That there should exist anything at all, let alone a universe as complex and as orderly as ours, is exceedingly strange. But if there is a God, it is not vastly unlikely that he should create such a universe.Richard Swinburne
Why does our universe operate the way it does? How likely was life to come about? As creative beings, we cannot help but ponder our existence and experience. The fact that we even ponder such questions communicates a lot about who we are. Yet, there is such mystery as to how order has emerged out of chaos.
When we look at the cosmos for answers, we initially have two options: conclude our existence is the result of coincidence and chance or attribute it all to intelligent design—to God. Experts on both sides of this debate posit reasons to adhere to their understandings of cosmology. But which is more compelling? Are there more reasons to believe our existence isn’t a cosmic accident? We live in an ordered universe, but how ordered? Could our experience be common in the vastness of the universe we observe?
The option that we choose must take into account that the universe contains many things we would not expect. For example, our universe curiously defies the second law of thermodynamics, which says order should decrease, not increase. American physicist Paul Davies, who is not a Christian, says,
If the universe is simply an accident, the odds against it containing any appreciable order are ludicrously small. If the big bang was just a random event, then the probability seems overwhelming (a colossal understatement) that the emerging cosmic material would be in thermodynamic equilibrium at maximum entropy with zero order. As this was clearly not the case, it appears hard to escape the conclusion that the actual state of the universe has been ‘chosen’ or selected…And if such an exceedingly improbable initial state was selected, there surely had to be a selector or designer to ‘choose’ it?”
In response to these observations, many Christians have presented the fine-tuning argument for the existence of God. This argument was initially posed in 1986 by John Barrow and Frank Tipler in the book The Anthropic Cosmological Principle. This principle, which highlighted the importance of the values of certain fundamental constants for the existence of our universe, was later developed into what is now known as the fine-tuning argument, which states:
The values of certain fundamental cosmological constants and the character of certain initial conditions of the universe appear to have played a decisive role in bringing about the emergence of a particular kind of universe, within which life is capable of developing.
In other words, the conditions that must be met for human life or any complex life to exist are so specific that even the slightest change in any of these values would make life impossible. These laws of physics, constants of physics, and initial conditions of the universe are so specific that British astronomer and atheist at the time Fred Hoyle argued that concluding our existence was a cosmic fluke would be without solid reasoning. In fact, he went as far to say,
A commonsense interpretation of the facts suggest that a super intellect has monkeyed with physics…the numbers one calculates from the facts seem to me so overwhelming as to put this conclusion beyond question.”
Six Defenses of the Fine-Tuning Argument
With this understanding, American philosopher Robin Collins (along with many others) argues that there are six solid defenses of the fine-tuning argument for the existence of God —
- cosmological constant
- strong and electromagnetic forces
- carbon production in stars
- proton/neutron mass difference
- weak force
- gravitational constant.
Though there are several other constants and variables that give evidence to how finely tuned our universe is, these six represent some of the most compelling arguments that there is a God behind the fine-tuned universe. Here are some examples of several of them.
At the earliest moment at which the concept of space and time has meaning, known as Planck time (10-43 seconds), if the Big Bang differed at all in its strength by only one part in 1060 (1 followed by 60 zeros) the universe would not exist. To give some meaning to these numbers, it would be like firing a bullet at a one-inch target on the other side of the known universe roughly twenty billion light years away and hitting that target. It is an unfathomably small number. Comparatively, the number of seconds in the entire history of the universe is only 1017.
Proton/neutron mass difference:
In atoms, the mass of neutrons and protons is perfectly balanced in such a way that stars are able to burn hydrogen and helium. The neutron has a mass of about 938 MeV, while protons have a mass of 1,293 MeV. If the mass of the neutron was increased .14% (1.4MeV), this critical process could not take place—and the universe would not exist.
Gravity is one of the weakest forces in the universe; however, it is in perfect balance. If it were only slightly larger, stars would be too hot and burn up too quickly for life to form. But if it were only slightly smaller, stars would be too cool, which would prevent nuclear fusion, and thus the heavy metals that are essential for life would not be produced.
Finely-tuned values like these have led many to think that it’s at least reasonable to believe that there is a God behind our existence, a God who fine-tuned this universe for life to occur.
Alternatives to the Finely-Tuned Universe
On the other hand, some have refused to entertain the idea of a God behind the universe. Ludwig Boltzmann, pioneer of statistical thermodynamics, argues that the universe fluctuates from total chaos to accidental order, but the majority of the time (by an astronomically large margin), it is in utter chaos. He suggests that the only reason we humans are present for such a time to view such order is because we are experiencing a rare period of accidental order, precisely the conditions that allow us to be here.
John Leslie responded to this explanation with his famous firing squad analogy, which essentially says, suppose a person was to be executed by a 50-man firing squad. They all aim, fire, and miss. The person who was supposed to be executed would assume something happened because it is extremely unlikely that all the trained shooters would miss. Leslie argues that just because the person survived doesn’t mean they shouldn’t wonder why they are still alive to witness such a thing, especially because their chance of survival was highly improbable. In the same way, it is even more unlikely (to an incredibly high degree) that our existence is a fluke.
Others have proposed a Multiverse theory under a naturalistic approach, which states there are possibly an infinite number of universes with cosmological constants that differ from the fundamental parameters of physics in our universe. In these regions there could be different initial conditions and possibly even different laws of nature. Therefore, it’s no surprise that at least one universe exists in which we are able to exist and observe it. With this understanding, the probability is alleged to be close to 100% that our universe would exist; however, just because the probability of something is high doesn’t mean the claims aren’t ridiculous. There is a difference between high probability and certainty when the concept of infinity is involved, which is precisely what the Multiverse invokes by suggesting that a near-infinite number of universes exists, thus making the probability of our particular universe nearly infinite as well.
Additionally, most theists point out that these universes would be unobservable because we can observe things only in our universe. Therefore, we would have to accept the existence of other universes on faith because we could not empirically test for their existence. Though the Multiverse theory presents a possible explanation of our finely tuned universe, its attempt to eliminate the stance from faith does not work. To this point, physicist John Polkinghorne says, “Let us recognize these speculations for what they are. They are not physics but, in the strictest sense, metaphysics.” Both the Multiverse and a God-designed universe make faith claims; the Multiverse theory just pushes the question further down the line.
Astrophysicists Bernard Carr and Martin Rees argue that even if all of the finely-tuned constants and variables could be explained by some theory like the Multiverse, it would still be fascinating that “the relationships dictated by physical theory happened also to be those propitious for life.” Therefore, even further scientific breakthroughs are unlikely to remove the significance of fine-tuning arguments.
It is on account of reasons like these that theists and non-theists alike agree that the best explanation for the fine-tuning of physical laws and constants is design. Theists finish their reasoning with the existence of God, but non-theists have gone as far as to consider extraterrestrial (i.e., directed panspermia) involvement or to believe simply that science will eventually discover a scientifically-based answer, which remains unknown right now (i.e., science of the gaps).
Putting it All Together
So what does all this mean? Does the fine-tuning argument prove that God exists? No, but it does raise a question to which Christianity provides a compelling answer. I do not find the fine-tuning argument for the existence of God to be effective in presenting Christianity as true by itself because it doesn’t give us any insight into the nature of the God who created the universe. Any deity could have created our universe. However, I do find the cumulative case (fine-tuning, moral law, consciousness, etc.) for the existence of God to be overwhelmingly favorable to the Christian worldview of a personal God of love.
Science continues to answer questions that help us make sense of our world; however, it has yet to answer our questions about the most meaningful things in life, such as morality, meaning, and love. Philosopher of science Philip Clayton says, “The single greatest positive result of current discussions in cosmology lies in the fact that scientific results plead for meta-physical, and ultimately theological, treatment and interpretation.” The discussion might start in the scientific realm, but the grand scheme involves the religious realm too. Indeed, it’s hard to appreciate or see why understanding our universe matters if we don’t know why we are here in the first place.
How our universe came to exist must play a role in how we live our lives. Science is a beautiful gift that has helped us understand our world, but it is when science and metaphysics come together that real beauty unfolds. The answers they provide together and how they affect our lives are what drive more discovery, and those discoveries continue to remain coherent within the Christian worldview. Christian thinker Alister McGrath says, “Theism offers the best ‘empirical fit’ of the various theories which set out to account for anthropic phenomena. Yet it must be emphasized that Christian theology has never seen itself as charged with the task of inventing an explanation for these observations; rather, they fit within, and resonate with, an existing way of thinking, which proves capable of satisfactorily incorporating such observations.”
The fine-tuning argument for the existence of God is considered by many to be the most compelling conclusion. It seems like there are so many things that could have gone wrong, so many things that had to be lined up in order for our world and human life to exist. Fine-tuning shows us that the smallest details matter on a grand scale. There is still a debate as to why and how our universe came to be finely-tuned for life, but the God of Christianity seems to answer this age-old question within the first few lines of Scripture: “In the beginning, God made the heavens and the earth” (Genesis 1:1).
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 Richard Swinburne, “Arguments to God from the Observable Universe,” in Stump, J. B., and Alan G. Padgett, eds. The Blackwell Companion to Science and Christianity. (Oxford: Blackwell Publishing, 2012) 125-6.
 Paul Davies, God and the New Physics. (London: J.M. Dent & Sons Ldt., 1983) 168.
 Alister E. McGrath, A Fine-tuned Universe: The Quest for God in Science and Theology; the 2009 Gifford Lectures. (Louisville, KY: Westminster John Knox Press, 2009) 116.
 Owen Gingrich. “Ingredients for Life,” In Stannard, Russell, ed. God for the 21st Century. (Philadelphia, PA: Templeton Foundation Press, 2000)19.
 Robin Collins, “Evidence for Fine-Tuning,” In Manson, Neil A., ed. God and Design: The Teleological Argument and Modern Science. (London: Routledge, 2003) 180.
 Paul Davies, God and the New Physics. (pp. 179). (London: J.M. Dent & Sons Ldt., 1983) 179.
 Robin Collins, “Evidence for Fine-Tuning,” In Manson, Neil A., ed. God and Design: The Teleological Argument and Modern Science. (London: Routledge, 2003) 186.
 John Leslie, “Anthropic Principle, world Ensemble, Design,” American Philosophical Quarterly, 19 (1982). 141-51.
 Robin Collins, “The Fine-Tuning of the Cosmos: A Fresh Look at Its Implications,” In Stump, J. B., and Alan G. Padgett, eds. The Blackwell Companion to Science and Christianity (pp. 208). Oxford: Blackwell Publishing, 2012.
 Owen Gingrich, “Ingredients for Life,” In Stannard, Russell, ed. God for the 21st Century. (Philadelphia, PA: Templeton Foundation Press, 2000) 20.
 John C Polkinghorne, One World: The Interaction of Science and Theology. (Philadelphia, PA: Templeton Foundation Press, 2007). 95.
 Robin Collins. “Evidence for Fine-Tuning,” In Manson, Neil A., ed. God and Design: The Teleological Argument and Modern Science. (London: Routledge, 2003) 191.
 William A. Dembski, “The Design Argument,” In Ferngren, Gary B., ed. Science and Religion: A Historical Introduction (Baltimore, MD: Johns Hopkins University Press, 2002) 340.
 Philip D Clayton, God and Contemporary Science. (Edinburgh: Edinburgh University Press, 1997) 161-162.
 Alister E McGrath, A Fine-tuned Universe: The Quest for God in Science and Theology; the 2009 Gifford Lectures. (Louisville, KY: Westminster John Knox Press, 2009) 121.