The Instigator
Pro (for)
4 Points
The Contender
Con (against)
15 Points

Evolution cannot account for irreducible complexity

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Post Voting Period
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Voting Style: Open Point System: 7 Point
Started: 11/9/2012 Category: Science
Updated: 4 years ago Status: Post Voting Period
Viewed: 6,313 times Debate No: 27046
Debate Rounds (5)
Comments (27)
Votes (6)




Here I will give GreenTeas a chance to restate his accusations as found in

Irreducible complexity: The theory that if a part of an apparatus, such as a mouse trap, is removed, the whole apparatus loses its ability to perform that function. Also see for a more comprehensive explanation:

Evolution: Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift that results in the formation of all living species from single celled organisms due to the increase in genetic information resulting in new genes.

Specifically, GreenTeas must show how irreducible complexity is explainable by evolution

I must show how irreducible complexity is inexplicable by evolution

Both debaters must show their case to be within the bounds of reasonable probability.

1. BoP is shared
2. No trolling/vulgarities
3. No plagiarism
4. All sources must be cited in the comments section
5. No arguments in the comment section

Debate structure
1. Acceptance
2. Opening statements
3-4. Arguments and rebuttels
5. Closing statement. No more than 1.5k characters


I would like to thank Muted for his challenge. I look forward to an interesting debate.

As CON, I will be arguing that evolution can explain irreducibly complexity. My opponent, as PRO, will be arguing that evolution cannot explain irreducible complexity.

Debate Round No. 1


Firstly, I would like to thank GreenTeas for accepting.

Now I will go into my arguments without further ado.

I will use two examples of irreducible complexity and show that evolution cannot account for these.

The Blood clotting cascade system [1][2]
There are three "prongs" to the blood clotting cascade: two pathways which initiate the cascade (the extrinsic and intrinsic pathways) and the cascade itself, which forms the clot.
This argument is only about the cascade itself, not the initiating portions.
"Leaving aside the system before the fork in the pathway, where some details are less well known, the blood-clotting system fits the definition of irreducible complexity." (Behe)
I will here list a short version of the clotting system. [3] 1. Formation of Prothrombinase, 2. Prothrombin converted into the enzyme Thrombin, 3. Fibrinogen (soluble) converted to Fibrin (insoluble)
The first step is not part of the irreducible system. I will now write a more technical version of this. [4]
The sequence is triggered off by a reaction involving XII which then reacts with factor XI, converting it to an active XIa, activating factor IX in turn.
In the presence of calcium ions IX reacts with factor VIII and phospholipids released from platelets to form a complex which converts factor X to the active Xa. Xa then reacts with factor V, platelet phospholipids and calcium ions to form a complex which converts prothrombin to thrombin.
This enzyme converts fibrinogen to fibrin monomer by splitting two small polypeptides from the molecule and the fibrin monomer then polymerizes to form a fibrin clot. This is rendered more stable and urea insoluble by factor XIII following its activation by thrombin.
The first traces of thrombin potentiate factors V and VIII which are destroyed as the level of thrombin increases. Clotting is now decelerated and the thrombin already formed is neutralized by antithrombin.
In the presence of tissue juices the above pathway (Intrinsic system) is short-circuited; a protein factor and certain phospholipids in the tissue react with VII in the presence of calcium to activate X directly. The subsequent events in this (Extrinsic system) is the same as the intrinsic system.

If at any point in time the cascade lacks a step, no clotting is performed. Not even in mice. That is not even intermediate.
Alone, these clotting components would have no selective priority and thus evolution would not be able to select for them. In fact, evolution would select against these, because they are unnecessary and useless, like "vestigial organs".

Bacteria flagellum [5][6]
I have included [5] for general reading. I will quote from [6].
"Some bacteria boast a marvelous swimming device, the flagellum, which has no counterpart in more complex cells. In 1973 it was discovered that some bacteria swim by rotating their flagella. So the bacterial flagellum acts as a rotary propellor -- in contrast to the cilium, which acts more like an oar.
The structure of a flagellum is quite different from that of a cilium. The flagellum is a long, hairlike filament embedded in the cell membrane. The external filament consists of a single type of protein, called "flagellin." The flagellin filament is the paddle surface that contacts the the liquid during swimming. At the end of the flagellin filament near the surface of the cell, there is a bulge in the thickness of the flagellum. It is here that the filament attaches to the rotor drive. The attachment material is comprised of something called "hook protein." The filament of a bacterial flagellum, unlike a cilium, contains no motor protein; if it is broken off, the filament just floats stiffly in the water. Therefore the motor that rotates the filament-propellor must be located somewhere else. Experiments have demonstrated that it is located at the base of the flagellum, where electron microscopy shows several ring structures occur. The rotary nature of the flagellum has clear, unavoidable consequences ..." (Behe)

"The consequences...[referred] to are inferred by the nature of its irreducibly complex components, the discovery of which undermines a Darwinian explanation of origins." (ARN)

"In summary, as biochemists have begun to examine apparently simple structures like cilia and flagella, they have discovered staggering complexity, with dozens or even hundreds of precisely tailored parts. It is very likely that many of the parts we have not considered here are required for any cilium to function in a cell. As the number of required parts increases, the difficulty of gradually putting the system together skyrockets, and the likelihood of indirect scenarios plummets. Darwin looks more and more forlorn. New research on the roles of the auxiliary proteins cannot simplify the irreducibly complex system The intransigence of the problem cannot be alleviated; it will only get worse. Darwinian theory has given no explanation for the cilium or flagellum. The overwhelming complexity of the swimming systems push us to think it may never give an explanation." (Behe)

The same observation in regard to the blood clotting cascade system applies here.

I will now state, clearly, that Michael Behe is no young-earth creationist. He agrees with evolution by common descent.

One cannot say there are other purposes for these components because quite simply there are not any others. (I typed this out except for the quotes from [6], by the way.)


Even though my opponent has not technically plagiarized, his entire argument against bacterial flagella – over 2200 characters – is just a series of quotes from two papers. I would ask that he please state his arguments in his own words, rather than pulling an entire argument from another paper and dropping it into the debate. I believe it is poor conduct.

Per the rules, I will not directly rebut my opponent this round.


Michael Behe, intelligent design advocate, defines irreducible complexity (IC) as “a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.”[1]

Can evolution explain IC systems? Even Behe states that “demonstrating that a system is irreducibly complex is not proof that there is absolutely no gradual route to its production. Although an irreducibly complex system can’t be produced directly, one can’t definitively rule out the possibility of an indirect circuitous route.” [2]

Fortunately, evolution works in indirect, circuitous routes that can lead to IC systems. It is not linear. It moves forward, back, and sideways. Evolution is known to alter biological systems by adding, removing, and modifying parts.[3][4][5]

IC systems were explained by evolutionary scientists as early as 1918.[4] H. J. Muller correctly pointed out that to create an IC system, you simply need to (1) add a part, and (2) make that part necessary for the system to function. After this, removal of that part will destroy the function. This is called the “Muller Two-Step,” more on this later.

The following section will show how these evolutionary principles of adding, removing, and modifying parts can lead to IC systems.

Evolutionary theory EXPLAINS the development of IC systems

1. Evolution of IC systems can occur through scaffolding

Scaffolding of parts is one evolutionary mechanism through which IC systems can be created. [6][7][8]

For clarity, I will explain this process through analogy. Consider the example of a bridge.[See diagram]

Imagine we have a precursor bridge of three parts. Two of these parts could be removed and the bridge would still function. This is NOT irreducibly complex because the function of the bridge can remain after removal of two of the parts. Now, let’s follow the Muller Two-Step for the evolutionary explanation of IC systems, we first (1) add a part and then (2) make that part necessary.

STEP ONE: evolution adds a part, a top stone. This part, part D, is functionally redundant to part B. Functional redundancy is commonly observed in evolution.[9] Next, STEP TWO: evolution makes that part necessary by removing the middle stone. We now have an IC system because none of the remaining three stones can be removed without losing the bridge’s function. Thus, evolutionary principles explain how an IC system can develop through a non-linear manner by adding and removing parts.

2. Evolution of IC systems can occur through incremental addition

The process of addition and modification of parts by evolution explains that IC systems can evolve when the interaction of components within a system goes from being merely “beneficial” to becoming “necessary”.[10][11]

Consider the following diagram, we have part A that performs an enzymatic function. Part A interacts with Part B. Part B is helpful in enhancing Part A’s function but is not necessary – such as through structural stabilization of Part A. There are many examples of molecules whose function is enhanced in the presence of another molecule[12][13] Part A and B are not irreducibly complex at this point.

Now, a mutation may occur in part A that causes it catalyze reactions faster – a good thing that improves survival – but that mutation might also cause it to destabilize in the absence of Part B, making B a necessary component of the system. Thus, in order for this system to perform its function, both parts are now required, and neither part can be removed without destroying function. It is therefore an IC system. Thus, evolution can explain the development of IC systems through the addition and modification of parts. An example of this process can be found here.[14]

3. Evolution of IC systems can occur through co-option

Evolution of IC systems can also occur through a process known as co-option. Through this process, new functions arise from existing systems, and it is not necessary for a new system to evolve in total.

Consider the following example of pentachlorophenol (PCP) metabolism by S. chlorophenolica.[15] PCP is a synthetic, highly toxic compound that was created by humans and used as a wood preservative since the 1930s.

After exposure to this chemical for 80 years, one species of bacteria evolved a biochemical system that is capable of breaking down this toxic compound. This system is composed of three parts, each of which is completely necessary for the breakdown of PCP into a non-toxic product.[15] Scientists found that the bacteria, through mutation and natural selection, took a previous biochemical system, modified the parts by mutation and added one new part by gene duplication to create this IC system.[15]

Thus, we have evidence of an IC system – that metabolizes a synthetic human-made compound – evolving in the last 80 years through the process of co-option.

Commonly referenced IC Systems (and why they might not even be IC)

Based on my previous sections, it should be clear to you now that evolution does explain the existence of IC systems. Thus, it does not matter whether the following systems are irreducibly complex or not, because evolution provides plausible explanations for their development. But I will point out their problems in any case.

1. Bacterial Flagellum

The bacterial flagellum is commonly cited as an irreducibly complex system. This assertion was made before recent studies that show the flagellum is not irreducible.

Parts of the flagellum can be removed and it will retain its function.[16][17] In 2010, two research groups independently removed two proteins – named Flil and FliH – from the bacterial flagella and found that it functioned even without these two proteins.[16][17] Thus, the bacterial flagellum is not irreducibly complex because its function does not cease when parts are removed. It demonstrably fails to meet the definition of IC.

*Detailed evolutionary explanations for the flagellum exist, and I may describe them in the next round.

2. Vertebrate Clotting System

The vertebrate clotting system is also claimed to be irreducibly complex. The jury is out on this issue, because no one has removed all the various components and determined function. There is reason to think it may not be IC, because it has been shown that at least two parts of the clotting system can be removed in mice and the system will still function.[18] Admittedly, the function is worse, wound-healing is worse, and the mice are more susceptible to certain ailments over their lifetime, but nonetheless it shows that the system can still perform its clotting functions without certain parts.

*Detailed evolutionary explanations for the clotting system exist, and I may describe them in the next round.


I have shown that three different evolutionary pathways: (1) scaffolding; (2) incremental addition; and (3) co-option are processes that have been observed by scientists and that such processes CAN EXPLAIN the development of irreducibly complex systems.

The notion of irreducible complexity fails because it demands that we work backwards from an existing system. Working backwards requires the incorrect assumption that evolution occurs by linear, gradual additions. We know, however, that evolution not only adds parts to systems, but can remove them, or cause them to change function. Thus, irreducibly complex systems can be explained by evolutionary theory.


In comments.

Debate Round No. 2


Plagiarism is masquerading another"s work as one"s own. Be sparse with that word.

I agree absolutely when you state "Evolution is known to alter biological systems by adding, removing, and modifying parts." I will clarify later why it does not apply to IC systems. And you left out one part. Selective pressure, which I will clarify later.

I will defend my examples first.

The argument for IC in blood clotting systems only work after the fork (Of the intrinsic, and extrinsic pathways), like I mentioned in the previous round.

The example of the mice fails because not only is there NO FUNCTIONAL clotting system in those mice, your source is also contradictory to your statements. The mice has lost two portions of the system and is thus able to survive. The loss of one of those parts results in "high mortality, wasting, spontaneous gastrointestinal ulceration, rectal prolapse, and severe thrombosis." To quote from your source. The loss of the second part reverses that trend but do not give back any clotting ability. Please do not misrepresent your sources as I regard Cell highly and they certainly published no such thing. [1]

As to bacteria flagellum, I am unable to find your [17], could you give a link to somewhere online? Here are the entries for the proteins you are talking about. [2][3] Quite simply, you have not responded to my arguments. From the sources, these are the functions of the proteins.
Flil-Probable catalytic subunit of a protein translocase for flagellum-specific export, or a proton translocase involved in local circuits at the flagellum. May be involved in a specialized protein export pathway that proceeds without signal peptide cleavage. [2] [4]
FliH-Needed for flagellar regrowth and assembly [3]

The Flil is not physically part of the flagellum, and thus cannot be used to rebut an argument about its IC. The FliH is only needed for regrowth and assembly. Certainly a fully grown flagellum would not need it any longer unless it is damaged. Therefore it cannot be used against IC unless you can show that flagellum can grow without it. If I am wrong about this please correct me.

Your [16] talks about function of the export process without these proteins, not the IC portion of the flagellum, which I have made clear in R2.

I would encourage you to post a detailed evolutionary synopsis.

You have proposed three solutions by which IC systems can arise. I will deal with each in turn. However, I will first address a common problem facing the first two.
All evolutionary changes function by selective pressure [5][6]. The lack of even one of the parts (In all your examples) means that there is no selective pressure FOR the changes. In fact, there will be a selective pressure AGAINST! I will explain following.

Argument from scaffolding (Your [7] does not work).
[7] Of all your sources, only [6] is relevant even though it still has a fatal flaw. (You don"t have to cite sources to try to win the source vote. Better quality sources is all that is needed.)
I will only rebut your analogy, since you have not provided a biological example. In the first diagram, there is already a function. The addition of D and the removal of B has no selective pressure because there is no benefit that would help the organism survive! In fact, the organism would require more energy to produce D and would be overwhelmed by competition from its more "normal" neighbors who would not have such a disadvantage. Thus, this argument cannot be used in any form due to its contradicting the theory of selective pressure (for which there is much evidence, unlike the scaffolding hypothesis)

Argument from incremental addition.
Your [10] is a duplicate of your [6]. You just needed to have written "10. Ref. 6." Your [11] is a repeat of [7], and is a 404 error. [8] I have placed a link to your [12] in my [9], and a link to [13] in my [10]. [11].
Now that the sources is cleared up, I will respond to the argument. Your example has internal biological errors. Firstly, increased catalysing speed is NOT beneficial. Furthermore, there are already examples of enzyme inhibition. [12] Inhibitors are analogous to your analogy"s part B. We know that inhibitors can be removed, so this is not a IC system.
Secondly, parts do not just pop up to solve problems. Let me give an illustration of how difficult it is to create a part.

[See 13, 14]. Let us assume
1. That nucleobases spontaneously generate and appear whenever we want them to.
2. That there is a perfectly random choice of nucleobases.
3. Each base has an equal probability to the other.
4. The gene length for part B is 1500 bp, half the average gene length.

Now there are four bases, Therefore, each base would have a 1/4 probability. We know from drawing a probability tree that the probability of this gene occurring is (1/4)^1500, which is incalculable with normal computer calculations. The base is way over an octodecillion. This, in human terms, is impossible.

In addition to all of the above objections, any mutation in an enzyme would denature it [15]. This is because enzymes are highly specific and does not allow for modifications.

Argument from co-option.
Once again, there is problems with your arguments and your source. I have included a link to your [15] in my [16].
Your argument is that S. chlorophenolica PCP metabolism is a IC system. This is your argument, not mine, or anyone"s else, including the article"s. The article talks about the evolution of the organism to metabolize PCP. You have extrapolated this and claim that it is an IC system. It is not! This organism shows that it is able to adapt under selective pressure, but it is not an example of an IC system.

In conclusion, two of your hypothesis cannot work, and one is not an example of an IC system. Your objections to my examples of an IC system has been responded to. Lastly, you have badly used your sources, something I request you refrain from doing in the future. It is perfectly fine to cite an inordinate amount of sources, as certainly I will go through them, and hopefully learn something. However, it is not alright to cite something that has no bearing on your arguments.

Now back to you.


My opponent is engaging in what is known as the “Gish Gallop,” wherein he makes a large number of untrue claims and half-truths and leaves me with the job of fixing them. This gives me less time and space to provide my own arguments, and allows my opponent to create the false illusion of challenging my existing arguments. I encourage the reader to recognize this as they read through.


1. The Vertebrate Blood Clotting System Is Not Irreducibly Complex

My opponent is wrong about everything he said in the previous round on this topic. He either chose not to read the study I cited, or he has chosen to mislead the readers. If he didn’t have access to the study, he could have told me.

The study I cited shows that REMOVAL OF TWO PARTS of the clotting system in mice, fibrinogen and plasminogen, leaves those mice in “good health” with “remarkably strong growth and survival characteristics.” [1] Moreover, the study shows that these mice – with two parts of the clotting system removed – had wound healing rates that were identical to normal mice.[1]

My opponent claims the mice had “high mortality, wasting, etc.” and “NO FUNCTIONAL clotting system.” He is wrong. Read the study. Mice that had ONE PART REMOVED had this problem, but mice that had TWO PARTS REMOVED from the clotting system were healthy and the clotting system functioned.[1] Thus, the system is NOT irreducible.

If my opponent isn’t going to read the study, then he might as well not provide a response to my argument.

2. The Bacterial Flagellum Is Not Irreducibly Complex

In the previous round, I noted that the flagellar system is not irreducibly complex. I showed that researchers recently discovered two proteins – FliH and FliI – can be removed from the flagellar system and it will still function.[2] These proteins are involved in the assembly of the flagellar structure, protein transport, and penetration of the flagella into the cell membrane.[2]

My opponent claims that proteins involved in assembly, transport, and penetration of the flagella into the membrane are not part of the flagellar system. This is convenient for him, because it allows him to continue claiming the system is irreducible.

But, in 2006, Behe, the creator of irreducible complexity, said himself that the flagellar system “requires about forty proteins for function. [T]hey include … proteins to allow the flagellum to penetrate the cell membrane and wall; [and] proteins to assist in the assembly of the structure.” [3]

In 2004, Behe stated “the bacterial flagellum is an even more sophisticated system than had been thought. Not only does it act as a rotary propulsion device, it also contains within itself an elegant mechanism to transport the proteins that make up the outer portion of the machine, from the inside of the cell to the outside.”[4]

He clearly states that assembly, transport, and penetration of the flagellum are components of the flagellar system. Notice also that his descriptions came before scientists discovered that these proteins weren’t required for the flagellum to function.

My opponent is now attempting to shrink the scope of this system so that he can continue to claim it is irreducibly complex. He is not making an argument. He is simply moving the goal posts because the evidence does not support his view.


1. Evolution by scaffolding can explain IC Systems

Regarding my diagram, my opponent says “the addition of D and the removal of B has no selective pressure because there is no benefit that would help that organism survive.” My opponent is wrong that there is no benefit.

Notice also that he does not deny that if there were selective pressures, that an IC system would be created.

I will now clarify why my opponent is wrong about there being no beneficial advantages and that there are indeed selective pressures.

He is correct that both Part D and Part B serve the same function, and this is known as functional redundancy. Functional redundancy itself can be a benefit.[5] It makes the system more robust because if one piece fails, the system will still work. Having both pieces is beneficial because it reduces the likelihood of system failure. This is why elevators have emergency brakes and parachutes have backups. My opponent ignores this possibility.

If the selective pressures against the organism changes, functional redundancy might no longer provide a survival benefit. If this happened, the extra use of resources by the cell to make both of these two parts could become harmful. As a result, Part B could then be removed by natural selection, as the diagram shows.

Additionally, my opponent ignores that Part D might be better than Part B. Part D may allow for a “sturdier” bridge than Part B, even though they both perform the same function. Thus, the addition of Part D would be beneficial because the bridge is better. And, because Part B would no longer be necessary, the removal of Part B would be beneficial and selected for. My opponent ignored this possibility as well.

My opponent does not deny that, if selective pressures existed, this process could lead to IC systems. I have shown that selective pressures could easily exist. Therefore, evolutionary scaffolding continues to explain how IC systems can be created.

2. Evolution by incremental addition can explain IC systems

Regarding incremental addition, my opponent claims “increased catalyzing speed is NOT beneficial.” Notice he has no source. It’s because he’s wrong.

Increasing catalytic activity could be evolutionarily beneficial. This is because it would improve the rate or efficiency at which new or existing enzymatic pathways work, and indeed there is evidence to support this idea.[6][7][8] For example, if a cell is exposed to toxic compounds, natural selection might select for enzymes that can remove these compounds faster. My opponent’s argument that increasing enzyme catalysis couldn’t be beneficial, and that this somehow refutes incremental addition, clearly fails.

That is not to say that increased catalytic activity couldn’t be harmful, it simply depends on the environment of the organism. In other environments, a high rate of catalysis might not be as important or could be harmful.

My opponent then makes a ridiculous strawman argument about creating parts that has nothing to do with the mechanism of evolution that I described. I won’t waste my time responding to it.

My opponent has offered no substantive rebuttal to the evolutionary mechanism of incremental addition. My claim that evolution through incremental addition explains IC systems is still supported by clear evidence and remains unchallenged.

3. Evolution by co-option can explain IC systems

My opponent also claims that the PCP system is not IC because the study doesn’t contain the words “irreducibly complex.”

The paper DOES say that all three parts of the system are required to perform its function of metabolizing PCP.[9] If any part is removed, the system is unable to perform its function and cannot convert the toxic compound of PCP into a non-toxic product.[9] This is quite literally the definition of IC.

My opponent may claim that the paper doesn’t use the language “irreducibly complex,” by why would it? The notion of “irreducible complexity” exists almost exclusively in the realm of creationism and few scientists would waste their alotted article space by addressing this fringe idea.

The system fits the definition of irreducible complexity, and we have evidence it evolved. This is all we need to know.


My opponent has not offered any logical or factual challenges against my claims that evolution can explain irreducible complexity. I provided three evolutionary mechanisms that explain the process of evolution creating IC systems, and he has failed to challenge them.

Further, my opponent has completely lied to or misled readers about the vertebrate clotting system, and has attempted the change the definition of the flagellar system.

Debate Round No. 3


Once again I have to defend myself against petty allegations.
A Gish Gallop? Well, I have responded to exactly five arguments, two of my own, and three of GreenTeas. How could this create any illusion at all? I am trying to understand how IC systems can be evolved, and you"re trying to denigrate me. He claims I have provided no "logical or factual" responses. He also claims that I have "completely lied or misled readers." I encourage readers to check out our sources to collaborate this claims. [1]

I will now defend my arguments.

A. Bacteria Flagellum
I now will defend my arguments. As in the blood clotting arguments, there is a certain limit to where the IC system goes. This is not "moving the goalposts" or any such contrivance. It is simple science. He quotes Behe"s summary of the function of the system, but does not note that this was not even part of the original proposed IC system! [2] As I said in the previous rounds, and as the source clearly testifies, the IC portion of the flagellum was noted WAY before the source came out. The studies did not in any way show that it was not IC. This is thus not shifting the goalposts. [3]

I will allege here that you are using a straw man! [4] What is a straw man? A straw man is an argument that refutes something that looks like mine, but is not.

Furthermore, I will allege that you have misrepresented Behe on the topic of bacteria flagellum. Your source 4 is a refutation of Miller, not an argument for an IC system! It notes the increasing knowledge of complexity, which is not necessarily IC, and you use it in support of your contentions!

B. Blood Clotting Cascade
The fact that you are unable to cite a particular sentence showing it still has a functional blood clotting system is remarkable! I read the study too, and find it, I did not! [5] The study uses the word "clotting" twice, both in reference to its lack! It states, "the absence of Fib restores the overall rate of wound healing in Plg−/− mice to normal."

Let me make a memorable statement. Wound healing =/= Blood Clotting.
Your whole contention rests on that.
In fact, you are trying to use a source that does not support you to support you.

I. Evolution by scaffolding
GreenTeas has emphatically asserted that I am wrong that there is no benefit. What proof is there? None at all! Bare assertions does not convince me.
You claim that B and D potentially have benefit. There is no evidence of this here. You claim that redundant phenotypes have benefit, and link to something on genetic redundancy! They are generally related, but in this case, they could not be more different. Furthermore, you have failed even to acknowledge my arguments against redundancy benefit.

You use the example of backup to support your arguments. Evolution does not allow for this. It is the survival of the strongest, and the death of the weakest. I have not at all ignored this possibility.
The energy used to create these parts would mean these organisms would lose out against their "normal" relatives. Note that your arguments does not refute mine. Also note that evolution does not take roundabout paths. It takes the most direct path. Thus, there would be parts A, C, and D from the start, but no B. Unless it is A, B, and C. This, as you have mentioned, is not as good as the former, and it would lose out.
Notice, however, that the A-C-D combination is not in any way "sturdier." That is an illusion granted by the drawing. [6]
Your argument is based on superfluity and evolution DOES NOT allow for that. Selective pressure ALWAYS exist. I have shown that selective pressure is AGAINST this phenotype. NOT for.

II. Evolution by addition
I did not cite that statement, not because I was wrong, but because I thought you knew about it already. [7] It was my assumption that you knew about enzymic activity. I was wrong.
It is a well known fact that the rate of reaction is changed by the enzyme concentration (I assume you speak of enzymes because you said "catalyze") and substrate concentration [8]. I have already cited denaturation.

Increased catalytic speed may be harmful, hence the large amount of regulatory DNA [9].

You have called my argument about the improbability of new phenotype formation a "straw man." Yet you have not provided any indication that B is not new. Furthermore, I have mentioned something that performed the function of B, the inhibitor, which I have cited. As I have shown, enzyme-inhibitor complexes are not IC systems and you cannot use them as such!
You have not responded or even acknowledged the substance of my rebuttals. From one statement, you have considered all of mine false. Such is the attitude of one who cannot refute the other"s arguments. You have also source-bombed me. Sources do not make an argument, they support one.

III. Evolution by co-option
GreenTeas, you have made a straw man of my arguments. It is not because the words "irreducible complexity" is not found. It is simply because it does not fit into the definition of an IC system. You have no source 9, so I will assume that it is the same as the study from the previous round. Your source 15. I even helped you get a link for it. Besides the which, you state that the paper does state certain things. Which it does NOT state. I downloaded the work and read it in its entirety. It is three pages long.

There is no evidence of it being an IC system, rather, it may be considered very close to an IC system. There is also no evidence that it evolved, actually. The paper states that it "probably" evolved. Extrapolating that to a certainty is simply twisting the source to fit your agenda.

Your three arguments has serious objections to which you did not respond. I request that you use your last argument round refuting my objections.
I have indeed made logical and factual objections. In fact, I used your sources against you in that I showed that they did not support your contention.
My two arguments have not been refuted. In one, you twisted the evidence to support your arguments. In the other, you shifted the IC system requirements beyond that originally proposed and declared that it was then not an IC system.


To clarify, last round I stated what I perceived to be my opponent’s tactics. This was not an ad hominem, but an observation. I will let the reader decide on whether he is engaging in this tactic.


1. The Vertebrate Clotting System Is Not Irreducibly Complex

As I noted in the comments earlier, I apologize to my opponent. I misread his sentence as saying that the previously discussed mice did not survive. As such, in a state of irritation, I wrote my section incorrectly believing he had made a statement that he didn’t. They clearly did survive, as we both stated.

In the first round, my opponent claimed that the vertebrate blood clotting cascade requires: (1) Factor XII, (2) Factor XI, (3) Factor IX, (4) Factor VIII, (5) Factor X, and (6) Factor V. Factor V and X then activate thrombin, and thrombin works with fibrin.

My opponent argues this system cannot be reduced because it will not function without all of its parts in this cascade.

However, we have clear evidence this is not true. One vertebrate, a jawless fish, has a blood clotting system that parallels the human system, except that it LACKS Factor IX and Factor V.[1]

My opponent argues that the vertebrate blood clotting system can't be reduced, because it would not function, yet here we have a vertebrate blood clotting system that functions without these supposedly necessary pieces. Not only that, but it provides compelling evidence that evolution can modify systems and increase the complexity of systems through the addition of more parts.[1]

Thus, the evidence shows that the vertebrate blood clotting system is not irreducibly complex. Parts of the vertebrate clotting system can be removed, as seen in jawless fish, and it will still retain its function. Moreover, these simpler vertebrate clotting systems provide compelling evidence into how the clotting cascade can increase in complexity and evolve through the addition of more parts.

2. The Bacterial Flagella Is Not Irreducibly Complex

Researchers have shown that two components of the flagellar system can be removed and it will still function. I demonstrated that the creator of IC, Michael Behe, said these components were part of the flagellar system back in 2004 and 2006.[2][3] My opponent claims the flagellar system doesn’t include these components, but he provides no evidence to support his claim that the system shouldn’t include them. Instead, he cites two sources that were both written AFTER it was discovered these components could be removed. Thus, my argument that he is attempting to “move the goal posts” still stands.

For further support though, let’s focus our analysis solely on the bacterial flagellum apparatus, and forget about other parts of the flagellar system. If the flagellar apparatus could function without a part, it would not be irreducible.

Unfortunately for my opponent, we have considerable evidence that these parts are not required for a flagellum to function.

The study of numerous bacteria indicates that MANY of these proteins are NOT required for the flagella to function. Several bacterial flagella function perfectly without many of these proteins. In Nature Reviews Microbiology, Dr. Matzke provides a detailed account of the proteins that are not required for the flagellar apparatus to function. I will list them here.

These supposed necessary components are missing in numerous bacterial flagella. Simpler flagella can exist and function without the parts my opponent claims are required. Thus, the bacterial flagella is not irreducibly complex, because parts of the system are not required for the flagellum to function.


1. Evolution by scaffolding can explain IC systems

I have shown that the evolutionary mechanism of scaffolding can create IC systems, and I have demonstrated how each step can be beneficial and selected for by natural selection.

My opponent says functional redundancy is not a benefit. But, he ignores the evidence, both logical and biological, that contradict his claim. First, in general systems theory, we know that functional redundancy can be beneficial because it reduces the likelihood of system failure. If one component fails, there is still the backup component – think parachutes and backups. Second, in biological systems we know functional redundancy can confer survival benefits. Yale researchers, for example, note that there is a “reduced risk of extinction via functional redundancy” that can lead to increased complexity.[4]

My opponent argues that when there is functional redundancy, there is an extra cost to the organism because it must produce an extra part. This is true. But, if the value of that extra part outweighs the cost of producing it, then we have a net benefit. That benefit is then selected for by natural selection. This is simply a fact.

Thus, the evolutionary mechanism of scaffolding can create IC systems.

2. Evolution by incremental addition can explain IC systems

I have previously shown how the evolutionary mechanism of incremental addition can lead to the development of IC systems.

My opponent continues to argue that increasing enzymatic activity can be harmful. This is true, and I said as much. But, he also continues to ignore that fact that increasing enzymatic activity can also be beneficial. It simply depends on the environment. [See sources in my previous round]

Consider the example of toxic compounds. Natural selection may select for biochemical pathways that can quickly and efficiently neutralize toxic compounds. Thus, having improved enzymatic activity would be a benefit in this scenario. My opponent does not contradict this claim; instead he misleadingly focuses on the fact that such changes could be harmful under different scenarios.

His other argument regarding the creation of new proteins remains a strawman. The issue he presents is well-understood and not related to whether IC systems can develop. My opponent needs to focus on the actual issues.

The evolutionary mechanism of addition remains unchallenged by my opponent. He continues to misdirect and focus on non-issues, rather than addressing the mechanism of evolution.

3. Evolution by co-option can explain IC systems

In the previous round, I showed that a PCP degradation pathway emerged through evolutionary co-option and was, in fact, IC.[5]

My opponent claims he read the study I cited and that the system isn’t IC. He says he “read it in its entirety. It is three pages long.”

First, it’s not three pages long. It’s five pages long.

Next, my opponent says “there is also no evidence that it evolved, actually.” However, the paper clearly discusses how the system evolved through the “particularly striking example of ‘patch-work’ combination of enzymes from two different existing pathways.”

Finally, my opponent claims there is “no evidence of it being an IC system.” Yet, the paper clearly states that the system requires all three parts in order to neutralize the toxic PCP compound. Without any component, the system fails. This is the definition of IC. My opponent can continue to falsely claim there is no evidence of it being an IC system, but the evidence is right in the paper.

Literally every objection offered by my opponent is contradicted by the study I cited. Thus, my argument stands and the evolutionary mechanism of co-option, as shown in the PCP degradation system, can lead to IC systems.


I have shown that three different evolutionary mechanisms can lead to the creation of irreducibly complex systems. Moreover, I have shown that there is evidence to believe that the flagella and clotting system are irreducibly complex, and there is significant evidence to believe that these systems are reducible.

My opponent offers a series of half-truths and false statements to attack my arguments. Even when I present evidence showing that he is incorrect, he continues his false claims into the following rounds.

Debate Round No. 4


It is unfortunate that GreenTeas continues on an attack on my person. You also brings up new arguments, which, due to the rules, I am unable to refute!
For conclusion, I would like to state that you have been shifting the goalposts of bacteria flagellum, you includes parts of the functions of the flagellum that were clearly not IC. This you have shown most clearly and glaringly in the previous round.
For your arguments against the blood clotting system, when you found out mice didn"t support you, instead of conceding, you cited a totally new animal, the jawless fish, and expect me to refute that in this round.
For your first argument, you have not refuted any of my points, you just restate yourself in different ways.
For your second argument, you totally ignore your previous rounds, where you stated "a mutation may occur in part A that causes it catalyze reactions faster..." This "A" I considered to be the enzyme, and I refuted this idea. Not willing to concede, you run off in another direction and claim I have not addressed your arguments!
For your third argument, I read your source. It was three pages long on my computer, maybe format. Notice that the authors always qualify their statements with "possibly," "maybe," "likely." They don"t have experimental evidence and are imposing their worldview on the study.

I have shown that your arguments contradict themselves and cannot be used as a valid argument. R2:"detailed evolutionary explanations" for my arguments exist, where?



First, I would like to thank my opponent for an interesting debate. I would also like to note that when I stated he was making half-truths and non-truths about factual claims, I was not attacking his person. If someone says “the sun is blue,” and then you say “the sun isn’t blue, it’s actually yellow. What you’ve said is wrong.” That’s not a personal attack. My opponent made many such factual errors and I pointed them out.

I have shown that evolution can explain the creation of irreducible systems. Throughout the debate, I provided three evolutionary mechanisms that can lead to irreducibly complex systems: (1) scaffolding; (2) incremental addition; and (3) co-option. I established how these changes could be beneficial and selected for by natural selection, and I provided examples of irreducible systems that had evolved – such as the PCP degradation system. My opponent’s counterarguments to these evolutionary mechanisms lacked factual basis, and I showed as much. Even when I flatly refuted his claims, he continued to repeat that it could not be possible. I will leave it to the reader to decide whose claims were factually based and whose were not.

Remember, both PRO and CON shared the burden of proof. My burden was to provide evolutionary explanations for the development of irreducibly complex systems. My opponent’s burden was to provide evidence that evolution could not create irreducibly complex systems. You should vote for who you believe did a better job of presenting arguments for their specific position.

Thanks to my opponent and the readers!

Debate Round No. 5
27 comments have been posted on this debate. Showing 1 through 10 records.
Posted by devient.genie 4 years ago
muted, that calls for an Encore :)

RIDDLES 6:66--The boogey man goes into a bar orders a few drinks, then a few more, gets drunk and stumbles around, whilst his drunkeness he finds god in the corner. He is so drunk he tells god.."As the Boogey Man I have done more good, produced the most benefits,(hiccup) and been the best overall blessing for this world than anything or anyone"...(Burp)..god replied "my son in your drunkeness you are a silly fool, for I am all highest of all those things, just read the bible. The Boogey Man said.."I meant to say that I am the biggest a-hole (hiccup) and meansest sexist S.O.B in all the universe...(Burp)..My son in your drunkeness you are a silly fool, for I am all highest of all those things, just read the bible :)
Posted by Muted 4 years ago
Posted by devient.genie 4 years ago
muted, get a tissue, there's no crying in baseball, come on, you know that. Walk It Off :)

Now back to big kids stuff :)

LOVE 8:14--What does a stalker do, that the character in the bible does?....They put you on a pedestal, but then once they're rejected, its anger, and rage :)
Posted by Muted 4 years ago
TomJeff, you are the roommate of GreenTeas, are you not? He has used your account mistakenly to comment. How am I to know if you are really TomJeff and not GreenTeas?
Posted by Muted 4 years ago
Is there anything coherent that your highness would like to add?
Posted by devient.genie 4 years ago
I dint say anybodys name in my last comment. You are experiencing amild hallucination common among those who suckle malnutrition from a holy binky.

FourHorsemen 3:15--Science we are told should NOT tread on the toes of theology. But why should scientists tiptoe respectfully away? Its time for people of reason to stand up, and say enough is enough. Religious FAITH discourages independant thought, its divisive and its dangerous--Richard Dawkins :)

STUDS 7:2--Richard Dawkins Foundation for Reason and Science "to support scientific education, critical thinking and evidence-based understanding of the natural world in the quest to overcome religious fundamentalism, superstition, intolerance and suffering." :)

DUH 12:31--In the buffet of life, choosing religious doctrine over logic and reason, is like choosing dried out liver over fresh prime rib :)

WAKEUP 2:2--Cornell University is a very respectable institution. The American Association for the Advancement of Science, and the National Academy of Sciences, and dozens of other scientific organizations, ALL AGREE with this.. :)
Posted by Muted 4 years ago
Muted you're saying that I'm too stupid to understand that? hmmm...
Posted by devient.genie 4 years ago
It doesnt have to account for complexity. Complexity is explained in extremely gradual evolution by natural selection over 4 billion yrs.

Billions of people cannot wrap their mind around 4 billion yrs, let alone there not being a god.

However when we step back. Clear our minds. Be honest with ourselves. Think about this for a moment. The reason for all the complexity, the Fibonacci Sequence, The Mandlebrot Set, the sub atomic world, fractal geometry, biology, even gravity, the REASON FOR EVERYTHING, thinks that a human sacrifice is the all knowing thing to do, if you really want to prove a point :)
Posted by Muted 4 years ago
BobbyYaz =votebomb!
Posted by GreenTeas 4 years ago

[2] Michael J. Behe, Darwin"s Black Box, pg. 73 (2006).
[3] Behe, M. J. 2004. Irreducible Complexity: Obstacle to Darwinian Evolution. In W. A. Dembski and M. Ruse, eds., Debating Design: From Darwin to DNA. Cambridge: Cambridge University Press.
6 votes have been placed for this debate. Showing 1 through 6 records.
Vote Placed by DeFool 4 years ago
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Reasons for voting decision: I was stunned by the almost poetic simplicity with which Con made many of his arguments. The best, in my view, was the "scaffolding" argument, which I had not heard before this debate. Muted continues to place his considerable skill as a debater into the service of unsupportable arguments - such as this one. I am beginning to follow his contests just to see how an impossible argument can be somehow made convincing. His arguments were all textbook - but unconvincing. I was unable to score for conduct, as both sides were respectful, if full-contact. I did not see plagiarism. Gish galloping: I will never, without reason, score "drops" as concessions. Some arguments do not deserve a response. I prefer to keep my own counsel as to which arguments needed to be answered - such as the "scaffolding" argument. I am glad to have found this debate.
Vote Placed by ThomasJefferson 4 years ago
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Reasons for voting decision: Con presented stronger arguments for his position. The burden of proof was shared, but Pro didn't really seem to present an argument explaining why evolution couldn't explain irreducible complexity. Instead, he presented two supposed examples of irreducible complexity, but didn't really provide any studies that showed they were irreducibly complex. I think Con established and defended his arguments better. I split conduct because both sides made stupid accusations. Con said Pro was misleading about one part, and Pro said Con was source bombing. Pro also quotes his entire argument in second round, which seems like poor conduct. I think Con's sources were more on point. Almost all of his sources were from peer-reviewed journals. Several of Pros sources were from intelligent design websites. One of Con's links didn't work, but it still seemed to cite to the appropriate source.
Vote Placed by emospongebob527 4 years ago
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Reasons for voting decision: Balancing all this VB/counter nonsense out.
Vote Placed by Smithereens 4 years ago
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Reasons for voting decision: Uncountering
Vote Placed by BobbyYaz 4 years ago
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Reasons for voting decision: Con still has my vote
Vote Placed by Microsuck 4 years ago
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Reasons for voting decision: I am still working on reading the entire debate. However, I feel that I have seen enough to award pro the conduct point. I felt that at times, Con was abusive and rude (I'll explain more in the comments). I will analyze the arguments and sources in a few days.