its not a complex change and thus irrelevant. by this logic even 2 amino acids changes are IC by definition (if the two depend in each other for a specific function). but 2 amino acids are not a complex biological system.
AND there it is - the goalposts have been moved.
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Please define what exactly does constitute a “complex biological system” in your understanding.
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let me ask you something: suppose i move a spare wheel to the front of the car. do you think I added a new system to the car in that case?
any system that seems to be too complex to evolve naturally.
I have rejected several critical comments which IMO did not move the discussion forward. This does not mean these criticisms were unwarranted.
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What is it with you and cars? This analogy is wrong is so many ways that it’s not worth considering. Try harder?
This is not Behe’s definition of IC, or anyone else’s to my knowledge. “Seems” is entirely subjective.
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So this is just begging the question.
The point of the hypothesis is that systems that meet the criteria are supposedly unable to evolve through natural means. If the definition is that they seem like they can’t evolve, then obviously the logic no longer works. It’s just assuming the conclusion you want.
Fortunately, Behe provided specific criteria in Darwin’s Black Box:
By irreducibly complex I mean 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.
An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on.
He subsequently revised that in 2002:
An irreducibly complex evolutionary pathway is one that contains one or more unselected steps (that is, one or more necessary-but-unselected mutations).
By either definition, and very specifically by the second, the Cit+ trait and tetherin antagonism in HIV-1 Group M VPU qualify as irreducibly complex, and yet clearly evolved before our eyes.
Therefore, the hypothesis “if a systems is irreducibly complex, it cannot evolve” is false.
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It’s circular too. If you’re trying to show that IC systems can’t evolve, and you define an IC system as one that can’t evolve, that goes nowhere.
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this is the same case: we can move the wheel to the front of the car and get a new function: now the car is less prone to frontal damage. this is very similar to what happened in the lenski experiment.
do you think that the conclusion that a watch need design is subjective?
Still not worth considering, for reasons already given by others.
We can use the shadow of a tree as a sundial, serving the same function as a watch. Is a tree also a watch?
It seems that you do not even agree to the accepted definition of IC, and you have provide no well defined alternative. What’s to discuss?
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This is a must-watch guys. I thoroughly loved it. Its educational and entertaining as well. I loved how Dr James Carter patiently listened to the corrections you gave and understood most of them (like when he noted that Sanford used the concept of fitness differently). You both were pleasing to watch.
I also observed how knowledge in your respective fields helped the discussion. He helped you with some biochemistry details and you with some genetics/evolutionary biology. This plays out on a bigger scale with biochemistry aiding evolutionary research and evolutionary research unlocking new frontiers of biochemical enquiry.
Overall, this is a good resource for those interested in what the Lenski LTEE is all about.
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It seems that you are wrongly equivocating evolution with life. Behe is not saying that biochemists are better equipped to understand evolution than evolutionary biologists. Rather, he is saying that biochemistry is more fundamental for understanding life than evolution. He rightly said « A mechanical engineer can’t contradict a physicist on fundamental principles of life ». Similarly, an evolutionary biologist can’t contradict a biochemist on fundamental principles of life. Would you deny this point?
However, the existence of those would not refute his hypothesis that there exist pathways that meet his criteria.
The bigger problem for him is that the criteria is completely useless. It puts the onus on Behe to show that every step in the evolution of some system or structure must have been selected in the past. How would he do so?
More importantly, it lays bare his fundamental misunderstanding of current evolutionary theory. There is no reason that every single step must be selected. A step needs only not be so deleterious that it will be removed by selection before the next step can occur.
I wish the devotees of ID would take the time to understand this concept. If they did, many of their objections to evolution would instantly vanish.
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why not? there are many things in the universe which we can conclude they cant evolve naturally. this is an objective conclusion, not a subjective one.
this is behe definition. not mine. besides, do you realy think that behe will consider two amino acids as a complex IC system?
im talking about digitial watch. do you agree that such a watch is an objective evidence for design? if so, my definition above (something that looks too complex to evolve naturally) is objective too.
I did a quick search and came up with 26 threads in this forum where you have argued for design using watches. The flaws in that analogy have been repeatedly explained. Can we just not do this again?
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Whether it is simple or complex change (whatever that means), what matters is that an irreducibly complex system evolved through it.
So?
Lenski’s work goes beyond 2 amino acid changes though. How you missed that and reverted to your hypothetical 2 amino acid irreducibly complex system beats me.
Totally irrelevant.
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No, we are talking about amino acids.
Definitely not a watch! Even ape-descended life forms who are so amazingly primitive that they still think digital watches are a pretty neat idea can tell the difference. 
Even better!
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He coined the term in its modern sense, so I think his definition is relevant.
He does consider a two-amino-acid system irreducibly complex. See for example his I want to say 2004 paper, with David Snoke. That was modeling at the evolution of a two-amino-acid interaction, and endlessly trumpeted (incorrectly) as showing how such systems could not evolve naturally.
His second definition in specifically relevant to the examples I gave, and I will not that both are significantly more complex than two amino acid changes.
But what is your definition? If it is, in part, “a system that cannot evolve”, then it’s useless as a scientific hypothesis. For all its flaws, Behe’s can be tested (and has been, and has been shown to be invalid).
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You had better reread what Behe wrote and I was responding to. He was talking about evolution.
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Right! There are most definitely evolutionary pathways that meet his criteria…it’s just that to go from something as basic as “there are steps that are unselectable” to “therefore such systems can’t evolve” would be silly. So when he writes this:
By irreducibly complex I mean 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.
Surely he can’t intend to imply that this is actually a problem? Like, could potentially cause evolutionary theory writ large to be called into question, right? RIGHT?
An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on.
…like…I don’t know what to do with that. It’s patently absurd. As if the last hundred years have never taken place.
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