Is Christianity incompatible with the theory of evolution?
Some people claim that Christianity is incompatible with the theory of evolution. Richard Dawkins—a prominent atheist—said that he lost his faith in God when he learned the theory of evolution. The theory of evolution is not always defined in precisely the same way and the theory contains several different theses. I will attempt to explain the different theses of evolution, and I will argue that there is no inherent conflict between Christianity and evolution. The 4 general theses that constitute the theory of evolution are:
The ancient earth thesis
The descent with modification thesis
The common ancestor thesis
The theory of natural selection (aka Darwinism)
If any of these theses are incompatible with Christianity then evolution is not compatible with Christianity. Each thesis must be examined separately, but first I have to define what I mean by Christianity.
Christianity can refer to a wide variety of beliefs and organizations such as the Catholic church, The Church of Jesus Christ of Latter-day Saints, The Lutheran Church, and the Southern Baptist Convention. Adherents of these organizations share a common belief that God exists, that Jesus Christ is divine, and that God played some role in our creation. C.S Lewis refers to Mere Christianity which is what all Christian faiths have in common. Mere Christianity could perhaps be thought of as the intersection of the Christian creeds such as the Nicene Creed, the apostles creed, the Heidelberg Catechism etc.
1. The ancient earth thesis
The first thesis of evolution is that the earth is very, very old. There are several different clocks that scientists can look at to measure the age of the earth. There are various kinds of radioactive decay clocks (such as Potassium argon, Carbon 14, and dozens more), tree ring clocks (which measures widths and thicknesses of tree rings), and molecular clocks (which measure the time when species diverged). When all of these clocks are calibrated to each other, each acts as a stopwatch that measures time from some starting point such as the solidification of molten rock, the death of an animal, the formation of tree rings, or the separation of one species into two. The scientific consensus is that these different clocks all confirm that the earth is about 4.6 billion years old.
Is the ancient earth thesis incompatible with Christianity?
Since the Christian creeds have nothing to say about the age of the earth, there is no conflict between Christianity as defined and this thesis of the theory of evolution. There are some individual sects within Christianity that teach that the earth was created within the past 10,000 year. They teach this because the book of Genesis says that God created the earth in 6 days. This literal interpretation is unnecessary since other parts of the bible use the word day figuratively. (See Genesis 2:17 and Gen 5:5) Christians don't lose anything essential to their faith by abandoning a fundamentalist belief in a 'young' earth.
2. The descent with modification thesis
Parents pass on traits to their children. This process is called heredity. The traits of an organism are expressions of genes. Genes in offspring tend to vary slightly from the genes of the parent. Given enough generations, the descendants of a given species may have very different traits from its ancestors. For example, all dogs from the chihuahua to the great dane are descendants of wolves. We know this through genetic evidence as well as the records of domesticating and breeding dogs. This leads to thesis 3.
3. The common ancestor thesis
Brothers and sisters look alike. People of the same race have the same skin color. Looking alike and sharing the same skin color are evidence for biological relationships. Similarly, the bone structures of different species provides evidence of relationships between species. This evidence suggests that different species share common ancestors. There is a mountain of evidence that every living thing is descended from a common ancestor. Perhaps the most powerful evidence is genetic evidence. Genetic evidence is accepted as sufficient to decide court cases. It can also be used to show the family relationships between different species. Given the scientific evidence, it is clear that every organism is a cousin to each other. Not only are we cousins with chimpanzees, but we are cousins with dung beetles and turnips. Here is a detailed phylogenic tree of life on earth.
Are theses 2 and 3 incompatible with Christianity?
Although Christianity teaches that God created us, there doesn't seem to be anything in the major creeds that suggests how God created us. These two theses of evolution and the belief that God created us can be reconciled by believing that God created us through a process of descent with modification from a common ancestor.
4. The theory of natural selection
The theory of natural selection or “Darwinism” is a theory that tries to demonstrate one way of how descent with modification happens. The theory goes something like this:
When an organism has offspring, most of the traits of the parent are passed on to the children.
Traits vary within a given population of organisms. Some are tall, short, fast, slow etc.
Some traits give organisms a reproductive advantage over other organisms. E.g. Organisms that can avoid danger better than their peers will likely have more offspring compared to their peers.
Traits that enhance reproductive advantage are passed on to offspring more often than less effective traits.
For example, Angler fish are deep sea fish that have nasty sharp teeth and a glowing lure attached to their head. This glowing lure is the last thing that many fish see before being gobbled up by the Angler fish. In a given population of Angler fish, some will have brighter lures than others which are better at attracting hungry fish. The Angler fish with brighter lures might tend to survive more often than Angler fish with dimmer lures. The Angler fish with brighter lures will be “naturally selected” to pass on their genetic traits to their children causing modification of the species over time. On an interesting side note, if the lure gets too bright, it could possibly attract larger fish that would just eat the whole Angler fish. Natural Selection could work in the other direction to make the lure a bit dimmer until some economic equilibrium is reached between attracting smaller fish and avoiding larger fish.
There are plenty of examples of natural selection. Many examples have even been observed such as Lenski’s experiments with e. coli.
Is the theory of natural selection incompatible with Christianity?
Natural selection doesn’t appear to conflict with Christianity either. I think there are several possible explanations that could bring the 2 beliefs into harmony. Here are a few suggestions:
God could have started the process and let natural selection run its course knowing that man would eventually evolve in the image of God.
The whole process started and ended without God’s interference and then God chose an Adam and Eve out of the existing homosapiens and taught them His Gospel—perhaps gave them the ability to understand it as well.
God could have directly influenced natural selection. If man can effect natural selection intentionally by altering genes or unintentionally by building wind turbines that kill thousands of birds, then surely God could have selected species quite deliberately to reach the outcomes He intended. Current scientific understanding shows that natural selection is the primary means of evolution, but it doesn’t rule it out as the only means.
God could have created Adam and Eve and then Adam and Eve’s children could have mixed with other homosapiens that did evolve from a common ancestor, thus giving us the genetic relationship with other species.
Some of these explanations will be more or less palatable to a Christian based on how literally they tend to translate the Bible. There will certainly be other explanations that are perhaps better or more nuanced; the limits of my own creativity leads me to think that it is something like one of the explanations mentioned above.
Conclusion
I used to think that evolution and Christianity were incompatible. I have briefly documented how my own beliefs evolved here. Christians don’t claim to know exactly how God created us and the “how” of creation is not essential to Mere Christianity. Some might object that the definition of Christianity that I have used is too broad. To answer the question I posed at the beginning, the definition needs to be broad in order to avoid the fallacy of concluding that the theory of evolution is incompatible with all of Christianity because it may be incompatible with some individual sects within Christianity.
The superficial contradictition between Christianity and evolution lies not in the theory of evolution itself but in the philosophical baggage that people attach to evolution or the philosophical baggage that some attach to Christianity. Once one discerns between the actual beliefs and the philosophical add-ons, the conflict between Christianity and evolution dissolves.