Posts Tagged ‘missing link’

SERMON: “Bad Arguments Against Evolution” by the not-so-reverend bob

Sunday, February 24th, 2013

I was listening to a preacher on the radio the other day, making what he thought was a good case against evolution.  He spent some time scoffing at the idea that “lots of time” was in any way a key to understanding Darwin’s theory.  He gave this example: “Suppose I take all the parts that make up a watch, and put them in a bag, and just shake them up.  They won’t just assemble themselves into a watch.  Now, suppose I shake that bag for a long, long time.  See what I mean?  It just doesn’t work.”

No, Barney, it doesn’t work.  But then, again, this is a popular creationist argument (a version of Hoyle’s self-assembling 747 argument — listen to Richard Dawkin’s refutation of this argument here).

When confronted with this kind of “argument”, it’s difficult to know where to begin, as the weeds of ignorance are so thick and so tall that they almost have to be attacked in multiple directions at once.  But writing (like conversation and argument) is linear, so I must take them on one at a time.

Let’s take the most glaring example of bad logic employed in this argument (so bad, in fact, I wonder if it’s fair to call it “logic” at all).  The preacher is using a mechanical device (a watch — presumably a classic “wind-up” watch) to stand in for a biological process.  Now, to be clear, there are mechanical processes to be found and described in biology, and there are chemical processes to be found in machinery (at least on the level of the metal parts of the watch being acted upon by the corrosive effects of exposure to air, or the energy stored and released by a main spring, or the transfer of electrons that can occur between dissimilar metals) but none of these processes have much of anything to do with the physical act of actually assembling a wound-up and functioning watch.

The bite marks of a Mosasaur on an ancient, extinct Ammonite.  The fossils speak.

The bite marks of a Mosasaur on an ancient, extinct Ammonite. The fossils speak.

And biology can build “machines”, in the sense that an organ such as the heart works in a manner similar to a mechanical pump, or bacterium grow flagellum that can “corkscrew” their bodies forward through fluids.  And it is also true that both the metal gears of a pocket watch and the living heart are built up out of the same storehouse of elements that make up our planet.  But, again, these are not the kinds of things the radio preacher is considering.  For no matter how clever the analogy sounds, the gears of a pocket watch are never going to be the product of biological actions.  They are manufactured by humans through a series of mechanical steps, from mining to smelting to design then machining or casting, to polishing and final assembly.

The dubious intellectual leap that almost always accompanies the crap analogies that are the bread and butter of the anti-science crowd is this fallacious assumption of equivalency between human technological creation and biological processes.  Perhaps this error is rendered too easy for us because science almost always has to draw on metaphor to communicate it’s discoveries.  Hence the heart is the “pump”, the venous system the “pipes”, the brain the “computer”, the bones the “levers” and the muscles the “pulleys”, but always only in a metaphorical sense.  Too many of us, it would seem, invest too heavily in the metaphor — we take the description of the thing for the thing itself.

Regardless, this is what this flavor of fallacious argument does: it conveniently substitutes one kind of thing for another, then breezily jumps to a false conclusion.  In this case, the preacher touches on one of the genuine conditions for the theory of evolution to work, namely: time.  But he then jumps from evolution (the mutational changes over life forms over time) to “origin of life” questions (where did the parts of the watch come from in the first place?), something that evolution has nothing to do with.  Evolution is the description of how (once begun) biological life blossomed into so many different forms over time.  Evolution has nothing to say about how, when, or where biological life began.  But that is of no concern to this kind of creationist, as he or she has the ability to leap back and forth between arguments with no regard to whether they are addressing genuine science or not (frequently “moving the goalposts” of their “argument” in the process).

So let’s get back to the watch analogy.  Clearly, the dismembered pocket watch is a stand-in for the “primordial stew” that is thought to have produced life.  But the comparison does not hold.  For the primordial stew involves liquid water, elements, chemical reactions and the input of energy (be it solar or terrestrial heat, or the energy of lightning — all of these produced by processes that science has been able to describe).  And in this area, experiments have shown that rudimentary life could, indeed, begin this way.  (In fact, the way the research seems to be going, I have the sense that we are going to find out that the starting up of life is not really all that hard, given the right circumstances.  We already suspect that life had to begin untold numbers of times on the planet, most all of which were short-lived events — ended by the various catastrophes that have befallen our globe since it cooled enough to form a crust).

But the preacher ignores this key difference, and sincerely thinks that the “soup of life” is the same as a collection of manufactured and machined metal gears, pins, screws and glass.  True, the parts-in-a-bag scenario does at least include the input of some energy (you or I “shaking” the bag), but that is hardly the same as solar or thermal energy working on dissolved elements within a watery environment, fueling chain after chain of chemical reactions.  (If, on the other hand, the preacher were to put the actual elements of life into his rhetorical “bag” and shake it with some solar energy, he might be very surprised to open it up and find it filled with the slime of early “life”).

Why do people buy these illogical anti-science arguments?  I don’t think that question is all that hard to answer, as we see examples of this every day.  We humans are deeply susceptible to false positives when it comes to causal relationships.  We are, in fact, crap at making the kinds of distinctions between “causal” and “casual” that is the very basis of science.  But, then, that is why we developed science: to finally figure reality out.  After centuries of making guesses about why this or that occurred, we finally found a way to reliably outwit our own intellectual limitations.

But science is challenging to our natural (and cherished) intuitive faculties, not least of all because it is really good at giving very specific answers to very specific questions under very specific conditions (which, it should be noted, is not the way most of us frame our questions about “life”).  And this is as it should be.  After all, to eliminate the possibility of bias or interference (a huge issue for humans), conditions that might affect an experiment must be tightly controlled, and all possible inputs carefully limited.  And, hence, a new scientific discovery might be hailed as a sweeping new truth by the media, even as the scientific community remains deeply circumspect, qualifying their discoveries with “Well, we now know that under conditions x or y, this or that can occur”.

A lot of people, I think, find this kind of qualification (and precision) damn frustrating.  This is perhaps most prevalent in “health news”, where we are often left asking: “Well, should I drink soda or not???”  And the answer is generally a qualified one, with a mix of yes and no, depending.

And so there will always be those who can preach the simple path to certainty that unqualified assertions can pave for the frustrated human psyche.  You can see this with almost any article having to do with evolution, where you can count on someone posting a variation of the comment that “There is absolutely zero proof for evolution.  None.”

This, of course, is just about as absurd as a modern human can get.  Like the radio preacher who then went on to say that no “missing link” had ever been found, going down the “cherry-picking” laundry list of the most notorious scientific frauds (such as the “Piltdown Man” and others), ignoring the reality that for every one of those frauds, there are, literally, millions of fossils that are genuine (not to mention the fact that it was other scientists who discovered the frauds).  Again, the most glaring flaw in this argument is that every single fossil ever found is a “missing link” between at two different species (with the exception of a specimen of a species preserved at the moment it went extinct).  If evolution is understood on even the most rudimentary level, then you must realize that every living thing is a transitional species between it’s ancestors and future descendants.  (Even the preacher himself)!

That preacher also expresses the familiar misconception that the fossil preservation of past life works like a scrapbook you might keep of your children’s growth — with page after sequential page of photos and clippings of all of the years of that child’s growth.  And therefore (if evolution is true) we should find all sorts of “missing links” in the fossil record.  Well, of course, this is just what we find when we are lucky enough to explore sedimentary deposits that have occurred in perfect conditions (which generally means landscapes that are subsiding at the edges of bodies of water — where sediments eroded from land can be laid down on the sea floor, burying dead critters, layer upon layer that are not then lifted up again to be eroded away by water and weather — at least not until scientists find them eons later).  But, the Earth being as geologically active as it is, these “perfect” conditions can only exist in certain locations for a limited period of time — like strips of images torn from a much longer movie (or from thousands and thousands of movies of all of the different ecosystems and locales that are filled with life).  And we will never know how many fine fossil deposits have been worn away into dust, or remain buried too deep underground for us to find.

I recently visited the La Brea Tar Pits in central Los Angeles.  Those natural tar seeps were almost perfect traps for every kind of living thing that lived in the local environment for the last 40,000 years.  They have pulled thousands and thousands of fossils out of that site, including sloths, mammoths and saber-toothed cats, but also birds and bugs and micro-fossils.  But that was one small site in one locale that only got into the “scrapbook” game after the last ice age.  It is a wonderful window into Southern California’s recent past, but it doesn’t tell us what was happening just over the mountains to the east, or further north or south.

But this is how fossilization works: the conditions have to be right, and then the fossils have to be exposed again through later geologic action or human digging.  Most animals die in places where their carcasses are consumed by other life forms or broken down to nothing by the corrosive effects of air, sun and water.  Even with our practice of human burial, look how few human remains we have found of our ancient ancestors (and we know there were a lot more humans alive in history than we have ever found).

The hard truth is that, despite the ever-increasing number and variety of fossilized species that come to light every year, most of every lion, tiger, bear, dinosaur or ancestral human that ever lived will never be found.  Creationists see this as a dodge, but only because they have such an astoundingly simplistic view of the way the earth (and biology) actually work (as well an apparent ignorance of the sheer volume of fossils residing in the museums of the world).  This ignorance is unfortunate, and difficult to eradicate, as I get the sense that a lot of public school teachers aren’t all that enthused about the workings of evolution themselves (I know that my education on that score was mostly a self-guided adult exercise).  Add into that the active campaign to oppose the acceptance of evolution (and science in general), and there remains a ready audience for the radio preacher I have used as my example today.

(This is why I support The National Center for Science Education).

I think that part of what we are really discovering is that the process of evolution (as well as the wide variety of life forms it “creates”) is not so strange or incomprehensible is it is made out to be.  It is actually a very simple process that appears complicated only because we are so used to seeing ourselves as different from all other life forms.  I can tell you that dinosaurs no longer look strange at all to my eyes.  To me a Hadrosaur is pretty much the “wild cow of the Cretaceous”, and the T-Rex is a giant toothed bird sort of thing.  Look up pictures of the strange-looking animals that live today (you can Google “ugliest animals”), and you will see any number of living critters whose weirdness tests both our intellect and stomach.

But, of course, these strange critters exist.  Just like you and I exist.  And this is the greatest testimony the the reality of evolution: it happened.

The preacher said that evolution is not a “fact” like gravity is a “fact” (because he could see gravity in action in a way he could not witness evolution at work).  I’m sorry his imaginative capacity is so limited, because evolution is on display all around us.  True, we can’t see it happening (like we can see ice melt or gravity break the glass we drop on the kitchen floor) but the simple fact that we need a different flu shot every year should tell us something about the mutations (“guided” by natural selection) that allow species to adapt to changing life conditions.  Plus, I hate to tell the preacher that gravity, like evolution, is also a descriptive theory of a certain physical reality, and that gravity is no more (or no less) a fact than Darwin’s theory of evolution.

t.n.s.r. bob

SERMON: “In a Strangers Face” by the not-so-reverend bob

Sunday, April 11th, 2010

Isn’t the most compelling feature of dinosaurs their very different-ness from anything we’ve ever seen?  Maybe that’s why kids love them so much.  And yet, there is something familiar about them as well (which is why kids are free to love them so much).

The timing of my own childhood and growth has paralleled years of progressively interesting dinosaur discoveries.  Even the big star dinos of my youth have been re-named and revised from lumbering dumb beasts to sprinting, bellowing, warm-blooded (and feathered!) creatures that probably tasted a lot like chicken.  Is it, then, the (now) near-constant revision of our ideas about dinosaurs, their ubiquity in computer-animated film and television or my own study of evolution of life that has caused the once exotic features of the dinosaurs to look a lot less exotic to me than they once did?  I wonder if it’s just me that thinks that prehistoric life doesn’t look all that strange (anymore).

Think about the face of a Hadrosaur (one of the duck-billed dinosaurs), then look at a living Platypus, or the mug of a giraffe.  There are faces on animals living today that are as wildly extravagant as anything that lived in the past (not to mention the faces that are relatively unchanged from their ancient predecessor’s).  To a child a dinosaur looks as if it might as well have been brought here from another planet — but the more of the existing critters you see, well…

In short, life is about as interesting today as it ever was.  And as odd.

The other day I saw a photo a friend shot in South America of a Vizcachas.  It’s a relative of the Chinchilla (in the rodent family).  But what it really is is a rabbit with a long curly tail (with a strip of squirrel-like hair on it).  That little critter just floored me:  I’d never seen one before.

Now I understand enough about evolution and natural selection to know that you would probably only need to switch on a couple of inactive genes in a regular rabbit to make it grow a tail like its South American cousin (or switch a couple off in the Vizcachas to make a rabbit), but still, a long-tailed rabbit just seems pretty damn funny to me: like a literal cut-and-paste conglomerate of animal parts.

But then, isn’t that what we are?  Not of parts cut and pasted from animals outside our line of descent, of course, but a continuous modification of the basic body plan that once swam in the ocean (with our telltale up and down fishy flexing of the spine)?

Creationists like to cry out for the “transitional” creatures in the fossil record: the midway point between the fish and the Tetrapod, or the early monkey and man.  But the glaring (so obvious we easily miss it) truth is this: we ourselves are the not-so-missing link between what we once were and what we are becoming.

If we were to meet a living Ardipithecus (the current candidate for the most recent common ancestor of monkeys, apes and man), she wouldn’t think herself a missing link at all, or a transitional being, for she would look just like her own mother, and were she to have a daughter, the child would not appear to have made any dramatic step towards homo sapiens sapiens.  But in truth grandmother, mother and daughter “Ardi” were quietly moving away from what their ancestors “were” to what their descendants would “become” (thank you Richard Dawkins for supplying the framework for this useful descriptive tool).

One of the few places we have actually been able to “observe” evolution is in the laboratory, where scientists have been culturing parallel generations of e-coli bacteria for twenty years and have observed one line actually evolving to make use of a food source the original colony was not able to feed upon.  But then bacteria reproduce incredibly fast compared to us humans.  We have to look back thousands and millions of years to see the branching of our family tree.

But if we could follow our line back, one after the other, we would eventually go all the way back to a bacteria, or a single celled organism that gave “birth” to every animal that walks, flies or swims across our earth, sky and oceans.  And if we followed the trail back to us, we would pass innumerable branches in the trail where we would see creatures that looked exactly like we did (then) taking a different road (to be, then,  separated from us by a mountain range, or a melting ice bridge, or a drifting continent) so that by the time we met them again, we (or they, or both) would have evolved into a different species and we might very well no longer recognize the cousinship that links us to our common ancestor.

Perhaps its natural that this kind of knowledge gives me different eyes for dinosaurs and dolphins, trout and trumpeter swans.  We are all variations on a theme, with mutation and natural selection (and sexual selection, let’s not forget) exerting pressure and favoring this slight change over that one until a bacteria grows a skeleton, a fish learns to walk and a hominid learns to play the piano.  So Whales are most closely related to Hippopotomuses, and Manatees to Elephants.  Chimpanzees are more closely related to Humans than they are to Orangutans.  Mice share 85% of our DNA, a head of lettuce 40%.

With facts as mind-blowing as that, Dinosaurs don’t look so strange to me at all.  They look, well, familiar.  Like some really wild cousins I never got the chance to meet.

t.n.s.r. bob