There are many laws that govern the peculiarities of everyday life, of which Murphy’s Law is the best known. But in my engagement with those teetering within the creationism debate, I’ve discovered a new pattern of behavior that perhaps deserves its own name. Let’s call it “Libby’s Law”. Simply put, the longer one discusses the age of the Earth, the more likely a flawed statement about radiocarbon dating will steer the conversation into futility.
Radiocarbon dating is relatively easy to visualize and understand on a basic level, unlike many other methods in geochronology. The atmosphere contains trace amounts of radioactive carbon (14C). Plants absorb that carbon through photosynthesis, and animals via plants. When they die, however, the radioactive carbon decays at a known rate. Measuring the ratio of radioactive to stable carbon, we can estimate the age of carbon-bearing samples.
On the other hand, the technical details of radiocarbon analysis are extremely difficult to understand. The process of sample preparation and analysis depends on the technique (gas proportional counting, liquid scintillation, or accelerator mass spectrometry, for example), of which each has its own limitations and potential for error and uncertainty. Mathematical corrections are complex, and the reliability of dates can even vary between samples. Hence geochronologists have devoted entire peer-reviewed journals to addressing the many challenges that arise.
In recent years, creation ministries have taken full advantage of both factors. They present radiocarbon dating as straightforward and easy to understand, while building their case on technical discussions that are simply inaccessible to the non-specialist reader. According to organizations like ICR, CMI, and AiG, ancient samples of coal, graphite, diamond, petrified wood, and even dinosaur bones have been dated confidently to only 30–70,000 years old, rather than the tens of millions of years assigned to them via other techniques. What a discrepancy! It’s abundantly clear why apparent contradictions involving the radiocarbon method are the preferred soundbite references for the everyday Young-Earth Creationist.
While I’ve written at length on how creation ministries deviously misrepresent the radiocarbon method to support their claims, I’m going to do something completely unexpected and refer you instead to a rebuttal published by…well, the Institute for Creation Research! Therein, Dr. Gerald Aardsma explains six common myths regarding radiocarbon dating. In response to the myth that samples of coal have been dated to only 20,000 years, he writes:
It is easy to contaminate a sample which contains very little radiocarbon with enough radiocarbon from the research environment to give it an apparent radiocarbon age which is much less than its actual radiocarbon age. For example, a sample with a true radiocarbon age of 100,000 radiocarbon years will yield a measured radiocarbon age of about 20,000 radiocarbon years if the sample is contaminated with a weight of modern carbon of just 5% of the weight of the sample’s carbon. It is not too difficult to supply contaminating radiocarbon since it is present in relatively high concentrations in the air and in the tissues of all living things including any individuals handling the sample. For this reason special precautions need to be exercised when sampling materials which contain only small amounts of radiocarbon.
Now, this article was published originally in 1989, which means two things. First, Dr. Aardsma’s statement that “no reliable historically dated artifacts exist…older than 5,000 years” is no longer true. Multiple collaborative studies have independently confirmed radiocarbon dates up to ~50,000 years. Secondly, Dr. Aardsma is writing prior to the time when creation ministries began to manipulate radiocarbon results to reinforce their position. Instead, he takes the more honest approach, which is to say that since radiocarbon dating yields ages often exceed 6,000 years, YEC’s can only assume that the Flood somehow distorted the carbon cycle and undermined the method’s assumptions.
From now on, whenever you encounter the claim that radiocarbon dating supports a young Earth, I hope you remember Libby’s Law.