The Explanatory Power of Darwinism

Which is why have less confidence on how, but more confidence that there is somehow a plausible natural explanation (though we cannot rule out God’s action either). We have too many possibilities for “how” it evolved, so the claims that “there isn’t just enough time” or “we can’t provide the specific mechanism in this case” now fall on unsympathetic ears. With so many complex and interacting mechanisms, we don’t expect to untangle them in many cases.

However, neutral theory gives us clear and quantitative tests of common descent. Our confidence in common descent, therefore, has only grown.

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They are hiding in a sea of neutral mutations. That is the challenge. I’ve just given you the math to explain why. That is the prediction of neutral theory, that beneficial mutations will appear to hide, and that is what we see.

You got it wrong though. It is not that most of the useful ones are things breaking down. Rather the beneficial breaking down of functions is easiest to find. This is a classic type of streetlight bias. We can find things that are broken easily, but we cannot identify new functions easily, for purely technical reasons. So the positive cases we have tend to be things breaking down. No surprise.

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This is a corollary of the maxim, “no news is good news”.

In the lab, we can set up selective conditions that allow us to isolate and identify cells carrying “positive mutations”. There are many classic experiments in microbiology where this was a key factor.

Out in the wild, this is more difficult. Actually, in the wild it’s not easy to determine whether a particular variant has a negative selective effect unless the effect is strong or the conditions are well understood and quantified. I think in most cases (@swamidass or others can correct me), the distribution of an allele in a population often serves as a rough proxy for the effects of selection. It’s hard to dig deeper in most cases.

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No, no surprise - but any argument that explains a lack of evidence for itself still has to compete withother explanations of lack of evidence: the car keys certainly aren’t under the street light, but that doesn’t prove they’re in the shadows across the road. Likewise lack of fossils may indicate millions of species not preserved in support of Darwinian gradualism - but equally that they never existed. Stasis and saltation in the record may support punc. eek’s theory of bursts of evolution below the resolution of the fossil record, but it may simply indicate saltations.

It seems to me partly a question of parsimony. Darwin had one main question: “Why is life so well adapted?”, and a parsimonious explanation for it. The question was agreed on all sides of science from the observations of nature by Aristotle and onwards, and even before that by pre-scientific thinkers like the Bible writers.

Now we have numerous explanatory mechanisms, and even the question has been split up into chunks to match them: “Why is life so well adapted?” (ans. natural selection or PRM). “Why is life so _un_adapted?” (ans. neutral theory, pleiotropy etc). “How does life compensate for lack of adaptation?” (ans. niche construction theory) and so on. But there is no clear way to match the questions to the theories - is this particular trait adaptive or not? (See the OP on the Hump for the expansion of that).

So we have a series of apparently well-attested theories which can only be be applied generally to say “natural causes are plausible,” whilst adding “…and so is divine action.”

However, divine action, including oversight of the observed mechanisms, is the most parsimonious explanation for Darwin’s original question, which despite everything remains intuitively obvious and observable throughout the world and won’t go away, ie “Why is life so well-adapted?” In other words, as I think I said somewhere further up on this thread, divine teleology is all that can provide a unifying umbrella for the otherwise disparate theories to disparate questions about life, now that Darwin’s unification has gone the way of all flesh.

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Well that is why I emphasize that we have not ruled out God’s direct inspiration of mutations. Those also would be hidden in the noise. However, that means there is no “competition” really to be had. The whole question of fully natural or not not resolvable. It is a silly strategy to puff confident answers. Neither Dawkins nor Axe has made their case for (or against) the “sufficiency” natural causes. Neither ever will.

Except I don’t really care what Darwin thought on this, and nor should you. Modern evolutionary science has very little to do with “Darwinism”.

And science does not definitively answer that question.

No clear way, but let’s not be nihilistic. There are sometimes ways we can get partial answers. Evolutionary science progresses by an immense amount of work to untangle this mess of uncertainty. Progress is often made.

That is what I have been saying now for YEARS. It makes enemies of ID, and enemies of fundo-militant science groupie atheists. But it has the unfortunate benefit of being true.

Not really. Divine teleology is consistent with evolutionary science, but it is by no means entailed by it (much like the de novo Adam). Nothing in science rules it out. Darwin’s view is gone, but population genetics reigns. Common descent, also, has become (as it always was) the unifying umbrella. @jongarvey, there is nothing wrong with evolutionary science, it is just an incomplete view of origins. It is obviously and inarguably incomplete.

Theologians are free to fill in the details as they wish (with for example divine teleology), but there isn’t anything to be gained from attacking it. That just awakens the beast, because science is just fine leaving it incomplete. Remember the waking world.

Great question. It is non intuitive, but the larger the population the more powerful selection will be. With large population sizes we can be confident that even slightly beneficial alleles are unlikely to be lost, and are likely tobe fixed very quickly. You can read about it in this article:

This is highly non-intuitive, but that is because population genetics is highly non-intuitive (just look at genetic vs. genealogical ancestry, or genetic ghosts). The math (and simulations) just work out this way. It is (much like genealogical ancestry) a consequence of the non-intuitively rapid growth of exponentials.

So you’ll find in that article. Good question by the way. I can explain if you have a hard time following after reading that.

I’m reminded of this post of Ken Keathley:

Historically biology stopped doing teleology with Darwin (which is one good reason for my referring back to him - he set the agenda for the research project, and his big question is still important).

But it can’t be intriniscally impossible to discern teleology (whether or not you call such discernment science), or else Sy Garte’s research on “innate intelligence” would be nonsensical, not to mention other realistic possibilities of Aristotelian innate teleology. If it is impossible, it would be a bizarre state of affairs that we teleological beings have no halfway reliable way to recognise our key feature.

I mentioned before that Bill Dembski considers teleology can be discerned statistically (but not distinguished as divine or not), and it seems to me not unreasonable, albeit as difficult in practice as teasing out actual causal chains in population genetics. It would seem that, in that respect, the recession to God as First Cause (specifically, the top of the teleological chain) follows as it does in Aquinas as well as Aristotle in embryonic form, from a rational inference.

So it seems to me that, in the course of time, evoultution may be seen not merely to be compatible with divine teleology, but to point to it via the elucidation of inherent teleology.

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A brief expansion on this. A proper understanding of probability has to do with the relationship between propositions, not just absolute frequencies in the universe, as I said in a recent comment.

So as in the damming of the Jordan, the question has something to do with the plausibility of causes (earthquakes, landslides in that case), but also to do with the context - the big question of why the biosphere works so well. This is the kind of area in which teleology must be sought.

Equally that they never existed”? I don’t think that symmetry holds. “Darwinian gradualism” (& also Punk Eek, FWIW), has the prediction that we’ll find support for transitions in the fossil record. And we have found numerous examples. Even further, they’ve been back up with genetic data. What modern evolutionary theory would not assume is that all or even most transitions would be found. That is due to the nature of fossilization for which we may have reasonable, testable models.

In contrast, the explanation that they never existed is defeated every time new fossils are found that elucidate genealogical relationships. The hypothesis that they never existed makes no predictions about which transitions will never be found. It is essentially, the null hypothesis against which taxonomic relationships are tested. What if we loosen the hypothesis and assume that some groups evolved and some others were specially created? How do we make any prediction about which groups were specially created? And if we do find lineages without good fossil evidence of transitions, how to we determine whether it’s because there never was a transition vs. incomplete fossil records?

Interestingly, for cases where the fossil record would be expected to be rich enough and deep enough to expect transitions to be found, we find them. Look up the foraminifera, particularly those with biomineralized structures. Researchers report finding both ‘gradual’ and ‘punctuated equilibrium’ modes of evolution. They can even quantitate the prevalence of both modes.

In summary, let’s review the hypotheses:
Common descent: Under both punctuated and gradual modes of evolution, transitions existed. Supportive fossil evidence may be found and that depends on the natural of fossilization process.

Special creation: Transitions never existed. Fossil evidence should not find supportive evidence of a transitions, irregardless of fossilization likelihood.

Given current knowledge, is it reasonable to propose that these are equally valid explanations?

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Argon

You make the same mistake as Darwin (though he did it deliberately) of opposing your argument to special creation, which (as I pointed out earlier in the thread) was not the subject of my post, nor of my comment, any more than it was the predominant biological theory or Darwin’s time…

The question was about using lack of evidence as a support for a theory, which is to me methodologically weak. Saltations (to use the transitions argument) don’t require “no transitions” but “far fewer transitions” than gradualism. Specifically, the 250,000 or so recorded fossil species is a number several orders of magnitude smaller than the number of species predicted to have existed under gradualism (1-4 billion), and the species discovered since Gould and Eldredge proposed punc. eek. have not changed that proportion significantly - it is still predominantly a picture of stasis and saltation. We still predominantly sample many examples of each taxon, across wide geographical areas, rather than individual examples of many gradated taxa.

To take a random example, Iguanodon is known from “large numbers” of specimens across Eurasia and North Africa, yet all of which are now considered to belong to just two species. The genus is indeed nested within a group of 6 genera called the Iguanodontidae, but despite the good fossil representation, “There is no consensus on the phylogeny of the group.”

Meanwhile, though, the work of those like Michael Benton has shown, by several different metrics, the essentially representative nature of the fossil record, which means that, at least, it is unsafe to assume the observed pattern to be a result of incompleteness of the fossil record.

Furthermore, of course, on gradualism’s assumptions we would have only have discovered around 1:4000 - 1:16000 species that have lived. That makes it not so much incomplete, as unlikely to reveal any reliable patterns of phylogenesis, which it clearly does.

So I feel justified in saying “sometimes there are transitions, but far more often there are not,” as evidence for the complexity of the evolutionary process, rather than treat the lack of fossils as evidence that they must have been there once.

@jongarvey, I’m honestly not sure what you are trying to accomplish here.

The place of highest theological significance, and the most scientific evidence, is human evolution. We see clear transitional forms and solid genetic evidence of transitions across these forms. I’m pretty sure you accept common descent here. If you do here, with humans, why in the world would you think something else is happening with Iguanodons?

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I think there is a ‘not’ missing in that sentence. That’s OK. As we’ve seen recently, even the most stable geniuses of US Presidents have difficulties with single and/or double negatives. :grin:

If ‘not’ really is missing, I agree.

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@jongarvey

I think you are taking the slow bus to reach your conclusion.

A. If God is guiding the arc of evolution… the invisible trace of the pacing for speciation is impossible to track… but also impossible to deny if you are a devout Christian.

B. The closest approximation to an alternative to common descent is speciation by periodic special creation that MIMICS common descent.

So how does one attempt to prove THAT?

Anomalies in developmental “pacing,” relatively sudden changes in organismal survivability, based upon coherent changes in morphology, mechanistic incredulity ( : ) --can’t avoid it!)… no matter what you say, it can be countered with skepticism; and rightly so, in a test for truth.

@Guy_Coe

The only way it can be countered is to say there are limits to how God executes Speciation.

I know no biblical text that says God doesn’t use both natural and supernatural methods.

And I’m a little surprised that you would attempt to imply this.

Not implying that, just noting that no matter what anyone says, it’s met with skepticism by somebody, and perhaps, rightly so, on topics like “progressive creation” “versus” “evolution.” That’s all.
It seems to me to be a truism, by definition, that God uses both natural and supernatural means.

@Guy_Coe

I agree with your statement completely.

And because it is true… the only way to object to one or the other method is to reject Christianity’s fundamental understanding of God’s nature.

Agreed, but it is worth the discussion to discover objections which keep, even provisionally, others from agreeing.

There is a difference between an honest “I don’t know how this happened” as opposed to the statement - “I don’t know the exact mechanism, though it is probably a combination of known/unknown natural phenomenon”.
I am fine with both statements to varying degrees. Though I reject the a priori assumption of a “natural” explanation.However that is not what is usually presented to the public by people like Dawkins and blogs like sandwalk. The presentation to the public is usually the chance +mutations+ natural selection= all life.
Besides, an increasing no: of complex mechanisms does not really explain much. It just pushes the buck to how these mechanisms themselves came to be. And how they work together produce a species with various different systems working together in sync to give distinct results.

The key contribution of Darwinism is natural selection as far as I can see… and it’s selection that is supposed to carve out a distinct species by accepting or rejecting traits. This makes sense only in a gradualistic scenario where change happens step by step over a long period of time.The evidence is not for a gradual process of change.