Tuesday, April 12, 2011

Missing Links? What Do You Mean, ‘Missing’

Creationists are deeply enamoured of the fossil record, because they have been taught (by each other) to repeat, over and over, the mantra that it is full of 'gaps': 'Show me your "intermediates"!' They fondly (very fondly) imagine that these 'gaps' are an embarrassment to evolutionists. Actually, we are lucky to have any fossils at all, let alone the massive numbers that we now do have to document evolutionary history - large numbers of which, by any standards, constitute beautiful 'intermediates'. We don't need fossils in order to demonstrate that evolution is a fact. The evidence for evolution would be entirely secure, even if not a single corpse had ever fossilized. It is a bonus that we do actually have rich seams of fossils to mine, and more are discovered every day. The fossil evidence for evolution in many major animal groups is wonderfully strong. Nevertheless there are, of course, gaps, and creationists love them obsessively.

Let us make use of our analogy of the detective coming to the scene of a crime to which there were no eye witnesses. The baronet has been shot. Fingerprints, footprints, DNA from a sweat stain on the pistol, and a strong motive all point towards the butler. It's pretty much an open and shut case, and the jury and everybody in the court is convinced that the butler did it. But a last minute piece of evidence is discovered, in the nick of time before the jury retires to consider what had seemed to be their inevitable verdict of guilty: somebody remembers that the baronet had installed spy cameras against burglars. With bated breath, the court watches the films. One of them shows the butler in the act of opening the drawer in his pantry, taking out a pistol, loading it, and creeping stealthily out of the room with a malevolent gleam in his eye. You might think that this solidifies the case against the butler even further. Mark the sequel, however. The butler's defense lawyer astutely points out that there was no spy camera in the library where the murder took place, and no spy camera in the corridor leading from the butler's pantry. He wags his finger, in that compelling way that lawyers have made their own. 'There's a gap in the video record! We don't know what happened after the butler left the pantry. There is clearly insufficient evidence to convict my client.'

In vain the prosecution lawyer points out that there was a second camera in the billiard room, and this shows, through the open door, the butler, gun at the ready, creeping on tiptoe along the passage towards the library. Surely this plugs the gap in the video record? Surely the case against the butler is now unassailable? But no. Triumphantly the defense lawyer plays his ace. 'We don't know what happened before or after the butler passed the open door of the billiard room. There are now two gaps in the video record. Ladies and gentlemen of the jury, my case rests. There is now even less evidence against my client than there was before.'

The fossil record, like the spy camera in the murder story, is a bonus, something that we had no right to expect as a matter of entitlement. There is already more than enough evidence to convict the butler without the spy camera, and the jury was about to deliver a guilty verdict before the spy camera was discovered. Similarly, there is more than enough evidence for the fact of evolution in the comparative study of modern species (Chapter 10) and their geographical distribution (Chapter 9). We don't need fossils - the case for evolution is watertight without them; so it is paradoxical to use gaps in the fossil record as though they were evidence against evolution. We are, as I say, lucky to have fossils at all.

What would be evidence against evolution, and very strong evidence at that, would be the discovery of even a single fossil in the wrong geological stratum. I have already made this point in Chapter 4. J. B. S. Haldane famously retorted, when asked to name an observation that would disprove the theory of evolution, 'Fossil rabbits in the Precambrian!' No such rabbits, no authentically anachronistic fossils of any kind, have ever been found. All the fossils that we have, and there are very very many indeed, occur, without a single authenticated exception, in the right temporal sequence. Yes, there are gaps, where there are no fossils at all, and that is only to be expected. But not a single solitary fossil has ever been found before it could have evolved. That is a very telling fact (and there is no reason why we should expect it on the creationist theory). As I briefly mentioned in Chapter 4, a good theory, a scientific theory, is one that is vulnerable to disproof, yet is not disproved. Evolution could so easily be disproved if just a single fossil turned up in the wrong date order. Evolution has passed this test with flying colours. Skeptics of evolution who wish to prove their case should be diligently scrabbling around in the rocks, desperately trying to find anachronistic fossils. Maybe they'll find one. Want a bet?

-Richard Dawkins, The Greatest Show on Earth

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