose the universe expanded from a non-measure zero set, namely a volume (and it better be bigger than the Planck Volume).
So the argument that there should be many universes because there are many points and many Quantum (Gravity) fluctuations flies apart.
Remains the argument that we need Cosmic Inflation. Yes, but if the universe expands from all over, all over, there is only one such. Cosmic Inflation does not have to appear at all points generating baby universes, It becomes more like Dark Energy.
Speaking of which, why should we have two Cosmic Inflations when we already have one? Even my spell checker does not like the idea of two inflations. It does not like the “s”. Ah, yes, the existing Big Bang needs its own Inflation.
Yet if there is only one inflation, presto, no more standard Big Bang, But then what of Helium, Lithium, etc? How do we synthesize enough of those? Well maybe we would have much more time to synthesize them, inside stars… Especially super giant stars.
Another word about these Quantum Fluctuations. Are they the fundamental lesson of Quantum Physics (as the Multiversists implicitly claim)? No.
Why? There are several most fundamental lessons about Quantum Physics. Most prominent: the DYNAMICAL universe is made of waves. That fact, by itself implies NON-LOCALITY. It also implies neighborhoods, no points, are the fundamental concepts (one cannot localize a wave at a point). This is the origin of the “Quantum Fluctuations”.
So we just saw that “Quantum Fluctuations” may not be the most fundamental concept. Fundamental, yes, but not most fundamental. When debating fundamentals with the Devil, you better bring exquisite logic, and a Non-Local spoon, otherwise you will be Quantum fluctuated out.