Similarities between living creatures is often touted as evidence of relatedness between the creatures. The similarities between humans and chimps, for example, are supposed evidence that humans and chimps have a common ancestor. For that matter, all mammals are believed to have a common ancestor and so have certain features in common. One argument creationists use to rebut the “evidence” of similar traits is to point out how non-related objects often possess similar traits. Bicycles and motorcycles have certain things in common. Does that mean that motorcycles evolved from bicycles? Of course it does not. They have features in common because they were designed for similar purpose.
I was browsing Youtube the other day (watching videos posted by evolutionists, by the way!) and came across a video where Kent Hovind (a controversial, young-earth creationist) made this very point during a discussion with a evolution-believing graduate student. The video is 9 minutes long and much of it isn't related to the point at hand so I won't post the whole thing here. You can view it for yourself at this link. The part I'm referring to begins around 55 seconds into the video when Kent offers the analogy of similarities in bridges. The student makes the following comments: “That has nothing to do with evolution... because a bridge is a horrible analogy to a living thing. I mean, it has nothing in common with a living thing.... And they [living things] reproduce which is one of the fundamental tenets of evolution. I mean, a thing can't evolve unless it reproduces. Here, we're talking about reproducing systems. Explain to me what this has to do with a common Designer because I really don't get it.”
Later in the video, Kent uses the analogy of similarities between cars and motorcycles. The student again makes the following comments: “Machinery is a horrible example. This has nothing to do with living things. They're not living things. I don't see why you insist on using machinery as an example.”
I think this student precisely knows why Kent is using it as an example. It's the same reason we often use it as an example – because it makes so obvious that common features are not de facto proof of common ancestry. His response is the usual response I hear from evolutionists when I use similar examples. They don't have a really good rebuttal so they simply ridicule the analogy. They believe that, if they disqualify the analogy as being invalid, then they excuse themselves from having to respond to it. This is a staple in the evolutionists' arsenal of responses and is usually employed as the first resort whenever the “common features are due to common Designer” argument is raised.
As often as I've heard evolutionists denounce machines as bad analogies to living things, you can imagine how amused I was when I came across a video (here) where an evolutionist uses machine design as evidence for evolution. And what errant soul wandered from the evolutionists' playbook and made this outrageous claim? It is none other than that most out-spoken of all atheist-evolutionists, Richard Dawkins! I kid you not – it's Mr. “God is a Delusion” himself.
Now, the person who made this video did not have the “common Designer” subject in mind when he posted it on Youtube. Instead, he made the video in response another claim made by Hovind, namely that evolution hasn't made any contributions to science. In the nine minute video, the last six minutes are devoted to a detailed monologue where Dawkins explains how “evolution” is being simulated in laboratories to help design more efficient machinery.
What can I say about the video? It fails in a couple of ways. Primarily, it doesn't demonstrate evolution at all. Evolution is supposed to be “aimless.” When Dr. Rechenberg (I'm not sure of the spelling) attempted to use artificial “mutation” and “selection” in his experiment, he had a goal in mind – to find an efficient wing. In the real world (or should I say, “the theoretical world of evolution”), evolution doesn't concern itself with some future goal. The only “objective” of natural selection is to remove those traits that don't convey an immediate benefit. In the supposed long transition from an arm to a wing, evolution had no idea it was heading toward a wing. Each generation of limb along the way had to convey a greater benefit to its host than the previous limb. If you start with a fully functioning arm, what benefit is there in a mutation that makes it less then an arm but not yet a wing?
I don't mean to digress into a discussion of transitional forms. My main point is the blatant hypocrisy of suddenly using the analogy of design in machines after having decried the analogy for so long. When it suits them, I guess it's a fine analogy.
Now that it's officially a good analogy after all, I have a suggestion: How about going back and answering the question evolutionists have been dodging for so long? Can't similarities in animals be evidence of design? A bike is similar to a motorcycle. Did the motorcycle evolve from the bike or were they just made that way? It's time to stop attacking the question and start answering it. You can't have it both ways.
The problem with analogies is that they have their limits - it is only possible to use an analogy to elucidate part of evolution, but not the whole thing. When it comes to claiming one thing evolving into another (bicycle to motorbike) there needs to be a way for them to get from A to B through natural process; this requires reproduction (not to mention variation in said progeny). When discussing bridges you are talking about things which necessitate a designer in order to be varied, whereas organisms can do things which inanimate objects cannot, namely reproduce.
ReplyDeleteWhen it comes to the common designer argument, it is those homologies which make little to no sense, particularly genetic ones such as pseudogenes, which go against it.
Analogies must have key things in common with their analogues in order for it to work, of which reproduction is a key in the previous analogy. The second use of it, by Dawkins et al, is an example highlighting cumulative processes. Darwin did the same, using artificial selection in animals to elucidate natural selection. The scientists in question are using an artificial kind of selection in mechanical engineering in order to elucidate the cumulative nature of natural selection.
Similarly, their analogy is also flawed when applied to evolution as a whole, as all analogies naturally will be. But for demonstrating cumulative selection it is ample.
Having an intelligent selector might appear to be a flaw in the latter analogy, however, the context of selection in nature determines the path of evolution, even if it is blind. What evolves will be better and better adapted to its environment.
PB,
ReplyDeleteYou said, “The problem with analogies is that they have their limits - it is only possible to use an analogy to elucidate part of evolution, but not the whole thing. When it comes to claiming one thing evolving into another (bicycle to motorbike) there needs to be a way for them to get from A to B through natural process; this requires reproduction (not to mention variation in said progeny). When discussing bridges you are talking about things which necessitate a designer in order to be varied, whereas organisms can do things which inanimate objects cannot, namely reproduce.”
Let me clear it up for you a little. A motorcycle has some similarities to a bicycle but neither evolved from the other. It's precisely because we know they don't reproduce that makes it such a good analogy. The similarities are clear to see and we know that they are not the result of common ancestry. So when we see similarities among animals in nature, it is not necessarily due to common ancestry. There is an equally valid theory that explains the similarities – namely that they are by design.
God bless!!
RKBentley
"Homologies" are more than just "similarities;" indeed, biology has two separate kinds of "similarity."
ReplyDelete"Analogy" is similarity dictated by a common function; the similarities between a bicycle and motorcycle may fall into this category (though I had always thought that motorcycles were indeed modified bicycles. It also accounts for the similarities between the box-camera eye of an octopus (with its "right-way round retina) and the box-camera eye of vertebrates (with their "inverted retina").
"Homology" is detailed similarity not required for similarity of function. As The Palaeobabbler noted, the most striking homologies are what are called "parahomologies" (Darwin called them "similar structures with dissimilar functions").
Pseudogenes are an example (all "vestigial" structures are instances of "parahomology"), but so are non-vestigial examples such as the bones of a bat's wing and those of a whale's flipper (and those of the human arm and hand). Those are similarities that go beyond those between a bicycle and a motorcycle, despite rather striking differences in function.
As Palaeobabbler also notes, the point of the video on genetic algorithms is that they work by cumulative selection, and that cumulative selection is better than [a] random selection, [b] trying to achieve a complex adaption in one fell swoop, and [c] can achieve results through pathways that an engineer probably would not consider.
Note that there are fossil theropod dinosaurs whose arms seem (as far as one can tell from fossils) quite functional as arms (they seem as though they should be able to grasp prey or branches), but whose feathers seem quite large enough to aid in gliding from branch to branch in somewhat the fashion of a flying squirrel. Such feathered arms may also have been used for display (to appear larger to a predator or more attractive to a potential mate).
Steven J,
ReplyDeleteAnalogous limbs are another great example of my point. Similarity between animals is not necessarily evidence of relatedness even according to your own theory. As you said, an octopus and a human have similar eyes (the inverted wiring notwithstanding) even though they are not considered closely related. Of course, if they were closely related (according to your theory), the similarity of their eyes would be attributed to common ancestry.
I've seen the same thing happen when examining the intelligence of chimps. Chimps admittedly are very intelligent. Evolutionists feel their higher intelligence is due to their close relation to humans. We even study chimps to try to help us understand how humans learn. Now, some birds are at least as intelligent as chimps. Is this evidence of their close relation to chimps? Actually, chimps are closer to birds in intelligence than they are to humans so wouldn't that mean they are more closely related to the birds?
So which is it? Are chimps more closely related to birds or are similar traits in different animals not necessarily due to common ancestry? If it is the latter, then why should I believe the similarity between humans and chimps must necessarily be due to a common ancestor?
God bless!!
RKBentley
Homology is not based on single traits (even when the homology in question is a singular trait). Numerous traits are taken into account in order to determine between synapomorphies (shared, derived characters from the most recent common ancestor) and symplesiomorphies (shared traits which can be traced back to a more distant ancestor).
ReplyDeleteWhen looking at birds and chimps you are focussing on one trait and ignoring the many derived traits which they do not have in common (feathers and fur for example). When these traits are analysed properly we find that nested hierarchies occur. Chimps and humans end up in their own little nest, whereas the nest which includes chimps and birds also includes all mammals, crocodiles and even dinosaurs.
The ability to group traits in nested hierarchies is a problem for creationism. No problem for evolution though.
This might not be the best of explanations as I am on the wrong end of an all nighter and am not very focussed right now.
PB,
ReplyDeleteYou said, “When looking at birds and chimps you are focussing on one trait and ignoring the many derived traits which they do not have in common (feathers and fur for example). When these traits are analysed properly we find that nested hierarchies occur. Chimps and humans end up in their own little nest, whereas the nest which includes chimps and birds also includes all mammals, crocodiles and even dinosaurs.”
The ability to group animals into a nested hierarchy could be explained by common ancestry but I'm puzzled why you think it's a problem for creationists. Did it occur to you that created things could also be grouped into nested hierarchies? If I had a bucket full of needles, pins, screws, staples, nails, and other assorted fasteners, all of various sizes, I suppose I could arrange them into nested hierarchy or draw some imagined family tree.
I understand your point but I also see your steadfast refusal to acknowledge a very simple concept; things can be similar without having evolved. It goes back to a point I made a while back: we have the same evidence but have different theories to explain the evidence. Chimps and humans have some similarities, Why? You say it's because they have a common ancestor. I say it's because they were created that way. Frankly, I think evolutionists do themselves a disservice when they so stubbornly refuse to acknowledge something even a lay person can see: created things can be similar. Get it? It sort of makes you all look foolish for denying something so obvious. But I'm not complaining. If you think it's a winning argument then by all means stick to it. It makes my job easier!
Finally, I always see a little circular reasoning whenever evolutionists begin talking about nested hierarchies. They use common ancestry to explain similarities among animals and then claim similarities among animals is proof of common ancestry. It's rather funny. If I found a purple rock with black stripes painted on it, I could say aliens painted the stripes on the rock. What proof do I have? Well, there's the rock and there are the stripes so it must be true!
God bless!!
RKBentley
RKBentley replied to Palaeobabbler:
ReplyDeleteThe ability to group animals into a nested hierarchy could be explained by common ancestry but I'm puzzled why you think it's a problem for creationists. Did it occur to you that created things could also be grouped into nested hierarchies? If I had a bucket full of needles, pins, screws, staples, nails, and other assorted fasteners, all of various sizes, I suppose I could arrange them into nested hierarchy or draw some imagined family tree.
You can arrange any suite of objects in a nested hierarchy. Take, e.g. books in a library: both the Dewey Decimal system and the Library of Congress classification are nested hierarchies. But there are books that fit in more than one place in either hierarchy. This is true of most nested hierarchies of most suites of objects: you get always get a tree of relationships, but you get different trees depending on which features you use to sort items.
Indeed, when Carolus Linnaeus set up his taxonomy, he attempted to set up a nested hierarchy of all nature: clouds and minerals, along with animals and vegetables. There's no single consistent tree pattern that works for rocks or clouds, as there is none for books.
But you get, e.g. the same taxon "mammals" whether you group vertebrates by "has one bone in the lower jaw, three bones in the inner ear, and a left but not a right aortic arch," or "has mammary glands and at least a few hairs," or group them by variations in the enzyme cytochrome-c. I don't think you'd get that consistency with a bucket of assorted fasteners; again, different suites of traits would yield different trees.
Artificers tend to cross-copy design features (e.g. wheels on vehicles from ox carts to motorcycles), producing not a neat tree but a complex web of design features. A single complex design is likely to be "descended" from several independent "ancestors" (e.g. the motorcycle from bicycles, engines, lighting fixtures, etc.). Consistent nested hierarchies, in our experience, result from simple branching descent with modification (just to complicate things, there are ways genes can be "laterally" transmitted between organisms, but this does not transmit complex traits, organs, etc.).