Since the time of the Dover trial in 2005, I’ve made a hobby of debating Intelligent Design proponents on the Web, chiefly at the pro-ID website Uncommon Descent. During that time I’ve seen ID proponents make certain mistakes again and again. This is the first of a series of posts in which (as time permits) I’ll point out these common mistakes and the misconceptions that lie behind them.
I encourage IDers to read these posts and, if they disagree, to comment here at TSZ. Unfortunately, dissenters at Uncommon Descent are typically banned or have their comments censored, all for the ‘crime’ of criticizing ID or defending evolution effectively. Most commenters at TSZ, including our blog host Elizabeth Liddle and I, have been banned from UD. Far better to have the discussion here at TSZ where free and open debate is encouraged and comments are not censored.
The first misconception I’ll tackle is a big one: it’s the idea that the evidence for common descent is not a serious threat to ID. As it turns out, ID is not just threatened by the evidence for common descent — it’s literally trillions of times worse than unguided evolution at explaining the evidence. No exaggeration. If you’re skeptical, read on and I’ll explain.
Common Descent and ID
The ‘Big Tent’ of the ID movement shelters two groups. The ‘creationists’ believe that the ‘kinds’ of life were created separately, as the Biblical account suggests, and these folks therefore deny common descent. The ‘common descent IDers’ accept common descent but argue that natural processes, unassisted by intelligence, cannot account for the complexity and diversity of life we see on earth today. They therefore believe that evolution was guided by an Intelligence that either actively intervened at critical moments, or else influenced evolution via information that was ‘front-loaded’ into the genome at an earlier time.
Creationists see common descent as a direct threat. If modern lifeforms descended from a single common ancestor, as evolutionary biologists believe, then creationism is false. Creationists fight back in two ways. Some creationists argue that the evidence for common descent is poor, or that the methods used by evolutionary biologists to reconstruct the tree of life are unreliable. Other creationists concede that the evidence for common descent is solid, but they argue that it can be explained equally well by a hypothesis of common design — the idea that the Creator reused certain design motifs when creating different organisms. Any similarities between created ‘kinds’ are thus explained not by common descent, but by design reuse, or ‘common design’.
The ‘common descent IDers’ do not see common descent as a threat. They accept it, because they see it as being compatible with guided evolution. And while they agree with biologists that unguided evolution can account for small-scale changes in organisms, they deny that it is powerful enough to explain macroevolutionary change, as revealed by the large-scale structure of the tree of life. Thus guided evolution is necessary, in their view. Since common descent IDers accept the reality of common descent, you might be surprised that the evidence for common descent is a problem for them, but it is — and it’s a serious one. Read on for details.
The Problem(s) for ID
I’ve mentioned three groups of IDers so far: 1) creationists who dispute the evidence for common descent; 2) creationists who accept the evidence for common descent, but believe that it can be equally well explained by the hypothesis of common design; and 3) IDers who accept common descent but believe that unguided evolution can’t account for macroevolutionary change. Let’s look at these groups in turn, and at why the the evidence for common descent is a serious problem for each of them.
The creationists who dispute the evidence for common descent face a daunting task, simply because the evidence is so massive and so persuasive. I can do no better than to point readers to Douglas Theobald’s magnificent 29+ Evidences for Macroevolution for a summary of all the distinct lines of evidence that converge in support of the hypothesis of common descent. Because Theobald does such a thorough and convincing job, there’s no need for me to rehash the evidence here. If any IDers wish to challenge the evidence, or the methodologies used to interpret it, I encourage them to leave comments. The good news is that we have Joe Felsenstein as a commenter here at TSZ. Joe literally wrote the book on inferring phylogenies from the data, so if he is willing to respond to objections and questions from IDers, we’re in good shape.
I have yet to encounter a creationist who both understood the evidence and was able to cast serious doubt on common descent. Usually the objections are raised by those who do not fully understand the evidence and the arguments for common descent. For this reason, I emphasize the importance of reading Theobald’s essay. Think of it this way: if you’re a creationist who participates in Internet discussions, the points raised by Theobald are bound to come up in debate. You might as well know your enemy, the better to argue against him or her. And if you’re open-minded, who knows? You might actually find yourself persuaded by the evidence.
The evidence also presents a problem for our second group of creationists, but for a different reason. These are the folks who accept the evidence for common descent, but argue that it supports the hypothesis of common design equally well. In other words, they claim that separate creation by a Creator who reuses designs would produce the same pattern of evidence that we actually see in nature, and that common design is therefore on an equal footing with common descent. This is completely wrong. The options open to a Creator are enormous. Only a minuscule fraction of them give rise to an objective nested hierarchy of the kind that we see in nature. In the face of this fact, the only way for a creationist to argue for common design is to stipulate that the Creator must have chosen one of these scant few possibilities out of the (literally) trillions available. In other words, to make their case, they have to assume that the Creator either chose (or was somehow forced) to make it appear that common descent is true, even though there were trillions of ways to avoid this. Besides being theologically problematic for most creationists (since it implies either deception or impotence on the part of the Creator), this is a completely arbitrary assumption, introduced only to force common design to match the evidence. There’s no independent reason for the assumption. Common descent requires no such arbitrary assumptions. It matches the evidence without them, and is therefore a superior explanation. And because gradual common descent predicts a nested hierarchy of the kind we actually observe in nature, out of the trillions of alternatives available to a ‘common designer’, it is literally not just millions, or billions, but trillions of times better at explaining the evidence.
What about our third subset of IDers — those who accept the truth of common descent but believe that intelligent guidance is necessary to explain macroevolution? The evidence is a problem for them, too, despite the fact that they accept common descent. The following asymmetry explains why: the discovery of an objective nested hierarchy implies common descent, but the converse is not true; common descent does not imply that we will be able to discover an objective nested hierarchy. There are many choices available to a Designer who guides evolution. Only a tiny fraction of them lead to a inferable, objective nested hierarchy. The Designer would have to restrict himself to gradual changes and predominantly vertical inheritance of features in order to leave behind evidence of the kind we see.
In other words, our ‘common descent IDers’ face a dilemma like the one faced by the creationists. They can force guided evolution to match the evidence, but only by making a completely arbitrary assumption about the behavior of the Designer. They must stipulate, for no particular reason, that the Designer restricts himself to a tiny subset of the available options, and that this subset just happens to be the subset that creates a recoverable, objective, nested hierarchy of the kind that is predicted by unguided evolution. Unguided evolution doesn’t require any such arbitrary assumptions. It matches the evidence without them, and is therefore a superior explanation. And because unguided evolution predicts a nested hierarchy of the kind we actually observe in nature, out of the trillions of alternatives available to a Designer who guides evolution, it is literally trillions of times better than ID at explaining the evidence.
One final point. Most IDers concede that if the evidence supports unguided evolution, then there is no scientific reason to invoke a Creator or Designer. (It’s Occam’s Razor — why posit a superfluous Creator/Designer if the evidence can be explained without one?) It is therefore not enough for ID to succeed at explaining the evidence (which it fails to do, for the reasons given above); it’s also essential for unguided evolution to fail at explaining the evidence.
This is a big problem for IDers. They concede that unguided evolution can bring about microevolutionary changes, but they claim that it cannot be responsible for macroevolutionary changes. Yet they give no plausible reasons why microevolutionary changes, accumulating over a long period of time, should fail to produce macroevolutionary changes. All they can assert is that somehow there is a barrier that prevents microevolution from accumulating and turning into macroevolution.
Having invented a barrier, they must invent a Designer to surmount it. And having invented a Designer, they must arbitrarily constrain his behavior (as explained above) to match the data. Three wild, unsupported assumptions: 1) that a barrier exists; 2) that a Designer exists; and 3) that the Designer always acts in ways that mimic evolution. (We often hear that evolution is a designer mimic, so it’s amusing to ponder a Designer who is an evolution mimic.) Unguided evolution requires no such wild assumptions in order to explain the data. Since it doesn’t require these arbitrary assumptions, it is superior to ID as an explanation.
Here’s an analogy that may help. Imagine you live during the time of Newton. You hear that he’s got this crazy idea that gravity, the force that makes things fall on earth, is also responsible for the orbits of the moon around the earth and of the earth and the other planets around the sun. You scoff, because you’re convinced that there is an invisible, undetected barrier around the earth, outside of which gravity cannot operate. Because of this barrier, you are convinced of the need for angels to explain why the moon and the planets follow the paths they do. If they weren’t pushed by angels, they would go in straight lines. And because the moon and planets follow the paths they do, which are the same paths predicted by Newton on the basis of gravity, you assume that the angels always choose those paths, even though there are trillions of other paths available to them.
Instead of extrapolating from earthly gravity to cosmic gravity, you assume there is a mysterious barrier. Because of the barrier, you invent angels. And once you invent angels, you have to restrict their behavior so that planetary paths match what would have been produced by gravity. Your angels end up being gravity mimics. Laughable, isn’t it?
Yet the ‘logic’ of ID is exactly the same. Instead of extrapolating from microevolution to macroevolution, IDers assume that there is a mysterious barrier that prevents unguided macroevolution from happening. Then they invent a Designer to leap across the barrier. Then they restrict the Designer’s behavior to match the evidence, which just happens to be what we would expect to see if unguided macroevolution were operating. The Designer ends up being an unguided evolution mimic.
The problem is stark. ID is trillions of times worse than unguided evolution at explaining the evidence, and the only way to achieve parity is to tack wild and unsupported assumptions onto it.
If you are still an IDer after reading, understanding, and digesting all of this, then it is safe to say that you are an IDer despite the evidence, not because of it. Your position is a matter of faith and is therefore a religious stance, not a scientific one.
Zachriel:
You’re the one who suggested there was “additional ‘information’ that distinguishes bears from cats.
I’m not exactly sure what Allan is referring to here, but there is the suggestion that what distinguishes bears from cats is some additional something, and that additional something seems to have the character of information.
From Allan Miller above:
Otherwise, we have to introduce a curious, and arbitrary, demarcation point. Common sequence in a species is uncontroversial common descent, maybe, if pressed, in a grouping of species – bears, or big cats, etc – but suddenly, the exact same signals stop giving the same information, commonality due to descent, round about the bear/cat divide.
Maybe I’ve completely misunderstood him here, but this is what I’m referring to when I’m speaking about the added “information.”
keiths:
They [IDers who accept “common descent”] can force guided evolution to match the evidence, but only by making a completely arbitrary assumption about the behavior of the Designer.
This is true. And in the pages of Genesis we read: “Be fertile, and multiply.” If we associate the Designer with the God of the Bible, then it seems clear that the Designer has introduced life and wishes it to “multiply” on its own. If it’s simple reproduction, then “fertile” covers that. But it says “be fertile and multiply.” So, with this association, and with this understanding of Genesis, it’s not such a big leap.
OTOH:
And because unguided evolution predicts a nested hierarchy of the kind we actually observe in nature, out of the trillions of alternatives available to a Designer who guides evolution, it is literally trillions of times better than ID at explaining the evidence.
As I have consistently pointed out from the beginning, both ID and Darwinism envision, via adaptive radiations, a “nested hierarchy”; however, Darwinism predicts one with species at the bottom and orders and families at the top, while ID predicts phyla, sub-phyla, and classes at the top and with species at the bottom. The fossil record falsifies the Darwinian “nested hierarchy” and confirms (is conformable to) the ID “nested hierarchy.”
You write as if the Cambrian Explosion never existed, and as if the fossil record extends backwards in time, all the way back to a billion years ago, with the same type of pattern that we see from the Cambrian to the present. This just doesn’t conform to known facts.
PaV says:
Yet, actually, the “divergences” they speak of do contradict the principle thesis of common descent. That’s why I pointed out the better results, recently reported, of using a “multispecies coalescent” method. The underlying suggestion of this method is that “genes” are inherited from even distant species. I don’t see this as “confirmation” of the Markov Chain ‘assumption’ of common descent.
I am not sure what these “actual ‘divergences'” are. Multispecies coalescents are trees of gene copies that form within a tree of species. (For an explanation of them see chapter 28 of my book.) There is a lot of interest and activity in methods that take them into account. For example, they predict that for human, chimp, and gorilla a fraction of genes will give gene trees that are discordant with the ((H,C),G) tree, and that these are expected to be equally divided between gene trees that show ((H,G),C) and gene trees that show ((C,G),H). Which is what is found.
And what assumption of change of DNA bases is used in all that work? The Markov process assumption. It is not contradicted by the assumptions about gene trees.
In the section you quoted, Allan Miller said that IDers would claim that the exact same pattern of evidence which applies to cat species or to paternity, no longer applies to a more distant divergence such as cat-bear—that it gives different information for some reason. There is this unexplained discontinuity in the ID position. It’s information *about* the genealogy, not the *amount* of information involved. Just clarifying the point.
You are misinformed.
PaV,
Why does ID envision a “nested hierarchy” at all? There is absolutely no reason for any designer to keep to such a hierarchy. The only justification you can make for this would involve the designers motivations and as we well know ID is not about the designer, only the design.
So I ask you, why does ID predict a “nested hierarchy” at all? On what basis do you make that claim?
PaV,
Good on you for coming out and simply stating that the designer == the god of the bible. Now all you have to do is get KF etc to be open about that also (how can the cosmos be fine tuned by something inside it?) and a new dawn of progress could be about to rise on UD. Once you all get that elephant in the big tent to be openly acknowledged, this pretence of “the designer” dropped, then I’m sure you can make real progress in apologetics. Which is, after all, what ID is all about anyway. No actual practical use in the real world.
Number of limbs can be changed by a single point mutation. The heavy lifting of gene invention was done by single celled populations in the billions of years prior to the cambrian.
Try reading Koonin on this.
Pav
The additional something is simply greater genetic distance, overlain with something about the phenotypes that does strike us, as observers, and enables us to readily categorise the two groups as distinct. The ‘information’ is in the way these groups of organisms appear to us, rather than something inherently different about their genes beyond simple cumulative divergence, varying depending on the time since the various speciation nodes in their ancestry.
I used the i-word in an entirely casual sense. I’ll call it ‘info’, informal-information. When we do a paternity test, we gain a piece of info – these individuals are (or are not) that closely related. When we test common sequences between species that a Creationist might agree arose by ‘natural’ speciation, again we gain a piece of info – these sequences do (or do not) support the hypothesis that these organisms are related by common descent.
In both cases, the info is non-controversial, unless one is talking to some ‘species-immutablist’ like Ray Martinez. But at some point, you decide that common sequences – say between bear and cat – are no longer ‘info’. They stop supporting the hypothesis of common descent, and must be explained in some other way. This is the ‘ID discontinuity’ I refer to. The info pointed at by commonality is no longer explained by a common origin in descent, but – presumably – by something coming out of a Design process. Something that maintains the appearance of genetic continuity, but isn’t due to it.
In my mind’s eye, I envision living species as a set of buds held up on twigs. Follow those twigs back, and you come to branching nodes at the point of speciation. Follow those branches back, you come to other nodes (that were once twig-tips). And so on, right back to a single cell, LUCA, and really, on beyond to her ancestors. In addition to the main branches of descent, thin filaments of HGT connect distant branches, which messes up the tree structure a little (or a lot, at the base).
Now, in your mind’s eye, you appear to see the same set of buds in the air, with twigs behind them going back to recent branching points, perhaps a little further back … then nothing. Fresh air. The twigs are just suspended, with a separate origin to each mini-bunch.
Now, common descent is demonstrable, by molecular techniques, in those twigs that we can both see. Yet those same techniques yield a pattern of branching well beyond that which you allow. Right back, indeed, deep into the Cambrian explosion and beyond. It may have been quick, but that is not what I mean by ‘discontinuity’. I mean that if the tree is patterned as you envision it, with completely separate origins, it would be expected that phylogenies should stop being constructable using a ‘tree’ hypothesis at the origins of your twig-bunches. We should be able to construct mini-trees, but not a big one. You would not expect distant Family or Order branches to yield patterns looking for all the world as if they had once been mere species apart.
My mental picture is based upon the data; yours is in spite of it. Because, essentially, you are an essentialist! Just not a species-essentialist.
I find this inversion a little confusing, as the two supposed trees must both be drawn in the same direction. In a simple linear version, time would be top-to-bottom or bottom-to-top, or left-to-right. (For some reason, it seems perverse to draw it right-to-left).
What you really seem to be saying is that, if we envisage the tree starting to grow, we would start with a bunch of separately created phylums, which would then ‘classate,’, then ‘orderate’, then ‘familyate’, then ‘genusate’ and finally ‘speciate’. That doesn’t make any sense (and is therefore probably not what you are saying).
The only process which in nature gives rise to a taxonomic classification is speciation. It is based on a biological capacity: interbreeding and its cessation, at least as far as sexual forms are concerned. Once it has happened, the separate lineages are free to diverge eternally. Time deepens all divisions, to the point at which lumping would be perverse.
So the Darwinist’s tree starts with a small group – the first sexual species, say – and all bustling activity is at the tips, among the living. Species, more species, more species, more species … the results of these bifurcations get more and more dissimilar as time since branching deepens, and higher and higher divisions become necessary. We just happen to have come along rather late in the game, and did not need to progressively extend our categories with deeper and deeper structure as evolution progressed – we started with the deep divisions appropriate to the modern era. “Bear!” “Cat!” Vertebrates, obviously. “Lobster!” “House Fly!”. Arthropods. Piece of cake, this taxonomy lark.
Allan Miller:
I mean that if the tree is patterned as you envision it, with completely separate origins, it would be expected that phylogenies should stop being constructable using a ‘tree’ hypothesis at the origins of your twig-bunches. We should be able to construct mini-trees, but not a big one. You would not expect distant Family or Order branches to yield patterns looking for all the world as if they had once been mere species apart.
I understand now the point you’re making. And I think the above quote captures this point.
Here is how I would respond:
You write: ” . . . it would be expected that phylogenies should stop being constructable using a ‘tree’ hypothesis at the orgins of your twig-branches.
I see no such expectation.
The best analogy would be that of computers and computer code.
There are two main divisions in computer codes: PC and Mac—just like the ‘Plant’ and ‘Animal’ Kingdoms.
And, there are different types of computer software: e.g., spread sheets, word processing, financial, games, security, etc.—kind of like different ‘Phyla’.
And then there are different makes/designers of the software: e.g., Quicken, Microsoft, Word Perfect —kind of like ‘Classes’,
And so we go developing the analogy.
But what is at bottom of this analogy is the common code being used all along the way: ascii, and other standards that are introduced.
So intelligent beings can go off in all kinds of directions using the same, or similar, underlying code. And, it’s very likely that we won’t find too many intermediate ‘forms’, if you will, since computer programmers set out with a spreadsheet, or a word processing program in mind, etc. So you end up with essentially the same code allowing, when implemented, a non-continuous/discrete pattern of computer software programs. It is the “teleos” that the programmers have in mind that determine the differences, even when using a common code.
So, again, I don’t see the expectation you seem to see.
Allan Miller:
What you really seem to be saying is that, if we envisage the tree starting to grow, we would start with a bunch of separately created phylums, which would then ‘classate,’, then ‘orderate’, then ‘familyate’, then ‘genusate’ and finally ‘speciate’. That doesn’t make any sense (and is therefore probably not what you are saying).
You seem to think that this is completely incompatible with “speciation.” I don’t see why that’s so.
For example, the Designer is required simply because abundant ‘information’ is needed to constitute different ‘phyla’. And, perhaps, more ‘information’ is needed to develop certain basic ‘types’ within the phyla.
Once that has been implemented, then, given the kind of environmental extremes that life must face and overcome, the Designer places within these basic ‘types’ a kind of information that allows life to ‘adapt’ itself to the various types of environmental forces that we see in existence today.
As these basic ‘types’ interbreed and ‘adapt’, we get more and more divergence of the main lines of the ‘phylum’s’ basic ‘types.’
What would this look like on a given time scale?
It would look like “punctuated equilibria.” It would look like the sudden appearance of new basic ‘types’, followed quickly by variations on a theme of these basic ‘types’, and then stasis—as the limits of the built-in system of adaptation is reached.
I’ve addressed in an earlier post the “logical flaw” in Darwinism–Darwin never addresses the fact of how ‘phyla’ are formed. He has no answer. He only hesitatingly allows for ‘orders’ to give rise to ‘classes’; but he goes no further.
And yet he wants us to believe, e.g., that the trilobite is the result of a gradualistic process of speciation that, if we had all the missing pieces, would look very much like what we see from the Cambrian on. We know better. And that’s why I envision the ‘twigs’ you talk about suspended in the air–as you correctly describe.
You know, the quantum world is ‘discrete’, and the larger, classical world is ‘continuous’. Neils Bohr, long ago, postulated the principle of complimentarity, saying, more or less, that there is some point where the ‘quantum world’ leaves off, and the ‘classical world’ begins. Likewise, the fossil record shows discreteness and continuity. This is all entirely consistent with the ID view, and, in fact, IMO, conforms much more readily to what we find in the actual fossil record.
P.S.
To all bloggers: I’m running out of time, and will only be able to judiciously answer posts as we go forward. I hope you understand; but this is only an avocation, not a vocation. Life must go on, you know. 🙂
Pav,
That’s actually a good analogy to make but you are making it at the wrong level.
If we want an analogy to biological dna, we should be looking at object code for the comparison.
Imagine the x86 object code as the LUCA with branches into different applications and computing platforms.
However you group them, the common factor will be the actual codes that “inform” the processor what action to take.
In later branches, you made find “extensions” to the code as instruction types are added.
You’ll also find sections of code, that while “functional”, are never executed in later systems, sort of like saying “junk DNA”.
But overall, it is obvious that all these “programs” are related at a very low level.
As fa as a Mac, that’s an “alien life-form”!
It’s not an analogy that stretches very fay, but if you insist, the code for most general computing devices goes back to UNIX.
One could easily make a nested hierarchy of UNIX flavors and track individual implementations back to earlier versions.
petrushka:
Perhaps PAV would care to address the Lenski experiment, which shows an unmistakeable gain of function with no corresponding loss.
Not only that, but it reaches or exceeds Behe’s Edge in a decade, in a tiny population.
This seems on the surface to be mildly impressive.
But there are certain facts:
Ann Gauger has pointed out that this ‘gain of function’ was not so clearly a ‘gain in function.’ The bacteria already had the ability to metabolize citrate; it simply couldn’t do it under aerobic conditions. And, apparently, the promoter region for a protein that allows the uptake of ‘citrate’ into the bacteria under aerobic conditions was modified. (Just ‘google’ Ann Gauger Lenski experiment)
So, is it truly a “gain in function”? That’s a tad debatable.
Nevertheless, let’s concede what microevolution is able to do.
Now I want to take a closer look:
You write that this happened in a “decade”. Maybe so, maybe not. But IIRC the number thrown around was 20,000 generations.
And bacterial populations are far from “tiny populations”, probably being anywhere between 106 to 108 members strong.
With that said, I want to do some calculations based on the 20,000 generation figure.
It turns out that the mutation rate here is critical.
A recent paper (Aug. 2012) determined the mutation rate of E. coli to be 1 x 10-3. Mammalian mutation rate is on the order of 1 x 107. So, there is a difference of 104, with E. coli mutating 10,000 times faster than mammals (as well as most vertebrates).
So, when we translate what happened in E. coli to what would be equivalent in vertebrates—which have a one-year generation time and a mutation rate of 10^7—this means that the equivalent time, in years, for vertebrates is (104 vertebrate generations for the equivalent number of mutations/1 E. coli generation) x 2 x 104 E. coli generations in the experiment, we get 2 x108 years for enough mutations to have formed to make a similar type change to a gene promoter region in a vertebrate. That is: 200 million years.
And if we’re talking about humans, with a much smaller population size ( up until the last 8-10,00 years, let’s say), and with a generation time of twenty years or so, this then means that for humans to have produced this somewhat simple change of a promoter region would require 4 billion years.
I think you would agree that this no longer seems so impressive.
P.S.
Attention all those leaving posts—
Again, I have my own time constraints and will only be responding sporadically from now on.
PaV,
I think your ‘code’ analogy misses the point.
In the first instance, do you accept that the markers used in relationship testing (eg paternity, sibling) are valid? This is based purely upon common sequence. There is variation between individuals in a population at many loci. PCR allows the sequences flanking a sequence of interest to be targetted with great precision, and the sequence between them amplified and compared between two individuals. The closer they are related, the more those sequences will match, compared to a random individual from the population.
Then you can take DNA from two species – a lion and a tiger, say. In exactly the same way, you can do PCR on those, even using the same flanking sequences. If those sequences are identical, or nearly so, common descent would be the favoured explanation here, if you aren’t looking for a designer to tinker endlessly and build every single species.
You can add in other cat sequences, and assemble their apparent branching relationship. Since you appear to have no difficulty with evolution at that level (despite every day being a “bad day for Darwinism”!), do you accept that commonality of sequence here indicates common descent, just like a sibling test?
Then you do the same for the bears. You assemble the relationships based upon sequences at this level, and confirm the presumably non-controversial common descent of the bears from a common ancestor.
OK so far? So what happens when you merge the sequence data from the bears with that from the cats? Why, if the ur-cat and ur-bear were separately created, is there any reason to expect that sequences showing relationships by descent within groups will match across the bear-cat divide, if they were separately created? Evolution and common descent accounted for commonality within the cats and within the bears. But not commonality between the cats and the bears…? What’s that all about?
Using your code analogy, we are not looking at multiple implementations of ascii, but extensive textual commonality. Some functional basics could be attributed to reuse in new designs. But we find the non-functional stuff to be common as well. Unless you’d like to deny that nonfunctional DNA exists, which is contradicted by the existence of natural variation, among many other lines of evidence. Let’s not quibble about how much there is.
It’s as if we found a bunch of programs, all doing the same basic thing (do “survive”; do “reproduce”) but stuffed to bursting with features that look just as if the code had simply been copied with minor amendment. Important lines like “make cytochrome c” may be invariant in designs, but we get the same pattern in “skip this – inactive pseudogene” in one and “skip this – inective pseudogone” in another, or an unreferenced dataname “WS-30-CHARACTERS-OF-TOSHHHHHHH” repeated with minor variations throughout our dataset. It can’t all be essential to the species … else how do they ever cope with mutation? And vary?
So how come, if we see the equivalent of WS-30-CHARACTERS-OF-TOSHHHHHHH in a paternity test, or in closely related species, we can reliably infer common descent, yet the same name (perhaps a little degraded: WS-30-CHARCTERS-OF-TISHHHXH) in more distant species is NOT due to common descent? That seems more than a tad arbitrary and inconsistent.
PaV – on your calculations comparing E. Coli with a 20-years generation vertebrate, you omit to include sexual recombination, which introduces a massive rate increase on the exploration of variation. If we were asexual, like E.Coli, things would indeed be different, for that and many other reasons. Lenski’s bugs are also subject to a severe daily population bottleneck. You can’t make any sensible inferences on limits to human evolution from this study.
I think you would agree that this no longer seems so impressive.
Of course the population from which most mutation selection occurs in sexually reproducing organisms is the sperm cells, which outnumber offspring by hundreds of million to one.
The gian of function is not honestly debatable. I would like to see Behe’s response, but his blog entry on the subject has been removed.
The key issues here are how many mutations contributed to the gain of function. So, is it truly a “gain in function”? That’s a tad debatable. Behe says it is unreasonable to have a gain of function that required two “simultaneous” mutations. Here we have not fewer than two and possibly three or four. in a tiny test tube population in a few years. There is no intellectually honest way to avoid this.
Move the goalposts all you want.
I found what is claimed to be Behe’s response:
I think the results fit a lot more easily into the viewpoint of The Edge of Evolution. One of the major points of the book was that if only one mutation is needed to confer some ability, then Darwinian evolution has little problem finding it. But if more than one is needed, the probability of getting all the right ones grows exponentially worse. “If two mutations have to occur before there is a net beneficial effect — if an intermediate state is harmful, or less fit than the starting state — then there is already a big evolutionary problem.” (4) And what if more than two are needed? The task quickly gets out of reach of random mutation.
We have reason to believe that three or four mutations occurred in the Lenski experiment. At least one and probably two occurred before any selectable benefit occurred.
We’re going to disagree with your claim. Common Descent puts limits on how the designer implemented their plan, but doesn’t preclude a designer. You’ve even mentioned such yourself. Darwin understood this, which is why he exerted so much effort working on the evidence for natural selection as a primary mechanism for adaptation.
Common Descent means that there is a historical unfolding of life. This unfolding (absent other evidence) could be due to vital forces, or the occasional intervention along with natural forces, what people used to call Providence. That is, the Designer puts everything in motion, and only intercedes at certain moments in history. It could even include evolution being a completely natural force (which is what preponderance of the evidence implies), but one where the Cosmic Gardner already knows the trajectory based on how the seed was planted.
Intelligent Design encompasses a number of sometimes inconsistent positions (by design). You can only preclude specific ID positions with Common Descent, though IDers will generally avoid being pinned down. Once Common Descent is established, the rest of the evidence strongly implies natural mechanisms.
Zachriel,
I believe ID is NOT compatible with the “evidence” for common descent.
The interpretation of the “evidence” is what the fight is actually centered on.
Seen from the point of view of the “evidence”, intelligent design doesn’t make sense.
Their attempt to turn the “evidence” for common descent into “evidence” for the “designer” should be clear to everyone.
If the ID movement wants to claim the cosmic gardener planted a garden and then sat back for billions of years watching it grow, that is something I could accept, but they’re claiming the evidence shows hands-on help, which is not what non-ID interpretation of the evidence for common descent indicates.
Zachriel,
Yay! ID supporters have been unable to rebut my argument, so I was thinking of asking my fellow ID critics to try to find holes in it (and I invite them to do so now). I’m glad you stepped up.
This also gives us a chance to demonstrate how a disagreement can be handled via substantive debate, wherein the opposing parties actually try to understand each other’s positions and don’t resort to invective or other cheap rhetorical ploys. Mung, please pay attention.
Zachriel:
Yes. When I say that ID is incompatible with the evidence for common descent, I’m not using ‘incompatible’ in the sense of ‘absolutely contradictory’; I just mean that ID doesn’t fit well with the evidence. Similarly, if I tell you that Bob and Alice are incompatible, it doesn’t necessarily mean that they will try to kill each other if placed in the same room. It just means that they don’t get along well.
I think my intent is clear if you look at the body of the OP:
Also:
And:
ID is ‘compatible’ with the evidence only in the sense that today’s weather is compatible with the “Rain Fairy” hypothesis. Not absolutely contradictory, but clearly a bad fit. Modern meteorology makes predictions that the Rain Fairy hypothesis doesn’t begin to match, so we reject the Rain Fairy and embrace meteorology. We should reject ID and embrace unguided evolution for the same reason.
It constrains how the Designer interacts with biology. Common Descent would be compatible with a designer that worked through history, a vital force that provided an impetus to adapt, or the planting of a Cosmic Seed with the occasional weeding.
Your original post limited the evidence to Common Descent. It’s a thought-experiment, and doesn’t quite match with your comparison to the full opus of meteorology. The entirety of the biological evidence (such as natural selection) would further constrain any design hypothesis. Nor does mere compatibility imply there is scientific evidence of a designer.
The actual challenge for Mung and others is to understand our positions, rather than just pointing at the disagreement and saying “See, even evolutionists disagree!”
Allan Miller:
So how come, if we see the equivalent of WS-30-CHARACTERS-OF-TOSHHHHHHH in a paternity test, or in closely related species, we can reliably infer common descent, yet the same name (perhaps a little degraded: WS-30-CHARCTERS-OF-TISHHHXH) in more distant species is NOT due to common descent? That seems more than a tad arbitrary and inconsistent.
And, a little before:
Using your code analogy, we are not looking at multiple implementations of ascii, but extensive textual commonality. Some functional basics could be attributed to reuse in new designs. But we find the non-functional stuff to be common as well.
The analogy at play here, as I see it, is that you’re comparing, let’s say, one web browser to another. They have similar functions, and use a similar language, and so will be very similar in their ‘text’ (you say ‘commonality’)
You use bears and cats–both mammals; i.e., both chordata (phyla), both vertebrata (class), both carnivora (order), but separate ‘families.’ So, should we expect huge differences?
I wouldn’t, especially at the level of coding DNA, or proteins. I would imagine they would be very, very similar. I would, from an ID perspective, expect that perhaps their so-called non-functional DNA, which is better described as non-coding DNA holds the true differences.
Proteins are simply the building blocks of cellular structures and bodily structures. What is important is how the proteins are utilized. And, from an ID perspective, you would expect that to found in the non-coding portions of the genome, and to involve regulatory sequences of all kinds.
You mention “separate creation” of the bear and cat forerunners. This is, more or less, what ID would expect. However, you simply make the assumption that “separate creation”=”huge differences in, or completely different, codes”. Even in the case of a YEC, I don’t know why you think these two qualities are equivalent.
Think of animal life: they all breathe, they all move, they all have a heart, most organs are very similar, they both have to eat through their mouths, they excrete at their lower ends, etc. There are huge kinds of similarities even in groups that would be more widely separated taxonomically. All a Designer would have to do is to ‘tweek’ the ‘design’.
And, in all of the above, I’ve left out the notion of “front-loading”. Should the Designer have “front-loaded” all those elements needed by later forms, then it is very possible that the elements would still be present even in more divergent forms: present, but unexpressed’; or, present in a pseudo-gene form.
Darwin, in his Origins, kept positing “special creation” versus his model, despite the fact that very few people thought of “special creation” the way in which he was portraying it. There’s room for subtlety. And to eschew the subtlety is to encourage false comparisons.
I must run……..
PaV,
You continue to miss the point, and I am running out of ways of making it. If you must pursue a computing analogy, Common Descent is looking at the ‘program’ not as a program, but as a file. The text of a program can be copied around through various media, without regard to what the program actually does. If we saw substantial textual commonality between various different programs, we would be much more likely to infer that they had been copied one from another. We would not likely infer that they were similar because they had a similar job to do – particularly if similarities extended to the way the program was laid out, spelling mistakes in comments, functionally irrelevant swaps etc.
And this, as I say, is what we do with paternity testing, which I presume you accept. And species-level taxonomy, which again I assume you accept. So how can you then flip and say that at higher levels, the same patterns of similarity are no longer due to common descent, but suddenly, ‘common design’? A commonality that fools objective statistical techniques into yielding trees of descent where no actual descent was involved?
Your argument becomes even less tenable when we look at something like the whale phylogeny. SINE markers give a binary signal. When a transposon jumps, descendants from prior to the jump will have the flanking sequences alone; those after the jump will have flanking sequence plus SINE. ie, it is a binary marker – xxxxyyyy in some species and xxxxSINEyyyy in others. Different SINEs are located at different points.
If you decide that all those species carrying xxxxSINEyyyy would be expected to be similar, because they are similar externally, you’d have to explain why whales, pigs, hippos and deer, for example, hardly ‘similar’, have such markers shared by them all. But there are also markers shared by whales and hippos but nothing else. And some by whales, hippos and pigs but not deer. This pattern repeats, gene by gene, converging on a tree of descent.
A nested hierarchy, in short.
So, forget your analogies, when actual descent yields a noncontroversial hierarchy at levels you don’t believe a Designer to be involved in, why do those same patterns stop showing actual descent at higher levels?
Or, trying the opposite tack, if Common Design is the explanation for ALL sequence similarity between cats and bears, why is it not the explanation for commonality between me and my daughters? Sure, you may think we follow the same celestial plan, but there is a more immediate reason we are more similar than two random individuals. We are more closely related.
Allan Miller:
And this, as I say, is what we do with paternity testing, which I presume you accept. And species-level taxonomy, which again I assume you accept. So how can you then flip and say that at higher levels, the same patterns of similarity are no longer due to common descent, but suddenly, ‘common design’?
This may be the nub of our disagreement.
You’re basically saying that I’m talking about both “common descent” and “common design”, and what perplexes you is that I’m choosing to switch from one to another as we move along the taxonomic scale. Correct?
And you want to say that it is EITHER “common descent” or “common design.”
Further, you’re saying that the evidence is all in favor of “common descent.”
Have I got it right now?
Supposing I do, then let me give you my answer.
Computer programmers set up what are called EA’s–evolutionary algorithms.
Now these EA’s use various models and random generators to try and “evolve” solutions to certain mathematical or physical problems.
Some have been know to actually produce worthwhile results.
I’ve now set the stage:
(1) The EA’s are “designed”
(2) the EA’s produce new “generations” which are related to previous ‘generations’ by something analogous to common descent.
(3) If the EA computes long enough, workable solutions are generated.
Thus, you have part of the EA that is “designed” and part that operates using “random variation”, usually NS via a “fitness function”, and with “generations” that are related via “common descent.”
Do you see my point?
Let me be more clear:
(1) * Without design, nothing would happen;
(2) It is the computation rules that the designer imposes that guides the EA in its problem-solving;
(3) These rules can be changed and modified depending on the kind of search taking place, and for the particular problem solution being attempted;
(4) ** If you have different types of problems to be solved, the computer rules will be similar, but not the same.
(5) *** The random part of the EA’s while still different, would be more similar than that portion of the program that is set up using rules and fitness functions: i.e., each succeeding generation would have a striking resemblance to the previous generation, especially as one reaches some kind of a limit.
* Thus, the “common descent” part of the program is completely dependent on the “common design” part of the program.
**Thus, “common design” principles, with a divergence in its final goal, will lead to greater differences between the basic “common design” of the EA.
***Thus, you end up with sets of differences due to different causes: one due to “fine-tuning” of the “design”, whereas the other differences arise because of random processes and selection (fitness function).
IOW, I don’t see “either”/”or” at work here; I see both principles at work.
Behe accepts “common descent”, but sees evolutionary processes as so highly limited as to not explain the species differences even in species belonging to different genera.
I don’t see much difference between his position and mine, except this: he believes that all species are in some way related to one another, whereas I, OTOH, see this same ‘relatedness’, but in a discrete, and not continuous, fashion.
Hope this helps.
PaV, to Allan:
I can’t speak for Allan, but I myself do not see common descent and common design as being mutually exclusive hypotheses.
The problem is not that they are mutually exclusive, but rather that their intersection — “common design via common descent” — doesn’t fit the evidence. I explain why in the section of the OP that discusses ‘common descent IDers’.
Zachriel:
You’re missing a crucial point. Let me quote myself from the OP:
You can assume that the Designer just happens to mimic unguided evolution in this regard, instead of choosing one of the trillions of alternatives, but what’s the basis for that assumption? If there’s no independent justification for it, then it’s merely an ad hoc attempt to force an ID-shaped peg into an evolution-shaped hole.
Unguided evolution doesn’t require unjustified, ad hoc assumptions like this in order to fit the evidence for common descent. For that reason, it is the better theory.
keiths:
The problem is not that they are mutually exclusive, but rather that their intersection — “common design via common descent” — doesn’t fit the evidence. I explain why in the section of the OP that discusses ‘common descent IDers’.
From OP:
In other words, our ‘common descent IDers’ face a dilemma like the one faced by the creationists. They can force guided evolution to match the evidence, but only by making a completely arbitrary assumption about the behavior of the Designer. They must stipulate, for no particular reason, that the Designer restricts himself to a tiny subset of the available options, and that this subset just happens to be the subset that creates a recoverable, objective, nested hierarchy of the kind that is predicted by unguided evolution.
We keep going round in circles.
If I invoke a Designer, haven’t I already first assumed that the Designer wanted to design? Haven’t I already assumed that the Designer had the power to design? Etc., etc.
One posits a Designer not because one is a theist, but because neo-Darwinism cannot explain the evidence.
Allan talks about all the minor variations between the genomes of human beings.
This was NOT supposed to be like this. Remember? Genetic load. Kimura. Neutral Theory.
Behe’s Edge of Evolution shows just how limited the cells putative evolutionary mechanisms are:
Parasite mano-a-mano versus humans. Life and death. Evolve or die. What is the parasite able to do in 1020 generations (or, 1016 generations if the 1020 figure drives you crazy)? Two amino acid substitutions.
And, finally, what I’ve pointed out on this post: Darwin’s “nested hierarchy” does not fit the fossil record. Temporally, it’s backwards. The fossil record is not a tree, but a collection of tree tops that one comes upon. It is like coming across the top of a tree in a badly flooded ravine, with only its top exposed to sight.
This is called: The Cambrian Explosion, the Mammalian Explosion, the Bird Explosion, etc. You know, . . . Punctuated equilibria.
The failure of Darwinian theory becomes clear when Darwin unequivocally states that he expects another fossil record, equivalent to one we know that stretches from the Cambrian to now, will someday be found stretching way back in time, and giving rise to the Cambrian fauna.
Do you know where we can find this pre-Cambrian fossil record?
Related to this giant lacuna in the fossil record, the failure of Darwin’s theory becomes clear when he never provides an explanation for the existence of either Phyla or Kingdoms. His theory can’t deal with either of those categories. Darwin ARBITRARILY says that the kind of divergence he infers happens can only rise up to the level of a “class.” Why? Why can’t divergence continue? What limits the process? Does Darwin say anything about this?
No. Instead, Darwin’s putative “nested hierarchies” are not quite as “nested” as they should be, or need to be.
Very likely, in what strikes one as an intellectually dishonest evasion, this is because he realizes that were he to postulate that this process of character divergence were to continue (the LAW of Divergence), then you would have “classes” giving rise to “phyla” and “phyla” giving rise to “kingdoms”; which, in turn, would mean that, given enough time, NS could take a parasite and make it into an orchid. This would be so patently an absurd proposition that it would have been laughed at to scorn. So, evasion instead.
Moreover, conveniently for him, and in what I can’t help but judge to be a sort intellectual ‘sleight of hand’, he finds a way of getting around all of this.
First, he never talks about anything in Origins higher than “orders” (‘classes’, ‘phyla’ and ‘kingdoms’ are not mentioned); and, second, he famously says at the end of his first edition of Origins: “There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; . . .”, thus effectively giving him a jump start to “body-plans,” and so circumventing discussion of ‘phyla.’
It’s perhaps convenient, one must admit. to at times have a “Creator” at the ready.
But there is this difficulty when invoking a Creator/Designer.
Since Darwin says that it was a Creator (Designer?) who made the original form/forms, then per your view, i.e., every form related to another via “common descent”, this Darwinian view ends up tracing itself all the way back to the first ‘descendants’ of the first ‘forms.’
And those ‘forms’ arose via a Designer. So how, then, are ID and Darwinism any different in this respect?
Doesn’t this vitiate your argument?
PaV
More that I want to see something more than arbitrary whim in assigning the position of the still-asserted discontinuity where sequence similarity due to actual genetic relationship ceases, is entirely superseded by sequence similarity due to commonality of design. You may see them in operation together, but they are evidently not of equal force throughout the taxonomic structure – no-one appears to have been busily Commonly Designing my children, for example, while you deny that there is any Common Descent joining ur-cat and ur-bear. So somewhere one process must supplant the other, while giving the same signal. Given that certain ID-ers are rather fond of Newton’s Rules, I would point to this one: “To the same natural effects we must, as far as possible, assign the same causes.”. The ‘effect’ is a hierarchic relationship of genetic characters. The cause of that within a species, even given the scrambling effects of sex, is a hierarchy of inheritance. Above the species, the same cause is agreed to be in operation, generating the hierarchy of cats, say. But not cats and bears, even though they form exactly the same hierarchies – even in sequence that can be excised from the organism with no ill effect, ie, it is not a vital part of ‘lion-ness’ or ‘grizzliness’.
That is arbitrary. If you perform an objective analysis on blind data, and do not pick up a discontinuity, the likeliest explanation is that there is no discontinuity.
If you plotted the ‘tree of copying’ in an EA, you would generate a ‘family tree’ for the sequences. All the sequences in a running EA are produced by copying and/or mutation – they are not designed by the programmer; she merely sets up the environment. Statistical techniques would allow the characteristics of the final strings to be put in sets and a hierarchy constructed, which you could confirm with the preserved historical tree.
But if you decided to create two ‘kinds’ of initial organism, these statistical techniques would show a discontinuity between strings descended from one and those descended from the other unless you took the precaution of making it appear that your two start strings themselves had a common ancestor. It’s not just the genes, but the order on the chromosome, the positions of insertions, amendments and deletions, numbers of repeats … where there is commonality, either the sequences commonly descend, or someone wants us to think they do.
Only people unversed in the methods of phylogenetic analysis seem able to detect the Hand of the Designer in the patterns of descent. From the rest, he hides.
PaV,
Yes, and you’ve also assumed the existence of the Designer, and that the Designer chose a design method that led to an objective nested hierarchy when trillions of alternatives were available.
That’s my point. ID has to be propped up by unsupported, unjustified assumptions. Unguided evolution does not. From the OP:
We replied to the thread, but our comments never appeared. Odd that.
keiths:
That’s my point. ID has to be propped up by unsupported, unjustified assumptions.
And my point, which you missed, was that there are several assumptions, if not more, that are implicit when you invoke a Designer. And for some reason, you let this bother you.
IOW, either a Designer is NEEDED to explain what we see, or the Designer is not. You, OTOH, simply refuse to see where neo-Darwinism reaches it limits, while, at the other end of things, want to criticize the notion of a Designer as a non-starter. This evades the question: is a Designer “needed” or not to explain the incredible amount of information stored in DNA?
The rest is just fumbling around in the bushes.
Yet they give no plausible reasons why microevolutionary changes, accumulating over a long period of time, should fail to produce macroevolutionary changes. All they can assert is that somehow there is a barrier that prevents microevolution from accumulating and turning into macroevolution.
Well, if all IDers do is “assert . . . that somehow there is a barrier that prevents microevolution from accumulating and turning into macroevolution,” then all you have to do is show that we’re wrong. After all, we’re just making an assertion.
Well, what about the ‘icon’ of evolution: the Galapagos finch.
Weiner’s book on the finches, based in great part on the Grant’s terrific and well-documented experiments and observations, shows that in the end you have “fission” and “fusion.” You see, “species” arise; and then they disappear, having fused into a hybrid with another finch species. What do we see, then? Modulation around some mean average for beak size.
What do we see with “breeders”? Modulation around some mean average. But dogs remain dogs; cats remain cats, and finches remain finches.
And this is supposed to be some of your best evidence for “macroevolution.”
If I find myself not persuaded in the least by all of this, I think you might understand.
In the meantime, Behe’s book, Behe’s paper with Snoke, all go uncontested. Or, better yet, contested, but only about this particular or that particular, with the bulk of the work demonstrating quite clearly just how limited nature is in changing. NS is a conservative force. The Hardy-Weinberg Law is conservative, a kind of “modulation around a mean.”
When you solve the problem of the Cambrian Explosion–and not just hand-wave it away–we IDers will perk up and listen. But not until then.
Allan Miller:
You may see them in operation together, but they are evidently not of equal force throughout the taxonomic structure – no-one appears to have been busily Commonly Designing my children, for example, while you deny that there is any Common Descent joining ur-cat and ur-bear.
I have denied that there is “common descent” joining ur-bear and ur-cat in the strict sense: i.e., the bridge between ur-bear and ur-cat is off-limits to neo-Darwinian processes. IOW, varieties and sub-species are all perfectly permissible to neo-Darwinism (though at the microevolutionary level Darwin said nothing that others hadn’t already said before him).
Now, at the other end of things–major phyla–meaning major body-types and major innovations based on a particular body-type, all this must clearly involve “design”, and ur-chordata and ur-arthropoda, while sharing similar cellular structures and codes, can, in no way, be “bridged over” via neo-Darwinian processes.
In between, we have a gray area. Here’s an example.
What if mules did not have sterile offspring? What would that look like?
Well, at some point millions of years ago, and even perhaps at episodic intervals along the way towards the present, horses and donkeys would have interbred and produced mules, which would then have continued forward in time.
Looking at the fossil record, we would have seen fossilized remains of the mule, and we would consider it, what, a separate genus, or family, to horses and donkeys?
Here is a case of significant phenotypic change where neo-Darwinian processes are not involved, and where “common descent” occurs.
How high up the taxonomic scale does such hybridization take us? To the level of orders and classes?
But, then, at some point, in a process similar to “common descent”, major modifications would have been implemented, said implementations causing a break in genomic continuity, which I term “common ancestry.”
One blends into the other, and imperfect knowledge ensues.
If I posit an Intelligent Designer who has included basic “adaptive” mechanisms in the genome, I’ve got all the bases covered as an IDer. But neo-Darwinism “explains” (as I’ve said, others before Darwin had already noted organisms’ power to adapt) only one ‘end’ of things, and not very well. It’s extremely limited (Edge of Evolution). And at the other end, you have nothing but pure speculation.
So why, again, is neo-Darwinism reigning supreme?
Allan Miller:
But if you decided to create two ‘kinds’ of initial organism, these statistical techniques would show a discontinuity between strings descended from one and those descended from the other unless you took the precaution of making it appear that your two start strings themselves had a common ancestor.
Yes, and if you compare two different body-types, I’m sure you would find significant differences. How did these differences come about?
Allan Miller: RV + NS + “common descent”.
[But, Allan, where are all of the intermediate forms that Darwin expected? Can you please point them out to me– intermediate forms that represent a “bridging over” from one form to the other? They’re missing. And with their absence, Darwinism is falsified.]
PaV: Design + “common ancestry”.
[We would expect no “intermediate forms” but, rather, sudden appearances]
That’s right: It also requires the assumption of bifurcating descent.
Perhaps. And some limits may be beyond our ken.
Yes. Butterflies don’t give birth to homunculi, and frogs don’t form from the mud.
The evidence of Common Descent restricts the set of designers significantly. So? That doesn’t make it incompatible with some notions of a designer. A Cosmic Gardner who plants the seed of life, then tends it occasionally would be compatible. So would a God who works through historical unfolding.
All theories select from an infinitude of possibilities. Facts constrain compatible theories from among this infinitude. Just because you restrain it to a tiny sliver of conceivable theories doesn’t mean that tiny sliver isn’t compatible. The Theory of Gravity is a tiny sliver of conceivable theories of gravity.
Zachriel:
I think that the problem is that keiths’ is not using the word “compatible” in its strict logical sense in the O.P. title phrase “I.D. is not compatible with the evidence for common descent”. This shows in his actual article, which makes the “tiny sliver” claim, not the “logically incompatible” one.
Linguistically, it’s fine to use compatible in the way that keiths’ has, but I personally would prefer to restrict the word to its strict meaning in logic when discussing hypotheses about the world. So, I think we should ignore the O.P. title, and concentrate on what he’s actually saying in the post.
The general I.D. hypothesis “life on earth was intelligently designed” would be logically compatible with any biosphere, including one that could have arisen by non-telic processes (because intelligent designers can make things that also arise by non-telic processes).
But what about the non-telic evolutionary hypothesis? It requires that “tiny sliver” and is therefore very tightly constrained, and more than 99.99% of conceivable intelligently designed biospheres would blow it out. It gives an explanation as to why we observe the evidence for common descent and and objective nested heirarchy.
It’s very unfortunate for the I.D. folk that their designers appear to have chosen the same tiny sliver or an area very very close to the sliver in which to operate. It’s just as if these designers are trying to hide themselves from any possible scientific observers. Which seems to be, sort of, the valid point that keiths’ is making .
Until such time as science can account for each and every weather event by necessity mechanisms, the rain fairy hypothesis empirically explains weather with 100 percent certainty.
Yes, but that wouldn’t be specific enough to constitute a testable scientific hypothesis (cf Intelligent Design).
Yes, but doesn’t preclude design in-and-of-itself. Only specific design hypotheses can be tested. For instance, directed panspermia is a valid hypothesis compatible with Common Descent. Or a Cosmic Gardner who plants the seed, and occasionally prunes undesirable branches (e.g. dinosaurs). Or a God who has set up the universe and intervenes once in a while for some Divine Purpose. You might say these are speculative and unsupported, even vacuous, but that’s different than saying they are incompatible in either sense of the word.
Remember, we’re considering Common Descent in a vacuum. As Darwin knew, it’s the evolutionary mechanisms of adaptation—along with Common Descent—that provides a natural explanation, instead of some intelligent force pervading the cosmos that pushes life into more complex forms, including human minds.
Well ID, from the time of Paley. rests on analogies with human designers. So it is reasonable to extend the analogy to the motives and methods of human designers.
I’m aware that ID advocates don’t want to go there, despite the fact that the analogy is the only basis for positing the existence of a designer of biology. The analogy is strengthened by the fact that most ID advocates are Abrahamic in religion, and a central tenant of that faith is that humans are made in the image of the Designer.
So if we ask why a designer would do that, we are asking the question because our minds, our understanding and our curiosity are derived from and analogous to the Designer’s.
Zachriel:
True, and the evidence also does not preclude the Rain Fairy. It’s just that meteorology fits the evidence far better than does the Rain Fairy hypothesis. A rational person looking for the best explanation will choose meteorology over the Rain Fairy.
Likewise, a rational person looking for the best explanation of the objective nested hierarchy will choose unguided evolution over ID — and that includes the forms of ID that accept common descent. Unguided evolution predicts the objective nested hierarchy, singling it out from the trillions of alternatives without requiring the addition of ad hoc, unjustified assumptions. ID can be made to fit the ONH only by the addition of ad hoc, unjustified assumptions.
Those all differ from ID in not denying the power of unguided evolution. For example, your Cosmic Gardener hypothesis actually requires unguided evolution to produce today’s diversity of life from the initial seed. Under the Cosmic Gardener hypothesis, unguided evolution is the explanation of the ONH, which reinforces my claim rather than undermining it.
It makes the Rain Fairy superfluous, but you have purposefully chosen to exclude much of the evidence for evolution. Common Descent is consistent with a Divine Intelligence that orders the universe so that life strives towards complexity or consciousness.
Are garden’s not the design of a gardener? Your claim is that they are incompatible. It would seem that compatible is precisely the right term to use when artifice and nature meet.
Zachriel:
Don’t forget that common descent and the evidence for common descent are separate things. The objective nested hierarchy implies common descent, but common descent does not imply the ONH. Life “striving towards complexity or consciousness” would not automatically generate an ONH, even if the striving were done via common descent. The only way to get an ONH is if the strivings just happen to leave a trace that looks exactly like unguided evolution, through gradual changes and primarily vertical inheritance. But why assume that without independent evidence? (For that matter, why assume a Designer at all without independent evidence, particularly when unguided evolution explains the evidence so well?)
Also, please note that the above argument only considers the evidence for common descent. The case becomes even stronger if we consider the rest of the evidence for unguided evolution.
A better analogy is a weed patch. I say the best explanation for a weed patch is that it arose naturally. You point out that it could have been created by a gardener. Well, it’s logically possible that a gardener carefully planted each weed, but this requires ad hoc and unjustified assumptions about the gardener’s aims, abilities and/or limitations. The natural hypothesis fits the evidence extremely well without any unjustified assumptions, while the gardener hypothesis requires them in order to fit. The natural hypothesis is thus a better explanation for the weed patch, and any rational person would prefer it over the gardener hypothesis.
Also note that as ridiculous as it sounds to invoke gardeners to explain weed patches, that hypothesis is actually more respectable than ID, because we actually know that gardeners exist.
This seems to be where we are missing your argument. Why would a bifurcating tree that is drawn to reach out into space not form a nested hierarchy? That’s what natural trees do, a process that can be considered a form of non-conscious intelligence.
Without a theory of adaptation, there’s no reason to suppose that organisms would become vastly more complex over time. There has to be a motive force of some sort, or evolution languishes.
Zachriel:
Yes, I think that is the crux of the misunderstanding. A bifurcating tree, if you observe it as it forms, will of course form a nested hierarchy. However, if you don’t observe it as it forms, then you won’t necessarily be able to infer the hierarchy from the evidence it leaves behind.
I’ll give a concrete example later tonight when I have more time, and then all will be clear (I hope).
Okay. As promised, a concrete example. Let’s reuse the sequences you created for Joe when trying to teach him about nested hierarchies:
The nested hierarchy we inferred from those sequences was: {1, {2}, {3,4} {5, 6, {7, 8}}}
That is the most sensible and parsimonious hierarchy to infer, particularly if unguided evolution is in operation, but it is certainly not the only hierarchy that can match your sequences. There are many others.
For example, suppose the true pattern of descent is a chain, where 8 is the ancestor of 7 which is the ancestor of 6, etc. Then the true history looks like this, with time increasing down the page (let’s assume for simplicity that the commas all represent actual comma characters):
8 ) , , EB, , , , , , , , , , , G
7 ) , , , B, , , , , , , , , , , G (E changes to comma)
6 ) , , , , , O, , , , , , , , , G (B to comma; comma to O)
5 ) , , , , , , , , , , , , , , , G (O reverts to comma)
4 ) , , , , , , , R, , I, , , , , (comma to R, comma to I, G to comma)
3 ) , , , , , , , , , , I, , , , , (R reverts to comma)
2 ) , , , , , , , , , , , , D, , , (I reverts to comma, comma to D)
1 ) , , , , , , , , , , , , , , , , (D reverts to comma)
What makes this odd hierarchy unlikely is that we would never expect unguided evolution to change a comma to an R and then back to a comma, and we would never expect to end up with all commas after starting with a mixture of commas and letters. The probability of these events is way too low, given unguided evolution.
However, if intelligence is involved, then this odd hierarchy is perfectly possible, as are many, many others. In fact, any historical hierarchy can be made to match your sequences if we simply assume that an intelligence caused the right changes to happen to the right sequences at the right times.
Note that in this simple example both hierarchies, the true one and the inferred one, are nested hierarchies. However, it’s possible to construct a list of sequences in a such a way that we cannot infer a single objective hierarchy. In these cases you get a different NH depending on how you “prioritize” the traits.
The point of all this is that the hierarchy we infer matches the actual historical hierarchy only if change is gradual and inheritance is primarily vertical — both of which are characteristics of unguided evolution. ID is not constrained in the same way and therefore does not predict a single objective nested hierarchy. ID can only be made to fit the ONH by adding ad hoc and unjustified assumptions. Unguided evolution fits the ONH without requiring such assumptions. It’s the better theory.
Zachriel,
Even with a theory of adaptation, there is no reason to suppose that organisms would become vastly more complex over time. Genotypes are ‘flat’. Their persistence requires only that they be template-copied by some mechanism. In a self-contained system, that mechanism is part of the string, giving a certain minimal phenotypic complexity to a self-replicator: replication itself, derivation of the energy and materials for it, probably competitive, and the basic ‘organismal’ consequences of those.
When the requirement to perform some particular part of that ensemble is removed, by provision of an external source, phenotypes tend to simplify. Viruses, parasites, endosymbionts etc.
Yet the phenotypes that most interest us – multicellular ensembles, forming food, pets, threats and mates – are decidedly complex. They are, nevertheless, in the minority (depending of course on what you count). They simply accumulate a great deal of biomass in the course of their lives, and are naturally more noticeable to each other – organisms that operate on what we think of as the ‘macro scale’.
Is there a necessity to construe an external force to generate that complexity? I don’t think so. The prime ‘drivers’ of that multicellular complexity are endosymbiosis and sex (sex being a kind of symmetric symbiosis at the genetic level, though massively asymmetric phenotypically in the derived state). There are a host of reasons for the drive to complexity that these have engendered – reasons both genetic and phenotypic. But they all come from within, preserved in response to what is encountered without. The complexities include the very constructs of ‘populations’ adapting by subgenome enhancements; the recombinational exploration of phase space and networking of ‘solutions’; the ‘glue’ that keeps multicellular diploid somas coherent via common interest (the gamete bottleneck); the strengthening of the signal of tree-like descent the more deeply embedded the germline becomes within this protective soma; the central role played by sex in species and higher taxonomic divergence in its absence; the coevolutionary effect of sexual dimorphs upon each other… if we were to land upon another ‘living’ planet, its biocomplexity would, IMO, depend largely upon whether it had ‘discovered’ sex, and that in turn would depend upon whether its organisms had freed their external membranes from an energetic role – eg, via endosymbiosis.
Zachriel:
Of course (to all that, excepting a slight quibble on the loose sense of “incompatible” – but as I said, I’d prefer it if we kept to its precise meaning in logic – keiths wouldn’t have laid himself open to Mung’s trick of taking his title literally and ignoring what he actually says in the post, which contradicts the literal/logical interpretation of the title, had he kept to that meaning).
But of course to the rest. Because the general I.D. hypothesis is logically compatible with anything, it’s inevitable that we can always make specific I.D. hypotheses to match any described hypothetical biosphere or any real observed one. Actually, the ones you’ve proposed are so general as to be (logically) compatible with pretty much anything. Try to think of their predictions. The pruning one can be said to require some extinctions, but that seems about it.
On incompatible. We can say that Johnny’s belief that the soccer team he supports is going to win the league is incompatible with his observation that they’re bottom of the league at present after 5 games having lost every single one. However, his belief is only incompatible in a loose probabilistic sense, not in a strict logical sense, because it isn’t logically impossible that they could win all of the remaining games and triumph. I think keiths would agree that that’s the sort of incompatible he’s using in the thread title.
That’s right. But that actually supports our point.
Endosymbiosis is adaptive and selective.
Without natural selection or some other mechanism, complexity would merely spill out across the floor rather than decisively rising above it.
We had presumed we were ignoring perverse designers, otherwise, you could posit a designer that made the world six thousand years ago to look much older.
We had thought there might be some interesting characteristic of the nested hierarchy that implies so-called unguided evolution. Rather, the analogy to the tree seems very a propos. The tree ‘attempts’ to fill the available spaces. It ‘strives’ to branch out. So does the Tree of Life. If a branch is broken, then other branches tend to grow into the available space. The tree ‘reaches’ into the surrounding space. Simple rules govern each inch of growth, but the result is a complex treed pattern. But you can’t tell from the existence of a nested hierarchy *alone* whether the tree is being pruned or the branches tied. You have to look at other evidence, such as how the branches are bunched, but with the Tree of Life, it might still be difficult to distinguish the natural from the artificial.
Still a nested hierarchy:
http://etc.usf.edu/clippix/pix/small-manicured-tree-at-the-morikami-japanese-garden_medium.jpg
Sure it is, in itself. But it also lifts the lid on complexity, in a way very distal to the original mutual benefit. Organisms can devote vastly more membrane surface to energy generation, and free up their outer membrane for engulment of food, rather than the diffusion-limited fate that kept the prokaryotes simple these 4 billion years or so. And you get a whole bunch of two-way traffic in recombinational genes, which again changes the tempo of evolution dramatically. And it enables an increase in size, such that adaptive tuning has a whole different range of physics to deal with. And it enables sex, which notches the tempo up still further, as well as directly favouring multicellularity and sexual selection.
Well, yes, without selection, there would simply be replication at best, and probably not even that after several billion years of environmental fluctuation. But there is selection, and there couldn’t not be selection unless all DNA molecules were identically competent, or someone intervened to help the ‘incompetent’ ones stay afloat.
Still, complexity is no guarantee of success (which is simply persistence). It just happens that more complex organisms inhabit our scale, it would appear, because for eukaryotes, such complexification is both possible, and can be adaptive in those niches.
So, without a theory of adaptation, there’s no reason to suppose that organisms would become vastly more complex over time. There has to be a motive force of some sort, or evolution languishes.