When Scientists Speak Inaccurately in Their Zeal to Show Some Theory Is "Beyond Doubt"

There are in academia quite a few highly intelligent thinkers who have widespread doubt about the reliability of most scientific theories. Such thinkers are often philosophers of science. Philosophers of science have often said that most scientific theories are underdetermined. A theory is said to be underdetermined if there is not sufficient evidence to establish its truth. A scientific theory is said to be underdetermined when there are no observations allowing us to tell that such a theory is true rather than other rival theories that can explain observations equally well. Such theories are called “empirical equivalents.” You can find out more about this topic by doing a Google search for “underdetermination of scientific theory.” The article here gives a detailed discussion of the topic.

In many cases, we can readily think of alternate theories to explain the things that a scientific theory was created to explain. For example, we can easily imagine a rival to the theory that man appeared by evolving from lower species : a theory that humanity was specifically introduced to our planet with help from visiting extraterrestrials. In other cases, we may not be able to readily think of a rival theory to a scientific theory. But in such a case there are typically five or ten possible theories that could be imagined by someone willing to expend enough time thinking up alternatives. When we can't think of some rival theory that might be an empirical equivalent to some popular scientific theory, this usually just reflects the weakness of our imagination, not a lack of possible alternatives.

The current theory of the origin of the universe is the Big Bang theory, which postulates that the universe began expanding from an infinitely dense point at a time nearly 14 billion years ago. There are two strong reasons for thinking that the theory is true. The first is that what are called the redshifts of galaxies suggest that the universe is expanding. An expanding universe seems to imply that the universe was once long ago in some state of extremely high density. Another reason for believing in the Big Bang is that it seems to explain something called the cosmic microwave radiation. 

However, like so many other major scientific theories, the Big Bang theory is underdetermined.  We lack any observations that prove the Big Bang theory beyond any doubt. There are also two major reasons why the Big Bang theory fails to be a predictively successful theory. The first reason is rather small: the Big Bang theory does not correctly predict the level of  ⁷Li (one of the isotopes of the element lithium) that now exists in the universe. This is known as the primordial lithium problem. According to the 2024 paper here, "there is still a disparity of ⁷Li abundance overestimated by a factor of ~2.5 when calculated theoretically." Successful scientific theories are supposed to make predictions that "hit the bulls-eye." Being wrong by a factor of 250% is not hitting the bulls-eye, but is instead missing the target entirely. 

A much larger problem is that the Big Bang theory does not actually predict a universe like the universe we live in. It instead predicts a universe that is either 50% matter and 50% antimatter, or a universe that is pure energy. The problem is illustrated in the infographic below. 

Experimenting with very high-speed particle collisions occurring in particle accelerators, scientists observe that when two very high-energy photons collide, they produce equal amounts of matter and antimatter; and they also observe that when matter collides with antimatter, it is converted into high-energy photons. Such collisions are observed in particle accelerators such as the Large Hadron Collider, where particles are accelerated to near the speed of light before they collide with each other. But such observations about matter, antimatter and photons leads to a great mystery as to why there is any matter at all in the universe.

Let us imagine the early minutes of the Big Bang about 13 billion years ago, when the density of the universe was incredibly great. At that time the universe should have consisted of energy, matter and antimatter. The energy should have been in the form of very high energy photons that were frequently colliding with each other. All such collisions should have produced equal amounts of matter and antimatter. So the amount of antimatter should have been exactly the same as the amount of matter. As a CERN page on this topic says, "The Big Bang should have created equal amounts of matter and antimatter in the early universe." But whenever a matter particle touched an antimatter particle, both would have been converted into photons. The eventual result should have been a universe consisting either of nothing but photons, or some matter but an equal amount of antimatter. But only trace amounts of antimatter are observed in the universe.

It would be incredibly inconvenient if matter and antimatter were equally distributed. So much energy is released when matter makes contact with antimatter that if there were trace amounts of antimatter lying about, you'd have “oops, someone blew up Europe because he stepped on a tiny piece of antimatter” situations all over the place. We know that there is very little antimatter in the universe because of the great rarity of high-energy events observed through telescopes. If there was lots of antimatter in outer space, we would be observing very frequently extremely high-energy events in space; because whenever matter came into contact with antimatter, enormous amounts of energy would be released. 

A scientific paper puts it this way: 

"In theory, a matter [amount] will be immediately annihilated if it meets with its antimatter, leaving nothing unless energy behind, and the amounts of matter with that of antimatter should be created equally in the Big Bang. So, none of us should exist in principle but we are indeed existing."

So the Big Bang theory does not actually predict a universe like ours. It instead predicts a universe that is either half-matter and half antimatter, or a universe with only energy (because all of the matter and antimatter made contact with each other in the early Big Bang, leaving nothing but photons). This shortfall of the Big Bang theory is called the matter-antimatter asymmetry problem or the baryon asymmetry problem. The problem is still unsolved. Do not be fooled by occasional speculative papers that appear claiming to provide a "solution" to such a problem. All such papers will involve extremely wild speculation that no one has verified. 

Another very severe limitation of the Big Bang theory is that it can never be proven true, given what the theory itself describes. The theory says that during the first 300,000 years of the universe's history, the density of matter was so great that all radiation coming from the universe's beginning must have been hopelessly scattered, because of innumerable collisions of particles in a very dense universe. So even though telescopes can in effect "look back in time" by looking at galaxies billions of light years away, there is no hope that telescopic observations will ever allow us to "look back in time" far enough to observe the very beginning of the universe, given the assumptions of the Big Bang theory. 

If our scientists were to honestly describe the Big Bang theory, they would describe it very humbly, saying something like this: 

"The Big Bang theory is our best guess about the universe's beginning, and there are some reasons for believing in it. But the Big Bang theory cannot be the full story. The theory does not actually predict a universe like ours. And we can never prove that the Big Bang actually happened, given the theory's assumptions. The early density was too great to ever observe what happened in the first 300,000 years. "

Instead of honestly speaking in such a way, some scientists have recently been speaking in a very misleading away about the Big Bang theory. For example, on the site The Conversation we have a long article by cosmologist Konstantinos Dimopoulos. It is reprinted on the Science Alert site with the title "The Big Bang is Beyond Doubt. An Expert Reveals Why." But that wasn't the original title of the article, so we can't use that title as evidence of a scientist claiming certainty where there is no certainty. 

However, reading the article we soon find evidence of just such a thing: a scientist claiming certainty where there is no certainty.  For in the article Konstantinos Dimopoulos says this: 

"The 14 billion year story of our universe begins with a cataclysmic explosion everywhere in space, which we call the Big Bang. That much is beyond reasonable doubt." 

No, such a thing certainly can be reasonably doubted, because no one ever directly observed such a thing, and also the Big Bang has two predictive failures, one of which is fairly small (the failure to correctly predict the abundance of one lithium isotope), and the other one extremely gigantic (the failure to predict a universe like ours, in which matter is very many times more abundant than antimatter). 

What does Dimopoulos say about the matter-antimatter asymmetry problem? He fails to even mention it. He does not even use the word "antimatter." He also fails to mention the problem that the Big Bang theory fails to correctly predict the level of  ⁷Li (one of the isotopes of the element lithium) that now exists in the universe. He says only one thing about predictions, and it is a very false claim. Referring to the theory of primordial cosmic inflation, a kind of offshoot of the Big Bang theory, he claims, "Precision observations of the cosmic microwave background in recent decades have spectacularly confirmed the predictions of inflation." No, that isn't true at all.

The theory of primordial cosmic inflation is actually a large family of theories, consisting of hundreds or dozens of theories. Each one of these theories can predict any of a million different things, based on what you supply as input parameters to the equations of the theory. The result is that the predictions of the theory of primordial cosmic inflation are "all over the map," as some cosmologists have confessed. The main prediction of cosmic inflation theories has been that there would be observed something called primordial b-modes. Huge amounts of money have been spent looking for such primordial b-modes, without any success. 

Dimopoulos has erred.  He has claimed that the basic idea of the Big Bang theory is "beyond reasonable doubt," but it is no such thing. He has claimed predictive success for a "cosmic inflation" offshoot of the Big Bang, a success that never occurred because there are so many versions of such a "cosmic inflation" theory that its predictions are all over the map (and because the primordial b-modes predicted by the theory were never found).  Dimopoulos has also ignored two predictive failures of the Big Bang theory (one very gigantic), which together mean that we have no warrant for claiming that the Big Bang theory is "beyond reasonable doubt." 

As bad as the misstatements by Dimopoulos are, they are nowhere near as bad as the grotesque fiction stated by astrophysicist Pablo G. Pérez González. He makes this huge misstatement:

"The first three minutes of the universe determined the current composition of the universe, along with all of its subsequent evolution. In other words, what we are today — everything that exists, everything that will exist, everything that does not exist and will not exist — was decided in just three minutes!"

Nonsense. Nothing that happened during the Big Bang did anything to guarantee that life and humans would one day exist. No one observing the first three minutes of the Big Bang would ever predict that the results billions of years later would one day include living things or beings as intelligent as humans. To the contrary, what they would predict from observing the first three minutes of the Big Bang is either a universe with 50% matter and 50% antimatter (which would be uninhabitable), or a universe in which all of the matter had combined with antimatter, leaving only energy photons left (which would be even more uninhabitable). 

What does Gonzalez say about this central problem with the Big Bang theory? Nothing at all. He does not even use the word "antimatter." 

There is a lesson to be learned here. The lesson is:  when a theory beloved by scientists has not been proven and when the theory has some gigantic problem that has not been resolved, scientists may speak as if so huge a problem does not even exist, and falsely claim that the theory is "beyond reasonable doubt" or "beyond doubt." It seems that scientists are very good about ignoring "the elephant in the room."