In
my last post, I talked about two traits that are critical to any
scientific theory: it must be predictive and falsifiable.
Evolution has often been criticized as a scientific theory on the
grounds that it isn't falsifiable. No discovery, no matter how
contrary it is to our current understanding of evolution, would ever
make mainstream scientists question the theory. I'm not
exaggerating. It's such a problem that frustrated creationists will
simply ask, “what is something that, if found, would falsify
evolution?”
Rational
Wiki (RW), has an article they titled, “Falsifiability
of evolution.” In their own words, they say, [A]ny
of the following would destroy the entire theory [of evolution].
Now
that's fairly committal of them. Thank you. However, as I look over
the list, I can hardly believe they're sincere. You'll see what I
mean by this in a minute. In this post, we're going to look at three
points to see how well they actually test the theory.
[The
theory of evolution would be destroyed] If it could be shown that
organisms with identical DNA have different genetic traits.
It's
hard to imagine a scenario where two, sexual creatures would have
identical DNA. The first thing that comes to my mind is identical
twins. This occurs when a single, fertilized egg splits and each
half develops into an embryo. So RW is saying if identical twins
weren't identical, evolution would be disproved. They can't be
serious. //RKBentley shakes his head// You can see what I
meant when I said these hardly seem like sincere tests of the theory.
But, OK – let's go with this for a moment.
If
you know any identical twins, you've probably noticed they usually
don't really look identical.
They look similar, of course, but each is distinct enough that they
can be told apart. Part of this is because of environmental factors
– one twin might have a different diet and so will weigh more, the
other might play sports and be more muscular, et
cetera. It used to be
that the differences between identical twins were always attributed
to environmental factors but further studies in genetics has
suggested this isn't always the case. One Scientific
American headline reads, “Identical
Twins' Genes Are Not Identical. Twins may appear to be cut from the
same cloth but their genes reveal a different pattern.”
Hmm. That's interesting. From the article we read this: Geneticist
Carl Bruder of the University of Alabama at Birmingham, and his
colleagues closely compared the genomes of 19 sets of adult identical
twins. In some cases, one twin's DNA differed from the other's at
various points on their genomes. At these sites of genetic
divergence, one bore a different number of copies of the same gene, a
genetic state called copy number variants.
Well
there you have it folks! The differences observed in identical twins
aren't necessarily due to environmental factors; sometimes they're
genetic
differences!
Put a fork in it, the theory of evolution is done! But we all know
it isn't. This highlights the frustration creationists face. I
doubt RW will write a rebuttal to this point but, if they did, they
would certainly be walking back how my example really doesn't address
what they were looking for and maybe this isn't even a good test of
the theory anyway.
The
tests of the theory suggested by evolutionists are usually extremely
vague and seldom sincere.
If
it could be shown that mutations do not occur.
Another
ridiculous suggestion. We already know that mutations occur in the
DNA so how could we show they don't occur? Consider this analogy:
suppose I have $20,000 in my bank account. I accidentally leave my
bank statement open on my desk and my supervisor sees my balance.
Not believing I could have legitimately saved that much money, he
accuses me of embezzlement. I protest and tell him I've been saving
that money for years. He refuses to believe me. Frustrated, I ask
him what it would take to convince him I'm innocent? He answers,
“Easy, just show me that you don't have $20,000 in the bank!” Do
you see the parallel there? We already know that do mutations occur,
so to say evolution would be falsified if they didn't occur is
disingenuous.
I've
seen many so called “tests” of this sort. One person actually
told me evolution could be falsified if it could be shown that
animals don't reproduce. //RKBentley, still shaking his head//
I
believe what these people are trying to say is that evolution
wouldn't be possible if mutations do not occur. We'll actually talk
about that in a second, but such a point is ridiculously obvious.
It's like saying evolution could not have happened if animals didn't
reproduce. We don't need evolutionists to point to something that
already happens and say, “Evolution couldn't be true if that
thing didn't happen.” What we want is someone to say, “If we
ever found thing-x, it would prove evolution didn't happen.”
Do you have anything like that?
If
it could be shown that when mutations do occur, they are not passed
down through the generations.
This
suffers from the same flaw as the previous suggestion because we
already know mutations can be inherited. However, this brings up
another problem with the theory – namely, that evolution is
poorly defined. Let me explain.
In
biological terms, the most preferred definition
of evolution is usually something like this: A
change
in the genetic composition of a population during successive
generations, often resulting in the development of new species.
In
other words, if 50% of a group of mice are gray in one generation,
then 55% are gray in the next generation, the population has
“evolved” by
definition.
However, this type of “evolution” doesn't even require there to
be any mutations. So if evolution can occur without mutations, then
whether or not mutations occur or are inherited is irrelevant to the
theory! How, then, can they be used to test the theory?!
If
these three items are meant to be serious tests of the theory of
evolution, then the theory doesn't have much concern about being
disproved any time soon. Perhaps that's why the the people at RW
chose them.
Stay
tuned for more of the same in my next post!
Related
articles:
Read
this entire series:
[The theory of evolution would be destroyed] If it could be shown that organisms with identical DNA have different genetic traits.
ReplyDeleteI'm not sure what this means. I'm also not sure what you think it means, yet somehow, I'm fairly sure that you're wrong about what it means.
Any discussion of evolutionary theory (including On the Origin of Species will discuss "heritability," the degree to which differences between individuals in a population are the result of differences in hereditary factors. Natural selection of a trait requires that the heritability of the trait be greater than zero, but not that it be 100%. The theory of evolution from the first has assumed that identical genes need not result in identical organisms, so pointing out that this is true cannot be a falsification of the theory, and no one familiar with the theory would suppose it is.
Side note: the existence of copy number variant of genetic elements doesn't mean that these copy number variants have any noticeable phenotypic effects. Some copy number variants are known to have such effects (e.g. in Huntington's disease), but some might be purely neutral genetic markers, irrelevant to differences in appearance or behavior between identical twins. Neither copy number variants nor the absence of them could falsify common descent or natural selection.
Note also that natural selection and common descent with modification are different things; the article is considering evidence that could falsify both the idea that you share ancestors with gibbons, goldfish, and goldenrod, and evidence that could falsify natural selection of random mutations as a mechanism for adaption. Either in principle might be true and the other false, after all.
Anyway, I think that "organisms with identical DNA but different genetic traits" must mean something like "traits are not inherited, or inheritance of DNA is randomly correlated with inheritance of phenotypic traits." I realize that's not very close to what the statement says, but it's the only meaning that makes any sense in context.
[Evolution -- or at least natural selection, could be falsified ]If it could be shown that mutations do not occur.
ReplyDeleteFirst, if this is a ridiculous suggestion, then why do so many creationist articles emphasize the error-correcting mechanisms of the genome as though they prevent mutations? Why have I encountered creationist tracts asserting that Mendel's discoveries somehow refute Darwin's ideas? If, as you say here, you already know that mutations to DNA occur, why do you invariably discuss natural selection as though they do not?
Second, there was a time (when Darwin was writing On the Origin of Species, for example) when mutations were not known to occur, and it was not in fact known if new inheritable variation could occur in populations. The rediscovery of Mendel's principles after Darwin's death was accompanied by the discovery of mutations, but in principle, it didn't have to be; mutations are (once genetics is discovered) an obvious, falsifiable implication of evolutionary theory.
Given this, is it absurd to say that non-existence of mutations would falsify evolution simply because the theory has survived that particular risk of falsification? You might as well argue that, once you've shown that yellow and blue mixed together do make green, the possibility that they make red isn't really a falsification to the theory that they do!
[Evolution -- or at least natural selection, could be falsified ] If it could be shown that when mutations do occur, they are not passed down through the generations.
A similar argument applies here. Again, if the error-correction mechanisms of our DNA were perfect, mutations wouldn't be passed on. This is a conceivable state of affairs. Or, conversely, if all mutations were not merely harmful but lethal, mutations would always be eliminated immediately by natural selection, and could never modify a population. This was, in the past, a possible falsification of the theory, which it has survived. Should not that count for something?
So if evolution can occur without mutations, then whether or not mutations occur or are inherited is irrelevant to the theory! How, then, can they be used to test the theory?!
Come, you are better than this. Evolution can occur without mutations, but even something so minor as the peppered moth required a novel trait (the carbonaria morph) that arose through mutation. That "evolution" applies to average beak size increasing by 10% as much as it does to lungfish turning into birds doesn't mean that it doesn't include the latter, or that it doesn't need to account for the latter -- and I'm pretty sure the latter requires mutations.
Steven J,
ReplyDeleteYou said, “I'm not sure what this means. I'm also not sure what you think it means, yet somehow, I'm fairly sure that you're wrong about what it means.”
I can only go by what RW has said. They didn't explain it any further than the quote I cited. I'm pretty sure, though, they don't mean anything about inherited traits in this point – especially considering that they talk about inherited mutations later.
They said, “identical DNA.” Even a parent and child do not have “identical DNA.” I understood it to mean how DNA is expressed by the host. That is, if a fish and a bird had the same DNA, it would prove the theory false.
Of course, I did lament in my post how many of these “tests” of the theory are extremely vague. I think RW intended that so they could criticize any potential example as “not what they meant.”
You said, “if this is a ridiculous suggestion, then why do so many creationist articles emphasize the error-correcting mechanisms of the genome as though they prevent mutations?”
I've never heard a creationist say that mutations do not occur. Indeed, if mutations didn't occur, why would the genome need to be self-correcting? I believe pointing out the observed, self-correcting mechanisms in the genome merely highlights how the gene should tend to work against descent with modification.
You said, “... is it absurd to say that non-existence of mutations would falsify evolution simply because the theory has survived that particular risk of falsification? ”
Yes. It is absurd because RW still lists this as a potential falsification of the theory.
You said, “if all mutations were not merely harmful but lethal, mutations would always be eliminated immediately by natural selection, and could never modify a population. This was, in the past, a possible falsification of the theory, which it has survived. Should not that count for something?”
No. It should not count for anything because it is no longer a potential falsification of the theory. Why would it still be on RW list of ways evolution could be falsified?
You said, “Come, you are better than this. Evolution can occur without mutations, but even something so minor as the peppered moth required a novel trait that arose through mutation.”
How can you seriously say “evolution can occur without mutations” and “even something so minor as the peppered moth [evolution] required a novel trait that arose through mutation” in the same sentence? Does evolution require mutation or not? If it doesn't, then you can't use this as a test. If it does, then your side needs to stop using “change in the frequency of an allele” as the definition of evolution.
But you have struck upon the very thing that I've argued on my blog for years – evolution requires the ADDITION of novel traits. Natural selection only REMOVES traits from a population. You can't add traits by continuously removing traits regardless of how long it continues. If evolutionists want to talk about “evolution in action,” they need to show examples of organisms acquiring novel traits and stop showing us examples of natural selection.
By the way, if evolution were true, then the entire genome (except in the alleged first ancestor) is mutated.
Thanks for your comments. God bless!!
RKBentley
No. It should not count for anything because it is no longer a potential falsification of the theory. Why would it still be on RW list of ways evolution could be falsified?
ReplyDeleteSo the more abundantly confirmed a theory is, the more potential falsifications it has withstood, the less falsifiable (and hence scientific) it is? Would you want to argue that as a consistent principle?
What would falsify the idea that the Earth is a globe?
How can you seriously say “evolution can occur without mutations” and “even something so minor as the peppered moth [evolution] required a novel trait that arose through mutation” in the same sentence?
Because both are true.
You are blinded by your need to distinguish categorically between a level of changes in populations that is consistent with your interpretation of Genesis, and a level that is not, so you complain about definitions that don't make that distinction. But you know, at least, that such definitions exist and are standard.
It is entirely possible for evolution, over a short time and small space, to occur without mutations, but large-scale evolution (e.g. fish to Gish) would require mutations.
Steven J,
ReplyDeleteThe saying goes that scientific theories can never be proven true, they can only be proven false. I don't necessarily even agree with your claim that, since mutations were once unknown that they could have potentially falsified evolution. As we began learning about DNA (there's still so much we don't understand), we discovered what we believe are mutations. Some people have speculated that mutations could be the raw material that allows the novel traits that drive evolution but that is merely shaping the theory to fit the observations (which is how theories should be formed). It's a stretch then, to turn around and say the mutations were predicted by the theory. Remember that falsifiability is just a prediction from another viewpoint? So you tweak the theory to accommodate mutations, then say that mutations could have falsified your theory. I'm sorry, but I'm not buying it.
Regardless, my point in this series is to ask how evolution, as a scientific theory, could be falsified. That is what RW claims to be presenting. In that context, even if your point were correct, past tests are irrelevant to what is being discussed.
You asked how I would falsify the idea that the earth is a globe? You're talking about an observation, not a theory. We have satellites in space and can view the earth rotating in real time. That's different from standing on an island and speculating about the shape of the earth. That's like asking me to prove a ball isn't a ball, even while I'm holding it in my hand.
Finally, if evolution only requires mutations “sometimes,” then mutations aren't a good test of the theory. In other words, if evolution can occur without mutations, RW can't say that evolution would be false if mutations didn't occur.
I understand that dinosaurs could not become birds without acquiring feathers. The only mechanism we know of, that could potentially add feathers to a dinosaur, is mutations in the DNA. But like I said, observed examples of trait-adding mutations are astonishingly rare. I haven't heard a convincing example of even one. I would even say the glaring lack of examples makes evolution implausible as a theory for common descent. Still, evolution is being propped up as a theory by examples like speciation. Speciation is macroevolution by definition – that is, evolution above the species level. I wrote a while back about “evolution in action” where a new species of finch was observed in the Galapagos. It was a hybrid of other species of finch. Yet hybridization doesn't require mutations!
There's more I could say but I'm pressed for time. I have to work on my next post in this series so I'm going to wrap up. Thanks for your comments. God bless!!
RKBentley