The Multiverse Has a Diversity Problem
The Reason Why Intelligent Design Is Unavoidable
By Paul Herrick
In my role as a philosophy instructor at a public community college I regularly introduce students to the fine-tuning argument, which many find to be compelling evidence for the existence of God or a supreme being. The main counterargument from atheists claims that the multiverse hypothesis better explains the surprising data (accepted by both sides) that the universal constants of physics at least appear to have been “fine-tuned” or precisely adjusted to make life possible.
In a previous work, Philosophy, Reasoned Belief, and Faith: An Introduction, I critiqued the multiverse hypothesis—roughly, the idea that our universe is just one universe within a multiverse containing an infinity of universes, each with randomly different values for the universal constants. But after reading Sir Martin Rees’s endorsement of the multiverse in his fascinating book Just Six Numbers: The Deep Forces That Shape the Universe, I have some new reflections to add to this great clash of worldviews, the divide between those who agree that “the heavens declare the glory of God” and those who wholly reject belief in God and in anything supernatural.[1]
Introducing Sir Martin Rees and the Universal Constants of Physics
Sir Martin Rees, the Royal Society Research Professor of Astronomy at Cambridge University, is one of the world’s most renowned astrophysicists. He has made major contributions to our knowledge of “black holes, galaxy formation, and high energy astrophysics.”[2] In his book, the subject of the multiverse comes after he has introduced six of the universal constants “imprinted” at the time of the Big Bang—numbers that “underpin the fabric of our universe” to determine its overall physical structure. Since these numbers are the data the multiverse is said to explain, we must begin with the universal constants, numbers that constitute the “recipe” for our universe (page 4, all page references are to Rees’s book). The first five on Rees’s list will suffice for present purposes.
1. The large number N, “equal to 1,000,000,000,000,000,000,000,000,000,000,000,000 [measures] the strength of the electrical forces that hold atoms together divided by the force of gravity between them.” If that ratio had been different by an unimaginably small amount at about the 36th decimal place, “only a short-lived miniature universe could exist...there would be no time for biological evolution.” (2)
2. Epsilon (ε) “defines how firmly atomic nuclei bind together and how all the atoms on Earth were made. Its value controls the power from the Sun and, more sensitively, how stars transmute hydrogen into all the atoms of the periodic table.” If ε had been ever so slightly different, “we could not exist.” (2) [3]
3. Omega (Ω) determines “the relative importance of gravity and expansion energy in the universe.” If this “cosmic number” had been slightly higher “the universe would have collapsed long ago.” Slightly lower and “no galaxies or stars would have formed. The initial expansion speed seems to have been finely tuned.” (3)
4. Lambda (λ), “fortunately for us (and very surprisingly to theorists), is very small.” If this number had been very slightly different “its effect would have stopped galaxies and stars from forming, and cosmic evolution would have been stifled before it could even begin.” (3)
5. Q “represents the ratio of two fundamental energies.” Had this number been slightly smaller, “the universe would be inert and structureless.” Slightly larger and the cosmos “would be a violent place, in which no stars or solar systems could survive, dominated by vast black holes.” (3)
Rees finds it “astonishing” that “if any one [of these numbers] were to be untuned, there would be no stars and no life.” (4) In other words, if even one of the constants had been different by a very small amount, life in any form would not have been possible. (4) The numbers, he says again and again, certainly look “finely tuned” for life. In other words, they appear to be the product of intelligent design.
Actually, the fine-tuning of the universe is even more astonishing than Rees’s short list suggests. Astrophysicists have now identified over 100 universal constants that fit together to determine the physical structure of the physical universe. They agree that if even one had been different, by an astronomically small amount, life in any form would not have been possible.
The Multiverse vs. Theism
A coincidence this big cries out for explanation. Astrophysicists such as John Polkinghorne argue that theism is the best explanation: our finely tuned universe is the product of a supreme mind. Rees agrees that an explanation is needed. His choice is different:
Is this tuning just a brute [unexplained] fact? Or is it the providence of a benign Creator? I take the view that it is neither. An infinity of other universes may well exist where the numbers are different. Most would be stillborn or sterile. We could only have emerged (and therefore we naturally now find ourselves) in a universe with the ‘right’ combination.
Later he expands on this idea:
So, on a much grander scale, there may be innumerable other universes that we cannot observe because light from them can never reach us. Would they be propitious for the kind of evolution that has happened on at least one planet around at least one star in our ‘home’ universe? In most of them, the six numbers could be different: only a few universes would then be ‘well-tuned’ for life. We should not [then] be surprised that, in our universe, the numbers seem providentially tuned… (26)
Diversity Enters the Picture
This is a multiverse hypothesis; however, an additional complication must be added.
If the underlying laws determine all the key numbers uniquely, so that no other universe is mathematically consistent with those laws, then we would have to accept that [ours is the only universe and that its] ‘tuning’ was a brute fact, or providence. On the other hand, the ultimate theory might permit a multiverse whose evolution is punctuated by repeated Big Bangs; the underlying physical laws, applying throughout the multiverse, may then permit diversity in the individual universes. (174-5)
So, we must suppose not only that our universe exists within a hyperspace containing an infinity of different universes—a multiverse—we must also hypothesize that the multiverse is suitably diverse: it must be filled with many, many different kinds of universes, with each universe springing from a randomly different set of fundamental constants and with some life-permitting. Only then does it (claims Rees) become “unsurprising” that we live in a universe fine-tuned for life, for “we could only have emerged in a universe with the ‘right’ combination” of constants” and therefore it is “natural” and not surprising that we find ourselves in a universe fine-tuned from the beginning for our existence.
Rees has now raised a new issue: the internal diversity of any given multiverse. To see this, we must go up a level. An infinite number of kinds of multiverses are possible. A multiverse could contain an infinity of universes all the same—an infinite ensemble of universes containing no diversity at all. But that would not make it “unsurprising” that in our universe “the numbers seem providentially tuned.” (25)
A multiverse could contain an infinity of lifeless universes. Again, too little diversity to make the fine-tuning data unsurprising. A multiverse containing nothing but short-lived universes each “with no time for biological evolution” is also certainly possible. (2) That obviously would not explain the fine-tuning. A list of other possible multiverses would include ensembles in which each universe within “is inert and structureless” (3); each universe inside contains ‘no stars and no life” (4); every internal universe is filled with nothing but hydrogen and thus lacks any complex chemistry. (55)
The point is that an infinite number of non-life-bearing multiverses are possible. None would explain (or make unsurprising) the fine-tuning of our universe. Thus, Rees (and any other multiverse theorist) needs a new constant, a meta-constant that specifies the internal diversity of any proposed multiverse. Call this constant D. Given that D can take an infinity of different values most of which (by Rees’s admission) would be inconsistent with a multiverse containing a universe fine-tuned for life, it seems that the value of D for Rees’s proposed multiverse must, like the values of his six numbers, be finely tuned for life, and to a very high degree.
Therefore, any atheistic multiverse hypothesis will not explain away fine-tuning. Rather, it will kick the can down the road, leaving us in the end with irreducible fine-tuning at the most basic level. And we are back where we started.
Why Infer God or a Supreme Mind?
Rees agrees with theists that the fine-tuning of our universe demands an explanation. He even calls the fine-tuning “astonishing.” Why do theists infer the existence of God or a supreme being from the data, whether the fine-tuned object is a universe or a multiverse? Many arguments have been given. Woven together they form a cumulative case for the conclusion that divine design is the best explanation. In Philosophy, Reasoned Belief, and Faith I began my case with the following two thought experiments.
Imagine that the pizza maker Vincenzo Ramaglia invents an automatic pizza machine. When dough, vegetables, seasonings, sauce, and other ingredients are fed into one end of the machine, intricately formed pizzas come out the other end—but only if the machine’s fifty dials are set properly. The outcome is so sensitive to the initial settings that all fifty dials must be set, each within a tolerance of one millionth of an inch, or the product that comes out will not be a pizza in any way, shape, or form.
Now, imagine walking into Vincenzo’s shop and seeing his machine cranking out intricately formed pizzas. Which hypothesis makes the best overall sense of this fine-tuning?
1. The fifty dials are very loose and wobbly. They were set in their present positions by a gust of wind that occurred when the door accidentally blew open.
2. The fifty dials were precisely adjusted by an intelligent being who intended to make intricately formed pizzas.
As you think about this, note that a gust of wind is a blind, unconscious process that has no goal. I am appealing to plain common sense here.
The second thought experiment involves a computer game that allows you to design a simulated universe on your laptop. After loading the game onto your computer, you design a model universe by typing in fifty mathematical equations, each containing a universal constant that must be entered to sixty decimal places. Together these numbers determine the overall structure of your simulation and the way it will function. Once you have typed in your numbers, the background order is in place and the program cranks out a simulation of your “possible universe.”
The goal of the game is to design a functional world containing diverse life-forms and interesting activity. However, such a universe will not result unless the numbers are set within extremely narrow limits. Most settings produce lifeless universes.
On the first day, you load the game onto your laptop and begin typing in your choice of all fifty fundamental constants. You are operating blindly because you lost the instruction manual and therefore have no hints at all. After you give the command, your universe starts to operate. But after days of waiting, it isn’t doing anything. The screen is just a disorderly blur.
This is a letdown because at the software store, the demo showed stars forming, galaxies coalescing, supernovas spewing out complex elements into space, and life-forms developing on planets with stable environments. After several weeks of effort, you give up. This was smart because out of millions of billions of trillions of possible combinations of values for the fundamental constants, a vanishingly small fraction produces a life-permitting universe.
Now suppose that a friend comes over and asks if she can give the game a try. She sits down and begins typing constants into the equations. Soon, a complex, stable, interesting universe is developing, complete with stars, galaxies, complex chemistry, and complicated life-forms. Would you believe your friend if she told you that she hit the right numbers by blind luck? Or would you be strongly inclined to suppose that she chose her numbers based on prior knowledge of what it takes to produce the background order needed for a life-sustaining universe?
Again, I am appealing to common sense here. Doesn’t life experience teach that the best explanation for any seemingly fine-tuned system is generally that the set-up is the product of a mind at work? Of an intelligent designer? The precisely adjusted order and coordination of parts observed in the architecture of a great building, in the beauty of a song, or in a work of art, always takes us back to an intelligent designer (architect, composer, artist) when we trace things back.
Explaining Rees’s Reluctance to Infer Intelligent Design
At one point Rees states that calling a theory “metaphysics” is “a damning put-down from a physicist’s viewpoint.” (166-7). This is surely due to the fact that most physicists feel bound by the doctrine known as “methodological naturalism,” which states that scientists, in their role as scientists, are not permitted to refer to anything beyond space, time, and matter when explaining some phenomenon. Put another way, a scientific explanation must never refer to anything supernatural. Now, setting aside the fact that no purely scientific theory or data justify this methodological rule, Rees and his fellow astrophysicists have another option. As scientists, they may choose to never refer to anything outside of physical nature in their explanations. However, as human beings they may do so if common sense reasoning requires it. Life experience teaches that fine-tuning, when traced back to its origin, is always the result of a mind at work, of intelligent design. As human beings, physicists may conclude, using common sense, that the ultimate fine-tuning, the ineliminable coordination of a hundred or more numbers at the end of the day, is best explained as the product of a supreme mind. Thus, as human beings rather than as scientists, Rees and his colleagues might very well agree with King David that “The Heavens declare the glory of God.” (Psalm 19:1)
Notes
[1] Martin Rees, Just Six Numbers: The Deep Forces That Shape the Universe (Basic Books, 2001).
[2] From the book’s cover.
[3] The fine-tuning of epsilon is interesting. “If the nuclear ‘glue’ were weaker, so that ε were 0.006 rather than 0.007, a proton could not be bonded to a neutron and deuterium would not be stable. Then the path to helium formation would be closed off. We would have a simple universe composed of [nothing but] hydrogen.”(55) On the other hand, “we couldn’t have existed if ε had been more than 0.008, because no hydrogen would have survived from the Big Bang.” (55) “The actual mix of elements [depends] on ε, but what is remarkable is that no carbon-based biosphere could exist if this number had been 0.006 or 0.008 rather than 0.007.” (57) Instead, “chemistry would be duller (and complex molecules of the kind essential for life would not exist).” (5)
— Paul Herrick is professor of philosophy at Shoreline Community College. He is the author of multiple textbooks in formal logic, critical thinking, and philosophy, including The Many Worlds of Logic, Think with Socrates, Christian Apologetics and Philosophy: An Introduction and Philosophy, Reasoned Belief, and Faith: An Introduction.
