Recently, I wrote about what I find as the most persuasive argument (scientifically speaking) for the truth of Christianity. Big bang cosmology reveals a marked correspondence between the biblical description of the universe and our best scientific explanation. The fine-tuning argument ranks second on my list of most persuasive arguments, but only because it has a less-direct connection to the Bible.
What Is Fine-Tuning?
Before getting into the details, it’s worth noting that a great wealth of scientific knowledge demonstrates the fine-tuning required for life to exist. By fine-tuning, I mean that (1) life requires some parameter to have particular value, and (2) the parameter in question has an unusual or atypical value. For example, life requires that the universe contains sufficient carbon and oxygen as well as hydrogen. When scientists assess what strengths of the electromagnetic and strong nuclear forces lead to sufficient quantities of these three elements, only a small range of values meet life’s requirements. The fine-tuning arises because small changes to these values lead to an apparently lifeless universe.
Evidence of Fine-Tuning Is Pervasive
Evidence of fine-tuning abounds in the universe. As scientists tried to understand why the universe contains carbon, they recognized that it requires two finely tuned energy states—one in the nucleus of carbon and the other in oxygen. Fred Hoyle first postulated the existence of these two states decades ago, and scientists experimentally verified them a few years later. More recent studies show that changing the quark masses or the fine structure constant by a few percent results in a universe with insufficient carbon and oxygen for life.
The chemical composition of the Sun (and the planets orbiting it) requires that the Sun must have formed in the aftermath of a few supernovae as well as some other specific kinds of stars. This means that the Sun must have formed in a large cluster containing thousands of stars. However, unless the Sun were ejected from this cluster early in its history, the interactions with the stars in the cluster would have disrupted the planetary orbits.
Plate tectonics on Earth play a critical role in regulating the temperature of the planet. Scientific studies indicate that Earth’s composition and size are tuned to provide long-lasting, active plate tectonics.
Along with plate tectonics, the Earth’s atmosphere and cloud cover also helped maintain an environment where liquid water could exist for billions of years. All of these factors, as well as the different kinds of life over Earth’s history, had to change and adjust in concert with one another or else the planet would have become uninhabitable.
As scientists probe the workings of life itself, they find incredibly well-designed systems. My personal favorite, the programming seen in the genetic code, shows a level of sophistication, error correction, and flexibility unmatched by those written by the best computer programmers on Earth.
A Common Objection
Most scientists recognize that the parameters must occupy a small range of values to permit life as we know it. The most straightforward conclusion, in my opinion, is that God fashioned the universe in a highly specific way in order to support life. Some object to this conclusion and assert that many different configurations would still support life. While we cannot verify this assertion in an experimental way (that would require making a new universe), scientists can assess whether multiple configurations of these parameters lead to a universe with the necessary requirements for life. These studies indicate that some parameters have flexibility while others don’t. Additionally, the existence of a few other states that might support life doesn’t change the central point that ratio of life-supporting states to life-prohibiting ones is incredibly small.
Fine-Tuning Points to God
The pervasive evidence of fine-tuning provides a compelling case that a supernatural Designer exists. One has to do some additional work to connect this Designer with the God of the Bible, but big bang cosmology helps out with that task.