Wednesday, December 14, 2011

Evolution: Part VII: Common Criticisms

And here I answer the standard arguments advanced against evolution. As I am currently busy with finals, I have brought in a co-lecturer to debate: Bob from the works of Jack T. Chick. Please give him a warm welcome.
The following material is flagged Green Level. It is intended to reflect material that the author believes to be a matter of consensus among experts in the field. This belief may be incorrect, however; and as the author is not an expert and does not have an expert fact-checking the article, errors may creep in.
Thank you. Now then, let's discuss evolution.
Yes. Let's.
So, do you really believe that you are descended from an ape?
Depends on your definitions, really.
But isn't that what your theory teaches?
Hardly. What evolution teaches is that all species are descended from common ancestors, and that some are more closely related than others. For any meaningful definition of "ape" for which humans are descended from apes, humans are apes.
But evolution is a racist theory in which some organisms were more evolved than others.
No. What you are referencing is an outdated idea called the ladder of being, which actually predates Darwin. The ladder of being is the idea that there is a hierarchy of living organisms, and that over time, they advance up the "ladder".
That's not to say, of course, that evolution has never been used to justify racist ideologies, but to be perfectly honest, the only ideas that haven't at some point or another are the ones that simply haven't been around long enough. Even the civil rights movement had its black supremacists. For the most part, the racist interpretations have been pretty thoroughly discredited.
All right. Let's try something else. How do you know this is where life originated? Were you there?
First of all, evolution has nothing at all to do with where or how life began, only with what happens once it has. Evolution doesn't care whether its replicators were created by an act of divine will, or originated when lightning struck the seas, or are illusions crafted by an insane god to venerate it. Evolution only cares that replicators exist, and they show heredity with variation.
Second, the "were you there" bit has its own share of problems. If you would follow a hypothetical for me, let's say you are a crime scene investigator. You are called in to investigate a death, and you find the decedent in his bathtub, with multiple stab wounds. In his kitchen is a bloodstained knife, matching the wounds, and in fact DNA analysis indicates that the blood is his. Fingerprints on the knife match those of one of his house-guests, and DNA analysis indicates that the blood under the decedent's fingernails is that of the house-guest, and the house-guest has injuries resembling fingernail gouges. What conclusions can you draw, despite not having been there at the time?
It's not the same thing. For one, there are no accounts from anyone who actually was there.
Okay, we'll modify the scenario. The house-guest claims that a wizard appeared in the house, killed the decedent, and magically transformed the fingerprints on the knife to those of said guest before animating the decedent as a zombie and commanding it to attack him. Said zombie scratched him, and then was ordered to lie down in the bathtub and return to death. The wizard then flew out the window, cackling. The other house-guests, all friends of the suspect, corroborate this, although they could have been coached.
All right. I'll admit that the theory of creation sounds a bit like magic to those without the faith to keep an open mind. But the situation isn't like that. Where's the prints, the wounds, and the blood?
First, we must consider that, in science, it is not sufficient to simply explain the existing data. We must also predict future information. So let us look at what evolution predicts.
Evolution predicts that when new fossils are discovered, they will, if sorted by age, show slow transitions from one form to another. Keep in mind, there will be no "crocoducks"; each form will be able to survive on its own. The closest thing there is to a "crocoduck" is the common ancestor shared by reptiles and birds. This general observation has been found.
But how do you know how old the fossils are? Isn't it circular reasoning to say that a fossil is a particular age because it was found in a particular layer, and that that layer is that age because it has those fossils in it?
That would be circular reasoning... if that were the actual reasoning. The way it actually works has to do with radioactive decay. A certain proportion of the matter in any organism, any stone, or any object on Earth, really, is radioactive. When a fossil forms, the minerals that replace the bone contain traces of radioactive material.
Now then, radioactive material decays according to a specific mathematical principle. For any unit of time, a certain proportion of the material transforms into another material, which will later transform into another material, and so on until it is no longer radioactive. This is called the decay chain. If the proportion, original composition, and decay chain are known (and each can be figured out: the proportion and decay chain by watching a sample of the original material decay, and the original composition by studying rocks in the area), it's easy to apply some simple algebra to figure out how long it's been since the fossil formed.
All right. Next prediction?
Second, evolution predicts that there will be vestigial components in an organism at all levels: vestigial organs, vestigial structures within functional organs, vestigial organelles within cells, vestigial DNA, and so forth.
Are you talking about the appendix, coccyx, and so forth? The appendix has bacteria in it, and the coccyx has muscle attachments. They are not vestigial!
So what function do they serve? A vestigial organ is one that serves no purpose or a purpose other than its original one, not one that is not integrated into the rest of the organism. The appendix is homologous to an organ in many other animals that assists in digesting cellulose, and the coccyx is quite obviously a now-nonfunctional tail. Both organs may be removed surgically without ill effect unrelated to the surgery itself, therefore they are vestigial.
Furthermore, there are a number of other items. The blind spot in the eye, noncoding sequences of DNA, the list goes on.
Okay. Next?
Third, evolution predicts that evidential common descent will be more recent between more similar species. That is, when a point of divergence between species (the time at which the species became separate) is found, it will be more recent if the divergence is between similar species, such as bonobos and humans, than if the divergence is between radically different species, such as lemurs and jellyfish.
Isn't this even worse circular reasoning? By assuming that a point of divergence exists, you presuppose your own conclusion!
Good point. Let me revise: the existence of surface similarities should imply the existence of deeper similarities. If two species are similar on the surface, they will have similarities that are not connected to their surface similarities. For instance, any two humans are members of the same species, and thus that implies that their non-coding DNA is more similar than that of either is to that of an orangutang. And the non-coding DNA of a human is more similar to that of an orangutang than to that of an earthworm, which is more similar than to a mushroom, which is more similar than that of a bacterium.
I see. I'll try a new tactic then: if all humans are no more than mere animals, there is no reason to act morally.
That's an old one. The first answer is basically, "So what?" Whether something is moral is no indicator of whether it is true, and vice versa. It is immoral that childhood cancer, methamphetamine addiction, torture, genocide, Ebola, and From Another Time Another Land exist, but they continue to do so anyway.
Are you saying-
Yes. I realize that's not exactly the strongest argument. A better one would be that being an animal may be no reason to act morally, but it's no reason to act immorally either. As I showed before, animals are able to act according to what some might call "morality", even if they are only compelled by their instincts.
But surely the morality that human beings should be held to is of a higher standard than that of beasts.
There are some who would disagree, but you do have something of a point. Unfortunately, it's irrelevant. It's entirely possible to have a morality that is of a higher standard than mere instinct, and there's quite a few ideas about morality that have nothing to do with any kind of supernatural creator. Kant, Mill, Rand, Nietzsche, and others have developed their own forms of morality that are utterly divorced from any idea of deity.
Do you seriously call those correct moralities? What of unnatural acts? What of blasphemy?
I didn't say that those were correct, merely that they were a higher standard than "beast morals". We could spend lifetimes discussing what the true morality, if one exists, is and not get anywhere. In fact, that's been done. In any case, this isn't the proper discussion for that.
Right. I have no chance of convincing you to abandon your heathen codes, and you have no chance of turning me from God's path.
Also, we're starting to run out of column-inches. So, until next semester, be seeing you.
Thanks for having me.

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