Before we get too far into this, I need to pause for a moment and acknowledge the horribly unfair situation that the Board members were put in. The specific wording of the amendment in question was proposed (and presumably written) by board chairman Don McLeroy. McLeroy's proposal came after the Board had already rejected an earlier attmept to re-insert language into the standards that would require students to learn about the "strengths and weaknesses" of scientific theories. Board members were given very little time to read and understand the amendment before they were forced to cast their vote on it. Even worse, they had no opportunity to consult with scientists in the room who could have explained why the wording of the amendment is nonsensical.

Below is the exact wording of the standard that has been added to section 7 of the Biology TEKS:


Bear with me because I'm going to have to break this into pieces.

The first problem is that the use of the phrase "sufficiency or insufficiency" portrays the inference of common ancestry as an open question. By leaving it open, the standard engenders improper doubt about the unifying principle of modern Biology. Among scientists, the fact of common ancestry of all living and fossil species is not in doubt. Just ask Intelligent Design proponent Michael Behe.

The apparent intent of including the "sufficiency or insufficiency" phrase is to imply that common ancestry ought to be rejected as an insufficient explanation. A Biology teacher who teaches that biologists have real doubts about common ancestry would be committing educational malpractice.

The most problematic part of the standard is that it confuses a scientific inference for a scientific explanation. Scientific inferences, like the inference of common ancestry, are conclusions that are drawn from the patterns in the available evidence. Scientific explanations, like the proposed mechanisms of evolutionary change, are attempts to identify and explicate the natural causes for those patterns.

If you are sitting at the dinner table and the doorbell rings, you will likely conclude that someone must be at the door. This is because you know the same thing has happened before. Your "someone is at the door" conclusion is an inference that you have drawn from patterns in the available evidence.

The same can be said of the inference of common ancestry. Scientists who have examined the patterns in the genetic, morphological, biogeographical, embryological, and fossil evidence have come to the conclusion that all living things have descended from common ancestors. This is because scientists know that living things today come from their ancestors and that an extrapolation of this phenomenon backwards in time is consistent with the patterns seen in the available evidence. Indeed, in many cases, common ancestry is the only reasonable explanation that makes sense of biological observations.

Now, let's go back to our doorbell example. Imagine that you were asked to give a detailed explanation of exactly how the ringing of a doorbell led you to conclude that someone was at the door. Such an explanation would probably involve a discussion of the circuitry of the doorbell system and how the sound is made when a button outside the door is pushed to complete the curcuit. You would probably then describe how the sound propagates through the air in your house as a longitudinal wave until it reaches your eardrum, causing it to vibrate. Next, you might delve into the anatomy of the ear, the perception of the sound of the doorbell, and the way in which your brain functions in recognizing and identifying the meaning of that sound. After all of this, you might even mention that there are other types of doorbells that use do not use electricity to generate sound.

The proposed mechanisms of evolutionary change are like your detailed explanation of how a doorbell works. These mechanisms provide the explanation for how the patterns in the scientific evidence (those patterns indicative of common ancestry) were generated. As I mentioned in my previous post, the "sudden appearance, stasis and sequential nature of groups in the fossil record" can be explained using various mechanisms, including natural selection, reproductive isolation, speciation, changes in the environment, and the formation, preservation, and discovery of fossils.

And here's where we get to the really bad news for anti-evolutionists: based on our current understanding of how these evolutionary mechanisms work, scientists actually predict the "sudden appearance, stasis and sequential nature of groups in the fossil record." That's because the formation of new species usually occurs quickly and in small, isolated populations. Therefore, scientists expect there to be less fossil evidence of species-to-species transitions. Even so, while it is certainly true that most fossil lineages exhibit relatively long periods of stasis, there are also many lineages that exhibit gradual change with clear transitional forms linking one species to another.

Ironically, despite the confusion, the standard correctly implies (albeit inadvertently) that the inference of common ancestry may be insufficient as an explanation for the patterns observed in the fossil record. That's because common ancestry is not a mechanism of evolutionary change. It is the result of the mechanisms of evolutionary change.

At this point, you might be wondering how someone like Dr. McLeroy could claim to know something about evolution and still get it so wrong. Well, I think if you scroll up to the banner at the top of this page, you'll see one possible explanation.

Or maybe this quote is more apt:


Either way, you can hopefully now see why the current political process of determining science curriculum in this country is ultimately bad for science education.

One Final Note:

It is quite easy for those of us who understand the problem with this amendment to get angry at the perceived arrogance of those who would so blindly criticize that which they clearly do not understand. But anger will not accomplish anything.

Instead of anger, we must calmly and patiently explain why the amendment is misguided. I am confident that the teachable members of the Board will correct their mistake when the final vote occurs in March.

Here's hoping that they have the humility and willingness to accept correction.