In a post last week, amidst a lot of discussion of evolution, Orrin Judd made the mistaken claim that evolution is not a falsifiable theory (in the Popperian sense), and that (even more bizarrely and egregiously) defenders of it thought that this strengthened it.
On a related note, he also added to his list of questions about evolution a twelfth one: What would it take to persuade me that evolution was not the best theory to explain life? What evidence, to me, would disprove it? I told him that it was a good question, and that I’d ponder it.
Well, I did ponder it, and here is my response.
First of all, the theory is certainly falsifiable (again, in the theoretical Popperian formulation). If I were coming to the problem fresh, with no data, and someone proposed the theory of evolution to me, I would ask things like:
Does all life seem to be related at some level?
Is there a mechanism by which small changes can occur in reproduction?
Does this mechanism allow beneficial changes?
Can these changes in turn be passed on to the offspring?
Is there sufficient time for such changes to result in the variety of phenotypes that we see today?
There are other questions that could be asked as well, but a “No” answer to any of the above would constitute a falsification of the theory. Thus the theory is indeed falsifiable, as any useful scientific theory must be.
The problem is not that the theory isn’t falsifiable, but that people opposed to evolution imagine that the answer to some or all of the above questions is “No,” and that the theory is indeed false.
But to answer Orrin’s question, at this point, knowing the overwhelming nature of the existing evidentiary record, no, I can’t imagine any new evidence that would change my mind at this point. Any anomalies are viewed as that, and an explanation for them is to be looked for within the prevailing theory.
And lest you think me close minded, consider an analogy. An ex-football player’s wife is brutally murdered, with a friend. All of the evidence points to his guilt, including the DNA evidence. There is little/no evidence that points to anyone else’s guilt. Had I been on the jury that decided that case, it would have at least hung. I might have even persuaded a different verdict, but that’s unlikely, because I’m sure that the jury had members who were a) predisposed to acquit regardless of the evidence and/or b) incapable of critical thinking and logic, as evidenced by post-trial interviews with them.
But for me to believe that ex-football player innocent, I would have to accept the following (which was in fact the defense strategy):
“I know that some of the evidence looks bad for my client, but he was framed. And I can show that some of the evidence is faulty, therefore you should throw all of it out as suspect. I don’t have an alternate theory as to who did the murders, but that’s not my job–I’m just showing that there’s insufficient evidence to prove that my client did it. Someone else did it–no one knows who–it doesn’t matter. And that someone else, or some other someone else, also planted evidence to make it look like my client did it. It might be the most logical conclusion to believe that my client did it, but that would be wrong–the real conclusion is that it is a plot to confuse, and it just looks like he did it. Therefore you shouldn’t believe the evidence.”
Is this a compelling argument? It was to some of the jury members. And it apparently is to people who don’t want to believe that life could evolve as a random, undirected process.
The only way that I could believe that OJ Simpson is innocent at this point would be for someone else to come forward, admit to the crime, and explain how he planted all of the abundant evidence that indicated Orenthal’s guilt.
The equivalent for evolution, I guess, would be for God (or whoever) to reveal himself to me in some clear, unambiguous, and convincing fashion, and to tell me that he planted the evidence. At which point, of course, science goes right out the window.
But absent that, the evidence compels me to believe that OJ Simpson murdered his wife (as it did a later jury in the civil suit), and the evidence compels me to believe that evolution is as valid a theory as is universal gravitation.