How could evolutionary theory be falsified?

cambrianrabbit

A rabbit fossil in Cambrian rock would be difficult to understand under current evolutionary theory.

Creationists often charge that evolutionary theory is unfalsifiable; that there is no way to potentially disprove it, if it were in fact incorrect. This is in essence an “I know you are but what am I” response to their critics who have rightfully pointed out that “God did it” as an explanation is not testable against the evidence from the natural world and therefore not a valid scientific explanation for anything.

This is because hypotheses, in order to qualify as scientific, must be testable against observable evidence in the natural world. In other words, in addition to there being potential observations that might support a given hypothesis, there should likewise be some potential observations that would tend to disprove a hypothesis.

Since God can do anything in any way, for any reason, here are no potential observations of the natural world that could disprove God’s involvement, which means the “God did it” hypothesis is unscientific in character.

In any event, is it true, as creationists charge, that there are no potential observations that would tend to disprove evolutionary theory?

The short answer is no, it is not true. However, for something more in depth you should head over to Why Evolution Is True where biologist Jerry Coyne provides several scenarios that would be highly problematic for current evolutionary theory.

In my general talk on the evidence for evolution, I give a list of seven observations that, if repeated and confirmed, would disprove parts of the theory of evolution described above. This shows that it is a scientific theory in the Popperian sense of being falsifiable.  Here are some of those conceivable observations:

  • Fossils in the wrong place (e.g., mammals in the Devonian). If the fossil record were all out of order like this (a single anomalous fossil might not overturn everything, of course, since it could be in the wrong place for other reasons), we’d have to seriously question the occurrence of evolution.

I recommend you hop over and check out the rest.

The last thing I want to say about this particular creationist claim, is that in addition to it being false, it is also stands in rather blatant contradiction to what creationists do on a regular basis, which is to argue that this or that bit of evidence somehow counts against evolutionary theory.

I mean what sense can we make of Duane Gish’s book Evolution, the Fossils Say No! (1978) if he was not arguing that the fossil evidence was disconfirming of the evolution hypothesis?

The mind boggles.

[And now John Wilkins, or some other philosopher of science, will yell at me about Popperian Falsificationism being passé with regards to the demarcation problem. Just to head that off somewhat I am not advocating naive falsificationism.]

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In which I yell at everyone on the interwebs

A Facebook friend posted a link to a YouTube video titled “Top Ten Creationist Arguments” by The Thinking Atheist. I had seen it before, it’s slickly produced and OK as far as it goes (though I would have a different list of 10 creationists arguments) but that’s not what got me going. In the video TTA gives a quote from the late Stephen Jay Gould:

This caught my eye because I have been researching stuff to do with philosophy of science, i.e. the testability of evolutionary theory and the difference between the so called experimental sciences and historical sciences. In particular I thought I had remembered reading a essay by Gould on the subject and I thought this quote might give me a lead on it. The problem is TTA doesn’t give a source for the quote. “No problem”, I thought, “I’ll just Google it and it should be a snap to find the source.” Bzzzt! Wrong. Oh if you Google the quote you’ll get a gillion links but none* of them give the source of the quote!

After a half and hour or so of Google mining I finally found a site that gave the source as Gould’s Dinosaur in a Haystack (1995), but it provided no page number! So I pulled my copy off the shelf, blew the dust off the top  (damn dust) and checked the index for references to creationism.

There were a couple and while Gould did say something like this in one part of the book referenced, it wasn’t an exact quote. Finally I went to Amazon.com and found that they allowed one to search the contents of the book, and at last I got the information I was looking for.

The quote appears on page 397 (of the 1st hardback edition) and is not one of the places listed in the index for the term creationism. Here it is with some context:

One tangential point before I leave this elegant study [a genetic study of certain crabs, see below – T.B.]. Creationists critics often charge that evolution cannot be tested, and therefore cannot be viewed as a properly scientific subject at all (see the next essay for a fuller discussion of this important issue). This claim is rhetorical nonsense. How could one ask for a better test, based on a very risky prediction, than this? The counterintuitive link between king and hermit crabs was postulated on the basis of classical evidence from morphology (the arguments detailed previously in this essay as points 1-3). This prediction was then tested by the completely independent data set of DNA sequence comparisons — and confirmed in spades, with even closer propinquity than suspected between king crab and hermit crab lines.

I regard this story of king and hermit crabs as one of the most elegant I have learned of late in evolutionary biology–a lovely combination of a fascinating and counterintuitive tale; a multifaceted, rigorous and convincing pile of supporting data; and a lesson of intriguing generality  (the difference between genealogical propinquity and any functional meaning of similarity–and the overriding importance of propinquity). (Gould 1995, p. 397, emphasis mine)

Great, curiosity satisfied!

So please, please, please, people, don’t just throw quote around willy-nilly. Give proper references. [I’ll make an exception for T-shirts, but that’s it!]

OK, I got that out of my system, end pedantic rant.

[* I didn’t look at every single Google result so this is a rhetorical “none”.]

Reference

Gould, Stephen Jay (1995) Dinosaur in a Haystack, Harmony Books, NY, 1st hardback edition

Responding to questions about “Darwinism” and intelligent design creationism

I’m moving this up from the comments on an earlier post as I think it will take more that a comment to respond to.

A commenter, Josh Caleb, says that he has “a few honest questions“. I am going to answer him as if that were true even though I am now somewhat suspect that it isn’t due to his having cited trueorigins.org, an antievolution knockoff of talkorigins.org, and because of several of his comments left in response to others.

Read on»