Irreducible Complexity: the Mullerian Insights - 100 yrs ago!

The thread identified below includes the important contribution that Dr. H.J. Muller made to evolutionary theory wayyyyy back in 1918! - - and then with greater clarity in 1939!

He predicts and explains just how something can become “irreducible”… and @swamidass is most clever to have either made the connection between Muller and the concept of Irreducible Complexity … or to have done enough research as to DISCOVER this century-old connection!

This is a must read for anyone who wants to discuss I.D. with intelligence and comprehension!

Continuing the discussion from Which Irreducible Complexity Argument?:

Here is the exact text… which benefits from a little reproduction - - so that the ideas are always easy to find!

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One issue I think needs mentioning is that IC2 incorporates a measure of evolvabilty into its definition. This turns it into a truism: “A system that by definition is unlikely to evolve by a mechanism is unlikely to have evolved by that mechanism.” It smuggles the desired answer into the formulation of the question.

I agree with Joshua that IC1 didn’t run into this problem.

The problem with calling all these completely different formulations “IC”, is that it leads to confusion. A system we can readily identify as IC per version 1 tells us nothing about whether it is IC per version 2. Hence, flagella or blood clotting cascade components, which are IC1 continue to used by some as examples of IC2 systems in their arguments when in fact, the assessment of IC2-ness has never been properly determined.

Perhaps better names for these definitions should be:

  • IC1 – ‘irreducible complexity’ (by definition, might or might not be accessible to evolution)
  • IC2 – ‘unevolvable complexity’ (by definition, cannot evolve via particular evolutionary mechanisms)

Over the past few years, I don’t think I’ve seen nearly as much talk about “IC” compared to a decade or so ago. Is is largely being abandoned in search of better arguments within the ID community?


Perhaps one of the ID advocates that frequent these boards to elucidate us. I wonder if the leadership knows the argument fails, but the crowds do not. I very rarely hear about IC from leaders, but it is often among the first arguments raised by amateur apologists. It would be good to know which option the ID leadership thinks it is:

  1. IC is a failed argument. It would build trust then to make that clear to the crowds. If they all agree it is an argument to be avoided, it is hurting their credibility to have everyone repeat it like a broken record.

  2. IC is not a failed argument. I’d like to know why, then, they think it still works when the logic and evidence is so solidly against it.

Yup, this contributes immensely to confusion. Here is my try at it:

  • IC1 – one way to objectively measure the complexity of any system, including biochemical systems, independent of the inference whether or not a specific level of complexity is evolvable.

  • IC2 – systems too complex (somehow) to evolve by positive selection alone (e.g. the long falsified theory of Darwinism).

  • IC3 – systems too complex (somehow) to evolve by known natural processes alone (e.g. the best current understanding of evolutionary science).

  • IC4 – systems too complex (somehow) to evolve by known and unknown natural processes alone (e.g. a total understanding of natural process, forever inaccessible).

  • IC5 – systems too complex (somehow) to evolve by known and unknown natural and providential processes (i.e. an empty set with no possible examples).

Christians that affirm evolutionary science, and common descent, know that there are zero systems that are IC5. That is what makes the recent Crossway Theistic Evolution book so strange. They seemed to think that IC5 = IC2, which is transparently false. Though that has to be true for any of their argumentation to make sense.

No one cannot possibly know if there are any systems that are IC4, as this seems like a question outside the bonds of science. It might be extrinsically beyond human knowledge. The ID movement almost never seems to engage IC3, though we evolutionary scientists are always looking at the boundary of IC3 and IC4 to expand our knowledge of evolutionary mechanisms.

Darwinism, though, everyone gave up a long long time ago, except people messing around with straw man arguments of evolution, like that in IC2.

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Naw, IC1 doesn’t do that. It’s pretty much a binary proposition. IC1 just specifies whether a ‘system’ of interacting parts has a particular response to the removal of a component or interaction. The minimal IC1-system has two components, but a system is IC1 regardless of whether it is made of 2 or 100 dependent interactions.

It’s a bit subjective too as the definition refers to ‘function’ or ‘original function’. That notion can be a bit hard to pin down when you dive deep into the details.

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Something else: I think IC systems can potentially arise via positive selection alone.

Take the case of some streptomycin resistant bacteria that persist in environment. Some of the initial mutations that produce streptomycin resistance in bacteria have a negative effect on growth rates. In a environment where streptomycin is present (e.g. like in patients being treated with streptomycin and hospitals), resistant mutants will arise. However, once the antibiotic exposure stops, you’d suspect that the resistant strains would tend to disappear from the environment, being out-competed by bacteria that don’t carry the resistance mutations. However, that’s not what happens. Instead, we find that the resistant mutants persist for decades.

They persist because secondary mutations arise that suppress the negative growth effect of the initial streptomycin-resistance mutations. What’s interesting is that individually, streptomycin resistance mutations or the secondary, suppresor mutations have a negative effect on growth. It’s only when they are both present that they persist. This is a minimal IC system. However this arises (repeatedly in experiments), more frequently under positive selection. Exposing bacteria to streptomycin “selects for” resistance mutations. Because the growth with the single resistance mutation is sub-optimal, there is selection among the streptomycin resistant survivors for secondary mutations that suppress the growth inhibition of the streptomycin resistance mutation.

That’s not quite right. Behe explicitly suggests measuring the size of the IC core, i.e. how many parts are required? That gives a quantitative measure of complexity. It is not binary. Regardless, even if it was binary (and its not), a binary read out is still a measurement.

And you are making my point. The first system is reducible to 2 components, the second is reducible to 100. The second one is supposed to be more complex.

Nope its not. That is another issue I didn’t even touch on. Behe means the “original function,” not any other function. When pressed he sometimes allowed for clearly indicated prior functions, but only if they were known.

The technical objection he is fighting against here is something called “exaptation.” That is what you are getting at too. There can be multiple functions over time as a system develops. This disconnects IC1 further from being a true measure of evolvability. Exaptation is another mechanism that IC1 (and IC2) does not consider.

Sure, perhaps that can happen sometimes. That misses the point. Demonstrating this is possible depends on the details (often unknowable) of the system. Remember, they were coming forward with specific IC1 systems, saying that this was de facto evidence that they were unevolvable. Then they were enforcing strict Darwinism (IC2) as criteria for plausibility. This strategy restricted evolution to a cartoon version of evolution, which is to say a widely understood, but false, understanding of evolution.

It was rhetorically effective in some restricted sense, but it really angered scientists. It is just a bizarre sort of argument for us, that seems to miss the point. And to be clear, many scientists were really bad with engaging ID, taking the bait to argue starting from this straw man version of evolution, and also insisting on only natural mechanisms at a metaphysical level. That was unfortunate.

I fear we are still in a whole because of the Dover disaster, and the Kansas hearings. Not only did ID double down on these things, it seems TE might have picked up some bad habits. I wonder if that episode is partly why TE/EC often has difficulty acknowledging the possibility of God’s action. They reacted too far in one direction away from ID, it seems.

I agree, these ID arguments are bad, but that does not mean at all that natural processes are sufficient, meaning that it did not require God. In fact, that is a question well beyond. Science does not make total claims like that, and it is silent on God. There were no adults in the room, sadly, until Francis Collins wrote is book.

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I see where you’re coming from. I see ICness as a category and IC-icity as a degree (number of parts). ICness describes a type of ‘system’ and not a degree of complexity. The issue with a notion of an “IC core” is difficulty in quantification and identification. This relates in part to the issue of properly defining ‘function’ in a biological context.

Further, the notion of ‘original function’ is problematic for IC1 as the assessment was supposed to be determinable in extant organisms, independent of any knowledge about historical paths. Behe’s discussion of ‘original function’ in his first book and articles seems to foreshadow the inclusion of ‘path-dependent’ criteria for IC2. Dembski took a shot at developing a quantitative metric of IC or complexity but again, that relied on historical knowledge or evolutionary trajectories.

Me: Something else: I think IC systems can potentially arise via positive selection alone.

Joshua: Sure, perhaps that can happen sometimes. That misses the point.

Just to clarify. I wasn’t addressing any of your points. I was just describing case of an IC1 system which was supposedly difficult to evolve step-wise, under selection. It’s putting another nail in the coffin of IC1.

[…] There were no adults in the room, sadly, until Francis Collins wrote is book.

Umm… I remember a number of adults, back in the day, who participated in the ASA reflector email list and even in the newsgroup. I’m sure Ted Davis personally knows many from the ASA list.

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Fair enough. Those adults however were being ignored.

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