pz

What the heck is your "knockout punch"? That Behe's claims are untenable? That the venus flytrap could not have evolved? That you can duck and weave with skill?

The reason this has gone on longer than it should is that you are thoroughly muddled. Even now I have no idea what you are trying to claim.

DNAunion

DNAunion: Wrong!

DNAunion: There’s your misrepresentation of Behe that turns your refutation into nothing more than an irrelevant tangent. The "IC eating system" of the Venus Fly Trap did not "continue to work by the same mechanism" throughout your evolutionary explanation.

Yours in, in fact, an INDIRECT route and does not counter Behe's statement, nor my confident proclamation of his correctness.

Of course, there were other problems with your "refutation" of Behe, but all I need is this one, alone, to completely destroy your refutation of Behe and me.

one...two...three...four...five...six...seven...ei ght.. it's a knockout!

[ November 23, 2002: Message edited by: DNAunion ]</p>

Nic Tamzek

'Course, if we do the bolding differently, to emphasize the part that actually defines "directly":

...then I'm right. Behe's prime example of a direct pathway is that from light-sensitive spot to camera eye...and certainly the "mechanism" is not precisely the same between these two cases. Cripes, if the "mechanism" can't change at all in a Beheian "direct" pathway, then you've just defined things such that any conceivable change will be an "indirect" one.

Clearly Behe means by "direct" simply that the initial function continuously improves. The "same mechanism" line is in there because Behe couldn't conceive of a situation where an IC system could work by a simpler mechanism, therefore a working IC system would have to be using the "same mechanism".

But let's have it out, DNAunion, for you, would the evolution of the camera eye by specialization of a light-sensitive spot be a Beheian "direct" or "indirect" pathway? (Recall that Behe conceeds that simplified eyes can "work" and are therefore not IC, therefore the Beheian "direct" pathway is not ruled out) Your answer to this question will tell us how we should interpret The Book of Behe.

nic

DNAunion

DNAunion: No I didn’t. That’s your interpretation of the matter, not what I said.

DNAunion: Sure did. See just above.

DNAunion: Wrong on one count, your personal interpretation on the other.

DNAunion: Not exactly.

(1) Behe confidently (and correctly) states that an IC biochemical system cannot “evolve into existence” by a specific type of route – to paraphrase, a direct evolutionary route through a continuous series of simple functional precursors that are reached by small, incremental, successive steps.

(2) Behe himself does say that it is possible for an IC biochemical system to arise by an indirect or circuitous route. But, he adds, because there are so many IC biochemical systems, we would have to rely on that explanation more than he feels is reasonable (and there’s the REAL point of contention, IMO). If the probability of one IC biochemical system arising by an indirect route is small, the more times we call upon that explanation the smaller the overall probability of success becomes, and less likely it is to be the correct explanation for ALL IC biochemical systems.

Do I have anything else to back up my position? Yes. Behe continually uses phrases like “an IC biochemical system poses a serious challenge for Darwinian evolution”. Note Behe doesn’t say that an IC biochemical system refutes Darwinian evolution, or refutes ANY kind of evolution. I think it has to do with how unlikely he feels it is that so many IC biochemical systems – ALL of them - could have arisen by circuitous routes.

DNAunion: Yes he did, for co-option. But he geared it towards the general population, since that was the target audience for the book. That part about the evolution of a bicycle into a motorcycle, and the part about the evolution of cilia by picking up parts that were already existent in the cell, to name two. He explained why each seems unlikely.

DNAunion: No, not for any SINGLE IC biochemical system. He concludes that only because there are so many IC biochemical systems and all of them would have to arise by an indirect or circuitous route. He finds THAT so unlikely as to be disregardable.

DNAunion: No, I don’t have to. Some people would look at the probability that ALL IC biochemical systems would arise by an indirect route and conclude that it is too small. I can’t argue with that because I don’t know the probability for each IC system’s arising by some unknown route. Do you? I think accepting Behe’s IC to ID conclusion comes down to personal opinions of how likely or unlikely all of this is.

I don’t hold the same view as Behe, but it’s not because it is possible for an IC biochemical system to arise by an indirect route. Behe knows that too, yet he and I don’t agree on ID.

DNAunion: No, that’s indirect, not direct.

But hey, don’t let PZ hear you calling that a direct route, because then he would be FORCED to state that you are not a biologist!

DNAunion

DNAunion: No you’re not – you’re still wrong. I still see those words in there that require directly to include “which continues to work by the same mechanism”.

Only if you remove those words could you claim to be right, but then, of course, you’d be guilty of quoting violations! And still be wrong to boot!

[ November 23, 2002: Message edited by: DNAunion ]</p>

pz

Again, you do not get to twist my words to declare what I think or what I would say.

And also, you have still failed completely to say what point you are trying to make here. Instead of going back and forth on what is indirect vs. direct, perhaps you could say something that makes sense for a change.

DNAunion

DNAunion: Clearly Behe means what you think he means, and not what he explicitly states. Sure Nic, you know so much better than Behe what he thinks. Hey, what’s he gonna have for breakfast tomorrow? Come on, tell me.

DNAunion

DNAunion: Please provide material that supports that claim.

DNAunion: Which of the several mechanisms involved with vision are you referring to?

You see, Behe explicitly states that a camera eye is not a single system, but rather is a collection of systems.
DNAunion: Thus it would be a mistake to consider the evolution of a camera-type eye from a simple light-sensitive spot as the evolution of one system, with one function, with one mechanism. For example, if photoreceptors worked the same way throughout, then they would use the same mechanism throughout.

DNAunion: I disagree with your interpretation.

However, what is abundantly clear is that a system that starts off trapping insects with a sticky substance - and lacking a closing leaf, and “hair triggers”, etc. - and then ends up trapping insects with a closing leaf, and hair triggers, etc. – and with its having lost the sticky secretion – is definitely a change in mechanism.

DNAunion: OOOOOH, I’m so scared! :-)

DNAunion: You need to rephrase your challenge. Remember, a camera-type eye is composed of several discrete systems.

DNAunion: By explicitly stating that Behe holds that simplified eyes are not IC, are you implying that Behe states that camera-type eyes are IC? I hope not.

ps418

Nic and Pz- much thanks for the info and discussion. I'm more confused than ever about which types of IC systems cannot be produced by evolution, and why. Also, even though I'd read the Behe passage several times before, I never properly caught on to his use of the crucial word 'directly,' which leaves open the 'indirect' pathways.

Patrick

DNAunion

DNAunion: Hmmmm...should I hold my breath for a retraction?!?