Soft Tissues and Logical Fallacies

In 2005, Palaeontologists lead by Mary Higby Schweitzer revealed to the world (in a paper in Science, read it here) of their discovery of ‘soft tissue’ in a bone of the ‘B. Rex’ Tryannosaurus specimen (MOR 1125), which was dug up in a 68 million year old portion of the Hell Creek formation. The proteins thought to be found included Collagen, pictured. This is pretty cool, but it seems Schweitzer had learnt from a previous announcement of hers in 1993, which seems to have since been largely discredited (I’m not too sure here). The 2005 paper admitted:

Whether preservation is strictly morphological and the result of some kind of unknown geochemical replacement process or whether it extends to the subcellular and molecular levels is uncertain.

Nevertheless, in the time since then it has been increasingly shown that the collagen from the bone is the real deal (although it could still be of bacterial origin), with — among other things — a small number of other dinosaurs having been found that show similar evidence, for example. The evidence is, apparently, so sound that Dr Schweitzer and a few others have published a study that compares the molecules of collagen themselves with those from “extant taxa”, i.e. living creatures, and discusses how the protein could have been preserved far beyond the expected length of time.

Creationists have, naturally, latched on to this saga as proof that dinosaurs and other fossils cannot be millions of years old as it is thought, at least theoretically, that Collagen can not survive nearly as long. Schweitzer herself takes great umbrage in such claims, as an article says:

Young-earth creationists also see Schweitzer’s work as revolutionary, but in an entirely different way. They first seized upon Schweitzer’s work after she wrote an article for the popular science magazine Earth in 1997 about possible red blood cells in her dinosaur specimens. Creation magazine claimed that Schweitzer’s research was “powerful testimony against the whole idea of dinosaurs living millions of years ago. It speaks volumes for the Bible’s account of a recent creation.”

This drives Schweitzer crazy. Geologists have established that the Hell Creek Formation, where B. rex was found, is 68 million years old, and so are the bones buried in it. She’s horrified that some Christians accuse her of hiding the true meaning of her data. “They treat you really bad,” she says. “They twist your words and they manipulate your data.” For her, science and religion represent two different ways of looking at the world; invoking the hand of God to explain natural phenomena breaks the rules of science. After all, she says, what God asks is faith, not evidence. “If you have all this evidence and proof positive that God exists, you don’t need faith. I think he kind of designed it so that we’d never be able to prove his existence. And I think that’s really cool.”

On to the ICR. With today’s DpSU, Latest Soft Tissue Study Skirts the Issues, Brian Thomas joins the club. In reality, he’s probably been there for a while…
As you can probably guess from the above quote, he is a bit conflicted about the whole thing. Obviously he is very keen on talking up the whole soft-tissues thing, but he is not happy that Dr Schweitzer wont say that this means hat the bones are very young because of it. He is very keen, then, on the existing models that predict the tissue would have long since decayed if it was millions of years old. This is in contrast with the last DpSU, which was positively ecstatic that the models (this time of galaxy distribution) were slightly off the observed reality. Mr Thomas incorrectly accuses the paper of “circular reasoning” and “begging the question” (a similar fallacy to circular reasoning – in common parlance it now incorrectly means something completely different). Mr Thomas seems to be indulging in cargo cult skepticism, where you use the lingo of skepticism (logical fallacy spotting etc), without actually being rational or skeptical, and just wanting yourself to, after a while of this, be skeptical by default, as it were.

Mr Thomas claims that Dr Schweitzer makes the assumption of the bones and collagen being 68 million years old (he says 67 – typo? I can’t find ’67’ anywhere else), and then demonstrates that this is, in fact, perfectly ok with the science. He then apparently misreads the paper, claiming that this is then used to justify the original premise, namely that the bones are old.

In fact, the reasoning more a line, not a circle. The 68 million years part come from other things. Without even reading any other information than Brian Thomas’ own article, it is obvious that the evidence for the age of the fossil must come from somewhere else, breaking the cycle. Tyrannosaurus existed right up to the 65.5 mya boundary, and if the argument truly was circular it would only claim that the dinosaur came from around this time, in that it was very old. Why sixty-eight million years ago, specifically? In fact, the fossil was dated by other means, not least of which the dating to that period of other fossils in the same strata and location.

Mr Thomas quotes this to support his circular reasoning argument:

Our results add to the evidence provided by sequence data, molecular phylogenetic analyses, microstructure and immunoreactivity to anti-collagen antibodies, that supports persistence of elements of native collagen fibril structure across geological time in some fossils.

But this doesn’t mean that they are using their findings to demonstrate that the fossil is, indeed, old due to the fact that the collagen could have survived this long. Instead what has happened is this:

• The fossil has been dated by other means
• The paper shows that the collagen does come from the fossil when it was laid down.
• Therefore, we have more evidence that collagen can survive “across geological time in some fossils”

The is no logical fallacy here.

As for the models, Dr Schweitzer et al are a little critical of them, with the opinion that they don’t accurately simulate the conditions that the protein experiences. Mr Thomas likes to call them ‘experiments’, criticising the use of the term ‘models’:

“Current temporal limits for survival of original biomaterials are based upon theoretical kinetics and laboratory experiments designed to simulate protein diagenesis [burial and fossilization] through exposure to harsh conditions…and predict complete degradation of measurable biomolecules in well under a million years if degradation proceeds at simulated rates.^“

But the authors then argued that because the remains are millions of years old, these collagen decay experiments, which they refer to as “models,” must be wrong. This is a bad argument.

Look, nobody has actually left collagen in the ground for a million years and tested how much is left after that time. Simulations have been run, and theory has been extrapolated from that. Hence, models.

Mr Thomas summarises:

Here are the scientific facts: First, the collagen is original to the dinosaur. Second, collagen decays in thousands of years or less. Scientists do not have wrong ideas about laboratory-measured collagen decay rates, but they do have wrong ideas about the age of the earth and its dinosaur-containing rock layers. The evidence points to a time span of thousands of years, just as the Bible records.

Models have been wrong before, and the evidence suggests that this is such a situation. For example, imagine you are trying to clean a dirty piece of fabric with a single, continuous and static flow of water. After a short while, much of the dirt will have washed off. However, the dirt that remains is probably in a tricky location for the water to get at, and so is unlikely to come off even after a lot longer. Similarly, the collagen found was in such a sheltered place, where it could well have clung on for millennia.

Finally, from Talk.Origins, on soft tissues:

If dinosaur fossils were as young as creationists claim, finding soft tissues in them would not be news, and recovering DNA from them should be easy enough that it would have been done by now.

I rest my case.