Assessing the Fine-Tuning Argument

Explaining The Fine-Tuning Argument

The Fine-Tuning Argument claims that because the physical constants of our universe are specified so precisely for life to exist, that they must have been the result of a creator or designer of the universe.

Some scientists recognize that much of the complexity and systems in the universe, including the conditions for life, depend on the particular form of the laws of physics and the specific initial conditions. It seems that in some cases nature is "finely balanced." ¹ In his book, The Language of God, physician-scientist Francis Collins explains "Altogether, there are fifteen physical constants whose values current theory is unable to predict. They are givens: they simply have the value they have. This list includes the speed of light, the strength of the weak and strong nuclear forces, various parameters associated with electromagnetism, and the force of gravity. The chance that all of these constants would take on the value necessary to result in a stable universe capable of sustaining complex life forms is almost infinitesimal. And yet those are exactly the parameters that we observe. In sum, our universe is wildly improbable." ²

An important related concept is called the anthropic principle, of which there are two versions:

• Weak anthropic principle states that the universe's physical laws and constants are the way they are because these conditions are necessary for intelligent observers to exist. In other words, if the universe's parameters were different, we wouldn't be here to observe it. This is largely uncontroversial and essentially a statement of fact.
• Strong anthropic principle states that because of the specific conditions required for life to be possible in the universe, the universe must allow intelligent observers at some point in history. ³

The weak anthropic principle is an example of a "selection effect" and is often used to explain why the universe appears to be finely-tuned for life. The strong anthropic principle takes it a step further and states that the universe must allow for life either because it was specifically designed for life or, if there is a multiverse, then because at least one universe must have the right conditions for life.

While very similar to the Intelligent Design theory, the Fine-Tuning Argument is focused on the initial conditions and physical laws of the universe. Intelligent Design incorporates the Fine-Tuning Argument but also encompasses other arguments regarding the complexity of life and consciousness.

The Fine-Tuning Argument is related to, but still different from, teleological arguments because it is focused on scientific aspects of the universe as opposed to the meaning of existence and final causality. ⁴

Exploring Previous Thought

While science continues to explain more of the mystery of the universe, some recognize the special circumstances necessary for our universe and life to exist. ⁵ Examples of this include:

• The unity of the universe - the laws of physics apply equally well everywhere and can be expressed in simple mathematical functions ⁶
• Changing the gravitational constant would either result in blue giant stars that die too quickly for life to emerge or red dwarf stars that are too dim to support planets with life
• Changing the electrical charge of electrons or protons would lead atoms to be unstable ⁷
• Astronomer Fred Hoyle commented that nuclear physical laws seem specifically designed to produce carbon, a necessary ingredient for life ⁸ In addition to the conditions of the universe, our place in the cosmos provided the specific environment needed for life:
• Our solar system is in the right place in the Milky Way galaxy, not too close to the center to be disturbed by black holes, but not too far from the edge to lack chemicals necessary for life
• Earth's orbit provides the right temperature for chemistry to work well and allows for water to exist in liquid form
• The rocky planets in our solar system, including earth, have chemical diversity, not just hydrogen and helium ⁹ The fundamental regularities and constants of physics must all have values that together fall into an extremely narrow range. The probability of this perfect calibration happening by chance is tiny. As mentioned above, the argument that these unlikely circumstances are reason to believe that we exist because of a creator is called the Fine-Tuning Argument. ¹⁰

Supporting this argument is the idea that the universe could have been different, less ordered, with less depth and complexity, but it is actually highly ordered, with well-defined laws of physics. ¹¹ In his book, The Fabric of the Cosmos, physicist Brian Greene describes it like this: "The laws of physics didn’t have to operate this way. We can imagine a universe in which physical laws are as variable as those of local and national governments; we can imagine a universe in which the laws of physics with which we are familiar tell us nothing about the laws of physics on the moon, in the Andromeda galaxy, in the Crab nebula, or on the other side of the universe. In fact, we don’t know with absolute certainty that the laws that work here are the same ones that work in far-flung corners of the cosmos. But we do know that should the laws somehow change way out there, it must be way out there, because ever more precise astronomical observations have provided ever more convincing evidence that the laws are uniform throughout space, at least the space we can see." ¹²

It is this ordered, regularity of nature that allowed scientists to develop theories around its laws. In fact many scholars have pointed out that it was likely the Christian belief in an all-powerful God who sustains an orderly universe that set the foundation for modern science. ¹³ Additionally, there is a simplicity and elegance to the laws of nature. They can be expressed in terms of simple mathematical functions. ¹⁴ This simplicity provides a guide and "feeling" for physicists as they continue to contemplate better understandings of the laws or propose theories and equations for phenomena and relationships we can't yet explain. Brian Greene explains the importance of symmetry in physical theories: "Physicists also believe these theories are on the right track because, in some hard-to-describe way, they feel right, and ideas of symmetry are essential to this feeling. It feels right that no location in the universe is somehow special compared with any other, so physicists have confidence that translational symmetry should be among the symmetries of nature’s laws... So the symmetries of nature are not merely consequences of nature’s laws. From our modern perspective, symmetries are the foundation from which laws spring." ¹⁵

However ordered the universe may be, some still question if it was specifically designed or "finely-tuned" for life. In his book The Varieties of Scientific Experience, Carl Sagan explains the Drake equation, which attempts to estimate, based on probabilities, the number of technical civilizations in the Galaxy. The factors used in the equation are highly uncertain, and could reasonably result in an estimated number of technical civilizations in our galaxy of just one or 1,000,000. ¹⁶ While these numbers are speculative, they indicate the wide variance of possibilities of how common life might be in our galaxy. Both ends of this spectrum could be used as arguments against the Fine-Tuning Argument. If the number of technical civilizations is extremely low or if we are the only one that has ever existed, one could argue that the universe really isn't that fine-tuned for life or that it was tuned just enough for us only. Alternatively, if we are only one of millions or even billions of civilizations in our universe, it may imply that the universe is finely-tuned, but that we no longer hold a special or unique place in it.

In response to the Fine-Tuning Argument, scientists have pointed out the weak version of the Anthropic Principle, which argues that the universe is the way it is because these conditions are necessary for intelligent observers to exist. In his book The Big Picture, physicist Sean Carroll argues why the Fine-Tuning Argument is not a good one, "It relies heavily on what statisticians call 'old evidence' - we didn't first formulate predictions of theism and naturalism and then go out and test them; we knew from the start that life exists. There is a selection effect: we can be having this conversation only in possible worlds where we exist, so our existence doesn't really tell us anything new." ¹⁷ This counter argument makes sense if the universe and its laws were somehow "selected" among alternatives. There are a few theories on how this may have happened.

One theory is that there are many universes or realities, and that the universe we experience is just one among a vast ensemble. This implies that all possible physical conditions are represented somewhere and that only in those suitable for life to develop will intelligent life arise to observe this. We must ask what evidence there is for other worlds. A commonly discussed theory is the Many-Worlds theory. ¹⁸ The Many-Worlds (or Everett) formulation of quantum mechanics posits that every time there is a measurement of a quantum system (particle level) the universe splits into different "worlds", each with a different measurement of the particle. Each is a slightly different, but still real, copy of this universe. To many scientists, this is the most straightforward interpretation of quantum mechanics, even though it is not intuitive or easy to understand. ¹⁹ There is not space to adequately explain quantum mechanics and why the Many-Worlds formulation makes sense, but the key point here is that this plausible explanation of quantum mechanics opens the door for multiple branches of the universe, each with slightly different outcomes and potentially different laws of physics.

Another theory is that different regions of the universe may have different physical laws. If the universe is infinitely large, it's possible there are other regions we cannot see that have laws, and therefore conditions, different from ours. If it is an ensemble of cosmological systems in which masses and forces take on different values, it would make sense that our region that contains life was "selected" against the regions that couldn't. Additionally, theoretical physicist Lee Smolin proposes the possibility that universes can birth each other and that, due to quantum effects during their "birth", each universe could have slightly different laws of physics, with some universes coincidentally possessing the right laws and conditions for life. ²⁰

Employing Method

From an empirical point of view, we are limited by what we can detect and measure from our vantage point in the universe. As Brian Greene explains above, we have no evidence that different regions of space have different physical laws. Any evidence for our universe being spawned by another universe with potentially different conditions is also outside of our ability to observe. Additionally, the alternate universes that would hypothetically be created by collapse of the wave function within the Many-Worlds interpretation of quantum mechanics would also be unobservable. There is no way for us in our universe to access or communicate with the other potential versions.

The Fine-Tuning Argument follows a logical structure: the fundamental physical constants and conditions are exactly the values needed for life to emerge, therefore there must be a designer. The statement implies that the probability that the physical constants are specified appropriately by chance is extremely small. Even though there may be more than one combination of constants that could provide the conditions for intelligent life, as a proportion of all the possibilities, the number likely remains small. However, the threat to this logic is the possibility that the current constants could have been "chosen" or "selected" from a larger, possibly infinite, set or ensemble. If there are an infinite number of worlds or if space is infinitely large and if the physical constants deviate between worlds or regions, then the numerator of that proportion can get much larger. In other words, if our physical constants are just one combination among many that do exist or have existed, then the probability of life is not as low as it would otherwise be.

When thinking about how specific the laws of nature must be for stability and for life to emerge, it is natural to feel that it wasn't by chance. In fact, to me it feels intuitive that a creator carefully dialed in the physical laws for us to appear. I must admit that much of this intuition could come from my subconscious worldview and the beliefs of the culture in which I grew up. But even considering those, there is definitely an appeal to the idea that we were not an accident.

It seems to me that the key strength of the argument relies on the small probability of the laws being specified appropriately for life to emerge. Without the possibility of potentially different physical laws in a multi-verse or different regions of infinite space, the probability must be extraordinarily small. Unfortunately we currently cannot, and possibly will never be able to, access these other universes or regions of our universe, so it is not possible to verify with science how improbable our conditions are. However, even if our universe's physical laws were in fact the result of a "natural selection" of universes, it still would beg the question of why our conditions were ever possible at all. Just as one could point to a designer creating life through Darwinian evolution, so one could point to a designer creating our universe with it's unique physical laws by means of "cosmic" evolution.

Based on this, I find it very likely (>90%) that the universe was designed for life and ultimately for intelligent life - us. I am open to reevaluating if future scientific discoveries provide more insight into the probabilities of fine-tuning and any evidence of a multi-verse, and there's enough uncertainty here that I wouldn't be surprised either way. In his book The Experience of God, philosopher David Bentley Hart sums up the conclusion well, "Certainly all of the cosmos’s exquisitely fine calibrations and consonances and exactitudes should speak powerfully to anyone who believes in a transcendent creator, and they might even have the power to make a reflective unbeliever curious about supernatural explanations, but, in the end, such arguments also remain only probabilistic, and anyone predisposed to explain them away will find plentiful ways of doing so." ²¹

¹ Paul Davies, The Mind of God: The Scientific Basis for a Rational World (New York, NY: Touchstone, 1992), 195.

² Francis S. Collins, The Language of God: A Scientist Presents Evidence for Belief (New York, NY: Free Press, 2006), 74.

³ Richard D. Barrow, "Life, the Universe, and the Anthropic Principle," The World & I Online, August 1987.

⁴ Richard G. Howe, "What Are the Classical Proofs for God's Existence?" in The Comprehensive Guide to Apologetics, ed. Joseph M. Holden (Eugene, OR: Harvest House Publishers, 2018), 85.

⁵ Davies, 194-195.

⁶ Davies, 197-198.

⁷ Carl Sagan, The Varieties of Scientific Experience: A Personal View of the Search for God (New York, NY: Penguin Books, 2007), 56.

⁸ Davies, 199.

⁹ David Christian, Origin Story: A Big History of Everything (New York, NY: Little, Brown Spark, 2018), 86-87.

¹⁰ Timothy Keller, The Reason for God: Belief in an Age of Skepticism (USA: Penguin Books, 2018), 134.

¹¹ Davies,195.

¹² Brian Greene, The Fabric of the Cosmos: Space. Time. and the Texture of Reality (New York, NY: Vintage Books, 2005), 222-223.

¹³ Keller, 136-137.

¹⁴ Davies, 198.

¹⁵ Greene, 225.

¹⁶ Sagan, 109-114.

¹⁷ Sean Carroll, The Big Picture (New York, NY: Dutton, 2017), 303.

¹⁸ Davies, 216.

¹⁹ Sean Carroll, Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime (USA: Dutton, 2019), 39.

²⁰ Davies, 217-222.

²¹ David Bentley Hart, The Experience of God (New Haven, CT: Yale University Press,2013), 39.