A few days ago, Todd Wood (one of the leading creation biologists today) made a medium-sized splash in the blogosphere with this post. In it, among other things, he said:
Evolution is not a theory in crisis. It is not teetering on the verge of collapse. It has not failed as a scientific explanation. There is evidence for evolution, gobs and gobs of it. It is not just speculation or a faith choice or an assumption or a religion. It is a productive framework for lots of biological research, and it has amazing explanatory power. There is no conspiracy to hide the truth about the failure of evolution. There has really been no failure of evolution as a scientific theory. It works, and it works well.
This was followed by another post which clarified some of his statements. The whole post is interesting, and I'll include a snippet here:
I think you've already figured out an important corollary to this line of thinking, that squabbling over low level theories has very little to do with the acceptance of the high level model. Scientists can argue over the effectiveness of natural selection without ever questioning the high level concept of common ancestry. Likewise, new fossils can be heralded as "changing our understanding of evoluion" in the sense that low level theories have to be modified. The strength of the high level model is relatively impervious to these changes.
Understandably, this post generated quite a bit of reaction among Creationists and non-Creationists.
So, is there evidence for evolution? Certainly if you read most anything from Answers in Genesis or CMI, it certainly seems the answer is "no". So what's up? Why is Todd thinking there is lots of evidence and AiG and CMI saying there isn't any?
I think that, ultimately, the reason is that they are speaking to two different questions.
The question that Todd probably often faces as a researcher is this - "is evolution a useful and helpful heuristic for my scientific research?" Or perhaps something like "is there a lot of corroborating evidence for evolution?" Or maybe even "are there legitimate reasons for a person to accept evolution as a fact?" The answer to all of these have in fact been a resounding "yes" for a lot of people - a lot of smart, educated people who are familiar with the data.
But that's not the end of the story.
There is a difference between something being a rational choice, and something being the only rational choice.
The problem is that many people not only use evolutionary theory as a valid framework for their own lives, research, and work, but that they require others to follow along or shut up. That is, they don't allow for other people to have come to different conclusions, and say that doing so is simply irrational.
I hope you can see that having valid evidence for yourself is different than having compelling evidence for others. Most people who are evolutionists believe that not only are they right, but that the evidence is compelling enough that you should think the same way, too.
And that, I think, is what AiG and CMI and the like are responding to. When someone says "there's no evidence for evolution," I think most people who say that are really saying, "there's no evidence for evolution that is publicly compelling." By "public" I don't mean the quantity of people who believe it, but rather that the nature of it is not universally compelling.
In the case of evolution, I would agree 100% with those people who say there is no evidence for evolution that is publicly compelling.
Now, of course, the question is, "what do you mean by evolution." If, by evolution, you simply mean "things change", well, that is obvious. If, instead, you mean "evolution by natural selection", then not only do I think that there's no evidence, I think it is logically unsound. If, though, you mean "universal common ancestry", then I think that while there is plenty of corroborating data, there is no piece of data that is externally compelling.
Todd, in fact, does us the favor of listing the basic reasoning for evolution:
Take for example the idea that species evolved from a common ancestor. This is a very simple high level idea that lots of people thought of before Darwin. There are several observations that support this model: (1) the "progress" recorded in the fossil record, (2) comparative biology (e.g., comparative anatomy, comparative embryology, etc.), and (3) the biogeography of species of high affinity. If you like, you could add the philosophical "consilience of induction" of common ancestry to explain many types of data. In my estimation, and I think most evolutionary biologists would agree, these evidences are sufficient to support the common ancestry of all species.
I would agree, especially having read some of the papers from the 1900s time frame. The main evidence for evolution is basically that (a) homologies exist, and (b) different fossils are found in different layers. While I can certainly see why these facts might lead people to believe in evolution, there is nothing in them that would be publicly compelling.
Without even getting into young-earth Creationism, changes in the fossil record are also consistent with multiple acts of creation, multiple origins of life, and probably a number of other possibilities. In fact, if you look at the major phyla of life, there is really nothing that would make someone think that there was a common ancestor to them.
In his post, Todd separates out neo-Darwinism from common ancestry, pointing out that even if neo-Darwinism fails, it would do nothing to detract from common ancestry. I agree with him if he is talking about personal reasons to believe in common ancestry. However, the key point of neo-Darwinism is that this was the idea which is used to cover the ground between personally-valid beliefs about the nature of evidence, and publicly-valid conclusions which we should all reach.
Before neo-Darwinism, there was no mechanism to link the different stages of fossils. Generally, if we know of a mechanistic method A of producing B from C, we tend to use A as the explanation for B when it occurs. When we find bullets in someone's body, we do not presume of an unorthodox way for the bullet to have gotten in there - we generally assume, unless there is specific evidence to the contrary - that the bullet was fired from a gun.
Thus, by this common mode of reasoning, many people used neo-Darwinism as the link to make personal views about evolution publicly compelling. Because, as the logic goes, we now have an experimentally-verified mechanism (so they said) of how evolution works, we now can say that it is publicly compelling that the way in which the fossils in layer A gave rise to the fossils in layer B was neo-Darwinism.
Now, of course, the neo-Darwinian mechanism never showed any such thing. Finally in the last few decades it has been realized that there is a fundamental difference between micro-evolution and macro-evolution. People in evolution say that macro-evolution is no less proven. However, I think that this confuses the boundary between personal validity and public validity. The evidence for macro-evolution is the fossil record, but without a clear mechanism demonstrably capable of performing that task, the evidence is not more publicly compelling than any other explanation.
Now, of course, some people may say that nothing is publicly compelling. I disagree, because there is a difference between being publicly compelling and being true. The fact is, if we have schools, we have to teach something in them. If we have a government, we need to have laws. So the point of a point of fact being publicly compelling is that, as far as the public goes, it is taken as a likely truth. This doesn't mean that it must be true or that you can't have a private disagreement, but that it doesn't carry much weight publicly.
And this leads us to why anyone cares in the first place. Most YECs, OECs, and IDists don't really care that scientists work using neo-Darwinism as a foundational truth. You don't generally find right-wing Christians picketing evolutionary biology labs. I've met a lot of creationists, but I've never met one who wanted to prevent a biologist from using evolution in their own work.
However, the fact is that science is currently a publicly-funded enterprise. It is taught in publicly-funded schools. It is used as an assumed truth in courts. So in these and other areas, what happens with science turns public.
Therefore, if evolution is to be used to the exclusion of other ideas in these areas, then it must be publicly-compelling, and not just personally so, or personally useful. It's one thing to teach evolution (which I think that there are publicly-compelling reasons to teach evolution. It's another thing to teach that it is true. It's one thing to allow evolutionary research. it's another thing to only allow evolutionary research.
So, in the case of Todd's blog post, he says this:
I'm motivated this morning by reading yet another clueless, well-meaning person pompously declaring that evolution is a failure. People who say that are either unacquainted with the inner workings of science or unacquainted with the evidence for evolution.
I don't know who Todd is speaking of, but I'm tempted to agree with both Todd and his clueless, well-meaning friend. Evolution has been very successful at producing a framework which has been useful to a number of people. Evolution (either as neo-Darwinism or universal common ancestry) has also been an utter failure in providing publicly-compelling evidence for its operation.
One concession I will make, though, is that, even as a Young-Earth Creationist, I think that the arguments for an old earth are publicly compelling. I disagree with them, and think that the evidence from history and scripture (as well as many interesting parts of the geologic column) points to a global flood. However, radiometric dating provides just the kind of evidence I pointed to above that makes something publicly-compelling. There are hints that radiometric dating is not the whole story, and it is my personal opinion that in the future we will find additional mechanisms by which radioactive rates can be dramatically altered, along with an understanding of how this fits in geology. The RATE group has made important progress, but they have not yet achieved a result that I think is publicly compelling. I find this information to be personally compelling, but I think that so far radiometric dating puts the question of the age of the earth as being publicly-compelling for an old earth.
Interestingly, that's also why I like academic freedom. As I pointed out, publicly-compelling is not the same thing as true. The freedom of conscience is always vital because even our most precious and seemingly self-evident assumptions about life are not guaranteed to be true. But the public sphere must be operated on some basis, and that is why it is important to distinguish things from being personally or publicly compelling, and why both Todd and the person he was frustrated with are probably both right.