Yesterday I posted my review of the new Zondervan book Four Views on The Historical Adam. One of the book’s contributors, Denis Lamoureux, offered a response. Despite the fact that I stated Lamoureux presented the strongest case, he didn’t seem very happy with the review and listed several points that he thought I got wrong. In this article I’m going to offer a response to a couple of his points. I will begin with a brief comment on miracles and then turn to discuss the question of evolution and falsification. In a subsequent article I will respond to Denis’ other points.
In his first point Denis complains that I misrepresented his view:
“I can’t offer a defense of when I believe real history begins in the Bible. However, I made it very clear (in italics) on p. 44 that history starts about Genesis 12 with Abraham. And I made it more than clear that I accept Jesus’ miracles and bodily resurrection. You conveniently overlooked these facts.”
This complaint puzzles me since I never denied that Lamoureux accepts biblical miracles. Indeed, I wrote in the review that “Lamoureux explicitly affirms miracles in his essay.” (emphasis added) You can’t get much more specific than that. As for the bodily resurrection of Jesus in particular, I never suggested that Lamoureux denies the doctrine. So this combative opening salvo leaves me puzzled.
On Falsifying Evolution
At this point Lamoureux moves into specific points of dispute. His first complaint (and the only other one I will address in this article) concerns my critique of a claim he makes in his essay. Here’s the original excerpt:
“evolution is the easiest theory to disprove. Find just one human tooth near the bottom of the geological record and you could destroy evolutionary science.” (40)
I objected to this statement, claiming that it is hyperbolic at best and outright false at worst. My point was that evolution is a good theory and good theories are not falsifiable in the way he describes because they explain multiple lines of evidence. Consequently, when recalcitrant facts (e.g. a human tooth near the bottom of the geological record) against a theory arise, they tend to be treated as anomalous exceptions outweighed by the overall explanatory power of theory. Or they are the catalyst for the theory being amended to some degree to accommodate the fact. I then provided a historical example to support my claim.
Denis was unpersuaded and replied as follows:
“(1) Not being an evolutionary scientist, you do not grasp the impact that finding a human tooth at the bottom of the fossil record would have. This would tip science upside down. I once raised this issue with a number of my paleontological and geological colleagues, and they completely agree with me.”
It is true, I’m not an evolutionary scientist. However, merely pointing that out doesn’t constitute a rebuttal. Indeed, responding to my objection by noting my lack of professional credentialing in the relevant field constitutes an ad hominem coupled with an argument from authority (this is what I believe and my colleagues agree with me). What is missing is a rebuttal that specifically addresses the point I make.
To reiterate, I make a claim that scientific theories are interpretive frameworks for multiple independent lines of data, and a good theory is one that successfully explains multiple lines of data. When a theory is very good, it can tolerate a limited number of recalcitrant facts — i.e. facts that do not fit within the theory.
In support of my claim, I gave the case of the supernova of 1054, an astronomical event which fit as poorly with classic Ptolemaic theory as that human tooth out of sequence in the strata would fit with evolution. The 1054 supernova (which created the Crab Nebula) was an extraordinary celestial event which was carefully documented by Chinese astronomers. By contrast, the event is curiously absent in the documentation of European astronomers. As Karl Giberson and Donald A. Yerxa observe,
“A curious anomaly associated with this extraordinary celestial event is its complete absence from extant historical records of Western astronomers. A new star, visible for months, so bright you could read by it at night, was somehow missed, probably because the prevalent Greek-influenced paradigm for understanding the heavens precluded the possibility of actual change.” (Species of Origins: America’s Search for a Creation Story (Rowman and Littlefield, 2002), 40, n. 35, emphasis added)
This is one way to deal with recalcitrant data: place it in the waste disposal bin of inexplicable anomalies.
A second way to deal with recalcitrant facts is by amending the theory. This is how the Ptolemaic theory dealt with motion in the planetary orbits which would otherwise falsify the theory. Epicycles were added to the overall orbit to explain the back-and-forth movement of the planets:
“This solved the problem at the cost of immense complexity. Instead of one circular orbit for each planet the Ptolemaic universe consisted of several dozens of cycles and epicycles rotating upon and about each other. There were equants, eccentrics, deferents, but still this system could only approximately match the observations.” (Oivind Andersson, Experiment! Planning, Implementing and Interpreting (Wiley, 2012), 20.)
Theories often require tweaks, that is, the proverbial epicycle. And for a time this can be tolerated if the theory has virtues which outweigh the cost of the added complexity of the emendations. But eventually the addition of epicycles becomes so excessive and the comparative virtues so diminished that the theory effectively becomes explanatorily moribund and is abandoned. Good theories tend to become bad not through one dramatic falsifying event, but rather through the gradual erosion of their explanatory power.
I think a comparison between scientific theory and an automobile is very helpful at this point. At what point do you send the car to the junkyard? When it needs a new muffler? A new transmission? A new engine? When the frame is bent?
It’s impossible to answer that question in a generalized way because the value of keeping the car on the road must be judged relative to the respective merits of the car. If you need a new transmission and the frame is bent and the car is a 1976 AMC Pacer, then chances are you’re sending it to the junkyard since there are few compensating virtues in keeping a Pacer on the road. (I speak from experience: when I was a teenager I test drove a dealership’s rusty old Pacer on a dare. It was a deeply traumatizing experience.)
But let’s say the car is a 1962 Ferrari 250 GTO that was once owned by Steve McQueen. In this case the value of the car far outweighs the cost of dealing with any particular issues with the transmission and frame. You’ll move heaven and earth to save this car.
Your willingness to fix the car is reflective of the prior assessed value of the car. In the analogy, the value of a theory is cashed out in terms of explanatory power. And evolution has enormous explanatory power. Consequently, the prediction is that advocates of the theory would be greatly motivated to “save the appearances” by ignoring the recalcitrant fact or amending the theory to explain the fact.
If you’re still skeptical, I would suggest you read Jerry Coyne’s Why Evolution is True (Penguin, 2010), Neil Shubin’s Your Inner Fish (Vintage, 2009) and Richard Dawkins’ The Greatest Show on Earth: The Evidence for Evolution (Free Press, 2010) and draw up a comprehensive list of all the evidence for evolution from those books. Then put all that evidence into one column on a (very long) sheet of paper. And on the other column write one phrase: “one human tooth near the bottom of the geological record”. Do you really think that one recalcitrant fact would be adequate to “destroy” all the evidence in the first column? I think not.
And so we are left with an ironic conclusion. Both Denis and I are concerned to defend the explanatory power of evolutionary theory. But we do so in completely different ways. He does so by claiming it is easy to falsify evolution. I do so by claiming that it is very hard to falsify evolution. The reader must judge which one of us is correct in light of the historical examples provided and an understanding of how successful scientific theories work as comprehensive explanatory frameworks.