12 Mar 2006

Intelligent Design: The Final Word, Part 3

The central question I have been trying to satisfy myself about with these notes is the following: is there a way to formulate Intelligent Design as a scientific theory? (See part 1 and part 2.)

By definition, a scientific theory is a model of a part of the world that makes verifiable and falsifiable predictions about specific observations. To answer this question, I will reformulate the statement of ID. Behe’s formulation looks like this (this is not a quote, I’m summing up his argument):

My summary of Behe’s argument:

Although evolution certainly takes place at a macroscopic level, certain biochemical processes inside our cells cannot be explained by step-by-step evolutionary processes because they involve several interacting parts that are each required for the process to function: they are irreducibly complex and so these must have been designed by an intelligent agent. It is mathematically possible for a random process like evolution to produce one of these systems, but the probability is absurdly low because all parts must mutate to their working form at the same time. The probability that all of our irreducibly complex systems evolved in this way is even more negligibly small.

I want to say up front that I am not going to attack the probability part of this argument in order to argue whether it is scientific. It is perfectly reasonable to say that something we observe has a very low probability of arising from some process, and to remove evidence from the applicability of that process in so doing. If you can demonstrate what that probability is. In a further essay I will look at this issue more closely, but only when I want to discuss the correctness of ID, not whether it is a scientific theory in the first place, which is our current aim.

I’m going to reformulate the statement above summarizing Behe a couple times to draw out out what I’m looking for. I expect that an ID enthusiast will object to my reformulations at some point because the conclusion will follow immediately from the final reformulation, but I wonder where the objections will arise exactly.

Reformulation 1:

Certain subcellular processes are irreducibly complex. Irreducible complexity implies design by an intelligent agent, because to arise randomly by a mutation has nearly zero probability. Therefore subcellular processes were designed by an intelligent agent.

I will now add to the discussion that I fully grant that all of Behe’s examples are in fact irreducibly complex, which simply means that the systems involve several interacting parts without any one of which the system fails to function. It’s a simple to define concept, and surely his examples are all in fact irreducibly complex. Granted. Now, also losing the bit about probability, we can reformulate:

Reformulation 2:

Evolution cannot explain irreducible complexity.

This is entirely equivalent to Behe’s statement of ID, once you remove the question about whether the systems are irreducibly complex, and replacing the caveat about probability with the blank statement “cannot explain.” If you agree with the complexity part, then all ID says is that evolution cannot explain this complexity.

The problem with ID is that this not the statement of a scientific theory. It is the contradiction of one, namely of evolution. It only makes one prediction, that evolution will not be able to explain irreducible complexity. The only way to study this idea is to study the evolution of molecular systems and try to explain how the irreducible complexity of some particular system came to be. See, ID doesn’t substitute anything for evolution, it merely fills the gap it creates with the Designer. It cannot make any new predictions, and it doesn’t try.

Here is an analogous scenario. The 6 o’clock news reports that there are crop circles on a farm outside town. A scientist on TV expresses his theory that it is the work of teenagers playing a prank. Another scientist puts forward the theory that the crop circles cannot be explained as the work of humans, they must be the work of extraterrestrials. Furthermore, the second scientist argues that his theory is just as scientific as the first theory, because they both purport to explain a particular phenomenon. The problem with the second theory is that its central claim is that the first claim is wrong, and in so doing it creates a gap, which it then fills with extraterrestrials. But the gap is not a theory, just the contradiction of one. The way to proceed to investigate crop circles, then, is to pursue the first theory and try to find a natural explanation. That’s the same course of action we’d take if there was no second theory. And of course crop circles were eventually found to be easily made by teenagers using planks of wood with rope handles to press down the crops in just a few hours overnight.

It’s the same with ID. The way to pursue this issue is to investigate natural ways that these irreducibly complex systems may have come about. That’s the same approach we’d take if there was no ID theory. ID theory adds nothing and makes no claims other than to contradict an existing line of inquiry.

The funny thing is that ID is falsifiable. Finding a viable evolutionary path for the cilium or any of the systems Behe is interested in will falsify ID, and Behe himself points this out. That’s an important point, because when I started this line of thinking I assumed I’d be determining that ID isn’t falsifiable. What I’ve learned instead is that ID isn’t predictive. No theory whose statement can be summarized as “that other theory over there won’t work in this case” is predictive. It doesn’t make any claims of its own that can be tested, and so the only way to investigate it is to investigate the original theory, making the contradictory theory actually meaningless.

What does this tell us about teaching ID in science classes? My short answer is that since it is not a scientific theory, it should not be taught. It certainly should not be required, and probably its absence should be required. But why? Because science is about skepticism, model-building and model-testing. It’s never about authority, never about personal preferences. It makes no contact with our political or spiritual structures. It is completely confined, completely focused on material predictions that can be tested and falsified. Theories that limit the domain of science, the way ID claims science will never apply to certain biological systems, may or may not be correct. But science does not place such limitiations on itself, for to do so is impossible within the framework of science. Scientists will be the first to admit that they have a poor understanding of how evolution applies to sub-cellular systems. Science demands such concessions — science is the requirement to make such concessions. And that state of affairs may continue to hold for a million years for all I know. It does not change the central point, that science is a process for adding to the accuracy of our models, not for defining boundaries.

12 Mar 2006

Intelligent Design: The Final Word, Part 2

This is a continuation of my discussion of ID (see part 1). Here in part 2 I have exerpted from Behe’s book in order to summarize his argument. I am using the 2003 trade paperback edition published by Free Press, lent to me by a work colleague.

The ID argument in a nutshell:

1) “For discrete physical systems — if there is not a gradual route to their production — design is evident when a number of separate, interacting components are ordered in such a way as to accomplish a function beyond the individual components.” (p. 194)

2) “Because the functions depend critically on the intricate interactions of the parts we must conclude that they, like a mousetrap, were designed.” (p. 205)

In particular for the cilium, a system used by cells for movement:

3) “The function of the cilium is to be a motorized paddle. In order to achieve this function microtubules, nexin linkers, and motor proteins all have to be ordered in a precise fashion. They have to recognize each other intimately, and interact exactly. The function is not present if any of the components is missing.” (p. 204)

On the identity of the designer:

4) “Inferences to design do not require that we have a candidate for the role of designer.” (p. 196)

On the falsifiability of ID:

5) “Might there be an as-yet-undiscovered natural process that would explain biochemical complexity? No one would be foolish enough to categorically deny the possibility. Nonetheless, we can say that if there is such a process, no one has a clue how it would work. Further, it would go against all human experience, like postulating that a natural process might explain computers. Concluding that no such process exists is as scientifically sound as concluding that mental telepathy is not possible, or that the Loch Ness monster doesn’t exist. In the face of the massive evidence we do have for biochemical design, ignoring that evidence in the name of a phantom process would be to play the role of the detectives who ignore an elephant.” (p. 203-204)

On the testability of ID:

6) “Hypothesis, careful testing, replicability — all these have served science well. But how can an intelligent designer be tested? Can a designer be put in a test tube? No, of course not. But neither can extinct common ancestors be put in test tubes. The problem is that whenever science tries to explain a unique historical event, careful testing and replicability are by definition impossible. Science may be able to study the motion of modern comets, and test Newton’s laws of motion that describe how the comets move. But science will never be able to study the comet that putatively struck the earth many millions of years ago. Science can, however, observe the comet’s lingering effects on the modern earth. Similarly, science can see the effects that a designer has had on life.” (emphasis in the original) (p. 242-243)

12 Mar 2006

Intelligent Design: The Final Word, Part 1

I am finally ready to write some definitive thoughts about Intelligent Design. I just finished reading Michael Behe’s book Darwin’s Black Box from 1996, and I’ve thought about it from the perspective of science, falsifiability, religion, and philosophy. I would like to be very careful about where I plan and do not plan to take issue with him, so let me start in Part 1 by delineating the argument.

First of all, the eponymous designer of ID need not be divine, says Behe, and I agree completely. It could be an alien species, or something way beyond our understanding, but non-divine. ID is not inherently theological. So this discussion will have nothing whatsoever to do with God or religion. Religious folks may want ID to become a political movement so they can impose their views into everyone’s lives, but that is the problem of those religious folks, and does not bear on ID’s validity.

Secondly, I will not contest any of Behe’s descriptions of various biochemical systems. The cilium, blood clotting, etc., are all assumed to work the way he describes, including the “irreducible complexity” of these systems (more on that in later parts, of course).

We both agree, further, that the earth is 5 billion years old, that Darwinian evolution does in fact take place in many domains (including the descent of man from a common ancestor with apes, the origin of new species, all that good stuff). ID does not deny these things, so we needn’t discuss them.

We both reject the counterargument to ID that goes like this: If an intelligent designer designed our cilia, or our blood clotting system, or our eyes, then he could have made them more efficient/effective/symmetric/beautiful or whatever, and so they were not designed. This argument requires an understanding of the motivation of the designer, as well as a claim to completely understand all the tradeoffs involved in the functioning of these systems, which no one has. We will not be discussing this argument further.

Any new scientific theory will be treated with skepticism, and ID touches religious nerves which makes this an especially complicated issue to deal with. I am not going to make the mistake of dismissing ID based on my own concerns about the political ramifications, or the granting of power to religious interests. I am attempting to understand Behe’s arguments on his terms. I want to know whether ID can be a truly testable, falsifiable scientific theory that stands on its own. I want to understand this because if it passes this test, then I invite it to be taught in science classrooms. If it fails this test, then I will join the fight to keep it out of the science classroom, where it can do no good and can do quite a bit of harm.

A few further clarifications are in order. I am not making the assumption that science is a good system. I am not requiring you to agree that science enhances our sense of wonder and of the divine. I do not claim that scientists are automatically benevolent, or are smarter than anyone else. I am not claiming that scientists should be the sole trustees of ethical decisions concerning technology. I am not trying to pass a value judgment on science itself, in other words. I may do so in future writings, but I am leaving it out of the discussion of ID. I am only studying a very narrow question:

Given that science is the study of natural phenomena, where testable, falsifiable models (a.k.a. theories) are proposed and measured against nature through controlled experiments, is Michael Behe’s theory of Intelligent Design a scientific theory?