Denton's Structuralist Challenge to Evolution

Denton’s Bio-Complexity paper is an improvement over most ID content. He at least delves into relevant biological topics which allows for some more constructive discussions.

I have skimmed through sections of the paper, and thought it would be a good idea to start a discussion thread if others are interested.

Here is the paper:

https://bio-complexity.org/ojs/index.php/main/article/view/BIO-C.2013.3/BIO-C.2013.3

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We have already had a discussion about this, though it tended to veer off into other directions, largely because Denton’s creationist defenders had little to say in defense of his actual claims.

If I may say so, I think my opening post in the discussion has Denton dead to rights, and there is not much more to say. But, of course, I would think that, right?

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This section of the paper piqued my interest:

I think Denton is misunderstanding some basic concepts. It is the physical characteristics, and ultimately the DNA sequence, of developmental genes that produces morphology through a diffusion feedback system. This is still very much a gene-centric system, contrary to Denton’s structuralist leanings.

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But! “(A) Turing-type reaction-diffusion model plays a critical role in generating the digits”! Wow! Don’t those words just scream “Science!” to you? They are so damned science-y!

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What struck me so strongly is that in all his many mentions of the 5-digit hand/foot, he never once mentions either the 7 or 8 digits in early fossils or the 6 digits that are rare mutations/developmental anomalies in extant species. Is he ignorant? Hiding? Neither is a good position.

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Just to avoid damaging my brain by reading Denton’s paper today, are you saying that Denton doesn’t understand that we understand that the gene regulation starts downstream of the positional information?

Or the single digit in the case of the horse, quite an evolutionary icon.

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He deals with that, sort of. He says the rule is no more than 5, not no less than 5. Not that he justifies that claim.

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7 is greater than 5. I guess he forgot that.

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So is 6. Plenty of people have polydactyly.

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As I said in another thread, to my embarrassment I only recently learned that having five fingers is a recessive condition. I wonder if that works in Denton’s idea.

I’m not clear how structuralism is a challenge to evolution. What am I missing?

From what little of Denton’s I’ve read(which, full disclosure, is one paper on early protein evolution) is saying some apparent adaptations aren’t really adaptive(that this is not why they emerged in the first place, as in gradually under selection), rather they’re sort of built into the fundamental physical constants and laws of nature.

So he’s not really challenging the fact that evolution occurs, nor common descent, nor even that the evolutionary process is blind to the future, rather he’s opposing/challenging some kind if view of evolution which (I think this is how he sees it) says that certain structures owe to a combination of chance historical contingencies, and gradualism+natural selection.

Going from memory here he says in one paper of his I’ve read on early biochemical evolution near the origin of life, that he thinks certain protein structures with certain functions were sort of “built into” the fundamental properties of amino acid polymers and the chemistry that gives rise to them.

He suggests that because of the physical processes that give rise to amino acids, there are going to be certain inherent biases in the frequencies of which amino acids are produced.

And then because you end up with a biased distribution in the frequencies of certain amino acids, these distributions have a bias towards yielding particular short peptides, and these peptides with their amino acid biases are going to have biases towards adopting particular secondary structures(say, an overabundance of glycines and alanines yield some secondary structure much more often than others), and these particular secondary structures are going to have biases towards assembling into certain even larger tertiary structures. And these in turn are going to be biased towards particular functions(such as nucleotide binding or something along those lines). And so on and so forth.

And at least with respect to early biochemical evolution, it doesn’t appear to me he’s talking total nonsense. There does appear to be evidence of various inherent biases in the kinds of chemistry that can happen, and what structures are more likely to emerge from that. But there are also some considerable open questions here.

The real question is how strong are these putative inherent biases, and do they result in the sort of extreme “funneling” effect, for lack of a better term, that he imagines where they basically lead to the same thing every time? That’s where the chain unhinges for me, because there’s just not any good evidence for that.
So he sort of imagines that the laws of physics are somehow “programmed”(paraphrasing) to give rise chemistry of a particular type under the right conditions, and that chemistry gives rise to life of a particular type, which makes him expect that if and when life arises elsewhere in the universe, it’s going to be pretty much the same everywhere. And from these very similar initial conditions, IIRC a genetic code like ours is going to evolve every time yadda yadda yadda, one thing funnels/is biased towards another, and then basically the same thing all the way to human-like primates.

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That’s how I read it. He compares the pentadactyl limb to crystalization. In other words, if we found a limbed organism on a distant planet who independently evolved we would still expect to see the same limb arrangement for the same reason that salt crystals on that planet also form cubes. He seems to back up the classic science fiction trope where everywhere we go we will only see slight variations on the human form for alien races.

Same here. I don’t see how basic protein chemistry must produce the tetrapod limbs.

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I’m reading Nature’s Destiny. So far I see nothing of interest. He advances no hypotheses. He merely points to some facts and says “See? God.” or perhaps “See? Destiny.”

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Others may point to some facts and say “See? Nature” :slight_smile:

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Name one such person. Generally, one advances facts to support a clearly stated hypothesis.

Attempt at humour fail…

ETA: Harsh by name, harsh by nature :smiley:

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Agreed. Even the emoji didn’t signal.

Well, stick with it. I want to hear how he handles the question of historical contingency, and someone has to read the book since no ID supporters seem able or willing to answer. Take one for the team :slight_smile:

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