In December 2009, I conducted an interview with cellular and molecular biologist Kenneth R. Miller, who was both then and now a biology professor at Brown University. The interview was for a feature in a Christian magazine exploring the possible reconciliation of the scientific consensus on evolution with an uncompromised biblical faith. I thought that, as an evolutionary biologist and opponent of creationism and intelligent design, as well as a Roman Catholic and theist, Dr. Miller was more qualified than most to speak to the issue.
I would be delighted to be able to say that, after three and a half years, the debate has progressed such that his comments no longer apply, but unfortunately that is not the case. And so, with Dr. Miller’s permission, I am reprinting our interview in several parts.
Part 1 | Dr. Ken Miller, on the definition of “evolution” and a small sampling of the evidence behind the theory.
Me: Dr. Miller, you say that evolution is both a theory and a fact. Could you please explain these terms?
Ken Miller: Sure. Evolution and evolutionary theory are not the same thing. In English, we often use the word “evolution” in two entirely different ways.
Evolution describes a process we can see and observe in nature. It is a fact, for example, that we have a record of the past history on earth called the fossil record. It’s a fact that living things in the past were different than living things today, and it’s also a fact that when we examine fossils over hundreds of millions of years, we see a series of relationships from one time period to another that document ancestor-descendant relationships as we move forward or backward in time. So, if what one means is the process of change over time, evolution is as much a fact as anything we know in science.
However, by evolution, sometimes we mean the explanation for how that process took place — a theory that ties together what we know about genetics, molecular biology, and developmental biology to explain the factual patterns of evolutionary change. In this sense, evolution is very much a theory, because scientific theories are used to explain facts. Scientific theories are not hunches or guesses, they’re explanations built upon facts and consistent with facts.
Me: Would you please describe some of the evidence that you believe supports evolutionary theory?
KM: [amused] Well, how much do you want? Walk into any museum of natural history anywhere in the world, and you will see so much evidence you could be buried under it: that life has changed over time, that our species is a relatively recent appearance on this planet, and that we and other species today were preceded by species that were clearly ancestral to us but also clearly different. Those are the documented facts of what life was like in the past.
Now the second thing is genetics. We understand that many of the physical characteristics of living organisms are determined genetically. If it were true that genes were incapable of change, the characteristics of living organisms would be pretty much fixed. But we know, as a fact, that living things contain genetic information that can and does change over time due to a variety of different processes that we can observe in the field and reproduce in the laboratory. They produce the kinds of changes in from one generation to another that create genetic diversity in a population.
Then, it’s perfectly clear, and Darwin [Charles Darwin… you knew that, right?] wrote about this brilliantly in the third chapter of “On the Origin of Species,” that any living organism, whether it be a dandelion, a humpbacked whale or a bacterium, can produce far more offspring that could possibly survive on this planet. And what this means is that there is a struggle for existence among all organisms. Take, for example, an oak tree on your front lawn. In a good growing season, an oak tree can drop two or three thousand acorns. Do every one of those acorns grow up to be a full-sized oak tree? Well, I would hope not! It doesn’t happen that way, and that means even among acorns, there is a struggle for existence. And in that struggle for existence, given the fact that there is variety and diversity within any population, those individuals whose particular characteristics suit them best to survive are going to contribute more to the gene pool in the next generation. And it is from this process of natural selection, operating on genetic diversity, that evolutionary change takes place.
And finally, evolution makes fairly specific predictions about what the sequences of DNA in our genome ought to look like with respect to our evolutionary relatives. It’s a fact, for example, that the human genome contains dozens of molecular errors from the remnants of transposable genetic elements and so forth that we share with our close relatives related by common ancestry. What I mean by that is that we have almost pointless genetic information — defective genes, pseudogenes, genetic mistakes and so forth — that we share in the exact same places with our evolutionary relatives, such as the other great apes. The notion that our species and other species were uniquely designed or intelligently created or simply brought into existence spontaneously doesn’t fulfill any of these predictions.
And that is why evolution has a very strong support of factual evidence in genetics, molecular biology and paleontology.
In the next installment, Kenneth Miller discusses intelligent design and addresses the claim that scientists have not discovered enough transitional fossils to support evolutionary theory.