Uncommon Descent Serving The Intelligent Design Community

Common Descent or Common Design – Is There a Difference?


As long as I’m on the subject of overwhelming points of similarity vs. underwhelming points of difference, a few points of similarity between man and chimp in no particular order, off the top of my head:

ten fingernails on ten fingers
two opposable thumbs
two wrists
two elbows
two eyes
two ears
two lungs
two shoulders
two nipples
four chamber heart
two kidneys
bile duct
small intestine
large intestine
private parts
red blood cells
white blood cells
bone marrow

yada yada yada

I could go on for pages and pages…

If man and chimp didn’t both descend from the same ancestor then surely the designer worked off the same template because there’s no denying the vast majority of parts and assembly are the same. What exactly is the practical difference between common descent and common design when the result is the same – so many undeniable points of similarity that there’s no question of a close relationship of some sort?

DaveScot Many thanks for the plug. John Davison
Of interest... http://www.discovery.org/scripts/viewDB/filesDB-download.php?id=119 Scott
What evidences argue against common ancestry that would make it plausibly deniable? -ds How about the facts that it is a) untestable and therefore b) unverifiable ? Ergo it is an un-scientific premise. How about the fact that science cannot even demonstrate that a population of single-celled organisms can "evolve" into anything but a population of single-celled organisms? And finally what about the evidence in chapter 11 ("From Ape to Human: The Ultimate Icon") of "Icons of Evolution: Science or Myth" by Jonathan Wells? Joseph

The writer of the article you cite is rather confused about both ERVs and common ancestry. For example:

"Moreover, transposons are inadequate in principle to support Dr. Theobald’s claim of universal common ancestry, because they are not shared by all groups of organisms"

Limbs, middle ear bones, enamelled teeth, exoskeletons and notochords (to name but five morphological features) are not shared by all groups of organisms either. Nevertheless, they allow us to construct hierarchies of organisms based on shared features. This applies to ERVs as well.

As to the function of ERVs or pseudogenes, there is evidence that some of them can act as enhancers. This is not surprising, because a) active retroviruses have powerful enhancer sequences in their genomes (which is how they become active in host cells in the first place) and pseudogenes are typically the result of duplications of existing genes, which can also include enhancer sequences.

Finally, it is true that retroviral insertion is not entirely random. But to claim that it is predictable is completely wrong. Even if you accept the propensity of certain viruses for certain sequences, there are still a huge number of potential integration sites to choose from. The evidence that integration targets diverge between species in the same pattern as morphological features is good evidence for nested hierarchies.


I found a good explantion of ERV markers here. Good stuff. The evidence that evolution happened is indeed overwhelming. The question is still did it happen by design or by accident. Every bit of evidence; the fossil record, macroscopic and microscopic homology, irreducible complexity, complex specified information, parallels between ontogeny and phylogeny, fit perfectly together by way of a hypothetical uber-genome deposited on this planet early in its history (from where and by whom may not be possible to answer) that was designed to multiply and diversify itself in a prescribed sequence just like a fertilized human egg multiplies and diversifies itself in a prescribed sequence. The timescale is the only thing markedly different in phlyogenesis vs. ontogenesis. They are both manifestations of the same process, like repeating patterns in a fractal are manifestations of the same process on different scales. Moreover the diversification llargely if not entirely occurs by prescribed saltational events in phylogeny just as it does in ontogeny with the environment serving little if any role other than supplying triggers for the next prescribed step. This is also in agreement with all the data. This is why there has never been an observation or even plausible inference from observation that tiny steps accomplished by random mutation + natural selection can add up into the creation of novel, highly specialized, fit to purpose cell types, tissue types, organs, and body plans. Now, DaveWatt, since we are in agreement that descent with modification happened and common ancestry is true, I would ask that you study this carefully and critically, as I have done over the last year, and point out what you think might be wrong with it. I can't find a thing wrong with it and it isn't for lack of trying. I've been bickering with its author incessantly for many months and the bottom line appears to be - it is the best fitting evolutionary hypothesis out there.

p.s. to DaveWatt - By definition ERVs are neutral and thus subject to wanton destruction by random mutation and will be obliterated in short order (short in geological timspans). They obviously persist long enough to tie the primate lineage together. Can they tie together primates and canines or mammals and birds, for instance? How long on average are they useful? DaveWatt
good point. Scott

Dave, the brand of non-Darwinian "common ancestry" which you ascribe to is thoroughly supported by the fossil record and the majority of the empirical evidence, in my opinion. i.e. the sudden appearance of fully formed and distinct body plans, etc... What I'm trying to demonstrate is that the gradualistic Darwinian model of undirected descent does not stand up under scrutiny.

Fair enough. We have two problems and you're addressing the second. The first problem is convincing the NAS that we're not in denial of the evidence supporting the continuity of life and descent with modification (evolution), and the second is convincing the same people that evolution happening without prescription is virtually impossible. Both problems must be solved. The former is the more delicate due to the financial and numeric support for the latter largely coming from those who deny even guided evolution and believe in creation ex niholo of existing "kinds". I don't believe the latter is all that difficult to solve and if the first problem is solved the second will be solved almost effortlessly. -ds


DaveWatt, remnants of this variety have always been intruiging to me. And, on the surface, what you have said would seem to demonstrate common ancestry. However, this issue is not quite so cut and dry...

http://www.trueorigin.org/theobald1e.asp [scroll down to PREDICTION 21]

"The suggestion that the hypothesis of common ancestry would be falsified by the discovery of the same ERV at the same locus in two species that are not believed to have shared a recent common ancestor is incorrect. ERVs simply would join the list of alleged markers for evolution that exhibit homoplasy. And given what is known of retrovirus selectivity, I doubt anyone would be surprised."

We have much evidence arguing for common ancestry. Each individual bit of evidence may be questionable at the margins but the bits are cumulative and taken together become virtually undeniable. What evidences argue against common ancestry that would make it plausibly deniable? -ds Scott

I posted this in another thread:

"What is, for me, the most compelling evidence of all is the recent discovery that humans and chimps share many endogenous retroviral insertions in their DNA. Put simply, this means that retroviruses often insert into an animal’s DNA, and frequently become inactive. The retroviral DNA stays in the genome and is inherited. If two species share this retroviral DNA, btu a third does not, this implies that the two species sharing the DNA are more closely related to each other than to the third species.

Here’s an analogy. Let’s say generations of monks were copying out the Bible, and passing copies on to younger monks. Let’s say you travelled round Europe and found a small area in Scotland where all the bibles began with the words “In the beginning Dog created the heaven and the earth”. It is much more likely that the mistake in all the Bibles in that region was inherited from a careless copyist in the area, rather than each monk making the same mistake independently.

The fact that chimps and humans share these retroviral insertions suggests they derived from a common ancestor. The fact that they have more of these retroviral insertions in common with each other than, say, between humans and gorillas, or humans and marmosets, or humans and donkeys, suggests that humans and chimps are most closely related.

It is of course possible that a Designer decided to stick these bits of DNA in our genomes to fool us. But once you start inviting such possibilities, pretty much anything is possible."


Agreed. ID however doesn't speak to the issue of common descent. The Darwinian apologist tactic is to use guilt by association to discredit ID. The claim is that most ID proponents reject common descent so by way of association ID must also reject common descent. Rejection of common descent will never, ever be accommodated by science. Anyone that thinks it will be is in denial. If the guilt by association tactic remains successful ID will continue to be excluded. ID basically has become a cause célèbre for common descent deniers and it's dragging the scientific argument for ID down a hole from which it cannot climb out whilst carrying that special creation burden on its back. -ds

Scott, There are a number of problems with Luskin's article. For now, I'll just point out a couple of things: 1. Noone expects phylogenetic trees generated from different genetic or molecular data to match exactly. But the degree of similarity is astounding. 2. W. Ford Doolittle's work on lateral transfer at most implies that there is some messiness to the tree of life. It by no means suggests, however, that all of the mammals do not have a common ancestor, or that humans are not related to chimpanzees. The latter is the real issue for most of the skeptics of common descent, who for religious reasons want to believe that humans were separately created and are therefore special. valerie
EJ Klone (comment #73): "Are you suggesting that each individual species (or at least some specific species) were intended, or are you just saying that the designer just intended to spur an explosion of species, with no specific ones in mind?" Thanks for the question. If the distinction between some of the species is due to functionally neutral or degrading changes, then I suppose its theoretically possible that they may not have been intended; They may have formed as the result of NS+RM, or some other dumb/purposeless/blind processe(s), in populations that were sufficiently isolated from one another. But this isn't consistent with the the fossil record. If such speciation occured, why wouldn't it occur continuously, perhaps slower in some species, faster in others? (Perhaps such changes only happen under extreme duress, as in bacterial antibiotic resistance? Although it's not yet led to speciation in them.) The stases in the fossil record imply that such randomly occuring, neutral or degrading changes are eliminated and/or prevented somehow. However, insofar as the distinction is due to functional innovation -- e.g. a new cell type, tissue type, organ, or body plan (credit: ds), then they need to have been intended. This general conclusion follows from observations in the field of evolutionary algorithms. j
YECist, "My answer is that we probably can’t tell whether one creature is similar to another because of common descent or common design because the two causes could have indistinguishable results." But they don't. Don't worry -the work has already been for you, and the winner is common descent. Boesman

"Doesn’t it seem just a bit odd to you that God would choose spokesmen who’re unable to demonstrate that they actually have some kind of hotline to God that the rest of us are denied?"

Have you read the Bible? God gave many spokesmen the abiblity to demonstatrate that they were in touch with a higher power. Jesus said (paraphrasing) unless you see these miracles you will not beleive.

If the physical evidence of the world (say, for instance, discontinuity in the biological world) fits what the "prophet" says (say, for instance, diversy among "kinds" -- not common descent) then we should be allowed to go with it, not constrian ourselves to materialistic explanations no matter how good or bad they are.

I don't want to get into battle of religious faith here. ID doesn't deny yours or mine. We ARE going to leave it at that. -ds YECist

Dave Scott,

You said …

“The argument is that they look so similar, right down the core molecular machinery and life codes, they must have linkage through common ancestry and/or common design. Anyone that doesn’t acknowledge the overwhelming similarities is plainly in denial and cannot be reasoned with. Common ancestry and common design are not mutually exclusive. Common ancestry may have simply been the way the abstract design of both humans and chimps was made real. The evolution of them was prescribed by the designer. What IS mutually exclusive is common ancestry and creation ex nihilo. There is abundant evidence of ancestry - life comes from life - and there is no evidence of life ever coming from non-life. Common ancestry is therefore the prevailing theory absent any evidence to the contrary.”

YECs don’t deny similarities between humans and chimps. We explain it by common design due to a common Designer, not common ancestry (just as you will find similarities between paintings by Monet). Obviously, if you are going to limit yourself to naturalistic processes then common ancestry of some kind is the only game in town. I believe science is all about learning about the world around us, and it should include an investigation of the truth about our origins, not a search for the best naturalistic explanation (no matter how well that explanation may, or may not, work). All things being equal, I prefer naturalistic explanations when they have no large difficulties. When they do – and I would think that most people reading this post would agree that Darwinian evolution has major problems – I am willing to consider “supernatural” explanations. I realize that most mainstream science journals won't consider such options, but I believe we need to get them to see their philosophical biases, not simply forfeit by capitulating to their biases.

What is your answer to your own question, “What is the difference between common ancestry and common design?” My answer is that we probably can’t tell whether one creature is similar to another because of common descent or common design because the two causes could have indistinguishable results. I am interested in your answer to your own question … ?

If your axiom is that all life descends from pre-existing life, then I assume you would think that abiogenesis is an impermissible explanation for the origin of life. If naturalistic abiogenesis is out, then the only thing we are left with is a supernatural start for life … but you are adverse to invoking supernatural explanations, right?

In regard to "only game in town" the only other game in town is revelation. Science is not built upon faith in prophets claiming to be speaking for God. Doesn't it seem just a bit odd to you that God would choose spokesmen who're unable to demonstrate that they actually have some kind of hotline to God that the rest of us are denied? -ds

Red, that is actually a great example of why the Darwinian mechanism fails, but I think the flavor of descent that DaveScot is talking about is a saltation approach. Where the designer programmed species to "unfold" abruptly. Scott
DaveScot wrote: "IC and CSI does nothing to either confirm or dispute common descent unless you’ve adopted some definition of them that isn’t as Behe and Dembski have defined them. -ds" I think your assertion that IC says nothing about common descent ignores IC's most obvious and most immediate implication: irreducibly complex structures *do* *not* *have* *precursors*. No precursor, no common descent. No supplimentary definition of IC required. Even Wikipedia (which I loathe) understands that the concept of IC wipes out common descent. Their article first cites Dr. Behe's definition of IC: .... The term "irreducible complexity" is defined by Behe as: "...a single system which is composed of several interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning". (Michael Behe, Molecular Machines: Experimental Support for the Design Inference) Supporters of the intelligent design theory use this term to refer to biological systems and organs that they believe could not have come about by an incremental series of small changes. They argue that anything less than the complete form of such a system or organ would not work at all, or would in fact be a detriment to the organism, and would therefore never survive the process of natural selection. .... Dave, I'll admit I've been wrong sometimes. And maybe I'm wrong now. But if I'm wrong, show me either --how IC allows for *precursors* or --how precursors are not neccessary for Common Desent. With great respect for your thoughts and moderation responsibilities... Red Reader
J said: "In these episodes, the intelligence has had a specific purpose in mind: to create various species." Are you suggesting that each individual species (or at least some specific species) were intended, or are you just saying that the designer just intended to spur an explosion of species, with no specific ones in mind? EJ Klone

Arghhh..... Why is every single comment now being fed into the RSS feed? COuld we not have 2 feeds if we feel a need to have all the comments on the RSS feed.

I'll forward your concern to the blog admin. -ds Shane
valerie (comment #68): "...design reuse in separately created designs. That is the position I am arguing against." I don't kno-ow. You're statement in comment #44 was pretty absolute: "...ONLY in this case..." However, I'm glad you agree that common design and real common descent can coexist. In the future, I hope that you'll remember to add the italicized: "...unless there is a designer at work who is “planting the evidence” to make common descent appear to be true, or who developed life using an evolutionary process." j
Boesman (comment #66): "Interesting that ‘design’ is mentioned as a synonym. I guess that’s why you left it out, or did you want to say that “NS+RM don’t DESIGN anything”? First you question my perfectly appropriate use of the word, "create." Then, when I provide a particular meaning to make it clear that I didn't simply mean that NS+RM couldn't create ex hihilo, or something, you seem to imply that I've been intellectually dishonest. How about trying to think about a legitimate reason for things before such actions? I saw the synonym "design" and chose not to include it because, confusingly and without any ability to demonstrate it, Darwinists actually insist that NS+RM can generate apparent design: the word has significant baggage. I felt that broaching this would be unproductive to the discussion; that I am having to address the issue right now makes me think my intuition was probably right. Actually, using any of the definitions of the verb "design" at www.m-w.com/dictionary/design , I have no problem with the statement, "NS+RM don't design (or apparently design) anything." That works, too. j
Luskin has some interesting things to say regarding Phylogenetic trees... http://www.ideacenter.org/contentmgr/showdetails.php/id/846 ""Family Trees" (called "phylogenetic trees") based off of DNA sequences in genes should make nice neat "Darwinian Trees" if common ancestry is true. However, it is well recognized in the field of classification (systematics) that very often phylogenetic trees based upon one gene or protein sequence, will lead to one tree, while a tree based upon some other biomolecule will look quite different. Molecular biologist W. Ford Doolittle wrote, "[m]olecular phylogenists will have failed to find the 'true tree,' not because their methods are inadequate or because they have chosen the wrong genes, but because the history of life cannot properly be represented as a tree."7 Yet, evolution predicts that molecular data should allow a phylogenetic "tree of life" to be reconstructed. Descent, apparently, has been falsified." Scott
Charlie says: "Phylogenetic trees based upon molecular analyses conflict in significant ways and fail to yield any single tree." It's true that these analyses often fail to yield a single tree, but the trees they do yield are so similar that the statistical significance is overwhelming (far better than one in a million). Consider this phylogenetic tree, including 30 major taxa: http://www.talkorigins.org/faqs/comdesc/phylo.html#fig1 Douglas Theobald writes concerning this tree, "quantitatively, independent morphological and molecular measurements such as these have determined the standard phylogenetic tree, as shown in Figure 1, to better than 38 decimal places." Of parsimony analysis, Red Reader says "This is just assuming the result before gathering the evidence." It's true that parsimony analysis will always produce a tree regardless of the data. If we stopped with a single tree and pointed to it as evidence of common descent then Red Reader would be right to accuse us of "assuming the result before gathering the evidence", as he puts it. But as I explained above, we don't stop with a single tree. We construct many trees based on independent analyses of different proteins, genes, etc. If common descent is false, then the trees should differ far more than they do, unless there is a designer at work who is "planting the evidence" to make common descent appear to be true. “Designer reuse" does not explain why the trees are so similar. Automobiles are a clear real-world case of "designer reuse", but think about the results you would get if you tried to reconstruct automobile "phylogenetic trees" based on independent parsimony analysis of changes to the different parts of the car (valve train, transmission, body styling, interior features, sound system, etc.). The trees produced would differ utterly from each other. j writes the following concerning the “episodic evolutionary development hypothesis”: "In this case, the designer would not be imitating common descent; common descent is just a byproduct of the mode of development." It's true that if the designer makes common descent happen, then he's not merely mimicking it, he's making it happen. But that is different from what most of the "common designists" in this thread and on this blog propose. They believe that the similarities among organisms are not due to inheritance, but due to design reuse in separately created designs. That is the position I am arguing against. valerie

“Apart from Dr. Davison, which other commenters have any formal training in biology or any other scientific discipline?”

I’m curious why you ask, Xavier, since intelligent people from all backgrounds can objectively look at the data and form a reasonable opinion.

Comment by Scott — February 7, 2006 @ 7:19 am

Sure, anyone can give an opinion, but whether that opinion has any 'weight' to it is another matter. If you pull up with your car running rough, I can give you my opinion as to what might be wrong with it. (such as you bought a X when you should have bought a Y, there's a gremlin under the hood, wrong gas, etc) but would you rather take my opinion or that of a certified auto mechanic?

And by the way, Xavier, I have an AS and a BS in biology, a BA in Anthropology, and will be graduating soon with a Masters in biology.


So when it comes to recognizing design an engineer seems to be the expert with the most "weight", right? As an engineer and patent maven in the computer and factory automation fields it is my professional opinion that the molecular machinery resident in every living cell is the product of intelligent agency. It's inconceivable the source could be anything else. -ds

j, "1 : to bring into existence 2 a : to invest with a new form, office, or rank b : to produce or bring about by a course of action or behavior 3 : CAUSE, OCCASION " None of those. Agreed. "b : DESIGN intransitive senses : to make or bring into existence something new" Interesting that 'design' is mentioned as a synonym. I guess that's why you left it out, or did you want to say that “NS+RM don’t DESIGN anything”? Boesman
"Apart from Dr. Davison, which other commenters have any formal training in biology or any other scientific discipline?" I'm curious why you ask, Xavier, since intelligent people from all backgrounds can objectively look at the data and form a reasonable opinion. Scott
create - 4b "to make or bring into existence something new" www.m-w.com/dictionary/create j
Apart from Dr. Davison, which other commenters have any formal training in biology or any other scientific discipline? Xavier
j, "NS+RM don’t create anything" Correct. They evolve. Boesman
Just wondering what you guys thought of baraminology. I don't really know that much about it. http://www.bryancore.org/bsg/ anteater
valerie (comment #44): "The only exception would be if the designer chose to imitate common descent for some reason. In this case, and ONLY in this case, common descent could not be distinguished from common design." Not so. For example consider the following "episodic evolutionary development hypothesis": Mankind is the product of a process of evolutionary development. The claims of the scientific community that the universe is about 13.7 billion years old, that the earth is about 4.5 billion years old, that the first life appeared on earth about 4 billion years ago, and that it evolved from relatively simple to highly complex forms, are all true. However, Darwin's hypothesis that evolution occured exclusively by means of blind/purposeless/dumb processes, is wrong. Episodically, either the selection, the mutations, or both, have occurred in accordance with the intent of an intelligence. In these episodes, the intelligence has had a specific purpose in mind: to create various species. Species have been allowed to exist for a limited amount of time, and then they (or part of their populations) have been formed into something slightly different. In this case, the designer would not be imitating common descent; common descent is just a byproduct of the mode of development. Echoing Professor Davison(comment #49): common descent and common design are not mutually exclusive. This hypothesis is consistent with the biological stases observed in the fossil record, the common descent that may be implied by genomics, and with the observation (in the field of evolutionary algorithms) that NS+RM don't create anything. (The intent of creating something has to be built in, and in that case it's not natural selection, since undirected nature is dumb, purposeless, and blind.) j
valerie wrote: "Using parsimony analysis, construct a tree showing the hypothetical relationships of the species to each other and to their common ancestors." This is just assuming the result before gathering the evidence. "Designer Reuse" also explains the similarities. See: https://uncommondescent.com/index.php/archives/687 Red Reader
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