The Fine-Tuned Universe:
An Elegant Handiwork
“This most beautiful system of the sun, planets, and comets, could only proceed from the counsel and dominion of an intelligent and powerful being.”
— Isaac Newton (1643–1727)
By the Editorial Staff
Updated 7/23/2023
Six Constants
Events such as the Eucharistic Miracles and the Resurrection are backed by evidence showing that the world is not governed by nature alone. What can we say about nature itself? Is it the product of chance, or was it “crafted” with you — yes, you who are reading this sentence right now – in mind?
In 197 AD, the Roman writer Minucius Felix described the universe as follows in Octavius:
Now if, on entering any house, you should behold everything refined, well-arranged, and adorned, assuredly you would believe that a master presided over it, and that he himself was much better than all those excellent things. So in this house of the world, when you see its providence, order, and law in the heavens and on earth, believe that there is a Lord and Parent of the universe far more glorious than the stars themselves, and the parts of the whole world.
British cosmologist and astrophysicist Martin Rees, in his book Just Six Numbers, discusses six dimensionless physical constants that, according to our current understanding, shape our universe. These numbers describe fundamental properties and quantities in physics that determine everything from the size and shape of galaxies to the possibilities for life on Earth. If any of these numbers were different, even slightly, the universe as we know it wouldn't exist.
N |
(~1036) |
This is the ratio of the strength of electromagnetism to the strength of gravity for a pair of protons. It's essentially a measure of the relative strengths of the two fundamental forces: gravity, which holds planets, stars, and galaxies together, and electromagnetism, which is responsible for light and is the force acting in the smaller scale of atoms. If N were significantly smaller, only a small and short-lived universe could exist; Rees notes “no creatures could grow larger than insects, and there would be no time for biological evolution.” |
ε |
(0.007) |
Defined as the fraction of mass energy converted to new energy when hydrogen fuses into helium. It determines how stars burn and how all the atoms of the periodic table were cooked inside the stars. Rees believes that if this constant were above 0.008, no hydrogen would exist. However, some physicists disagree and believe that this constant should be replaced by αs (~0.1179), the strong force coupling constant; substantial hydrogen remains as long as this constant doesn’t increase by more than 50%. |
Ω |
(~1) |
Represents the amount of matter in the universe. If Ω were very different, the universe could not have survived for billions of years in a form hospitable to life. A value greater than one would mean the universe would collapse back on itself, a value less than one would imply too little matter for galaxies to form. A value near one is critical for the formation of galaxies and stars and hence life as we know it. Rees notes, “The initial expansion speed seems to have been finely tuned.” |
λ |
(~0.7) |
Represents the cosmological constant, a measure of the repulsive "dark energy" that is causing the universe's expansion to accelerate. If λ were significantly larger, the universe would have expanded too rapidly for galaxies and stars to form. |
Q |
(~10-5) |
Pertains to the initial irregularities in the universe's mass distribution. A smaller Q would result in a universe forever barren of anything complex; a larger one would result in a violent universe with no galaxies at all. |
D |
(3) |
The number of spatial dimensions in our world. In a universe with more than three dimensions, gravity would not fall off with distance as it does in our universe, likely leading to unstable planetary orbits. In a universe with fewer than three dimensions, many complex structures (like our brains) would not be possible. |
Common Objections to the Fine-Tuning Argument
Weak Anthropic Principle
One common response states that we shouldn't be surprised to find ourselves in a universe that allows for our existence since, after all, we are here. Philosopher John Leslie counters this with the following analogy, retold by Francis Collins:
In this parable, an individual faces a firing squad, and fifty expert marksmen aim their tifles to carry out the deed. The order is given, the shots ring out, and yet somehow all the bullets miss and the condemned individual walks away unscathed.
How could such a remarkable event be explained? Leslie suggests that there are two possible alternatives ... In the first place, there may have been thousands of executions being carried out in that same day, and even the best marksman will occasionally miss. So the odds just happen to be in favor of this one individual, and all fifty of the marksmen fail to hit the target. The other option is that something more directed is going on, and the apparent poor aim of the fifty experts was actually intentional. Which seems more plausible?
The fact that we exist doesn't dismiss the extraordinary fine-tuning of these fundamental constants. The question isn't why we find ourselves in a life-supporting universe, but why a life-supporting universe exists in the first place, given the immensely improbable tuning required.
Multiverse Theory
The multiverse theory proposes that our universe is just one among a potentially infinite number of universes, each with different physical constants. We happen to exist in a universe with constants that allow for life. But there are several problems with this theory:
The multiverse theory is currently untestable, which is a significant hurdle in a scientific context. There is no known way to gather empirical evidence of other universes, so the theory largely remains a philosophical or theoretical construct.
Even if the multiverse exists, it's unclear why we would find ourselves in a universe with constants that not only allow life but also allow for the development of sentient beings capable of contemplating these questions.
The multiverse theory merely shifts the fine-tuning problem up a level: even if multiple universes exist, why do they collectively exhibit a range of constants that happens to include a life-supporting universe? What mechanism generates these universes, and why does it produce this particular distribution of physical laws and constants?
Big Bang: The Origin of a Fine-Tuned Universe
Something that is fine-tuned must have first been designed and created.
One of the prevailing theories about the universe was the Steady State Theory. According to this theory, the universe had no beginning or end in time and it had always existed in an unchanging state. This concept was in line with the beliefs of scientific materialism, because it didn't necessitate the intervention of a creator.
American theoretical physicist and Nobel laureate in physics Stephen Weinberg stated:
The steady-state theory is philosophically the most attractive theory because it least resembles the account given in Genesis.
The Big Bang Theory, as proposed by Georges Lemaître, a Belgian physicist and Roman Catholic priest, suggested that the universe is expanding and, if tracked back, there would be a point of origin where everything started from a singularity around 13.8 billion years ago. This was a major shift from the previous Steady State Theory and made scientific materialists uncomfortable.
Albert Einstein, too, initially resisted the idea of an expanding universe. When he formulated his general theory of relativity in 1915, it allowed for various potential structures of the universe, and he originally proposed a static, non-expanding model of the universe. His initial reaction to Lemaître’s proposal was starkly negative:
Your calculations are correct, but your physics is atrocious.
However, Edwin Hubble's observations in the late 1920s provided empirical evidence for an expanding universe. Hubble observed that distant galaxies were receding from the Milky Way, and the farther away a galaxy was, the faster it was receding. This phenomenon, now known as Hubble's Law, offered strong support for an expanding universe.
Confronted with Hubble's empirical evidence, Einstein eventually abandoned his static model of the universe and accepted the Big Bang theory, which is now the most accepted cosmological model for the observable universe.
Georges Lemaître and Albert Einstein after Lemaître’s lecture at CalTech in 1933