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- Posted: Sat, 22 Sep 2007 18:31:29 +0000
In recent years, one of the most popular arguments of the proponents of creationism (which includes the so called “Intelligent Design”) is that of “Irreducible Complexity” (IC). It’s creator (at least in its modern form) is Michael Behe, a biochemist at Lehigh University. Perhaps the most complete definition of IC was given by Behe’s colleague, William Dembski who defined it by saying
Since evolution relies on gradual changes that must be selected for, if an IC system were found, it would be inconceivable that such a complex system could be formed by evolution which cannot bridge that complexity gap.
Behe's classic example of this is the mousetrap. He claims that if any part is removed, the system can no longer catch mice and is thus, useless.
However, while Behe is the originator of the term “Irreducible Complexity”, the core of this argument can easily be traced back to at least 1802, to theologian William Paley. Paley’s form is known as the “watchmaker argument”. Essentially it says that if we observe a complex system with well matched parts (like a watch), we know by virtue of its complexity that it must have had a designer (ie, a watchmaker).
The purpose of this post is to demonstrate clearly why IC is an intellectually devoid argument.
The Short Story:
1. Irreducible Complexity fails because it relies on an argument from ignorance. In short, it says, “We don’t know how this formed, so it couldn’t have.”
2. It has no way to prove that a system cannot be formed through evolution (ie, you can’t prove a negative).
3. Since it cannot actually support its arguments, it merely claims systems to be IC without any evidence. Yet despite this, every system that Behe has claimed to be IC has been shown to indeed be reducible.
4. The form of IC that creationists (again, including ID proponents) use relies on a strawman of evolution.
5. There is no quantitative description of when something is or is not IC. This allows creationists to do what’s known as “moving the goalposts”.
6. Ultimately it relies on the "God of the Gaps" fallacy (which is intimately tied to the argument from ignorance).
The Long Story:
For those with a slightly longer attention span than the average ED'er, I'll address each one of these points in depth now. The first two should be pretty self explanatory, so there's not much more to say about them. They're logical fallacies. The end.
However, the third point can do with a good deal of explanation. While it's impossible to go through every biological system in existence and give a step by step process, we can hit a few of the highlights that are most often used by creationists.
The Eye
With this system, we often hear the canard of "What good is half an eye?" The answer can clearly be found in nature. Many organisms, such as the Planarium, have very limited sight which is little more than light detection. It allows the organism to detect which direction light is coming from, even if no clear image is formed. Thus, without even looking too hard, we see that we find reduced eyes in nature. In short, IC of the eye is entirely falsified (yet Behe still uses this example in his book Darwin's Black Box).
This is far less than "half an eye", but is still a huge advantage over creatures that are completely blind. Even looking at humans alone, it's clear that those with visual impairments are still far more able to perform normally (even without corrective measures) than one completely blind.
But while the development of the eye has been understood for a long time now, the principle which it demonstrates has been utterly lost on Creationists. This is wonderfully summed up in a quote from Science of Diskworld III: Darwin's Watch, which states:
Blood Clotting Cascade
The ability to allow blood to clot and thus stop small cuts from becoming lethal is vitally important to organisms. In humans and many other mammals, it involves a complex sequence of steps to achieve clotting.
However, if we look at other organisms, we can find blood clotting systems that are missing steps. The blood clotting system is thought to have developed in chordates far in the past. As this diagram shows, many have steps that can be omitted without the blood clotting system failing. Thus, IC of the blood clotting system is falsified.
But we can go even further. If Behe wishes to limit our search to mammals, we can see that blood clotting can still work without all its components. Specifically, species such as dolphins clot perfectly well without a component known as the Hagemann factor. This was discovered in 1969 by Robinson et al. Yet this did not stop Behe from claiming that the system was IC. Pufferfish and Zebrafish also lack several steps in the blood clotting cascade but are still able to clot. Again, claiming the blood clotting cascade is IC is completely incorrect.
The Bacterial Flagellum
This is the poster child of the modern form of IC. The flagellum is a whip like tail that bacteria use as propulsion. As with all other systems that creationists claim are IC, it is a complex network of interlocking parts.
However, it's been shown that removing several parts from the flagellum produces the Type III Secretory System (TTSS). The TTSS is a needle like device that bacteria use to inject victims.
The response from creationists is frequently that the flagellum must have originated first and the TTSS came later. "What good is a syringe if you can't go anywhere to stab someone with it?" they ask. However, common sense should tell you that most disease is transmitted by the victim providing the contact. Similarly, jellyfish have little self propelled motion and are primarily moved by tides. Yet they have stinging cells similar to the TTSS that allow them to capture food that wanders into them.
But the TTSS isn't the only step in the developmental chain that Behe implicitly ignores. In fact, a step by step evolutionary pathway has been worked out. I'll not go into the details here, but instead point to this summary from Nick Matzke who goes over it in great detail.
So again, IC fails and the objections are nonsense.
The Mouse Trap
OK. So it's not a biological system, but given that it's the prime example Behe uses, it's fair game. However, it can be broken down and still work. If even the examples fail, how can Behe ever hope to find a non-reducible system in nature!?
The next point I wished to make was that Irreducible Complexity creates an impossible challenge by relying on a straw man version of evolution. I didn't mention it before, because it fits better in this section, but Behe has another objection to the TTSS being a reducible form of the flagellum.
His argument is that biologists have not met the challenge he presents. Namely, the reduced system that we can demonstrate must have the same function. Thus, since the TTSS does not act as a means of propulsion, it's not a reducible form of the flagellum. It's a different system all together. This was the argument he presented at a lecture in December of 2006 at the University of Kansas Video here (Real Player required).
The problem with this is that Behe is demanding that the development of such systems be explained via evolution. But evolution doesn't work on one system at a time. It borrows bits and pieces from other systems, "junk" DNA, and any source it can get its hands on. Thus, Behe presents an impossible challenge. Essentially was he says is "Show how it's possible to create system X via evolution, without using evolution."
The entire proposition is nonsense.
The last point is that there is no quantitative description of how complete a developmental pathway need be to be IC. In other words, we can ask "How many steps do you need before you can accept that evolution is a sufficient mechanism?"
Creationists refuse to answer this question. This is very much the same problem that we face with the fossil record. Between every fossil we have, there is a "gap". If we fill that gap with a new fossil, then there are now two new gaps on either side of that fossil.
The same can be said for Irreducible Complexity. No matter how many steps we fill in, creationists can always claim that "it's not good enough" and that we need more. Thus, they can continually "move the goalpost" a little further so that it is impossible to ever reach a "acceptable" level of detail. Chief ID Creationism proponent William Dembski recently made this admission during a recent talk. In fact, as early as 2002, Dembski made the admission that Intelligent Design has no interest in actually providing mechanisms. In one of the forums Dembski moderates, he admits that:
In other words, ID does not need to actually provide anything. It merely needs to rely on the god of the gaps argument I've already discussed.
Similarly, even if we do provide sufficient detail for most people, they can always move the goalpost in another way: To a different field. There are so many biological systems that if they fail on one, they can simply pull another system out of the hat and claim it to be IC.
At what point have we shown that evolution is sufficient for enough systems that we can confidently say that it is sufficient for all systems in the same way we can confidently say that we've demonstrated gravity well enough in our solar system that we can apply it to different galaxies? An honest scientist would say that, without reasonable cause, it's perfectly fine to extend an explanation that works well to a wide variety of similar situations.
But creationists reject this because it's convenient for their purposes. Instead, they insist that anything unexplained is a result of supernatural creation. This is the "God of the Gaps" fallacy. So yet again, IC is not a valid argument.
If you made it all the way to the end of this post, congratulations. As a reminder, what I've demonstrated is that the notion of Irreducible Complexity is a poor argument because it relies on several logical fallacies, and fails to make any testable predictions since you cannot prove a negative. Every claim it has made (even it's posterchild and prime example) have been shown to be reducible. Thus, the argument of Irreducible Complexity should not be used.
Further reading:
Evidence & Testing in the Scientific Field
Evolution, Entropy, the Big Bang, and the Second Law
Is Intelligent Design Different that Creationism?
Why are ID Proponents/Creationists intellectually dishonest?
Evolution - What it is and isn’t
Evolution and its Compatibility with Creationism
Expelled: No Intelligence Allowed (An ID Propaganda Film)
Updates:
9/23/07 - Added link to ERV blog re: Dembski's refusal to accept sufficient evidence.
10/11/07 - Replaced previous link to one involving transcript and added another re: Dembski admitting that IC is not a positive argument, but rather an argument from ignorance.
10/21/07 - Added quote from Science of Diskworld III: Darwin's Watch
12/26/07 - Added additional link to Further Reading section: Why are ID Proponents/Creationists intellectually dishonest?
4/15/08 - Added link to Expelled: No Intelligence Allowed (An ID Propaganda Film).
6/13/08 - Added further link on development of Bacterial Flagellum.
William Dembski
A system performing a given basic function is irreducibly complex if it includes a set of well-matched, mutually interacting, nonarbitrarily individuated parts such that each part in the set is indispensable to maintaining the system's basic, and therefore original, function. The set of these indispensable parts is known as the irreducible core of the system.
Behe's classic example of this is the mousetrap. He claims that if any part is removed, the system can no longer catch mice and is thus, useless.
However, while Behe is the originator of the term “Irreducible Complexity”, the core of this argument can easily be traced back to at least 1802, to theologian William Paley. Paley’s form is known as the “watchmaker argument”. Essentially it says that if we observe a complex system with well matched parts (like a watch), we know by virtue of its complexity that it must have had a designer (ie, a watchmaker).
The purpose of this post is to demonstrate clearly why IC is an intellectually devoid argument.
The Short Story:
1. Irreducible Complexity fails because it relies on an argument from ignorance. In short, it says, “We don’t know how this formed, so it couldn’t have.”
2. It has no way to prove that a system cannot be formed through evolution (ie, you can’t prove a negative).
3. Since it cannot actually support its arguments, it merely claims systems to be IC without any evidence. Yet despite this, every system that Behe has claimed to be IC has been shown to indeed be reducible.
4. The form of IC that creationists (again, including ID proponents) use relies on a strawman of evolution.
5. There is no quantitative description of when something is or is not IC. This allows creationists to do what’s known as “moving the goalposts”.
6. Ultimately it relies on the "God of the Gaps" fallacy (which is intimately tied to the argument from ignorance).
The Long Story:
For those with a slightly longer attention span than the average ED'er, I'll address each one of these points in depth now. The first two should be pretty self explanatory, so there's not much more to say about them. They're logical fallacies. The end.
However, the third point can do with a good deal of explanation. While it's impossible to go through every biological system in existence and give a step by step process, we can hit a few of the highlights that are most often used by creationists.
The Eye
With this system, we often hear the canard of "What good is half an eye?" The answer can clearly be found in nature. Many organisms, such as the Planarium, have very limited sight which is little more than light detection. It allows the organism to detect which direction light is coming from, even if no clear image is formed. Thus, without even looking too hard, we see that we find reduced eyes in nature. In short, IC of the eye is entirely falsified (yet Behe still uses this example in his book Darwin's Black Box).
This is far less than "half an eye", but is still a huge advantage over creatures that are completely blind. Even looking at humans alone, it's clear that those with visual impairments are still far more able to perform normally (even without corrective measures) than one completely blind.
But while the development of the eye has been understood for a long time now, the principle which it demonstrates has been utterly lost on Creationists. This is wonderfully summed up in a quote from Science of Diskworld III: Darwin's Watch, which states:
Science of Diskworld III: Darwin's Watch
Yes, the proponents of intelligent design understand the eye . . . but as only one example, not as the basis of a general principle. ‘Oh yes, we know all about the eye,’ they say (we paraphrase). ‘We’re not going to ask you what use half an eye is. That’s simple-minded nonsense.’ So instead, they ask what use half a bacterial flagellum is, and thereby repeat the identical error in a different context.
Blood Clotting Cascade
The ability to allow blood to clot and thus stop small cuts from becoming lethal is vitally important to organisms. In humans and many other mammals, it involves a complex sequence of steps to achieve clotting.
However, if we look at other organisms, we can find blood clotting systems that are missing steps. The blood clotting system is thought to have developed in chordates far in the past. As this diagram shows, many have steps that can be omitted without the blood clotting system failing. Thus, IC of the blood clotting system is falsified.
But we can go even further. If Behe wishes to limit our search to mammals, we can see that blood clotting can still work without all its components. Specifically, species such as dolphins clot perfectly well without a component known as the Hagemann factor. This was discovered in 1969 by Robinson et al. Yet this did not stop Behe from claiming that the system was IC. Pufferfish and Zebrafish also lack several steps in the blood clotting cascade but are still able to clot. Again, claiming the blood clotting cascade is IC is completely incorrect.
The Bacterial Flagellum
This is the poster child of the modern form of IC. The flagellum is a whip like tail that bacteria use as propulsion. As with all other systems that creationists claim are IC, it is a complex network of interlocking parts.
However, it's been shown that removing several parts from the flagellum produces the Type III Secretory System (TTSS). The TTSS is a needle like device that bacteria use to inject victims.
The response from creationists is frequently that the flagellum must have originated first and the TTSS came later. "What good is a syringe if you can't go anywhere to stab someone with it?" they ask. However, common sense should tell you that most disease is transmitted by the victim providing the contact. Similarly, jellyfish have little self propelled motion and are primarily moved by tides. Yet they have stinging cells similar to the TTSS that allow them to capture food that wanders into them.
But the TTSS isn't the only step in the developmental chain that Behe implicitly ignores. In fact, a step by step evolutionary pathway has been worked out. I'll not go into the details here, but instead point to this summary from Nick Matzke who goes over it in great detail.
So again, IC fails and the objections are nonsense.
The Mouse Trap
OK. So it's not a biological system, but given that it's the prime example Behe uses, it's fair game. However, it can be broken down and still work. If even the examples fail, how can Behe ever hope to find a non-reducible system in nature!?
The next point I wished to make was that Irreducible Complexity creates an impossible challenge by relying on a straw man version of evolution. I didn't mention it before, because it fits better in this section, but Behe has another objection to the TTSS being a reducible form of the flagellum.
His argument is that biologists have not met the challenge he presents. Namely, the reduced system that we can demonstrate must have the same function. Thus, since the TTSS does not act as a means of propulsion, it's not a reducible form of the flagellum. It's a different system all together. This was the argument he presented at a lecture in December of 2006 at the University of Kansas Video here (Real Player required).
The problem with this is that Behe is demanding that the development of such systems be explained via evolution. But evolution doesn't work on one system at a time. It borrows bits and pieces from other systems, "junk" DNA, and any source it can get its hands on. Thus, Behe presents an impossible challenge. Essentially was he says is "Show how it's possible to create system X via evolution, without using evolution."
The entire proposition is nonsense.
The last point is that there is no quantitative description of how complete a developmental pathway need be to be IC. In other words, we can ask "How many steps do you need before you can accept that evolution is a sufficient mechanism?"
Creationists refuse to answer this question. This is very much the same problem that we face with the fossil record. Between every fossil we have, there is a "gap". If we fill that gap with a new fossil, then there are now two new gaps on either side of that fossil.
The same can be said for Irreducible Complexity. No matter how many steps we fill in, creationists can always claim that "it's not good enough" and that we need more. Thus, they can continually "move the goalpost" a little further so that it is impossible to ever reach a "acceptable" level of detail. Chief ID Creationism proponent William Dembski recently made this admission during a recent talk. In fact, as early as 2002, Dembski made the admission that Intelligent Design has no interest in actually providing mechanisms. In one of the forums Dembski moderates, he admits that:
William Dembski
ID is not a mechanistic theory, and it’s not ID’s task to match your pathetic level of detail in telling mechanistic stories.
Similarly, even if we do provide sufficient detail for most people, they can always move the goalpost in another way: To a different field. There are so many biological systems that if they fail on one, they can simply pull another system out of the hat and claim it to be IC.
At what point have we shown that evolution is sufficient for enough systems that we can confidently say that it is sufficient for all systems in the same way we can confidently say that we've demonstrated gravity well enough in our solar system that we can apply it to different galaxies? An honest scientist would say that, without reasonable cause, it's perfectly fine to extend an explanation that works well to a wide variety of similar situations.
But creationists reject this because it's convenient for their purposes. Instead, they insist that anything unexplained is a result of supernatural creation. This is the "God of the Gaps" fallacy. So yet again, IC is not a valid argument.
If you made it all the way to the end of this post, congratulations. As a reminder, what I've demonstrated is that the notion of Irreducible Complexity is a poor argument because it relies on several logical fallacies, and fails to make any testable predictions since you cannot prove a negative. Every claim it has made (even it's posterchild and prime example) have been shown to be reducible. Thus, the argument of Irreducible Complexity should not be used.
Further reading:
Evidence & Testing in the Scientific Field
Evolution, Entropy, the Big Bang, and the Second Law
Is Intelligent Design Different that Creationism?
Why are ID Proponents/Creationists intellectually dishonest?
Evolution - What it is and isn’t
Evolution and its Compatibility with Creationism
Expelled: No Intelligence Allowed (An ID Propaganda Film)
Updates:
9/23/07 - Added link to ERV blog re: Dembski's refusal to accept sufficient evidence.
10/11/07 - Replaced previous link to one involving transcript and added another re: Dembski admitting that IC is not a positive argument, but rather an argument from ignorance.
10/21/07 - Added quote from Science of Diskworld III: Darwin's Watch
12/26/07 - Added additional link to Further Reading section: Why are ID Proponents/Creationists intellectually dishonest?
4/15/08 - Added link to Expelled: No Intelligence Allowed (An ID Propaganda Film).
6/13/08 - Added further link on development of Bacterial Flagellum.
