JP Holding on homology

[SteveF]

TWebs very own JP Holding has an article over at CMI (the offshoot from AiG) concerning homology. I thought it might be nice if the Nat Sci forum members could take a look at this article. It has a theological feel to it, but ultimately homology comes under Natural Science so I posted this here.

http://www.creationontheweb.com/content/view/4781/

What do we think of the above?

[Sparko]

What do we think of the above?

You need someone to tell you how you should think?

[SteveF]

You need someone to tell you how you should think?

Yes. I have no mind of my own.

[Sparko]

Yes. I have no mind of my own.

OK. makes perfect sense to me.

I think JP makes a valid point. You can look at an artist's work and tell that a piece of art is from a particular artist because it exhibits common traits with the artist's other works. Homologuous elements in animals could be argued to be similar. At worse, neither side should be using it as a "proof" they are right.

[jpholding]

Since I know Skeptics who aren't as thoughtful as Steve will say so (maybe even if I say this), let me say that I do NOT consider what I wrote to be some sort of debunker of evolution. I only consider it to be a slam dunk against one PARTICULAR argument used AGAINST special creation/ID arguments. I also do NOT say that it only supports the YEC view (even though I wrote it for CMI) -- obviously it is just as useful for OEC or even some forms of theistic evolution I have seen proposed.

So let's be sure not to make me say more than I did. Be like Steve....be thoughtful and make sure you read what I say, and no more than that.

[SteveF]

Just to clarify, I noticed that JP had an article over at CMI and, given the prominence of this organisation I thought it would be nice if there could be a group discussion of it here. Homology isn't a subject that is discussed all that often here (usually it is Dembski or various other things) and I was interested in the range of opinion. JP's article seemed like a good starting point as it is representative of YEC though and this is what motivated me to start this thread.

[Soundsurfr]

Just to clarify, I noticed that JP had an article over at CMI and, given the prominence of this organisation I thought it would be nice if there could be a group discussion of it here. Homology isn't a subject that is discussed all that often here (usually it is Dembski or various other things) and I was interested in the range of opinion. JP's article seemed like a good starting point as it is representative of YEC though and this is what motivated me to start this thread.

The entire article is a straw man, as this:

We can apply this analysis to a major evolutionary argument:

1) If organisms X and Y have a common ancestor, they will have homologous structures;
2) X and Y have homologous structures;
3) X and Y have a common ancestor.

Is not a "major evolutionary argument". It's a mischaracterization of an evolutionary argument. There is a host of scientific evidence for descent through modification, and the existence of homologous structures in and of itself is not considered by scientists to be some end-all proof of common ancestry.

Holding's argument is akin to pointing out the flaws in the following:

Jane was stabbed to death with a Japanese sushi knife.
Jane's husband owns a Japanese sushi knife.
Therefore Jane was stabbed to death by her husband.

Obviously, this is not solid proof of anything. However, if there are a litany of other clues that point to Jane's husband as a suspect, then we would look for and not be surprised to find that Jane's husband owned or had access to a japanese sushi knife, and this context, the discovery adds considerable weight to the argument.

We don't see anything in Holding's argument as to whether or not there are other factors involved in scientific analyses of common ancestry. We only see innuendo that the fallacy above is being committed, in general, by evolutionists. Holding has the gall to close with the following gratuitous statement:

We may conclude, in summary, that the evolutionist argument based on homologous structures is deeply flawed and highly subjective.

What a crock.

[Roy]

Since I know Skeptics who aren't as thoughtful as Steve will say so (maybe even if I say this), let me say that I do NOT consider what I wrote to be some sort of debunker of evolution. I only consider it to be a slam dunk against one PARTICULAR argument used AGAINST special creation/ID arguments. I also do NOT say that it only supports the YEC view (even though I wrote it for CMI) -- obviously it is just as useful for OEC or even some forms of theistic evolution I have seen proposed.

Ok, but I still think you've picked the wrong form of the argument to critique.

You critiqued:

1) If organisms X and Y have a common ancestor, they will have homologous structures;
2) X and Y have homologous structures;
3) X and Y have a common ancestor.

But this is only used when working within an evolutionary framework, to determine whether X and Y have a recent common ancestor, rather than a remote one. The homology argument against creationism/ID would be

1) Homologous structures are unnecessary similarities that betray evolutionary constraints.
2) If organisms X, Y, Z etc were designed (by an unrestrained designer), they will not have homologous structures.
3) X, Y, Z etc have homologous structures.
4) X, Y, Z etc were not designed (by an unrestrained designer).

Roy

[jpholding]

The entire article is a straw man, as this:


Is not a "major evolutionary argument".

Well it sure is funny how I find it on evolutionary websites then isn't it.

Apparently you have nothing to say that actually answers what I wrote, so it must be sound.

and the existence of homologous structures in and of itself is not considered by scientists to be some end-all proof of common ancestry.

Please do feel free to quote where I say, " homologous structures in and of itself is not considered by scientists to be some end-all proof of common ancestry."

Oh. You missed my last post in which I said to answer what I wrote and not what I didn't. Must be because of the brain damage you received from the last beating I gave you.

I am not answering the idea of homologous structures as positive proof for evolution, stupid. I'm answering the idea of them as negative proof against ID.

We don't see anything in Holding's argument as to whether or not there are other factors involved in scientific analyses of common ancestry.

We don't see a reciple for creme brulee either. That must mean I think it doesn't exist.

When the Stupid Train finishes running over you, clean up the tracks after yourself, please.

Ok, but I still think you've picked the wrong form of the argument to critique.

My answer would be no different. "Homologous structures are unnecessary similarities that betray evolutionary constraints" makes the same presumption of originality as a means value for a Creator.

[NeilUnreal]

I think the place where the argument runs into rough going is when one gets into the scientific details.

At a superficial enough level, of course, homology agues neither for nor against evolution.

However, when you get into the details, including (but not limited too): history of homology in the fossil record, harmony of homology with the nested hierarchy of genetics and taxonomy, genetic details associated with specific homolgies, etc., the fact that observed homologies have never been observed to contradict any of these means homology provides strong inductive support for common descent.

In the end, the best arguments for evolution are the lack of contradictory evidence and and the strong confluence of independent lines of evidence. Homology supports both of these arguments.

-Neil

[Bald Ape]

From JP's article:

The conclusion is not proven—the homologous structures could be due to a common designer, leaving a ‘biotic message’ that there is a single designer of life rather than many.

So, can we infer that the cephalopod eye and vertebrate eye - similar in function but fantastically different in form - were created by many designers?

[LGM]

I am not answering the idea of homologous structures as positive proof for evolution, stupid. I'm answering the idea of them as negative proof against ID.

Professor Holding,

Can you enlighten us with some "negative proofs" of ID? I'm sure we'd all be fascinated by your scientific insights.

Perhaps you'd consider the overwhelming number of genetic defects that causes so much suffering and death in your own species?

Or is that something an "intelligent" designer would do on purpose?
Are Down's syndrome and Cystic Fibrosis the result of the intelligent design?

I wonder why the alleged intelligent designer can never seem to make up his mind about what the best design is for any homologous structures?

Why wouldn't he have designed eyes for his favorite species, as good as eagle's or squid's eyes?

See if you can get the answers when you talk to the designer before you go to bed tonight.

Thanks.

[Bald Ape]

JP,

A follow-up thought: The case from homology is best expressed like this:
Evolution predicts that animals with recent common ancestors will have co-located organs with similar form (and underlying genetics) even though they may differ dramatically in function. Inversely, evolution predicts that animals with remote ancestry will have organs that may be colocated and identical in function, yet vary drastically in function (and underlying genetics).

To put you on the spot: Under the "biotic message theory", would you expect a whale fin to more closely resemble a shark fin or a human hand? Would you expect a bat wing bone structure to more closely resemble that of the sparrow's wing or that of a horse's hoof? Using your expertise in such matters, tell me: what might the ancients have thought of a designer who used such drastically different structures for such similar appendages as a bat wing and bird wing?

[Dwevlo]

This is an example of an Abductive inference (or more commonly, an inference to the best explanation). Its deductively fallacious, but quite useful. Indeed most interesting philosophy/theology, and pretty much all science follows this same basic pattern.

JP Holding's point on this matter is a good one. As an argument against creationism/ID, homology gets you know where since it can explain the evidence just as well. (The two competing theories are equally predictive on this point)

The difference here is that ID can cope with the reverse as well (non homologous structures) whereas most evolutionary models cannot. This seems to imply that ID is less falsifiable than evolution.

This dichotomy between attacking an argument, and defending a theory is easy to get mixed up. Notice how the immediate response to Holding's argument was along the lines of:

"What would ID predict about such and such situation"

But this is a different question - one not addressed in his argument. I agree that its important, but its on a different level then a standard objection:

1) "Your theory has less explanatory power / is less falsifiable than mine"

versus

2) "Your theory predicts X but ~X"

(2) is usually a far bigger problem than (1).

Interestingly some philosophy of science is willing to deal with inconsistencies if the theory as a whole is useful... Something like, "Well I know my theory is strictly wrong, but most of the time it works pretty good, far better than its competitors"

[LGM]

JP Holding's point on this matter is a good one. As an argument against creationism/ID, homology gets you know where since it can explain the evidence just as well. (The two competing theories are equally predictive on this point)

Can you tell me what the "theory of ID" is?

The difference here is that ID can cope with the reverse as well (non homologous structures) whereas most evolutionary models cannot.

"magic" can cope with anything, if I'm not mistaken.

The "designer" could have designed purposeless, genetic mutation and selection, and could care less what comes out the other end. But for some odd reason, that doesn't jive with our ancient myths.

There's no theory of ID, it's simply an attact on gaps of knowledge that exist in evolutionary theories and models.

Saying a "designer", (wink, wink, nod towards evangelical Christian heaven), shows up occasionally and duct tapes a flagellum on a cell, or a blood clot sequence in a vertebrate, isn't science, it's surrendering. And it can't be reconciled with any revealed religion.

Again, a simple question that I've yet to see answered.

Does the poor design evident in countless biological organisms, or the fact that there are so many extinct species, falsify ID?

Or is it that ID stands for incompetent design?