Selection Implies A Selector

A while back I debated making a post about an old canard that had popped up once or twice in debates. It was usually one of the red herrings that one learns to avoid if you want to try and actually stay on topic so it’s something that I never really confronted directly. I eventually decided that it was so idiotic that I changed my mind about posting at all on the subject. I decided that no one actually takes the idea seriously.

Then a couple of days ago a post showed up on UD highlighting two different articles, and wouldn’t you know it one of the main ideas brought up in one of the articles was exactly the one that I had deemed too idiotic to be taken seriously. In the article the author summarizes an argument made by Jerry Fodor, co-author of the book “What Darwin Got Wrong“.

Before I continue allow me to clarify that I haven’t read What Darwin Got Wrong, and I’m not sure whether this is an argument put forward in the book itself. The author of the article states that the particular point being made was arrived at in a personal conversation with Fodor. As such this post is aimed not at Fodor, but the author of the article itself who for all I know may have completely mangled Fodor’s point.

Anyway back to the original theme. Here’s the relevant portion of the article:

As far as I can make out, [Fodor’s point] can be summarized in three steps. Step one: Fodor notes – undeniably correctly – that not every trait a creature possesses is necessarily adaptive. Some just come along for the ride: for example, genes that express as tameness in domesticated foxes and dogs also seem to express as floppy ears, for no evident reason. Other traits are, as logicians say, “coextensive”: a polar bear, for example, has the trait of “whiteness” and also the trait of “being the same colour as its environment”. (Yes, that’s a brain-stretching, possibly insanity-inducing statement. Take a deep breath.) Step two: natural selection, according to its theorists, is a force that “selects for” certain traits. (Floppy ears appear to serve no purpose, so while they may have been “selected”, as a matter of fact, they weren’t “selected for”. And polar bears, we’d surely all agree, were “selected for” being the same colour as their environment, not for being white per se: being white is no use as camouflage if snow is, say, orange.)

Step three is Fodor’s coup de grace: how, he says, can that possibly be? The whole point of Darwinian evolution is that it has no mind, no intelligence. But to “select for” certain traits – as opposed to just “selecting” them by not having them die out – wouldn’t natural selection have to have some kind of mind? It might be obvious to you that being the same colour as your environment is more important than being white, if you’re a polar bear, but that’s because you just ran a thought-experiment about a hypothetical situation involving orange snow. Evolution can’t run thought experiments, because it can’t think.

This final step is the idea that I thought too idiotic to warrant comment before now. The idea that a selection of one thing instead of another requires someone to make that selection is ridiculous on the face of it. “Selection implies a selector” is just as flawed as “creation implies a creator”.

A bunch of seeds are blown by the wind so that some land in your yard and some land on the road. The ones in your yard are much more likely to be able to sprout and grow while the ones on the road are much less likely to be able to do so. A selection was made as to which ones live and which one’s don’t, so who decided it? No one, of course! When something dies or is prevented from reproducing it doesn’t mean that someone somewhere made the determination that that should be the case. It just means that something died or didn’t get to reproduce.

The problem here, as is usually the case, is one of sloppy use of language. The phrase “select for” implies an active role in selecting one trait over another. This error is highlighted in the quoted section with the sentence: “But to “select for” certain traits – as opposed to just “selecting” them by not having them die out…“. This implies that there are two different things happening depending on which phrase you are using. To “select for” something is to actively decide that the trait will help survival so that trait is “allowed” to propagate. To simply “select” them by not having them die out is to passively do nothing while that trait is propagated.

In reality the phrase “selects for” is not descriptive of whether selection is active or passive as implied in the article. It is descriptive of the trait being selected and whether the same passive selection which is always present is likely to result in greater prevalence of that trait. An adaptive trait is one that increases the likelihood of survival, therefore we say that it is “selected for” because that trait is likely to become more prevalent over time due to the advantages it confers on the owner of that trait. Other traits are simply “selected” because they are just along for the ride and do not affect the survivability of the owner of that trait. If they are tied to an adaptive trait they may become more prevalent over time as well, but they are by no means guaranteed to do so. Both types of selection are passive in the sense that traits were only “selected” by not having them die out. The difference is that adaptive traits modify the likelihood of survival itself by simple virtue of their existence…without needing to have anyone or anything dictate that fact.

Having said all of that, I understand that, at least in the authors eyes, the fact that some traits which are “selected for” are inextricably linked to others which are not is an important point. The question seems to be essentially “how does it know whether to select for the adaptive trait and not the non-adaptive trait?” or possibly “how does it know to select the non-adaptive trait along with the adaptive trait?” (a quick reminder that I’m referring only to what I’ve read in the article, so if I’m misstating Fodor’s original thesis please forgive me…I’m working with essentially a summary) The answer is that it doesn’t know. It doesn’t have to know.

For any single organism, it’s survivability can be thought of as the sum of all of it’s traits whether they are positive, negative or neutral. If a so called adaptive trait reduces it’s chances of dying by 3 (to throw a ridiculously random number at it), and it’s inextricably linked to 2 otherwise neutral traits, the simple fact that it’s more likely to survive because of the one adaptive trait automatically means that the other two are coming along for the ride. So are any other traits which may have no relation whatsoever to any other trait, but which by pure accident happen to be present in that creature. The adaptive traits drive natural selection not because anything is actively causing them to do so, but because that is the simple result of the trait making survival more likely.

One final note, which has little to do with the rest of the post, but which just plain bugs me. Why the sarcasm after pointing out the traits of “whiteness” and “being the same color as its environment”? There are three main options that I can think of. One, he thought the two separate traits were in fact one single trait described separately, rendering it a non-statement like “It’s white and also it’s white.” This doesn’t seem likely since he describes exactly why this isn’t the case in the very next aside. The other option is that he believes it’s so obvious that even feeling the need to point it out is worthy of ridicule. But then why describe exactly why they are different right afterward? The last option is simply that I’m reading more into it than intended. Maybe it’s much more innocent than it seems (like faux sarcasm between friends) and only seems mocking because of the lack of context which is a constant problem in written works.

Re-evaluation

I think that many people who are anti-science, or even just anti-my-pet-theory, have trouble not with the science itself but with their own inability to re-evaluate their position. You might remember a post I made awhile back called Cognitive Disfunction. It was about the inability to accept evidence contrary to one’s own belief regardless of the reason. As an example I used the Plane on a Conveyor Belt episode of Mythbusters. As I thought about it more I came to the realization that the major problem there was an inability to re-evaluate the original conclusion that they reached.

In part the problem arose because of that way that it was worded (which was most likely by design). Here again is the actual description of the problem.

[N]ormally a plane sits on the runway, spins up its engines, moves forwards gets enough air over its wings and takes off. But in this case, the plane is sitting not on the runway, but a huge conveyor belt that is matching the planes forward speed in reverse, and the grand question is can the plane take off? The myth is that it can’t

On first hearing it, the mental image that you might form is one of the plane standing still because the faster it moves, the faster the conveyor belt moves, thereby nullifying it’s forward speed and preventing it from getting any airflow over the wings so it can fly. It just remains stationary. I admit that this was my first impression and I was one of those people who were fooled by the wording.

The breakthrough moment comes when you realize that this conclusion is based on the false premise that the wheels are powering the forward movement of the plane. They aren’t. The forward movement comes from the propellers (or possible the jet), which is independent of the wheels. Therefore it doesn’t matter how fast the conveyor belt moves, the plane will move forward.

I think many of the people who were arguing against the Mythbuster’s conclusion were stuck with their first impression of the problem. Arguments that the wheels didn’t affect the forward movement of the plane weren’t even relevant to them because as far as they were concerned the description said that the plane was stationary, and a stationary plane cannot take off. The fact that you were arguing against that simple premise demonstrated that you didn’t actually understand the original description.

A similar problem seems to affect people who are dead set against the Theory of Evolution. I’ve been in many debates with anti-evolutionists who obviously had a great misunderstanding of how evolution works. For example they would say that mutations can only be detrimental, meaning that natural selection could only allow organisms to survive which couldn’t survive because of the mutations. The absurdity of that proves that evolution is false. Or they would question exactly who it is that is deciding which organisms live or die. Without someone to make that decision evolution simply cannot work. These are obviously profound misunderstandings of how evolution works, but of course from their point of view I am the one that doesn’t understand. And just like the stationary plane they are based on initial misunderstandings that they either can’t or won’t re-evaluate.