Evolution and Science

Karl Lembke

Years ago, a friend launched a crusade against telling people things "in Christian love." She would walk up to a fellow church member, and say, "I have something to say to you, 'in Christian love'." She could see her target bracing for an attack. When she gave her target a genuine, unmitigated compliment, she could see delighted relief written all over the other person's face. Eventually, "in Christian love" became a joke.

For years, "in Christian love" had meant, "I'm going to attack you, and you're not allowed to take offense at it." Using the phrase was waving a red flag.

Evolution has become a similar red flag. If anything, it's even worse, as opponents have loaded the word with all kinds of negative baggage.

Evolution is seen as a denial of God, of religion, of goodness, of baseball, mom, and apple pie. It is blamed for Hitler, Stalin, communism and totalitarianism, promiscuity, drug abuse, rising crime rates, and falling arches.

In any debate, we need to define our terms. If we don't, we're liable to argue at cross purposes. It's like arguing over the merits of "stealing home", when one side is thinking about baseball, and the other side is thinking about Kelo v. New London.

In the century and a half since Darwin published, the meaning of evolution has changed. As the idea has been applied to different life forms in different environments, it's been expanded to account for what's observed. It was also modified after the development of the gene theory of inheritence, and the discovery of DNA. As a result, scientific definitions of evolution have -- well -- evolved.

I'd like to go over some of these, just so we're all on the same page. You don't have to believe in them. You don't have to accept that they're true. You only have to know what they are, because they're a major part of the case I'm arguing. And face it -- if you don't aim your argument at the case I'm making, you forfeit the game.

Darwin's original notion was descent with slight modifications. His contribution was to realize that random changes were a source of variation, and that at the same time, the environment was a source of direction. Some changes would leave a creature better able to survive in some environment, and others would leave a creature worse off. The creatures with the first change would be more successful that those with the second, and all things being equal, subsequent generations would see more of the one than the other.

These modified creatures would then form the baseline for further random changes. Plug in the new creatures, and repeat. As long as change in any direction results in an improvement, change will be selected for, and the next generation will be slightly different from the last. Just as the journey of a thousand miles begins with a single step, the journey across a thousand species begins with a single small change.

Later, the discovery of the mechanisms of heredity would change the details, or at least nail them down. Researchers and theorists would identify different mechanisms, including ones like "neutral drift". Neutral drift is the notion that change happens, and in the absence of any selective pressure, small changes can add up to one big change.

The definition that's become the standard, and that's used in many textbooks, is "a change in allele frequencies in a population over time." An allele is a variant type of a gene -- a "flavor", if you will. Blood types are the physical expressions of different alleles of one gene; eye color is the expression of different alleles of another gene. Different genes can rise and fall in frequency in a population from generation to generation. Sometimes an allele will disappear completely, and its frequency goes to zero.

On occasion, a new gene will appear, and its frequency goes from zero to a smidgen. From a smidgen, it may increase, or it might drop back to zero and disappear. Granted, these changes are small changes. But take enough small changes, and you get one big change.

Other ideas that have been attached to the term "evolution" include:

o Life has changed over time -- There are creatures that lived in the past, which are extinct now, and there are creatures that exist now which did not exist in the past.

o Life has a history -- the changes that have taken place over time have left traces, and these traces can be found and analyzed. We can determine a lot from these traces.

o Individual species have a history, and are descended from other species that were different from what we see now.

o Common ancestry -- all living things descend from one, or at most, a few common ancestors.

o Yes, us too. We share a common ancestor with apes. And with lizards. And with oak trees. If you go back far enough.

Then there are the definitions opponents of evolution like to use. These include:

o Denial of God.

o Worship of Charles Darwin

o Worship of science.

o Rejection of morality.

o Denial of any meaning to life, the universe, or anything.

o Dogs giving birth to cats, or other sudden creations of species.

o Complex molecules magically self-assembling from random atoms.

Any statements about God, of course, are outside the realm of science. One of the rules of science is "methodological materialism". [1] Science is allowed to call on material causes only. This is not to deny the existence or the importance of the spiritual realm. Science is simply not capable of saying anything meaningful about it.

Science also can't say anything about morality. Science treats what *can* be done, not what *should* be done. Science can tell you how to eradicate smallpox. Science can't tell you whether you *should* do this -- only your values and morals can do that. Similarly, worship -- deciding what is worthy of reverence, and to what extent -- is outside the realm of science.

Of the last two -- no serious student of evolution believes either of them, and you will be completely unable to find a paper in any science journal that claims they happen.

So what does the science say?

Well, we have a bundle of claims -- two of them being that life has a history, and all living things trace back to a few common ancestors, maybe only one. These claims are either true or false, and either way, there should be evidence we can find to support them.

We're pretty sure life has changed over time. We find fossils of creatures that absolutely don't exist now, and we find a complete absence in the fossil record of any trace of life forms that are all over the place now. Dinosaurs died out over 65 million years ago, and before that extinction, there was a succession of dinosaurs that existed for a while, and then disappeared. And during most of the time dinosaurs roamed the earth, there were no flowering plants. Nowadays, you can find pollen from flowering plants in just about any sample of soil you care to examine. Pollen is extremely rugged, and can be identified pretty readily under a microscope. We can see fossilized pollen in rocks dating from the end of the age of dinosaurs. Before that time, there are no traces of flowering plants, including their pollen, in any rocks yet discovered.

As for common ancestry: Many people, even before Darwin, were struck by the number of similarities in living things. Carolus Linnaeus used these to classify living things into the well known levels of kingdom, phylum, class, order, family, genus, and species. Many people figured this was evidence of common design, but it is also consistent (and in some ways, more consistent) with shared ancestry with subsequent modification. It seemed as if the designer had made a few types of living thing, and then adapted them to fit different purposes.

Is this the result of common ancestry, or common design? As it happens, the fossil record has been very helpful here. Fossils are very rare, and finding the right fossil to illuminate some portion of history is a matter of luck. However, a lot of fossils have been found, and we've found a lot of cases of living things that fall somewhere between major design types. If you believe the science, it looks like quite a few different types of living thing were a lot less different in the past.

Darwin's theory was controversial from the moment it appeared, and it's a lightning rod for controversy today. How does it measure up as science?

I've mentioned the first rule of science -- methodogical materialism. Is Darwin's theory materialistic?

Oh, yes. In fact, that's what the detractors object to. Darwin's theory, and the modifications that have been made in subsequent decades, all fall back on natural causes and natural processes that can be observed today. We can observe that the offspring of any living thing tend to look *mostly* like their parents. "Mostly" alike is not *completely* alike, and the differences are variation. We can watch natural selection at work. Sometimes, a variation arises that makes a difference in survival rates. Sometimes, we can understand why some variation matters, other times it's harder to figure out. But we can see these differences, and we can measure survival rates.

Darwin invoked two effects -- random variation, and natural selection. Both of these are materialistic, and neither calls for any intervention on the part of any force outside of nature. Other effects have been proposed and discussed. Some have been accepted, others rejected. But none of them have demanded the influence of any force outside of nature.

So far, evolution follows rule 1.

How about falsifiability? Is there anything that can prove evolution false?

As it happens, lots of things could do that.

If it turned out that variation simply did not occur, natural selection would have nothing to work on.

If it turned out that survival, and especially the ability to leave behind offspring, were independent of any inheritable variation, natural selection would be meaningless.

If life had been the same forever -- there had always been people, cats, dogs, and everything else we see as far back as we could find -- that would falsify the theory.

Ideally, a theory should make predictions which can be tested against observations in the real world. Darwin made a few. One prediction had to do with moths. Noting that a particular orchid had a very long spur, he predicted a moth would be found with an eleven-inch-long proboscis to extract the nectar. A few years after his death, such a moth was found. [2] (article on deception) ]

Other predictions, involving anatomical similarities in creatures believed to be closely related, also kept proving true. Later, as we learned to explore life on the molecular level, similar predictions about proteins and DNA kept proving true. [3] (TO faq)

And in fact, article after article in the biology journals assume evolution is true in the design of their research. Every time evolution turns out to be true enough to make the research work out, that's another test evolution has passed. [4] (tech central station article)

I could go on, but this is enough to show that evolution definitely meets rule 2. It is falsifiable. There are observations that can be conceived of, any of which would spell serious trouble for the theory.

Ironically, perhaps the best evidence that evolution is falsifiable comes from its detractors. In article after article, you will read the claim that evolution isn't science because it can't be falsified -- followed by at least five paragraphs of stuff that's supposed to prove it false, precisely what the first paragraph claimed was impossible!

Moving right along -- rule 3.

How well does the theory explain what we see?

This is the most contentious area of evolution, and in fact, it's what those multi-paragraph listings of problems are all about. The authors believe that by pointing out "problems", they can convince people that evolution is unable to explain what we observe.

I won't go into the quality of any of the arguments that have been offered lately. Some of them are more than a century old, and were thoroughly discredited very shortly after they were first made, and some of them are relatively new. All of them are addressed by people far more capable than I.

One tactic involves noting some intricate feature and asserting that because there's no explanation *yet*, there never will be. [5] This tactic has a particularly dismal track record. Things tend to get explained if they hang around long enough. Yesterday's intractible conundrums are today's obvious implications of the theory, and there's no reason to believe today's head-scratchers won't be considered equally obvious tomorrow.

Evolution doesn't explain everything there is about how life got here. There may well be things evolution can't answer. In fact, I'm perfectly happy to stipulate as much. The thing is, evolution explains an awful lot, and those explanations don't quit working simply because some item winds up demanding some alternative explanation.

As the quantum mechanic in my last essay pointed out, any new explanation has to meet several tests before he's willing to spend any time on it. It has to explain things that are already accounted for by the old explanation, and it has to explain other things better than the old theory does.

Evolution meets all three rules for sound science, so it deserves to be covered in a science class. Assuming, of course, that we're interested in teaching science.

Next essay: How well "the alternatives" fare under the same test.

1) "Intelligent Science Education Policy" [http://www.opinioneditorials.com/freedomwriters/klembke_20050817.html] accessed 8/23/05.

2) "The Beauty of Deceit" [http://www.corante.com/loom/archives/2005/08/28/the_beauty_of_deceit.php] accessed 8/30/05.

3) "29+ Evidences for Macroevolution -- Part 4: -- The Molecular Sequence Evidence" [http://www.talkorigins.org/faqs/comdesc/section4.html] accessed 8/30/05

4) "Darwin Among the Believers" [http://www.techcentralstation.com/072205B.html] accessed 8/30/05

5) "Turning 'Unknown' into 'Unknowable'" [http://www.techcentralstation.com/081005E.html] accessed 8/30/05