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## Thursday, 12 January 2017

### Mind the Gap!

If it takes five men four hours to dig one hole, how long does it take one apologist to fill it?

This is a post about gaps.

Gaps are really beloved by apologists, and not just gaps in knowledge, but gaps of all kinds. Indeed, there's a famous fallacy known as the 'god of the gaps' fallacy, in which some gap in our knowledge is automatically filled with a deity. Nothing is more likely to get a religious apologist excited than a gap. In reality, it isn't even god they're worshipping in these circumstances, it's the gaps themselves, so perhaps we should rename this fallacy 'god IS the gaps'.

Here, I want to pick apart this fallacy and show some popular instances of its commission. Along the way, we're going to learn some interesting things about gaps that are often not well appreciated among the uninitiated and in apologetics circles.

Properly, the 'god of the gaps' fallacy is a subset of the argumentum ad ignorantiam, or argument from ignorance. It's committed when we identify something that we don't know about and insert our preferred solution in its place. It actually commits several other fallacies by default, including the bare assertion and the ever-ubiquitous 'affirming the consequent'.

Many of the gaps leapt upon with relish are genuine gaps in knowledge, while others are not. Specifically, there's a single type of gap that is treated as a gap in knowledge when it really isn't or, at least, not in the sense that the apologist needs it to be.

I often trawl Youtube for interesting topics to talk about, and a pass at a very old episode of The Atheist Experience brought this particular instance to mind. In it, Martin Wagner was dealing with somebody who asserted that evolution is faith-based. I won't waste time padding the specifics out, not least because I've covered them at some significant length elsewhere, but Martin gave an analogy that was wonderfully elegant and dealt with just this kind of gap; a gap in information. I will, as usual, add the video at the bottom of the page.

Now, one might think that a gap in information constitutes a gap in knowledge, but it needn't be the case, and Martin's analogy highlights this quite nicely.

Picture a jigsaw puzzle. As you get toward the end of the puzzle, it becomes clear that quite a lot of pieces are missing. Nevertheless, once all the pieces you do have are in place, it becomes fairly clear that the puzzle is a picture of the Eiffel Tower. Those missing pieces, while certainly constituting a substantial lack of information, don't actually affect the fact that the overall picture is clear.

In this instance, the caller said that, when he visited Paris during the Millennium celebrations, the tower had a countdown clock on it and that, because the puzzle might not show this countdown clock, that somehow our picture was wrong. This is silly, of course, because while there are things not included in our puzzle, and we may be missing details that would be apparent if those pieces were in place, there's absolutely no uncertainty that what we're looking at is a picture of the Eiffel Tower.

A fair bit of science is like this. In fact, this is the main reason that scientific conclusions are somewhat tentative. To stretch this analogy a bit further, let's reverse the numbers so that we have even less information.

Now, our certainty is massively reduced, yet we can still be justified in positing that this is a tower of some description, or a pylon, or some such. We could even infer that it's probably the Eiffel Tower, though our justification would be quite weak on the information available.

Sometimes, we can even think we have all the pieces and that the picture is complete. Just such an instance is Newtonian gravity, which stood unchallenged for more than two centuries. We had a perfect picture of a tower. It withstood every assault, and predictions validated up the wazoo for all that time.

Then something happened that changed the game. We realised, via a few critical observations - such as a long-known disagreement between Newton's predictions and observations of the precession of Mercury's perihelion - and the work of one man, that there was something not quite right with the picture; that we were missing not just a smattering of individual pieces, but entire sections of the puzzle.

It turned out that Newton was wrong. When Einstein published the general theory of relativity in 1915, it became clear that what Newton thought was the whole puzzle was just a tiny piece of it. The general theory showed us not only the most accurate picture of the Eiffel Tower we'd ever seen, it revealed a vast cityscape dominated by Montmartre. All right, mea culpa. As is my wont, I've stretched this analogy to breaking point (which is not to say that I won't revisit it).

It's worth noting here that, although Newton was wrong, Einstein showed that the more accurate relativistic picture reduces approximately to Newton's picture under certain circumstances, those circumstances being the speeds and distances that Newton had access to. This is why all the world's space agencies still use Newtonian mechanics for all space missions, namely that it's close enough for government work - the errors being so small as to be insignificant - as well as being considerably easier to work with. For example, the Cassini-Huygens mission, after executing four gravitational slingshot manoeuvres (two around Venus, one around Earth and one around Jupiter), and a journey through space of something in the order of $15 \times 10^{11}$ kilometres, inserted itself into Saturn's orbit within twenty metres of its intended target. That's a fairly spectacular demonstration of just how piddling the errors are at those speeds and distances.

Anybody who's good at pool and has ever tried to play snooker on a full-size table will have a visceral grasp of how this works. Increasing distance magnifies errors. What's a fairly straightforward shot on a six-foot table can miss the pocket by a margin on a twelve-foot table. The same is true of speed. Once we get past about ten percent of the speed of light, inaccuracies are commensurately magnified.

So, moving on from that minor digression, I want to look at another gap, and this one is truly colossal, yet is still subject to the same reasoning as above. It's the 'missing link' or 'no transitional forms' gap (these are not the same thing, but they are closely related, so I'm going to treat them as the same for now).

Back in 2006, a wonderful discovery was announced. This was, of course, the first the wider community had heard of it, and it still isn't fully appreciated what this discovery signified, so let's get the backstory out of the way.

It's often thought that fossils are found in a somewhat arbitrary manner and, in many cases, they can be, but there are certain finds that buck this. For a long time, we had fossil evidence for later lobe-finned fish, in the form of, for example, Panderichthys, which was discovered in 1930, and early tetrapods, such as Ichthyostega, discovered in 1932. It's worth noting here that both these organisms show transitional features between fish and amphibians, a point we'll return to shortly. These two organisms are separated in time by approximately twenty million years, Panderichthys having lived about 385 million years ago, and Ichthyostega having lived about 365 million years ago.

On the basis of these, and taking into account plate movements in plate tectonics (the original habitat of this organism was equatorial streams), a team from the University of Chicago, led by Neil Shubin, predicted that an organism showing transitional features between these two groups would be found in the region of Ellesmere Island in Northern Canada. Several expeditions and six years later, in 2004, the team hit the jackpot, finding a fossil of an organism now known to the world as Tiktaalik roseae, an intermediate between fish and amphibians, living almost exactly in between those other organisms at 375 million years ago.
 By Graphic by dave souza, incorporating images by others, as description - via Wikipedia
This is a wonderful example of something that apologists insist evolutionary theory is not, namely a fully predictive science.

I'd like to add that, when something of this nature is pointed out to the apologist, an extremely common counter is 'now you have two gaps where before you only had one!' This shows quite beautifully how debilitating cognitive inertia can be. It takes a special kind of barrier to think this is a valid counter when presented with evidence.

I should note for completeness that the placement of Tiktaalik  as a transition between fish and tetrapods is currently a matter of some discussion based on research that's been conducted in the interim, not least by the wonderful Per Ahlberg, one-time denizen of the talkrational forum and creationism counter-apologist. This uncertainty doesn't materially affect any of the points being made here. What is meant in the relevant fields by transitional doesn't actually rely on an organism actually being directly ancestral to later organisms, only that features can be shown to appear in the fossil record with some degree of time and taxonomic ordering or, as it's known in the jargon, nested hierarchy.

As we can see, this example is a perfect reflection of what we were discussing earlier, namely that, while this discovery fills in a large gap in informational terms, it doesn't affect the overall picture at all. In other words, we're still looking at the Eiffel Tower.

Tiktaalik isn't the only example we have of this, of course. There are many of these fossils between major groups, not least the stunning Archaeopteryx, which was discovered in Darwin's time, with the first feather being discovered only a year after the publication of On the Origin of Species, and a full skeleton being found a year later still. Indeed, the primary literature is replete with examples of just such findings, and that's setting aside the fact that this idea of a transitional form is, if not treated carefully and with a little understanding, problematic in and of itself.

What all of these fossils do, in terms of the overall picture, is simply add detail. In the grand scheme of things, they have very little impact on evolutionary theory other than to raise interesting questions and new lines of research. As far as the veracity of evolution is concerned, they have no impact whatsoever, not least because evolution has been observed occurring at every level predicted by the theory. It certainly isn't the case that all of evolutionary theory is based only on a few fossils. We have millions of them, and all reflect the broader picture of how evolution occurs.

It's also important to note that, even were we entirely bereft of fossils, the evidence that we have for evolution - notably the molecular evidence - makes it a slam-dunk for the best supported theory in science.

Much of what I've said here also applies to the 'missing link' version of the god-of-the-gaps fallacy, but the missing link in particular carries with it what I'm sure the Hitch would refer to as a 'curious species of solipsism', and reminds us that we have to be careful in our thinking. It's a term that harks back to Lamarckian evolution, the idea that 'lower animals' were recent creations, and that all life was striving to 'more evolved' status. The term itself generally refers to any transitional form, but most often more narrowly to human ancestry, and more specifically to the last common ancestor of chimpanzees and humans.

The fact that we still think in terms of missing links is largely a result of shoddy science journalism since, in light of Darwin's work, it's mostly nonsense. In a previous post, Fuzzy Logic, Classification and the Fallacy of the Excluded Middle, we looked at some of the problems inherent in our need to put things in little boxes, while nature itself is rarely so conveniently digital. Still this notion is promulgated in the popular science press, so that every new discovery of a species that could plausibly be a distant ancestor is hailed as the long-lost missing link. This entire notion is anthropocentric in the extreme, and we have to be wary of such targeted thinking. Evolution has no targets, no goals, and no purpose. It's simply a process.

Here's the problem, and it's where I'm going to finish. What evolutionary theory teaches us without ambiguity or equivocation is that all species are transitional. Indeed, all organisms are transitional. Evolution is itself nothing more nor less than one big transition. It also teaches us that there are no such things as 'lower animals', no such thing as 'more evolved'. I am exactly as evolved as a modern paramecium, and so are you.

Ultimately, and this is the important thing to take away from this waffle, there is no gap in our knowledge that requires a deity to fill it.

I can't recall where I got this quote from, but it's worth sharing anyway:
Blaise Pascal stated that there's a god-shaped hole in all of us. However, he wasn't noted as an anatomist.
Pascal almost certainly didn't say that, but where's the comedy in that? Either way, if you're of a certain disposition, all holes are god-shaped, which answers the question at the head of the post nicely. The answer is, of course, no time at all, because the apologist has instantly filled it with god.

Thanks for reading. Typos, nits and crits welcome, as always.

Other posts on evolutionary theory: