Thinking about the evidence for why God is real and why Christianity is true builds up my faith. There are many categories of such evidence: evidence for the resurrection of Jesus, supernatural experiences, the existence of universal moral principles, the nature and content of the Bible, my subjective experience of God’s presence, seeing evidence for God in nature, and more. When it comes to seeing evidence for God in nature there is a scientific aspect of this evidence. This scientific aspect includes what is commonly called “fine-tuning.” In my opinion, fine-tuning provides extraordinarily strong evidence for the existence of a great, wise Creator.
What is fine-tuning? Fine-tuning refers to a whole group of scientific discoveries that have occurred mostly over the last 70 years that all show that the laws of nature and the initial conditions of the universe are amazingly fine-tuned to produce a universe that allows life to exist in it. It’s like the story of Goldilocks, where a number of things are “just right”. I wanted to understand a little more clearly and deeply how this fine-tuning works, so I ordered and read A Fortunate Universe: Life in a Finely Tuned Cosmos by Geraint F. Lewis and Luke A. Barnes. I’m glad I did!
In terms of providing a detailed (~350 pages) explanation of fine-tuning intended for a science-minded, but non-professional, audience, I would say that A Fortunate Universe is the best so far of several good books I have read on this topic. The authors are gifted at explaining complex and sometimes esoteric aspects of physics from quarks to galaxies and the history of the universe in ways that I could (mostly) understand. They make an exceedingly strong cumulative case that fine-tuning is a wide and deep characteristic of the world we live in. They also have a good sense of humor and I found myself smiling and sometimes laughing out loud as I read their book. I think this helps when wading through what is at times unavoidably complex and heavy material.
After leading the reader through a lot of physics and cosmology and pointing out many examples of fine-tuning along the way, Geraint and Luke (they use their own first names throughout the book, so I’ll follow their example) include two chapters on a wide range of reactions to, and possible explanations for, fine-tuning. In the penultimate chapter, Geraint and Luke together address a wide range of reactions which in one way or the other mostly attempt to argue that fine-tuning is not something that calls for any special explanation. They very successfully (in my opinion)) demonstrate that fine-tuning is real, extraordinary, and that it does call for special explanations. Then, in the final chapter, Geraint explains several possible explanations that are consistent with atheism and a materialist worldview. The three explanations he proposes are that either (1) further discoveries in physics may explain fine-tuning in a way that does not call for any further explanation beyond the laws of physics themselves, or (2) the multiverse may exist and be able to explain fine-tuning, or (3) we are living in a computer simulation and this explains fine-tuning. Luke then gives the answer that I am convinced is correct: fine-tuning is strong evidence that a wise, powerful Creator is responsible for establishing the laws of the nature and for making a universe that can support life. In other words, our universe is fine-tuned for life because it was intended and planned to be our home.
In the final chapter, Geraint and Luke ask each other both clarifying and challenging questions about the various proposed explanations for fine-tuning. Their dialog, while it includes some tough questions for each of them, is refreshingly mutually respectful and friendly. I wish discussions between people with different world views would more often be so reasonable and helpful. Geraint and Luke set a good example in how they interact even when they disagree. Like the rest of the book, this final chapter is well-written. I would also recommend Stephen Meyer’s new book that also covers fine-tuning: Return of the God Hypothesis. Meyer’s book does an excellent job of explaining why God is a better explanation for fine-tuning than the multiverse or other explanations that don’t involve God (I wrote a blog post summarizing these arguments, which you may find here: God vs. The Multiverse).
Fine-tuning: What it is and examples
Most of the 350+ pages in Geraint and Luke’s informative and enlightening book are spent explaining the physics behind various examples of fine-tuning and then discussing the examples themselves. To give you a feel for this I will attempt to summarize some of this material. My summary is a poor substitute for their book both because I do not understand the topic as well as they do nor is it possible to do justice to their explanations in this short space. But this summary might still be helpful in terms of either motivating you to buy their book or helping you get a very simple idea of what this is all about.
As best as we can tell based on science, for any type of life to exist at all in a universe, a couple of things are needed (we are not saying these factors are sufficient to produce life, but that they are among the necessary factors):
1. Complex chemistry. I’m not referring to the fact that chemistry seems like a complex topic to many students. I’m referring to the fact that all life that exists, from whales to bacteria, and also any life forms that we can imagine based on the science we know, requires complex molecules that can copy and store information (like DNA and RNA) and perform functions necessary to keep life going (like many proteins and the molecular machines they form). We need complex, but fairly stable, chemistry. We specifically need hydrogen, carbon, oxygen (no hydrogen or oxygen means no water – H2O) and quite a few other elements from the periodic table or else other elements with very similar properties.
2. Stars. Our Sun, is of course, a star. Life needs stable stars that produce useful energy in the right form and also produce the needed elements. At least some of these stars need to explode to spread these elements around to form planets, oceans, grass, and people. Stars are formed in galaxies, so to get stars we need galaxies.
Scientists have discovered a lot about the fundamental laws of physics that govern the material aspects of our universe and they have also learned a lot about the initial conditions near the beginning of the universe. There are quite a few aspects of these laws and initial conditions which, for all we know, could have been different. Scientists can and have measured the strength of the four fundamental forces of physics. But they do not know why these forces each have the strength they do. Based on current physics, there is no known reason that these forces could not have had far different values. Likewise, scientists have calculated the mass of each of a group of fundamental particles. But they don’t know why each particle has the mass it does, and again it could have been different. Scientists also have good estimates for the density, distribution, and make-up of matter near the very beginning of the universe. But again, there is no known reason that these initial conditions could not have been far different.
Now here is the amazing thing. It is mind blowing when you start to study it and the more you understand it the more amazing it is. Many of these aspects of the universe that have values that we have discovered but which could have been different, must have very nearly the precise values they do have or the universe could not support life. If any of these values changed, either there would be no complex chemistry, or there would be no stars, or there would be only stars of a kind that could not support life, or the whole universe would quickly have crunched back into something resembling a black hole. These are not scenarios where life would merely be more difficult. These are scenarios where there is no conceivable way that we or anything like us, or even bacteria or anything like bacteria, could exist.
How unlikely are each of these fine-tuning parameters to have the correct value for life? It is difficult to put exact numbers on any of these, but in many cases it appears that if you just randomly picked a value from a range of what seems like reasonable and possible values, your chances of getting the right value to allow for life would be far less than your chances of buying one lottery ticket and winning. In fact, with some of the examples, your chances would be far less than the chances of buying one lottery ticket and winning and then doing the same thing in a hundred lotteries in a row. Long before someone won a hundred lotteries like that, we would be right to call for an investigation. Someone can get lucky, but it is not reasonable to think that anyone could be that lucky. In the same way, it is not reasonable to appeal to luck or chance for the combination of exquisitely fine-tuned parameters we find in our universe.
I’ve summarized a sample of fine-tuning examples from A Fortunate Universe. This table does not contain all the examples in the book and my summary explanations are not a good substitute for the many pages of well written background, explanation, and discussion that are found in the book. But, I hope it still gives you some idea of what we are talking about.
|
What is Fine-Tuned |
What Bad Things Would Happen if it was Not Fine-Tuned |
|
dark energy |
Too much dark energy would result in the universe expanding so rapidly that no galaxies, stars, or planets would form and the universe would basically be “a thin soup of hydrogen and helium” (pg. 13). |
|
mass of the down quark (1) |
Too high of a mass results in a universe being filled with only a helium-like element based on the Δ++ (delta-plus-plus) particle or a hydrogen only universe. No complex chemistry would be possible. (pp. 50-51) Too low of a mass produces a neutron universe, where complex chemistry is also not possible. |
|
mass of the up quark (1) |
Too high of a mass results in the universe being dominated by the Δ-- (delta-minus-minus) particle, or a neutron universe again. Which of these you get depends on how much you increase the mass of the up quark by. These results prohibit complex chemistry. (pg. 50-51) |
|
mass of the electron (1) |
Too much mass creates a neutron universe again (pg. 51). No complex chemistry is possible. (pg. 51) |
|
mass of the electron (2) |
If the electron’s mass were within a factor of a hundred of the proton’s mass, there would be no solids (no cell walls, no DNA, no organs, etc.) (pg. 58) |
|
strong force (1) |
If the strong force were a little bit stronger then all, or nearly all, of the hydrogen produced in the big bang would have been turned to helium. This would negatively affect stars. Also, we really need hydrogen. For example, water is H20. (pp. 77-78) |
|
strong force (2) |
A weaker strong force would result in all elements from carbon up being unstable. We need carbon and some of those other elements for life. (pg. 90) |
|
electromagnetic force (1) |
If it was strengthened it would result in causing some of the elements that we need for life to become radioactive and unstable, making life impossible. (pg. 90) |
|
gravity (1) |
A lower strength of gravity would result in stars that would not expel the elements needed for life like carbon (pg. 107-109) |
|
gravity (2) |
If gravity was too strong, stars either would not be stable at all or could burn through all their matter in just a matter of years instead of being stable for billions of years. (pg. 109) |
|
strong force (3) |
Increasing the strong force by just 0.4% would result in stars producing no oxygen, which would mean there could be no water (H2O) and no life. Decreasing the strong force by just 0.4% would produce oxygen, but no carbon, again leading to no life. (pg. 118-119) |
|
mass of quarks (2) |
The quark masses are also very fine-tuned to allow the production of oxygen and carbon in stars (pg. 120) |
|
initial condition: low entropy |
Our universe started off with a low entropy compared to possible higher entropy initial conditions. Higher entropy would result in a universe that starts off full of black holes and which never produces galaxies and stars. This is one of the most “astonishing” levels of fine tuning that has been calculated. (pg. 127) |
|
initial condition: the amount of matter |
Too much matter at the beginning of the universe would have caused it to quickly crunch back on itself before life exists and too little matter would have resulted in a universe with no galaxies and no stars. This factor appears to be also incredibly fine-tuned when densities shortly after the Big Bang are considered. (pp 166-167) |
|
neutrino mass |
A slight increase in neutrino mass would inhibit galaxy formation (and thus star formation and thus life). (pg. 177) |
Not included in the above table are many examples that either I felt that I did not understand well enough to give a good summary for or which are more complex and that just don’t fit very well into a table like this. These include things like nature of electron spins, the mass of the Higgs boson, dark mass, the nature and strength of the weak force, the cosmological constant, the initial smoothness/lumpiness of the universe, Plank’s constant, the net charge of the universe (which is zero), symmetry and conservation in many (but interestingly, not all) laws of nature, the fortunate fact that there was apparently a tiny bit more matter than anti-matter in the early universe, the nature of time and the fact that we live in a universe with one time and three spatial dimensions, and the beautiful fact that our universe faithfully follows a set of regular laws that can be expressed mathematically.
As Geraint and Luke put it, summarizing some of the above examples:
So, the fact that we are here typing these words, and you are there reading them, all constructed from molecules of carbon and oxygen, is only possible because the masses of the quarks and the strength of the forces lie within an outrageously narrow range (pg. 120).
Our universe is super, incredibly, beautifully, brilliantly fine-tuned for life!
This leads me to worship our great Creator. He is so wise and powerful. These truths also remind me that if He is wise enough and powerful enough to fine-tune the laws of physics and create the universe with life-friendly initial conditions, then I should trust that He is wise and powerful enough to help me with all of the little problems in my life that often seem so big to me.
One thing I didn’t like about the book
While the authors defend the reality of fine-tuning in physics (although they have different ideas about what explains this fine-tuning), they seem blind to the analogous evidence for intelligent design for life. In a number of places their words seem to assume that, given a life-friendly universe, material forces and random events would be enough to bring life into existence. Here are a few of those quotes
“Our physical properties, our
bone structure, our organs, our senses, result from life continually changing
and evolving over the last 3.5 billion years, adapting to the conditions that
surround us.” xiii
“We are the result of the action of the laws of physics over the history of the Universe.” – Luke (pg. 7)
“Life has pulled itself together from the hodgepodge of chemical reactions in this Universe.” – Luke (pg. 8)
This is unfortunate because there is a type of fine-tuning in life as well. All living things contain both a large amount of functional information encoded in DNA and a stunning array of complex molecular machines working together in coordinated systems. These aspects of life, like the fine-tuning of the universe to provide a setting where life is even possible, are also strong evidence for a great, wise Creator. I have a collection of material related to this here: Mark’s Resources on Scientific Evidence for God.
Although I would not say that this blemish in the book is insignificant, it does not prevent me from heartily recommending A Fortunate Universe to anyone who wants to better understand what fine-tuning is all about. I thank God for the hard work that Geraint and Luke put into this excellent and helpful resource!
Hebrews 13:16 And do not forget to do good and to share with others . . .
