(This post is part 6 of the series entitled “Contesting Christianity.” Please see the index for the other posts in this series.)

Creationism was always one of my favourite issues as a Christian. I spent time online debating people who defended evolution, and I enjoyed “poking holes” in their arguments. Of course, despite my zeal for debates and apologetics, I had never actually read any books by evolutionists or spent any time researching what evolutionists said—my information always came from creationist sources. So, I would hear what creationists had to say, and I would hear what creationists said evolutionists had to say, but I never heard what evolutionists themselves had to say (outside of the debates I had). Creationists, of course, aren’t going to bring up arguments that they can’t deal with, so I was clearly missing out on the best arguments for evolution. When I actually spent some time researching the issue, I realized just how much I had missed. So this post will attempt to summarize the arguments for a young earth and for creationism, as well as what I feel to be the best arguments against these views. Obviously I don’t have room to cover everything (this post is long enough as it is!), but there is plenty of information out there for those who are interested in learning more. I will put some links to further reading at the bottom of this article.

Age of the Earth

Not all creationists are young-earth creationists. There are some who accept the age of the earth as concluded by science, which places it at approximately 4.54 billion years old. Other creationists, however, do not accept this age, so I thought it best to separate this topic from the more general claims of creationism.

Often it is claimed by young-earth creationists (YECs) that the earth is somewhere around 6,000-10,000 years old. The lower bound of this claim is derived from work by Archbishop James Ussher, who created a chronology from the lists of lineages found in the Bible and arrived at the conclusion that the world had been created by God on Sunday, October 23, 4004 BCE. Of course, Ussher’s conclusions were based on the ages listed for the people mentioned, as well as assumptions about when they would have had children. Today, most creationists view it as, at the very least, too specific of a conclusion for what can be known about the biblical chronology. However, many still use the 6,000-year estimate as some sort of reference point.

There are two major claims made by YECs that are most relevant to the age of the earth. The first is that the Noahic Flood can account for many of the geological changes that scientists claim would take millions or billions of years to create. The second is that radiometric dating methods are unreliable and/or give estimates that are much longer than they should be. I will deal with each of these in turn, and then provide a few positive arguments for the age of the earth as determined by science.

Flood Geology

There are some creationists who make arguments such as, “The erosion rates of Niagara Falls limit it to an age less than 10,000 years, so it can’t be older than that!” The correct response to this is, “Okay fine, so what?” The first thing to remember is that scientists do not claim that every natural phenomenon was always here from the beginning of the earth. The earth has undergone massive changes over its rich history, and so it is not at all useful to point to specific things as being “young” and then extending this to mean that the earth must therefore be young. However, it does work the opposite way. If someone can point to something as being “old”, that can be extended to mean the earth must be at least that old—since the earth had to already be there for the phenomenon to take place on it. So it is important to keep in mind that YECs have their work cut out for them—the existence of even one old phenomenon means that their model of the world is wrong. Of course, such phenomena must be dated properly, etc., but if just one can be proven to be millions or billions of years old, then YEC is false.

With that in mind, let’s take a look at some common examples. Creationists sometimes point to the Grand Canyon, stating that it could have been carved out by the massive currents of water present in the Flood. Any competent geologist, however, would tell you that this is absurd. The Grand Canyon was formed by the Colorado River, and the basin cuts through about 18 different layers of rock which span about 1 billion years of time. Even if the Grand Canyon itself was of recent origin, one would still have to explain the many layers of the geologic column and how they got there. Moreover, the Canyon does not look anything like what we see from other sudden floods. Floods create wide, shallow beds rather than deep, winding channels. They don’t meander around in twisting paths; they are fairly wide and straight. We have examples of both, and the differences are quite apparent, especially to a trained geologist. Finally, since most YECs are forced into claiming that the geological column was also laid down during the Flood (to explain fossils and such), it is difficult to see how the Flood could lay down 18 distinct types of sediment, allow time for it to harden, and then cut through it extremely quickly (as far as erosion is concerned). It all begins to get extremely implausible when the Flood has to explain it all.

Another phenomenon that can be difficult for creationists is the creation of caves. Caves can be created through a number of means, including erosion, dissolution, lava, glaciers, and fractures. But the most common type of formation, including that of caves like the Carlsbad Cavern, is dissolution. This is where an acid, like sulfuric or carbonic acid, is brought to an area by water, and slowly eats away at limestone bit by bit until a cavern is formed. Caves formed by sulfuric acid typically are formed more quickly (because sulfuric acid is much stronger than carbonic acid), but these processes still take time. A large amount of time. And these reactions cannot really be sped up, because the acid can only react with the surface area of the limestone with which it comes in contact. As it eats away at the rock, obviously that surface area grows, but the reaction itself simply takes time. And increasing the amount of water or the amount of acid simply does not do anything to speed it up. With the Carlsbad Cavern, although the different “rooms” were formed at different times, estimates place the “Big Room” at about 4 million years old. There is simply no way to explain these caves through a large Flood (in fact, increasing the amount of water would only dilute the acid solution, making the process slower).

There are so many other natural phenomena that I could point to as evidence of an old earth. The geologic column itself is evidence for an old earth, since it is difficult to see how a Flood could lay down so many layers of sediment, allowing each to harden before laying down the next one (so they won’t mix together), and also preserving details like footprints, mud cracks, raindrop impressions, and so on. But I simply have neither the time nor the space to cover them all. Those who want more examples can view the links at the bottom of the page. However, as I mentioned, if even one natural phenomenon took place millions of years ago, this makes the earth at a minimum that old. I have given two examples where it seems clear that the processes took much longer than 6,000-10,000 years to complete. Thus, if this is correct, the age of the earth must be older than this.

Radiometric Dating

Another claim of YECs is that radiometric dating is flawed, therefore giving unreliable results. I’ll try to give a (very brief) explanation of what radiometric dating is and how it is used, and then we’ll examine if it truly is unreliable.

Radiometric dating is the process by which materials such as rocks, minerals, or organic compounds are analyzed to determine their age. It relies on observing the amount of a certain radioactive isotope (of which various ones are used) and determining how much of it has decayed. A common isotope that many people know is carbon-14. This element is exactly the same as regular carbon (carbon-12), except that it has 8 neutrons instead of 6. But over time, carbon-14 breaks down, or “decays”, into carbon-12, and this decay occurs over a predictable length of time known as the “decay rate”. The decay rate is measured by half-life, which is the point at which half the carbon-14 will have decayed into carbon-12.

However, carbon-14 is not the only isotope used to date objects. In fact, it has a relatively short half-life (5,730 years), so it is not useful for dating anything older than about 58,000 years. Other dating methods include potassium-argon, uranium-lead, and rubidium-strontium. The principle is the same for these isotopes, but the half-lives of these isotopes are much longer than carbon-14. Thus, they can be used to measure the age of materials much older.

Radiometric dating does rely on several assumptions, which creationists claim are false. These assumptions include:

The initial conditions of the rock sample are accurately known. The amount of parent or daughter elements in a sample has not been altered by processes other than radioactive decay. The decay rate (or half-life) of the parent isotope has remained constant since the rock was formed.

The first assumption can be avoided by using isochron dating. I don’t have the space to discuss this in detail, but essentially it does not rely on any assumptions about the initial conditions. The second assumption is important, but is something that can generally be avoided by doing good research. Scientists have found certain cases where contamination can be an issue; for instance, mollusks cannot be dated properly using carbon dating methods, because the shells that they form can come from limestone which is much older than they are. But once scientists know this, they can simply avoid using that method in that situation. The fact that the method doesn’t work under some conditions doesn’t mean that it does not work at all when used in proper conditions.

The third assumption is a little trickier. After all, we haven’t been measuring the half-life of uranium for billions of years to know if it has remained constant. What scientists have done, however, is subjected isotopes to numerous tests to see if they can artificially change the decay rates. Temperature, pressure, chemical environments, and electromagnetic fields do nothing to influence the rate. So it is reasonable to assume that it would not be affected by normal conditions on Earth. However, we can go further than that. Radiometric dating can be calibrated using non-radiometric dating methods, such as reliable natural cycles on earth, luminescence dating, and observation of gamma rays (given off by radioactive isotopes) from supernovae. For carbon-14, another method that can be used is tree ring dating. Essentially, one can take a large tree, count the rings, and also use carbon dating on sections of the tree. Carbon-14 dating lines up very well with this independent dating method. So, there are other dating methods that help support the assumption that the decay rate of radioactive isotopes has remained constant over time.

If these three assumptions are true, and if good research is done (by not contaminating samples, using the methods improperly, etc.), radiometric dating can provide an important and reliable tool for dating ancient objects. And since this method routinely produces dates for rocks and other objects that are millions of years old, we can be reasonably confident that these objects are, in fact, millions of years old. Thus, the world itself cannot be young.

Evolution

As previously mentioned, not all creationists are young-earth creationists. Some accept the age of the earth, but still object to evolution on other grounds. This subject has been the topic of entire books—see, for example, Why Evolution Is True by Jerry Coyne (amazon.ca) and The Greatest Show on Earth by Richard Dawkins (amazon.ca)—so I can’t possibly hope to cover all the arguments either for or against, but I will try to provide a few of the common arguments.

Transitional Fossils

One of the most common arguments made against evolution is that “there are no transitional fossils.” Unfortunately, this is simply untrue, despite its prevalence. As far as I can tell, the argument relies on an ambiguity in what exactly a “transitional fossil” is. If one is looking for a bizarre mix of organisms that is half of one species and half of another, like a crocoduck, then of course there are no transitional fossils. Despite what Ray Comfort and Kirk Cameron have said, such a hybrid would be more of a disproof of evolution than support for it. Evolution does not predict half-lizard, half-bird creatures in that sense. But a more accurate understanding of what would constitute a transitional fossil is that it would show a mix of characteristics between two species or phyla. So while we might not expect lizards with half a wing, we might expect lizards with proto-feathers, or lizards that show evidence of perching on trees. And we do find many of these sorts of fossils.

For example, many fossils have been uncovered that are clearly intermediates between theropod dinosaurs and birds. Several of these fossils have been discovered fairly recently, and include species such as Anchiornis huxleyi, Epidexipteryx hui, and Archaeopteryx lithographica. These fossils display animals which are clearly lizard-like, but have distinctive characteristics similar to modern birds (the most prominent of which are the proto-feathers, but there are other differences as well). Another example is the evolution of modern whales from Pakicetus inachus. Whale evolution is one of the best documented examples of evolution, and shows a clear transition from a land-dwelling, four-legged animal to the sleek, ocean-dwelling animal we know today. Particularly clear is the transition of the nasal cavity from the front of the skull up to the top (where whales now have a blowhole), and the diminishing size of the pelvic bone as whales lost their legs. And let’s not forget human evolution, which is also well documented, to the point where creationists themselves don’t always agree one whether to classify certain fossils as “human” or “ape”. Simply put, we have ample evidence of transitional fossils.

Human Evolution

Speaking of human evolution, there has always been resistance to the idea that humans evolved from “lower” animals. Even Alfred Russel Wallace, the man who independently struck upon the idea of natural selection around the same time as Charles Darwin, accepted evolution for other animals, but denied that it could explain the development of humans. However, there are many reasons to believe that humans are, indeed, relatives of the great apes. I’d like to mention just one that I find particularly interesting.

Humans have 23 pairs of chromosomes in our genome. The other great apes (chimpanzees, gorillas, and orangutans) all have 24 pairs. This might cast some suspicion on the claim of a common ancestor—where did the extra pair go in humans? However, what we have discovered from sequencing the genome of humans and other apes is that human chromosome #2 is the product of two ape chromosomes that have fused together. There are clear, unambiguous signs that are present when two chromosomes fuse, and the fused chromosome that we have is (with a little variance) identical to these other two ape chromosomes. Ken Miller, himself a theist, has given an excellent talk describing this finding. The YouTube video is here; it is only four-and-a-half minutes long, but it succinctly describes the amazing evidence that this provides for human evolution. To me, this is essentially proof beyond all reasonable doubt.

Endogenous Retroviruses

Endogenous Retroviruses (ERVs) are viruses with a very special skill. When an organism is infected, what the virus does is inject its own RNA code into the host cell’s DNA, so that the cell now diverts resources to producing more copies of the virus. If the virus happens to infect the sex cells of the organism, these additions to the DNA get passed onto the offspring, and can therefore become a permanent part of the genome of that species given enough time. Since ERVs are hereditary, these can provide a useful tool for determining ancestry.

When examining the genomes of different species, we can compare them and see if they include ERVs in the same location. With the relatively tiny size of these ERVs compared to the entire genome, the odds of even one of the exact same ERV appearing in the exact same place one two genomes is vanishingly small. But when we examine species, we find they often have ERVs in the same location. For example, humans and chimpanzees both have thousands of these retroviral insertions, and humans share all but 82 ERV insertions with chimpanzees. When examining the genomes of other organisms, one can establish a nested hierarchy that shows ancestry based on how many ERVs the organisms share with each other. To claim that an intelligent designer put these ERVs in the same location within all these species would be strange, to say the least, and to say that these similarities came about without shared ancestry is incredulous. The probability of such an event is so low it is not even worth considering.

Converging Evolutionary Trees

The final proof for evolution that I want to mention is the convergence between different disciplines. Scientists have many ways to produce an evolutionary tree showing ancestry. For example, they can compare the anatomy (the bones, organs, and other structures) of organisms to look for similarities. They can examine the fossil record to look at transitional forms. The fossil record also can be used to indicate relative time periods; fossils appearing in older rock formations can be concluded to be older than those appearing only in newer rock formations. Geographical studies can reveal how the locations of current organisms and fossils show divergence in species. (For example, it helps to answer the question of why marsupials are, with few exceptions, only found in Australia.) Embryology can be used to compare common characteristics between embryos of different species. Genetics offers us many new ways to compare species. Scientists can compare them based on total nucleotides (“letters”) in the DNA, or on ERVs, or on non-coding regions of DNA, or on each individual gene, of which there are thousands. All of these disciplines can independently produce a “tree of life”, showing the hierarchical ancestry between species. And without fail, these trees line up with each other. For the millions of species to be mapped by independent fields and yet converge on a similar result would be astonishing if the ancestry underlying it did not actually exist. The hierarchy can be proven over and over again using thousands of different methods, and yet the results are always the same. There is no other answer for such convergence unless one is willing to believe that God is intentionally deceiving us.

Conclusion

The evidence I’ve provided here appears, at least to me, to be conclusive. I have not even had the space to provide half the evidence in favour of evolution, yet it seems clear that the earth is in fact old, and that evolution did indeed occur. There are simply too many ways for evolution to prove itself true, and without fail, it does so every time. Of course, scientists are not finished studying evolution. There are still many details to be worked out. But the overall picture is clear: Evolution is a fact of life. While this does not challenge the existence of God, or refute that he “set things off”, it does mean that creationists must, at the very least, come to a different understanding of what their God is like. There are certainly theistic evolutionists who update their beliefs in light of the evidence for evolution. But a full examination of the evidence prevents any sort of answer that denies the common ancestry of life on earth. As such, a Christian belief system that includes creationism (in the sense of rejecting evolution) is simply in contradiction with the world in which it exists.

More Information

Notes: