Monday, November 28, 2005

Strict Darwinism.

Dr Andy Groves asked:
"What is "strict Darwinism"? Was Stephen Jay Gould a "strict Darwinist"? How about Lynn Margulis? Or George Gaylord Simpson? Or Theodosius Dobzhansky?"

I would say that “strict Darwinists” regard the issue of explaining biological complexity as essentially solved.

They say….
Darwin found the answer and we are just tinkering with a few loose ends.
All we need is chance and time.

As Sir Peter Medawar put it at the Wistar Institute meeting :

Clearly the eye has evolved therefore there must be errors in the equations the mathematicians were using.

And Ernst Mayr at the same meeting:
Somehow or other by adjusting these figures we will come out all right. We are comforted by the fact that evolution has occurred

Any thinking outside a rigid time plus chance box is regarded as “unscientific.”

Using this definition the above scientists ...I would guess (I have not read anything of Simpson or Dobzhansky other than brief quotes) were/are pushing at the edges of the “strict Darwinists” box but are/were not willing to look over the edge.

15 Comments:

Anonymous Andy Groves said...

What I think you are trying to say is that a “strict Darwinist” believes that a) biological evolution is a fact and b) there are no new mechanisms of evolution that have yet to be discovered.

Part (a) is pretty uncontroversial. Only Young Earth Creationists would deny that life on Earth has changed over time. Part (b) is more tricky, and revolves around what you regard as “filling in the details” or “essentially solved”. My own feeling is that there’s plenty of healthy debate among biologists as to the relative effect of different evolutionary mechanisms in specific situations, and whether the same or different mechanisms work above the level of species. A flavour of this can be gained by following the debates on species selection or species sorting.

Where I think your explanation wanders close to straw man territory is where you infer that “strict Darwinists” think that historical evolutionary scenarios have been explained at an acceptable level of detail. No one knows how the first cell came about, or exactly how the modern horse arose from a Hyracotherium-like ancestor. (Parenthetically, here’s a Dobzhansky quote for you, when he wrote to the creationist Frank Lewis Marsh fifty years ago, “If you demand that biologists demonstrate the origins of a horse from a mouse in the laboratory, you will never be convinced”).

It is fine to say that a weakness of evolutionary theory is that it cannot presently show how the first cell arose. It is not fine to say that such weakness is evidence for an alternative theory, which is all that ID does,

6:09 pm  
Blogger Andrew Rowell said...

Andy,

Thanks for your comments.

I got told off on Panda's thumb for confusing evolution with the origin of life!

The word evolution has become a very elastic word. I don't know if you accept the distinction between micro-evolution and macro-evolution. Micro-evolution is uncontroversial. Macro-evolution is not uncontroversial. The idea that whole new body plans occur using random DNA rearrangement and change plus natural selection alone is not uncontroversial.

A Strict Darwinist will only look inside the time plus chance box and will reject intelligent activity as a possible cause for biological complexity.

My problem is with those who are **certain** that evolution does in fact explain the origin of new developmental body plans. That is why I gave those quotes from the Wistar meeting.

You admit ignorance about the origin of life on earth and then effectively say you know that there was no intelligent agent involved.

I do not demand a mouse to a horse demonstration in your lab.... but a detailed theoretical pathway from a Type two secretory system to a working motor would be helpful. Is that unreasonable? This is a much better known example and is a much simpler system to put together than a whole new body plan.

7:34 pm  
Anonymous Andy Groves said...

I don't know if you accept the distinction between micro-evolution and macro-evolution.

Macro-evolution is evolution above the species level, i.e. the formation of new species, and the historical trajectory of those species. That new species arise is not controversial. The mechanisms of speciation are a topic of debate among biologists. I know of no one who thinks that mutation and selection alone can account for macro-evolutionary processes. For example, one of the most common forms of speciation is thought to be allopatric speciation, in which two geographically separated populations diverge over time. While selection might play a role in that process, genetic drift may also account for the changes. People argue about the degree to which either process is important.

A Strict Darwinist will only look inside the time plus chance box and will reject intelligent activity as a possible cause for biological complexity.

I think that’s an unfair characterization. You are giving the impression that biologists reject intelligent causes a priori, which is simply not true. If ID proponents were able to provide evidence of an intelligent cause, we could consider it. You suggest I have effectively said that I “know” no intelligent force was involved. In fact, I think it is perfectly possible – in theory - that an intelligent designer created all life on Earth. However, I see no evidence for that at present.

If you list the arguments for intelligent design of life, they all tend to fall into the category of eliminative arguments: Event A is too improbable to have happened by chance, therefore Event A had an intelligent cause. Scientists attack both parts of this argument – first, there is no rigorous description of the probability of the event occurring that is free from assumptions based on our current knowledge. Second, evidence against one hypothesis is not evidence for a second hypothesis, unless it is worded in such general terms as to reduce to “hypothesis 2 = NOT hypothesis 1”, in which case it lacks much explanatory power.

My problem is with those who are **certain** that evolution does in fact explain the origin of new developmental body plans. That is why I gave those quotes from the Wistar meeting.

Well, again I think you’re mischaracterizing their position. Your Medawar quote is “Clearly the eye has evolved”. That’s a fact. The fossil record shows a animals without eyes followed by animals with eyes. The Mayr quote “We are comforted by the fact that evolution has occurred” is also non-controversial. Neither quote said anything about evolutionary theory being sufficient to explain the origin of new body plans. I personally think that evolutionary theory is the best current explanation for the origin of new body plans. Is that “strict Darwinist”?


I do not demand a mouse to a horse demonstration in your lab.... but a detailed theoretical pathway from a Type two secretory system to a working motor would be helpful. Is that unreasonable?

No, it’s not. But a failure to provide a scenario of sufficient detail does not falsify evolutionary theory, nor does it strengthen the case for design.

By phrasing your question as the transition from a TTSS to a flagellum, you have already shown one of the weaknesses of the ID argument – that it is a “designer of the gaps” argument. Recall that the original demand was for a model of how the flagellum evolved. Now one possible precursor (the TTSS) has been proposed, the demand is now for a pathway from the precursor to the flagellum, but the weak argument remains the same – if you can’t show x--->y to a certain level of detail, then y was designed.

Interestingly, Behe fell into a trap of his own making when he said that he thought hemoglobin was not an irreducibly complex molecule, as it clearly arose from myoglobin. Using his own argument against him, one can ask how he can be so sure. Has he provided a detailed theoretical pathway from myoglobin to hemoglobin? I don’t think so………..

10:09 pm  
Blogger Andrew Rowell said...

(AR)I do not demand a mouse to a horse demonstration in your lab.... but a detailed theoretical pathway from a Type two secretory system to a working motor would be helpful. Is that unreasonable? (/AR)

(AG)No, it’s not. But a failure to provide a scenario of sufficient detail does not falsify evolutionary theory, nor does it strengthen the case for design.
(/AG)

(AR)I disagree. Our options are limited.
(a) some kind of astonishingly weird co –option event
(b) some impossible fluke
(c) some engineering brilliance
(d) some other utterly unknown cause.

If (a) and (b) are no good then we should at least consider (c) before we resort to (d)(/AR)

(AG)By phrasing your question as the transition from a TTSS to a flagellum, you have already shown one of the weaknesses of the ID argument – that it is a “designer of the gaps” argument. Recall that the original demand was for a model of how the flagellum evolved. Now one possible precursor (the TTSS) has been proposed, the demand is now for a pathway from the precursor to the flagellum, but the weak argument remains the same – if you can’t show x--->y to a certain level of detail, then y was designed.(/AG)

(AR)Scott Minnich believes the evidence points in the other direction ie that the TTSS is a broken flagellum rather than a useful step on the way there.
It is not so much not being able to show x to y in a certain amount of detail. It is that x to y is totally the wrong sort of step to be reached with numerous successive slight modifications.
If the whole argument is so weak why is the TTSS important for anti-ID thinkers?
If the argument is such a weak one why did Darwin identify it as the crucial point at which his theory could be falsified?
"If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case.”
(Charles Darwin)

Imagine for a moment that it was possible to demonstrate mathematically that x-> y cannot occur using random change….and gradual stepwise improvement. What are our options if we do indeed get to that point? (/AR)

(AG)Interestingly, Behe fell into a trap of his own making when he said that he thought hemoglobin was not an irreducibly complex molecule, as it clearly arose from myoglobin. Using his own argument against him, one can ask how he can be so sure. Has he provided a detailed theoretical pathway from myoglobin to hemoglobin? I don’t think so………..(/AG)

(AR)Behe (I would imagine) is not too bothered whether hemglobin is or isn’t.
Just one example of irreducible complexity is sufficient to break the Darwinist monopoly. If you want one good clear example it is best to pick one that is well clear of the undergrowth first.

The motor function of the flagellum is the good clear, example of what we are trying to say. Gradual change and improvement is just not on the cards here. It is a big jump and that is the whole point of the problem. (/AR)

8:01 am  
Blogger Sergio said...

ONly Young Earth Creationists would deny that life on Earth has changed over time

To be honest, I know of no YEC who would say that life forms haven't changed with time. The thing is, they change, but remain what they were before the change.
For example, dogs can change. One can get a bigger dog, ora smaller dog. One can get a dog with bigger ears, or another with smaller ones. One can get skinny dogs of chubby ones. Variation WITHIN a kind is an observed uncontroversial fact.

The problem is that Darwinists extrapolate from variation WITHIN a kind, and use such variation as evidence for variation ACROSS kinds. This is not honest.

9:05 pm  
Anonymous Andy Groves said...

I disagree. Our options are limited.
(a) some kind of astonishingly weird co –option event
(b) some impossible fluke
(c) some engineering brilliance
(d) some other utterly unknown cause.

If (a) and (b) are no good then we should at least consider (c) before we resort to (d)


That doesn’t address the point I made. I’ll repeat it – pointing out a perceived weakness in evolutionary theory does not constitute evidence for design, unless you define design as = (NOT Evolution).


Scott Minnich believes the evidence points in the other direction ie that the TTSS is a broken flagellum rather than a useful step on the way there.
It is not so much not being able to show x to y in a certain amount of detail. It is that x to y is totally the wrong sort of step to be reached with numerous successive slight modifications.


I was actually being sloppy in what I wrote previously – the idea is not that the flagellum could have evolved from a modern TTSS, but that both the flagellum and modern TTSS may have arisen from a TTSS-like precursor. But anyway…..your argument is trying to demonstrate a negative. It is very hard to show that x > y cannot ever be reached.

If the whole argument is so weak why is the TTSS important for anti-ID thinkers?
If the argument is such a weak one why did Darwin identify it as the crucial point at which his theory could be falsified?
"If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case.”
(Charles Darwin)
Imagine for a moment that it was possible to demonstrate mathematically that x-> y cannot occur using random change….and gradual stepwise improvement. What are our options if we do indeed get to that point?


It’s a weak argument because it’s a negative argument. How can you ever show that any complex organ (or biochemical system) could not possibly have been formed by numerous, successive, slight modifications? How can you ever be certain? The reason why people like the TTSS hypothesis is that it shows how Behe’s argument is an argument from ignorance. Behe wrote about several systems that he said could not have evolved. After his book was published, people pointed out that there were indeed plausible intermediates for his so-called irreducibly complex systems. Thus, the simple demonstration of at least one possible intermediate shows how dependent Behe’s argument is on his current state of knowledge. By the by, such a criticism also applies to Dembski’s explantory filter, which is also critically dependent on the current state of knowledge.

(AG)Interestingly, Behe fell into a trap of his own making when he said that he thought hemoglobin was not an irreducibly complex molecule, as it clearly arose from myoglobin. Using his own argument against him, one can ask how he can be so sure. Has he provided a detailed theoretical pathway from myoglobin to hemoglobin? I don’t think so………..(/AG)

Behe (I would imagine) is not too bothered whether hemglobin is or isn’t.
Just one example of irreducible complexity is sufficient to break the Darwinist monopoly. If you want one good clear example it is best to pick one that is well clear of the undergrowth first.

The motor function of the flagellum is the good clear, example of what we are trying to say. Gradual change and improvement is just not on the cards here. It is a big jump and that is the whole point of the problem.


Well, Behe should be bothered about it, because it shows the total vacuity of his argument:

“The bacterial flagellum is IC because scientists cannot provide a detailed evolutionary scenario for its origin”

“Hemoglobin is not IC because I can see it evolved from myoglobin, although I cannot provide a detailed evolutionary scenario for its origin”

He’s resorting to the pornography argument – “I know it when I see it”.

In sum, ID flits back an forth between an argument from ignorance and a designer-of-the gaps argument. If ID proponents cannot see how something evolved, it must be designed. When people point out a possible intermediate in the process, ID proponents then say they cannot see how the intermediate evolved. And so on.

1:49 am  
Anonymous Andy Groves said...

Sergio - I was referring to a change over geological time. Dog-like animals such as Hesperocyon can only be seen in the fossil record for the last 40 million years or so. Before that, there were no dog-like animals of any kind. Since YECs don’t think the Earth is more than 10,000 years old, How do they explain the appearance of Hesperocyon in the fossil record?

You bring up a discussion of “kinds” (or to give them their scientific creationist term, baramins) and say that variation across kinds is controversial. There are many fossils that show forms intermediate between:
- primitive jawless fish to sharks and rays,
- primitive jawless fish to bony fish.
- Fish to amphibians
- Amphibians to reptiles
- Reptiles to mammals
- Reptiles to birds

In addition, there are many intermediate fossils within a group, for example, among mammals. What creationists do is to look at a fossil which has features of two groups (like the old favorite, Archaeopteryx, which clearly has feathers, but a reptilian skeleton), and just say “It’s a bird”.

1:50 am  
Anonymous Nathan said...

Andy you are mistaken about your last statement on Archaeopteryx. It isn't creationists who are saying that archaeopteryx is a bird, it is world renowned scientists such as Alan Feduccia, who is an expert in ornithology.
Here is a quote from Dr. Feduccia:
“Paleontologists have tried to turn Archaeopteryx into an earth-bound, feathered dinosaur. But it’s not. It is a bird, a perching bird. And no amount of ‘paleobabble’ is going to change that.”

Please note that Dr. Feduccia is an evolutionist like yourself.

6:18 pm  
Blogger Andrew Rowell said...

Andy,

You said:
"It’s a weak argument because it’s a negative argument."

Do you believe that all negative arguments are weak? Do you believe that they do not have an important place in science?

You said:
"pointing out a perceived weakness in evolutionary theory does not constitute evidence for design, unless you define design as = (NOT Evolution)."

If you rule out chance and necessity have you got other suggestions apart from design?

Do you think SETI was logically flawed?

9:10 pm  
Anonymous Andy Groves said...

Nathan,

You are correct that Feduccia does not believed that birds arose from dinosaurs. He believes that birds arose from more primitive basal reptiles - more closely related to turtles or crocodiles than to theropod lizards. He still thinks Archaeopteryx is a transitional fossil between birds and reptiles - just not birds and dinosaurs/theropods. For what it's worth, he is in a minority position on that.

9:52 pm  
Anonymous Andy Groves said...

Andrew,

Do you believe that all negative arguments are weak? Do you believe that they do not have an important place in science?

Yes, I think that negative arguments are weak, and that they should not have an important placce in science. Anyone who makes a negative scientific argument ("X cannot happen", "X does not exist", etc) has to acknowledge that their claim is based only on the absence of data. To paraphrase Karl Popper, saying "I saw a black swan today" is a much stronger claim than to say "There are no black swans".

If you rule out chance and necessity have you got other suggestions apart from design?

Yes, there are two other important categories.

1. Chance and necessity which is actually a better description of how evolution works (the non-random survival of randomly varying replicators, as Dawkins puts it)

2. "We don't have enough information to tell".

Do you think SETI was logically flawed?

Not at all. SETI starts off by looking for signals based on particular criteria. Those criteria derive from what we would expect human-like creatures to do. SETI filters out signals that are known to be caused by natural phenomena (like pulsars) and humans.

ID has no positive criteria for designed objects. The one they use - irreducible complexity and specified complexity - are based on what ID proponents think evolution cannot do.

Actually, Dembki's concept of specified complexity is even worse than that, as he assumes that the "conceptual information" encoded in the specification will be readily comprehensible to us. Translation: If we think it looks designed, it is designed.

10:21 pm  
Anonymous Anonymous said...

"In fact, I think it is perfectly possible – in theory - that an intelligent designer created all life on Earth. However, I see no evidence for that at present."

Could I ask Dr. Groves to tell us what evidence would convince him that a given biological structure was intelligently designed?

2:28 am  
Anonymous Anonymous said...

"Yes, I think that negative arguments are weak, and that they should not have an important placce in science."

I think that negative arguments DO have an important place in science (and anywhere else) when the two competing options are mutually exclusive and exhaustive.

There are two views under consideration here.

UE ("undirected evolution") states that there was no intelligent agency involved in the evolution of life. (Neo-Darwinism is the most plausible version of UE around.)

ID ("intelligent design") states that some intelligent agency was involved in the evolution of life.

Problems and difficulties in UE constitute evidence for ID, in much the same way that problems and difficulties for th view that I am in the house constitute difficulties for the view that I am outside the house.

"Anyone who makes a negative scientific argument ("X cannot happen", "X does not exist", etc) has to acknowledge that their claim is based only on the absence of data. "

This is not true. A scientific argument can be based on thoroughly confirmed scientific laws like the second law of thermodynamics, which undirected evolution violates in a truly spectacular fashion.

See, for example, Granville Sewell's

"Evolution's Thermodynamic Failure."

http://www.spectator.org/dsp_article.asp?art_id=9128

2:47 am  
Anonymous Anonymous said...

"It’s a weak argument because it’s a negative argument. How can you ever show that any complex organ (or biochemical system) could not possibly have been formed by numerous, successive, slight modifications? How can you ever be certain?"

(W.T.F.???) Every debate forum that I’ve seen without exception, ID is rejected because it is claimed to be 'unscientific' since it is deemed un-falsifiable. Since fasifiability is a fundamental necessity to all scientific theories you have just insulated evolution from any kind of falsification.


“How can you ever show that any complex organ (or biochemical system) could not possibly have been formed by numerous, successive, slight modifications?”

So in plain English it is impossible to disprove evolution by slight successive modification! This is offensive to anyone with the ability to think! If evolution is not falsifiable then why is it allowed to be a scientific theory and not ID???

And if you want to now claim that it can be falsifiable then give specific point-by-point descriptions of what conditions would falsify it!

5:43 pm  
Blogger Andrew Rowell said...

Annonymous,

Good points! Thank you!

6:09 pm  

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