Wednesday, May 26, 2010

Neandertal non sequitur

In my previous works on anthropological topics, I maintained that creationists do not at present have a model to explain biological similarity. In my chimp genome paper, I elaborate the reasons for this in some detail. In my hominid baraminology paper, I merely cite Darwin's claim that similarities form a pattern that looks like a genealogy, thus supporting the inference of common ancestry.

I've been criticized for this stance, but I'm not going to address those criticisms today. I'll just assert that I'm correct, which I am. The fact of similarity is easy to account for. Being created by one God would be a good reason for some degree of similarity to exist. Likewise, being created to occupy the same world or to participate in the same ecosystem would also necessitate some biological similarity. These types of considerations could explain why all living things use the same basic biochemical building blocks (amino acids, nucleotides, etc.), for example.

What these considerations do not explain is the pattern of similarity. This is quite a different problem that is easy to confuse with the fact of similarity. What we're dealing with in creation is not just bare similarity or random similarity. There is a definite pattern, and it's a pattern that Darwin says is uniquely explained by the inference of common ancestry. As I noted previously with Theobald's work, one can even devise statistical tests to evaluate how well genealogy-like phylogenetic trees match observed similarities. Generally speaking, creationists have not offered a compelling alternative explanation, although I think there are promising avenues of research that could lead to an alternative, which I explained in my chimp genome paper.

With that background, imagine my surprise when I heard these words coming out of Fuz Rana's mouth in that RTB podcast on the Neandertal genome:
I think it's important to realize is that we should expect biological similarity between humans and Neanderthals, and humans and the other hominids for that matter, in fact, humans and all animals, because as Genesis 2 says, human beings and the animals are made from the dust of the earth. And I take that to indicate that we're made out of the same physical stuff. Maybe that physical stuff is arranged differently, but we're still made out of the same physical stuff. And so you would expect biological similarity to the point that the possibility for interbreeding exists, and interbreeding in such a way to produce viable offspring.
The first term that came to mind when I heard that was non sequitur, the conclusion does not follow from the premise. Think about it. When are building materials sufficient to justify a conclusion that things built will be strongly similar in form? If I get two homework assignments that are identical word-for-word, I do not conclude that the similarity is inevitable given that they're both written in English. Likewise, Rana's claim that we should expect God to create an animal so similar to humans that we could interbreed and produce viable, fertile offspring because we're all made of dust is an absurd non sequitur.

Rana's statement is also eisegetical. Eisegesis is a term in biblical studies for reading a meaning into a text. It's contrasted with exegesis, the process of drawing a meaning out of a text. Obviously, exegesis is good, and eisegesis is bad. Rana correctly notes that according to Genesis 2, humans are made of "dust" and some land animals are made from the "ground." He then reads into that text his bizarro idea that this requires an astonishing degree of biological similarity that is nowhere to be found in the text.

So far, I'm not a big fan of the RTB response to the Neandertal genome. I'm certainly finding a lot of reasons to disbelieve their claims about Neandertals.

In the next post of this series, I'm going to dissect RTB's claims about the image of God.

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