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.
It’s a confirmation of monophyly.
Yes. But Theobald’s results are perfectly consistent with design that works by pruning and tying branches on the tree; and would yield the exact same result. In other words, your use of “trillions of times better” is misplaced.
Any assumption about the designer is unwarranted in the sense of being unevidenced. But your claim is lack of compatibility, which means you have to account for every reasonable designer hypothesis.
Even without a mechanism of adaptation, design would just be conjectural. We’re in agreement that design is superfluous in light of the Theory of Evolution, and you would want positive evidence to support such a claim.
Zachriel:
Surely a design hypothesis becomes unreasonable once unreasonable constraints are placed on the designers.
Zachriel:
Sure, and of unguided evolution. But what you originally said was
…which is incorrect. All of the 1038 trees considered by Theobald are monophyletic.
Zachriel:
No, because intelligent selection by a designer can produce results that don’t fit an objective nested hierarchy (for example, a designer who employs my “repressor-shadow” technique to create identical genes in 25 separate lineages simultaneously).
No, “trillions of times better” is in fact correct. If anything, I should be criticized for understating the case, not overstating it.
There are 1038 possible trees involving the 30 major taxa. A designer could choose any of those trees. Furthermore, the designer could choose different trees for different traits or groups of traits.
The morphological evidence points to one tree out of the 1038 possibilities. The molecular evidence points to the same tree out of 1038 possibilities.
Under a design hypothesis (including your ‘pruning’ hypothesis), we have no reason to expect these trees to be the same, and the odds of it happening by chance are 1 in 1038.
Unguided evolution predicts that the trees will be highly congruent, if not identical. The prediction is confirmed, and ID is blown out of the water.
The only designer hypothesis that fits the evidence is one in which the designer mimics (by desire, coincidence, or limitation) the patterns of unguided evolution. The only Rain Fairy hypothesis that fits the evidence is one in which the Rain Fairy mimics (by desire, coincidence, or limitation) the patterns of unguided meteorology. Any reasonable person will reject the Rain Fairy and Designer hypotheses in favor of their competitors, which explain the evidence far, far better.
Sure. Now we’re only quibbling over the source of the claim that unguided evolution fits the evidence “trillions of times better — than ID does”, which keiths based on a
studyanalysis that only concerns monophyly.It’s really not an important point, as we are in agreement that design is superfluous based on modern evolutionary theory.
Thought you were referring to Theobald 2010. Our mistake.
That’s the number of possible monophyletic arrangements of the 30 major taxa. That’s important because the morphological tree matches the molecular tree, which is very unlikely by chance.
That still doesn’t support anything other than monophyly.
That’s right.
Any design hypothesis that encompasses monophyly would not be incompatible with that result, including a designer who prunes and ties the branches.
http://etc.usf.edu/clippix/pix/small-manicured-tree-at-the-morikami-japanese-garden_medium.jpg
Zachriel:
Apparently you’re not reading what I write. I pointed that out two comments ago:
Zachriel:
Not true. There’s a difference between actual monophyly and inferrable monophyly, just as there is a difference between actual common descent and inferrable common descent. As I’ve pointed out several times already, design (including guided common descent and ‘pruning’) does not imply that we will find a single objective nested hierarchy. I’ve even supplied concrete examples to illustrate this.
In a similar way, guided monophyletic common descent (including by pruning) does not imply that we will infer monophyly. The designer can choose to produce a different pattern. The designer could even employ actual polyphyly to produce a pattern that causes us to infer monophyly. That’s what “separate creation through common design” amounts to.
The number of patterns open to a designer is enormous, even if the designer is merely pruning a monophyletic evolutionary process. If a designer is operating, there is no reason to expect the morphological evidence and the molecular evidence to converge on the same tree (out of 1038 possibilities). Unguided evolution, on the other hand, predicts that they will be the same (or at least highly congruent).
Unguided evolution thus fits the evidence trillions of times better than design. As I said in my last comment:
There are evolutionary theories that are consistent with multiple origins. And rates of change and horizontal transfers have to be slow enough to leave an inferrable common descent.
Maybe it just grew that way.
http://etc.usf.edu/clippix/pix/small-manicured-tree-at-the-morikami-japanese-garden_medium.jpg
Some designers, perhaps, but not all, including apparently, some horticulturalists.
It would depends on the designer, and the history of the relationship between the designer and the tree.
No. Only some evolutionary theories predict universal common descent. Indeed, Darwin’s original theory did not. Only some evolutionary theories predict an inferrable monophyly. That depends on the particulars of evolutionary change.
Similarly with design hypotheses. Some predict this. Some predict that. Your claim requires showing that every reasonable design hypothesis is *incompatible* with design, and that leaves leaves.
http://etc.usf.edu/clippix/pix/small-manicured-tree-at-the-morikami-japanese-garden_medium.jpg
There are an infinitude of possible design conjectures, but there are also an infinitude of possible evolution conjectures. Any reasonable theory has to account for the known facts, so we select from among the evolutionary or design conjectures that are consistent with those facts.
Based on Theobald’s analysis, any evolution or design conjecture must be *compatible* with the evidence for monophyly. Most are not, and so that eliminates the vast majority of evolution and design conjectures. The remaining design conjectures can be rendered extraneous by consideration of other evidence, but not by the evidence for monophyly alone.
Zachriel:
Sure, including modern evolutionary theory. Mutation, selection, adaptation, fixation, drift, draft, etc., do not depend on universal common descent.
Thank you for acknowledging that. It’s an important point, which is why I’ve stressed it so many times.
keiths:
Zachriel:
You mean, without guidance or interference from a Designer? Sure. In fact, that is by far the best explanation we have for the observed tree.
Zachriel,
In focusing exclusively on the issue of a theory’s consistency with the evidence for common descent, you’re missing a very important point. Consistency is a requirement for a successful theory, but it is far from the only requirement.
Mere consistency just means that a theory doesn’t absolutely contradict the evidence. That’s a very low bar. The Rain Fairy hypothesis clears it, as does ID.
What we want are theories that actually fit the evidence, rather than merely not contradicting it. And we want theories that can do this with a minimum of ad hoc assumptions.
The Rain Fairy hypothesis, in its most general form, doesn’t fit the evidence well at all. It’s vastly inferior to modern meteorology in that regard. We can make it fit the evidence by adding a bunch of ad hoc assumptions, but then the assumptions themselves render it inferior.
Likewise, ID in its most general form doesn’t fit the evidence of the objective nested hierarchy well at all. It’s vastly inferior to modern evolutionary theory in that regard. We can make it fit the evidence by adding a bunch of ad hoc assumptions, but then the assumptions themselves render it inferior.
I assume you agree that the Rain Fairy hypothesis is vastly inferior to modern meteorology in terms of its ability to explain the meteorological evidence. If so, then how can you argue that ID is not vastly inferior to MET in explaining the objective nested hierarchy?
Modern evolution theory explains the objective nested hierarchy because it posits bifurcating descent with variation. ID can incorporate the very same mechanism of bifurcating descent with variation.
The problem is that you are assigning a probability derived from monophyly to unguided evolution. If ID incorporates monophyly, then that means the probability of unguided evolution compared to Monophyletic ID depends not on the probability of monophyly, which is presumed, but the probability of other mechanisms explaining the known history of life, the probability of which you have not *quantitatively* established.
Zachriel:
Bifurcating descent with variation isn’t a mechanism, it’s a consequence of mechanisms. Mechanisms that produce an inferrable objective nested hierarchy differ in important ways from those that merely produce bifurcating descent with variation. Change must be gradual and inheritance must be predominantly vertical. Modern evolutionary theory satisfies those criteria, but ID does not.
You can assume a form of ID in which change is gradual and inheritance is primarily vertical, but then the only function of the assumptions is to artificially force a fit between theory and evidence. There’s no independent justification for the assumptions, just as there’s no independent justification for assuming that the Rain Fairy always behaves in a way that conforms to the predictions of modern meteorology.
ID and the Rain Fairy hypothesis are in the same sinking boat.
Zachriel:
Don’t forget that an objective nested hierarchy implies common descent, but common descent (including guided monophyletic common descent) does not imply an objective nested hierarchy. The asymmetry is crucial.
Modern evolutionary theory predicts that the nested hierarchy derived from morphological data will be highly congruent (if not identical) to the nested hierarchy derived from molecular data, out of 1038 possibilities. ID, including guided monophyletic common descent, makes no such prediction. Under ID, the morphological hierarchy could be similar to the molecular hierarchy, or it could be completely different, even if we assume that ID proceeds by monophyletic common descent. The fact that the hierarchies are identical is a decisive point in favor of modern evolutionary theory.
The only way to make ID fit the objective nested hierarchy as well as modern evolutionary theory does is by adding assumptions that are completely ad hoc and unjustified.
Unguided evolution is the vastly superior theory — trillions of times better than ID, including its ‘guided monophyletic common descent’ variant — even when we restrict our attention to the objective nested hierarchy. When we admit the rest of the evidence, the verdict is even more lopsided in favor of unguided evolution over ID.
ID can subsume those mechanisms, such as artificial selection.
Zachriel,
As I’ve already explained, artificial selection doesn’t necessarily lead to an objective nested hierarchy:
Modern evolutionary theory fits the objective nested hierarchy as is. To make ID fit, you have to assume 1) the existence of a designer at all the crucial moments , 2) that the designer has the requisite capabilities, and 3) that the designer just happens to behave in a way that mimics MET, instead of one of the trillions of other possibilities. There is no justification for these assumptions. They are purely ad hoc, introduced to force an artificial fit between theory and evidence.
MET explains the objective nested hierarchy trillions of times better than ID.
The nested hierarchy is due to bifurcating descent. A design conjecture can certainly encompass this process.
You take one example of possible design conjectures (a very strained example that concerns genomes). You then claim that you have encompassed all reasonable design conjectures, that the rest are all so ad hoc as to be unreasonable, but that is not the case.
Artificial selection typically leaves a discernible nested hierarchy. “Made for each other” sexual selection can also strongly direct evolution while leaving the nested hierarchy intact. Culling leaves the nested hierarchy intact. So does a mysterious force that draws life upwards towards enlightenment. There are many other reasonable conjectures that leave the nested hierarchy intact. We keep pointing to one, but you keep ignoring it.
http://www.flowers-like-people.com/wp-content/uploads/2012/02/Bonsai2.jpg
Given the tree, in order to calculate your ‘odds’, you would have to determine the probability of natural selection being the mechanism that shapes the tree. You haven’t done that.
Zachriel,
I think we can get to the heart of our disagreement if you’ll address the following point.
The Rain Fairy hypothesis can be made to fit the evidence beautifully if we adopt a set of ad hoc, unjustified assumptions. Yet I (and presumably you) regard the Rain Fairy hypothesis as massively inferior to modern meteorology as an explanation for the weather. Why? Because the ad hoc assumptions are doing all the work. The close fit between theory and evidence is entirely due to the assumptions, and not to the theory itself. If the evidence were completely different, no problem — simply change the assumptions and you still have a perfect fit.
Contrast that with modern meteorological theory. It fits the evidence without needing the ad hoc assumptions. The theory is actually doing the work. The close fit between theory and evidence is due to the theory, not to the assumptions you’ve tacked onto it. If the evidence were completely different, the theory would be falsified.
The Rain Fairy hypothesis is clearly inferior, despite the fact that it can be matched perfectly to the evidence by the addition of a set of ad hoc assumptions.
Likewise, ID can be made to fit the evidence beautifully if we adopt a set of ad hoc, unjustified assumptions. Yet I regard the ID hypothesis as massively inferior to modern evolutionary theory as an explanation for the objective nested hierachy. Why? Because the ad hoc assumptions are doing all the work. The close fit between theory and evidence is entirely due to the assumptions, and not to the theory itself. If the evidence were completely different, no problem — simply change the assumptions and you still have a perfect fit.
Contrast that with modern evolutionary theory. It fits the evidence without needing the ad hoc assumptions. The theory is actually doing the work. The close fit between theory and evidence is due to the theory, not to the assumptions you’ve tacked onto it. If the evidence were completely different, the theory would be falsified.
The ID hypothesis is clearly inferior, despite the fact that it can be matched perfectly to the evidence by the addition of a set of ad hoc assumptions.
My question for you:
If you agree that the Rain Fairy hypothesis is massively inferior to modern meteorology in explaining the weather, then why don’t you agree that the ID hypothesis is massively inferior to modern evolutionary theory in explaining the objective nested hierarchy?
I claim that the same logic applies to both cases. If you disagree, please highlight the relevant differences.
That’s not quite what is happening with your argument about the nested hierarchy. You have cleaved the Theory of Evolution and claim that the nested hierarchy *in-and-of-itself* overwhelmingly supports unguided evolution.
Let’s do this with weather. Wind and storm are due to variations in atmospheric pressure. K then claims that this *in-and-of-itself* eliminates any reasonable design conjectures. Yet Z notes that these pressure differences might be due to design, such as a wind god that blows the air about. In fact, any design conjecture that encompasses pressure differences as the mechanism of wind and storm would be “compatible” with pressure differences as the mechanism of wind and storm.
Only by referring to the uncloven theory of meteorology, which posits that these pressure differences are due to mechanisms such as uneven solar heating, does the Rain Fairy become superfluous.
We’re not concerned whether it is perhaps inferior as a designer-of-the-gaps argument, but your argument that the evidence for common descent *in-and-of-itself* makes any design conjecture “literally trillions of times worse than unguided evolution at explaining the evidence.”
Zachriel:
You’re confusing the theory itself with the evidence it is meant to explain. I haven’t cleaved the theory; I’ve cleaved the evidence, so that I’m considering only the objective nested hierarchy.
The question throughout this thread has been “which is better at explaining the objective nested hierarchy, modern evolutionary theory (uncloven) or ID (uncloven)?” The answer is that MET is trillions of times better, and the only way for an IDer to close the gap is to make a set of ad hoc, arbitrary, unjustified assumptions that force a fit between ID and the objective nested hierarchy.
ID is terrible at explaining the objective nested hierarchy, just as the Rain Fairy hypothesis is terrible at explaining the weather.
That’s right. We observe a tree. And from that fact alone, you can’t determine whether the tree was shaped by nature or artifice.
http://www.flowers-like-people.com/wp-content/uploads/2012/02/Bonsai2.jpg
We’re obviously going in circles.
sez zachriel: “We observe a tree. And from that fact alone, you can’t determine whether the tree was shaped by nature or artifice.”
True—but we can determine whether the tree was shaped by artifice-that-apes-nature, or artifice-that-does-not-ape-nature. And if the answer is “the tree was shaped by artifice-that-apes-nature”, we have every reason to wonder what’s the friggin’ point of throwing in the ‘artifice’, if it’s just going to end up with the same result as ‘nature’?
Zachriel:
We observe the weather. And from that fact alone, you can’t determine whether the weather was caused by physical processes or by the Rain Fairy.
Yet every sane person thinks that modern meteorology is vastly superior to the Rain Fairy hypothesis. Obviously, we want more from our theories than mere consistency with the evidence.
What is the extra ingredient we desire? Predictive power, without the need for ad hoc assumptions. The Rain Fairy hypothesis doesn’t have this, and neither does ID. Meteorology and modern evolutionary theory do have it, in spades. They are better theories.
Which could be prevented, I think, if you would do this: Every time you’re about to lodge an objection against my argument in favor of modern evolutionary theory, ask yourself if the same objection can be lodged against modern meteorological theory. If it can, then there must be a separate, stronger reason that you reject the Rain Fairy hypothesis in favor of modern meteorology. See if a similar reason supports evolutionary theory over ID.
If you can find an asymmetric case where an objection applies to the evolution/ID question but not to the meteorology/Rain Fairy question, then let me know.
Based only on the observation of the nested hierarchy, how?
You pointedly asked us to respond to the Rain Fairy hypothesis. We did, but you apparently didn’t digest our response.
We did exactly that.
Our design theorist and our natural theorist both observe the nested hierarchy. They both agree that this implies a tree due to bifurcating descent. They further agree that baptists and baboons are relatives, that baboons and barnacles share a common ancestor, and that barnacles and buttercups are cousins. They differ on the mechanisms that explain the shape of the tree, but the mechanism can’t be directly inferred from the existence of the tree alone. Indeed, without a mechanism of adaptation, natural evolution would tend to hug the fitness floor like a vine, so the natural theorist would have to posit a mysterious élan évolutif.
Zachriel,
I keep reminding you that we are measuring modern evolutionary theory against ID, and you keep ignoring me and asking a different question.
It was true eight days ago, when I wrote:
You acknowledged it then:
And it’s still true now:
You keep asking a completely different question, which amounts to this:
The OP makes it clear that we are not talking about your imaginary world:
I claim that modern evolutionary theory is trillions of times better than ID at explaining the objective nested hierarchy. Do you disagree? If so, why?
By noting that artifice-that-does-not-ape-nature is astronomically unlikely to produce a nested hierarchy. That standard of ‘determining’ is good enough for pretty much everything else in science, so if you want to raise the hypertechnical philosophical point that it’s mathematically possible that artifice-that-does-not-ape-nature has a non-zero chance of yielding a nested hierarchy, well, I wish you joy of your hypertechnical philosophical point.
We are presuming that the design theoretician accepts that the nested hierarchy represents common descent. Try to be specific.
If you mean ID doesn’t explain the particular historical pattern of common descent as well as modern evolutionary theory, sure. We have no disagreement on that point, of course. But that’s not how your post reads, which is that “Intelligent Design is not compatible with the evidence for Common Descent”, a different statement which puts strictures on the evidence to be considered. You made numerous statements that used the same construction, seemed to argue the point, and cited Theobald’s analysis for support. Yet, none of this is consequential to that particular question. Theobald’s “trillions” still applies to common descent regardless of what mechanism forms the overall shape of the tree, so that claim still doesn’t belong.
Trying to use Critical Rationalist’s argument, ID is easily modified. It does not require common descent. It doesn’t have any limitations or constraints. It is compatible with any history, including Last Thursdayism.
So yes, it is “compatible with” common descent, but also with any of an infinite list of other histories.
Actually, so is evolutionary theory; however, it is a tiny subset of all possible histories.
Sure. However, while ID as a cultural phenomena is okay with just about anything that includes some role for a designer, it is possible to conceive of design conjectures that are reasonably consistent with common descent.
Zachriel:
That’s incorrect. I keep explaining this, and you keep ignoring me. I don’t understand why.
I made this point all the way back in the OP:
I’ve reiterated that point at least a half a dozen times in comments addressed directly to you, including this recent one:
You’re free to ignore this again, of course, but I hope that instead you’ll extend me the courtesy of trying to understand and respond to my actual argument.
We discussed this already. The design theorist and the natural theorist agree that the congruence of the genotypic and phenotypic nested hierarchy implies common descent and constrains plausible design conjectures. For instance, this eliminates your rather strained example above of a design conjecture that does not imply this congruence.
Without additional evidence, you haven’t explained the shape of the tree. It could be due to any number of possible mechanisms.
http://upload.wikimedia.org/wikipedia/commons/6/61/Japanese_tree.jpg
(Indeed, {absent some sort of mechanism,} natural {‘unguided’} evolution would tend to hug the fitness floor.)
Zachriel,
You’re back in the imaginary world I mentioned a few comments ago:
This thread is not, nor has it ever been, about that imaginary (and rather uninteresting) world.
Instead, I have placed modern evolutionary theory (complete with its mechanisms) side-by-side with ID to determine which one better explains the objective nested hierarchy.
ID can be made to fit the objective nested hierarchy, or its opposite, or anything in between. It conforms to all of them because it has no structure of its own. It explains everything and therefore nothing.
MET sticks its neck out and predicts an objective nested hierarchy out of trillions of possibilities. It did so even before we knew that the molecular hierarchy matched the morphological hierarchy. Zuckerkandl and Pauling:
MET is trillions of times better than ID at explaining the objective nested hierarchy. It’s the better theory, by far.
No. We believe ourselves open to your argument, but remain unconvinced. There is confusion because you say you are including the entire Theory of Evolution, but your calculation tells a different story.
Actually, it’s a very interesting question, though one you say you are not addressing. Your claim, though, is that the congruence in the nested hierarchy is not “compatible” with any reasonable design conjecture. That means we should be able to show that incompatibility by looking only at the nested hierarchy. That’s how we would read it. Otherwise, you would say ID is not compatible with the evidence for evolution generally.
Your claim is that congruence in the nested hierarchy is not “compatible” with any reasonable design conjecture, and your calculation is based only on evidence for the nested hierarchy.
Sure. We do that with all scientific conjectures. We discard those that do not fit the evidence and retain those that do.
There is a class of conjectures that fit the congruency in the nested hierarchy. Your claim is that none of these conjectures can reasonably incorporate design. You have not shown that to be the case.
Our design theoretician and our natural theoretician agree that congruence confirms common descent.
Any conjectures that encompasses monophyly and congruency is consistent with “trillions of times” better than the contrary case.
You have repeatedly ignored a very simple model.
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Zachriel:
It’s really quite simple. Perhaps an analogy will help. If I tell you that modern physics explains the properties of a laser beam far better than a competing theory, then all I am claiming is that modern physics explains it better. I am not claiming that all of modern physics can be derived from observing the properties of the laser beam.
Likewise, when I say that modern evolutionary theory explains the objective nested hierarchy far better than ID, all I am claiming is that MET explains it better. I am not claiming that all of MET can be derived from the ONH.
My claim, yet again, is that modern evolutionary theory — the whole shebang, including its mechanisms — fits the evidence of the ONH trillions of times better than ID. You can force-fit ID to the evidence only by adding a set of ad hoc, unjustified assumptions. MET doesn’t require such assumptions. It fits the evidence without them and is therefore a superior theory.
Yes, but that’s not all we do. If it were, then the Rain Fairy hypothesis would still be viable. We discard the Rain Fairy hypothesis without hesitation, despite the fact that it can be made to fit the evidence perfectly. Why? Because the perfect fit requires a set of ad hoc assumptions for which there is no independent evidence.
Any rational person will reject ID for the same reason.
Not if the congruence is achieved only via unjustified assumptions. In the case of ID, the unjustified assumptions are doing all of the work. In the case of MET, it is the theory itself which is doing the work.
New evidence could falsify MET. ID could adapt simply by changing its ad hoc assumptions. ID is infinitely malleable and therefore unfalsifiable.
Let me repeat my earlier challenge to you:
Please be specific.
But that’s not the claim we are taking issue with.
Again, that’s not the claim we are taking issue with.
But that’s not the claim we are taking issue with. Here’s the title of your post: “Intelligent Design is not compatible with the evidence for common descent.” That is the statement we are taking issue with.
We responded to this above. We’ll do so again.
Finally, that’s not the claim we are taking issue with, but “Intelligent Design is not compatible with the evidence for common descent.”
The analogy would be this claim: Design is not compatible with ‘Pressure Theory’ (that differences in air pressure account for wind and storm). That claim is not correct. Æolus, while speculative and fanciful, is compatible with Pressure Theory, though not with modern meteorological theory.
Here Æolus, in cavern vast,
With bolt and barrier fetters fast.
Rebellious storm and howling blast
As an aside, design is one of many metaphysical gap fillers, and assigns characteristics (perhaps by analogy, but without any particular evidence) to what we are attempting to explain. If we have a natural theory that explains most related phenomena, then the designer is relegated to disjointed nooks and crannies, and will exhibit many ad hoc characteristics to make it fit. But when there is a substantial gap, then design can be more convincing, even if only speculative.
Zachriel,
You’re being dishonest, and I’m calling you on it.
You started out by quibbling over the word ‘incompatible’. dr who and I explained my use of the word, and you accepted it:
In the two weeks since then, your argument has morphed several times. I’ve responded to each variant, and each time you’ve quietly dropped it and raised a different objection.
Now you are back to your original quibble, pretending that it has been the issue all along, and acting as if you hadn’t already accepted my use of the word:
Knock it off, Zachriel. I thought you were better than this.
Inaccuracy is a bad way to start such an accusation. We did not quibble over your use of the word “compatible”.
Our first comment on the subject was “Common Descent puts limits on how the designer implemented their plan, but doesn’t preclude a designer.” More particularly, design is compatible with the evidence for common descent, but not compatible with (extraneous to) modern evolutionary theory.
Our point has been consistent. We readily agreed that the evidence for evolution in toto is incompatible with Intelligent Design, in the sense that a designer is extraneous as an explanation. We are addressing the conflation of the evidence for common descent with the evidence for evolution in the phrase “Intelligent Design is not compatible with the evidence for common descent”.
You have said that you meant that phrase to encompass the evidence for evolution generally, but haven’t really indicated that your original wording should be changed. Instead, you insist upon equating the probability of congruence between the genomic and phenomic nested hierarchies to the probability of guided evolution, indicating you haven’t abandoned your original position.
Well, no. You haven’t actually. Of course, it depends on what you think is our point of disagreement.
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Your explanation was that this restricts the universe of possible designers to a tiny subset, which is correct.
This is correct; however, that doesn’t mean the entire restricted set of designers is wholly unreasonable. Please note that you were arguing based solely on evidence of the nested hierarchy.
keiths,
We’ve fairly well covered the question, and not sure where else to take the discussion. We may very well be wrong, but we remain unconvinced—or confused, as the case may be.
Zachriel,
Reasonable and intelligent people don’t always agree, but they can usually isolate the crux of a disagreement. I know you’re intelligent, and I know that you can be reasonable when you choose to be, so let’s see if we can at least identify the root of the difference between our positions.
You wrote:
I think the entire restricted set is unreasonable, because the restriction itself is unreasonable. There is no justification for the restriction other than a desire to force-fit the theory to the evidence.
A sufficiently vague theory, such as ID or the Rain Fairy hypothesis, can always be restricted so that it fits the evidence — any evidence — perfectly. That doesn’t make it a good theory. Good theories are those that fit the evidence without the need for arbitrary, extraneous and ad hoc assumptions.
So far you haven’t offered any justification for assuming that the designer 1) always makes small changes, 2) uses primarily vertical inheritance, avoiding horizontal transfers, and 3) generally behaves in a fashion that mimics the effects of unguided evolution (as described by modern evolutionary theory). Without those assumptions, ID doesn’t fit the evidence of the objective nested hierarchy.
Can you justify those assumptions? If not, then I claim that your version of ID is just as ridiculous as the Rain Fairy hypothesis, because both depend utterly on unjustified, ad hoc assumptions that force-fit them to the evidence.
Usually.
You have to be willing to accept our genuine disagreement, otherwise, you won’t understand the point we are raising. Frankly, you don’t seem to understand it well enough to restate it clearly.
Yes. That’s your claim, and according to the original post, you can determined this from common descent alone.
Every working theory is forced to fit the evidence. We discussed this above.
Zachriel: design is one of many metaphysical gap fillers, and assigns characteristics (perhaps by analogy, but without any particular evidence) to what we are attempting to explain. If we have a natural theory that explains most related phenomena, then the designer is relegated to disjointed nooks and crannies, and will exhibit many ad hoc characteristics to make it fit. But when there is a substantial gap, then design can be more convincing, even if only speculative.
We’re not considering unreasonable fits. There’s a huge enough gap when considering common descent alone to mean that design is compatible, even if only speculative.
Inheritance just so happens to be a natural property of life. Maybe life and the universe were designed that way, but that’s not directly relevant. The design theorist looks at the very same evidence of common descent and finds the exact same justification that the natural theorist does. They agree on this. Life naturally forms the tree. The difference is that the design theorist posits (among several possible conjectures) that the shape of the tree is designed.
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My problem is with the word “trillions.” Everything about ID is ad hoc, so it explains nothing and has zero explanatory power.
As evidence that ID is completely ad hoc and has no explanatory power, we have UD, which has everything from Michael Denton fine tuners to YEC creationists to gpuccio, who seems to believe there are invisible, non-material active agents continuously at work. Or something like that. All these conjectures exist side by side with no disagreement or interaction.
You cannot make a ratio unless you have two actual numbers. ID simply hasn’t put forth a theory that evaluates to a likelihood,
That’s right. You can’t calculate a probability of something ambiguous. You can only calculate probability for specific alternative explanations. In the case of Theobald’s “trillions”, it’s congruence due to common descent compared to chance.
We’re taking ID to mean any reasonable design conjecture compatible with common descent, not the cultural phenomenon.
But that is a Fisher-like ratio. It’s comparing common descent to chance, not to ID. ID presents no number.
“ID” is too vague to present a number, but specific design conjectures can be tested, such as separate creation.
I’ll respond to Zachriel in more detail later, but let me comment on whether ID “presents a number”. I claim it does, in the following sense:
For the 30 taxa that Theobald considers, there are 1038 possible nested hierarchies. The actual morphological tree is one of those 1038 possibilities, and so is the molecular tree. It turns out that they are identical.
Evolutionary theory predicts that the two trees will be highly congruent, if not identical. In other words, evolution predicts that given a morphological tree, the molecular tree will come from the tiny sliver of possible trees that are highly congruent to the morphological tree.
By contrast, ID is compatible with any combination of morphological and molecular trees. Given a particular morphological tree, any of the 1038 possibilities are open for the molecular tree.
Now compare evolutionary theory to ID:
Given a particular morphological tree, evolutionary theory predicts that the molecular tree will come from a tiny sliver of the 1038 possibilities.
Given a particular morphological tree, ID predicts only that the molecular tree will be one of the 1038 possibilities.
Evolutionary theory narrows the possibilities down to a tiny sliver. ID doesn’t narrow the possibilities at all.
Evolutionary theory is trillions of times more specific than ID in its prediction, and the prediction is confirmed.
If ID is “compatible” with any tree or any history, then no number can be assigned and no numeric comparison can be made. You are comparing apples and unicorns.
Petrushka:
Sure it can. If ID were compatible with 35% of possible molecular trees, then we would assign the number 0.35. If it were 57%, we’d assign 0.57. It’s actually compatible with 100% of trees, so we assign the number 1.00.
Why do you find that problematic?
As petrushka pointed out, ID is not a theory, but a broad collection of ideas. You have to deal with specific claims. For instance, a design theorist might accept the diversification from common ancestors as a natural outcome, but not the shape of the tree. The person shaping the branches accepts that when she plants the seed, it will bifurcate. Frankly, don’t know why this is so difficult.
I don’t see how you arrive at a number fo ID. You use Something like Fisher to decide the probability of the tree being attributable to chance is very low. That’s one of many lines of supporting evidence.
What I fail to see is a competing hypothesis. It’s not that I fail to see the weakness of ID. It’s that I fail to see any ID hypothesis that has the tree as an entailment. Without that, I don’t see how you can have a ratio of p values. It has been 40 years since I took statistics, so I may just be making a hash of this.
That’s always the problem with modern IDers. However, we can compare it to specific design conjectures. For instance, the existence of the nested hierarchy largely precludes separate creation. It does not preclude artificial selection or a cosmic intelligence guiding life along certain paths.
These latter options can be largely precluded as scientific conjectures with other evidence, but not from the existence of the nested hierarchy alone.