Why Gradualism?

In Why Evolution is True, Jerry Coyne writes that gradualism is one of the six tenets of “the modern theory of evolution” (which he equates with Darwinism – see page 3).

Eugene Koonin writes that the tenet of gradualism is known to be false (The Logic of Chance p. 398).

Yet gradualism is obviously still quite popular here in “The Skeptical Zone.”

Surely gradualism is not a logical requirement or entailment of the theory of evolution. Neither is it supported by the evidence.

So given what we know about evolution, why do evolutionists still cling to gradualism? My suspicion is that the alternative smacks too much of miracles. So gradualism is more of a religious conviction than a scientific one.

What is the evidence for and against the gradualist hypothesis?

195 thoughts on “Why Gradualism?

  1. Alan Fox,

    Not these days but it started out as a controversial idea. Could be there’s a slow-burning fuse on the evolution of sex!

    Heh. It’s on the cusp of incomprehensibility and incontrovertibility at the mo! 😉

    I’m pushing the idea that sex is completely explicable without the need for yet another theory – the mainstream says no! Not quite the stuff of revolutions. I think there was a time people thought there was a great prize in solving it, and you needed a theory succinct enough to get on the citation!

  2. Allan Miller:
    Rumraket,

    When said IDist uses salmon/aardvark as an example of a convergent pair, I really sit up and take notice!

    Not very impressive reading skills Allan, maybe take another shot at it.

    Aardvaarks and South American Anteaters. The aardvark is the descendant of the salmon in this evolution tale. You are really struggling with something pretty easy.

    If this is the best understanding you can manage, I think I see the problem.

  3. colewd:
    phoodoo,

    Do you think it contradicts the idea of the nested hierarchy?

    I think the idea that there are more than one possible trees of nested hierarchies contradicts the idea of a tree of nested hierarchy.

  4. This article by Casey Luskin is a good rundown of the problems with the nested hierarchy theory:

    https://evolutionnews.org/2015/06/do_all_life_for/

    Just a snippet:

    But sometimes after we sequence an organism’s genome we find that its place in the tree of life is even less clear than it was before.

    This is exactly what happened after the comb jelly genome was sequenced. As I wrote last year, comb jellies (phylum ctenophora) have muscles and complex nervous systems, but molecular studies suggest they branch off very close to the base of the animal tree. However, sponges — which branch off later according to molecular data — lack such structures. This means that either complex muscle and nervous cells were lost in sponges (even though these are complex, useful traits you’d probably want to keep around) or muscles and brains evolved convergently in later animals. Either way, you’re left with a situation where comb jellies don’t fit neatly into the animal tree. They show a mosaic of traits that shouldn’t be the case under common descent.

  5. phoodoo: Aardvaarks and South American Anteaters. The aardvark is the descendant of the salmon in this evolution tale. You are really struggling with something pretty easy.

    You have a link , should be pretty easy.

  6. phoodoo: But sometimes after we sequence an organism’s genome we find that its place in the tree of life is even less clear than it was before.

    Sometimes, so not always?

  7. phoodoo: They show a mosaic of traits that shouldn’t be the case under common descent.

    But phoodoo, this “mosaic of traits” is exactly what we would expect under common descent by accidents coupled with conservation and/or loss due to random environmental changes. It’s the theory of anything is possible unless you can prove otherwise.

  8. phoodoo: I think the idea that there are more than one possible trees of nested hierarchies contradicts the idea of a tree of nested hierarchy.

  9. phoodoo,

    Not very impressive reading skills Allan, maybe take another shot at it.

    Aardvaarks and South American Anteaters. The aardvark is the descendant of the salmon in this evolution tale.

    Gah, that’s even worse. When you flail, you really give it a good go, I’ll credit you that.

    Your original had salmon and anteater as having a common ancestor. Now you are proposing direct descent of anteater from salmon. In neither case have you even given an inkling that you know what is meant by evolutionary convergence.

    If this is the best understanding you can manage, I think I see the problem.

    No, you really don’t.

  10. All the same old shit over and over and over again. You never learn.

    http://www.talkorigins.org/faqs/comdesc/section1.html#independent_convergence

    In science, independent measurements of theoretical values are never exact. When inferring any value (such as a physical constant like the charge of the electron, the mass of the proton, or the speed of light) some error always exists in the measurement, and all independent measurements are incongruent to some extent. Of course, the true value of something is never known for certain in science—all we have are measurements that we hope approximate the true value. Scientifically, then, the important relevant questions are “When comparing two measurements, how much of a discrepancy does it take to be a problem?” and “How close must the measurements be in order to give a strong confirmation?” Scientists answer these questions quantitatively with probability and statistics (Box 1978; Fisher 1990; Wadsworth 1997). To be scientifically rigorous we require statistical significance. Some measurements of a given value match with statistical significance (good), and some do not (bad), even though no measurements match exactly (reality).

    (…)

    When two independently determined trees mismatch by some branches, they are called “incongruent”. In general, phylogenetic trees may be very incongruent and still match with an extremely high degree of statistical significance (Hendy et al. 1984; Penny et al. 1982; Penny and Hendy 1986; Steel and Penny 1993). Even for a phylogeny with a small number of organisms, the total number of possible trees is extremely large. For example, there are about a thousand different possible phylogenies for only six organisms; for nine organisms, there are millions of possible phylogenies; for 12 organisms, there are nearly 14 trillion different possible phylogenies (Table 1.3.1; Felsenstein 1982; Li 1997, p. 102). Thus, the probability of finding two similar trees by chance via two independent methods is extremely small in most cases. In fact, two different trees of 16 organisms that mismatch by as many as 10 branches still match with high statistical significance (Hendy et al. 1984, Table 4; Steel and Penny 1993). For more information on the statistical significance of trees that do not match exactly, see “Statistics of Incongruent Phylogenetic Trees”.

    The stunning degree of match between even the most incongruent phylogenetic trees found in the biological literature is widely unappreciated, mainly because most people (including many biologists) are unaware of the mathematics involved (Bryant et al. 2002; Penny et al. 1982; Penny and Hendy 1986). Penny and Hendy have performed a series of detailed statistical analyses of the significance of incongruent phylogenetic trees, and here is their conclusion:

    “Biologists seem to seek the ‘The One Tree’ and appear not to be satisfied by a range of options. However, there is no logical difficulty in having a range of trees. There are 34,459,425 possible [unrooted] trees for 11 taxa (Penny et al. 1982), and to reduce this to the order of 10-50 trees is analogous to an accuracy of measurement of approximately one part in 10^6.” (Penny and Hendy 1986, p. 414)

  11. Mung,

    But phoodoo, this “mosaic of traits” is exactly what we would expect under common descent by accidents coupled with conservation and/or loss due to random environmental changes.

    No it isn’t. It does pose an interesting scientific conundrum though, which research is endeavouring to solve, regarding the correct placement of comb jellies on the tree of life. It is entirely forced by the fact that you can’t just stick them anywhere. That is, the opposite of what you caricature.

    How’s the study of ‘teleology’ coming along, meanwhile? The deeply illuminating theory that whatever we see is what the Designer wanted to happen?

  12. The Designer has, indeed, taken great pains to ensure that traits don’t get ‘mixed up’, fooling generations of systematists into thinking the pattern represents a phylogeny. Why did he get it so wrong in the case of the comb jellies, one wonders?

  13. Allan Miller:
    The Designer has, indeed, taken great pains to ensure that traits don’t get ‘mixed up’, fooling generations of systematists into thinking the pattern represents a phylogeny. Why did he get it so wrong in the case of the comb jellies, one wonders?

    It designed it on a Monday after a long weekend

  14. newton: phoodoo: But sometimes after we sequence an organism’s genome we find that its place in the tree of life is even less clear than it was before.

    Sometimes, so not always?

    Right, sometimes its still just as confusing afterwards.

  15. Allan Miller:
    phoodoo,

    Gah, that’s even worse. When you flail, you really give it a good go, I’ll credit you that.

    Your original had salmon and anteater as having a common ancestor. Now you are proposing direct descent of anteater from salmon. In neither case have you even given an inkling that you know what is meant by evolutionary convergence.

    No, you really don’t.

    Allan, did you hit your head with a paddle?

    Not only have you completely failed to understand even the simplest of concepts, you now aren’t even capable of using complete sentences as a rebuttal. What are you even trying to say? Do you even know?

    Your original had salmon and anteater as having a common ancestor. Now you are proposing direct descent of anteater from salmon. In neither case have you even given an inkling that you know what is meant by evolutionary convergence.

    No, you really don’t.

    You don’t even have the faintest idea what you are saying, do you? Where in your screwed up mind did you come up with the notion that I said salmon and aardvarks (not anteaters fool, I even explained the difference) were examples of convergent evolution?

    Anteaters and aardvarks Allan! Try reading. And pull the dam oar out of your skull.

  16. Allan Miller: Mung,

    But phoodoo, this “mosaic of traits” is exactly what we would expect under common descent by accidents coupled with conservation and/or loss due to random environmental changes.

    No it isn’t

    No fucking kidding Allan? Its almost as if Mung was being facetious.

    Did you contract some strange bacterial meningitis at the same time you whacked yourself paddling?

  17. When Allan Miller isn’t here to set people straight it’s as if there is simply no alternative to gradualism. So I guess it’s good to have Allan back. 🙂

    Now if he could spend some times explaining probability to Rumraket …

  18. phoodoo, you might consider that Allan hasn’t quite recovered yet from his contact with Alan Fox. Now that he’s back in the company of reasonable folks like you and I he’ll come back into his right mind. Just you wait and see.

  19. Mung,

    Look Mung, nobody, I mean NOBODY would advance this crazy reverse gambler’s fallacy that because something happens more than once its probability is even more likely.

    No fool would advance that whacky strawman, not even Rumra…

    Ok, look nevermind. I gotta get this canoe out of the water somehow, its not going to be easy with this wooden thing sticking out of my head.

  20. phoodoo: You don’t even have the faintest idea what you are saying, do you? Where in your screwed up mind did you come up with the notion that I said salmon and aardvarks (not anteaters fool, I even explained the difference) were examples of convergent evolution?

    I was curious about the last common ancestor of salmon and aardvark.

  21. newton: I was curious about the last common ancestor of salmon and aardvark.

    Well then just make up a story about it.

    That’s what evolutionists always do. It always works.

  22. And if you can make up a story, that means the story is at least plausible, and that teleology is false.

  23. newton:

    I was curious about the last common ancestor of salmon and aardvark.

    According to phoodoo, aardvarks are directly descended from salmon:

    The aardvark is the descendant of the salmon in this evolution tale.

    Dear God,

    Where do you find these guys?

    I mean, phoodoo, Mung, and colewd? These are the folks you’ve chosen to represent you here at TSZ?

  24. phoodoo,

    You don’t even have the faintest idea what you are saying, do you? Where in your screwed up mind did you come up with the notion that I said salmon and aardvarks (not anteaters fool, I even explained the difference) were examples of convergent evolution?

    My screwed up mind was confused largely by the confused portrait you sketched, under the illusion you were being amusing. But then further confused by your declaration that, in your thigh-slapping, eye-wipingly hil-arious caricature, one or other species (I can barely be arsed to find out which) was a direct descendant of the salmon.

    I should, I realise, stay off the hard stuff.

  25. phoodoo,

    No fucking kidding Allan? Its almost as if Mung was being facetious.

    It’s almost as if I knew that, but chose to address the matter anyway.

  26. Actually, re-reading, I concede to phoodoo that I got it wrong. He was not actually talking of the salmon and the anteater/aardvark being convergent at all.

    This concession and apology were made far easier by the calm, reasoned and gentlemanly fashion in which phoodoo pointed this out to me. An example to us all, I think.

  27. GlenDavidson: When and why was cluelessness designed?

    Designed traits are very good. Of course, I’m not saying so because God’s Word tells us so: “And God saw every thing that he had made, and, behold, it was very good” (Genesis 1:31). The empirical evidence strongly supports it. Plus it stands to reason. And Aristotle said so, too. Thus it can’t be a religious belief. Or not a distinctively Abrahamic religious belief, anyway.

    Not very good traits are the result of evolutionary decay, because mutation only breaks stuff.

  28. Tom English: Not very good traits are the result of evolutionary decay, because mutation only breaks stuff.

    They don’t call them repair enzymes for no reason!

  29. Nice to see keiths praying. He ought to consider praying for himself.

    Dear God, why does no one like me when I am so perfect? Why didn’t you chose me to represent you? What’s wrong with you, God?

  30. Mung,

    Nice to see keiths praying. He ought to consider praying for himself.

    You, phoodoo, and colewd illustrate perfectly why praying is a waste of time. (I’d be remiss not to mention fifthmonarchyman, too.)

    Why doesn’t God ever help you guys out when you’re defending him? Aren’t you praying hard enough? Does he like atheists better than believers? Or does it have something to do with the fact that he doesn’t exist?

    And if he does exist, he sure seems to enjoy watching his devotees fail, again and again. How do you explain this peculiar predilection of his?

  31. So your excuse for failure is that you don’t pray for God’s help, since witnessing is no more important to you than eating jello?

  32. I thought you were whining about my failure to “defend God.” Have you given up on that line and decided to try another?

  33. I think I get it. If it’s hard for keiths, it must be hard for everyone else too. It never occurred to him that he might be the one that needs help.

    Can I get a witness!

  34. Mung,

    I thought you were whining about my failure to “defend God.”

    No, I’m laughing at your inability to defend him:

    Why doesn’t God ever help you guys out when you’re defending him? Aren’t you praying hard enough? Does he like atheists better than believers? Or does it have something to do with the fact that he doesn’t exist?

    And if he does exist, he sure seems to enjoy watching his devotees fail, again and again. How do you explain this peculiar predilection of his?

    You fail repeatedly because the case for your faith is weak and you are inept at defending it. The fact that God never bails you out is just the icing on the cake. Your faith is a faith for suckers.

    (I don’t blame your God for letting you dangle. It’s hard for him to intervene when he doesn’t exist.)

  35. keiths:
    Your faith is a faith for suckers.

    (I don’t blame your God for letting you dangle.It’s hard for him to intervene when he doesn’t exist.)

    You’d think they’d notice that peculiar absence after a while.

  36. Pedant: You’d think they’d notice that peculiar absence after a while.

    Well in a way they do, but they’ve invested too much to recognize it for what it is. Thus apologetics is born in all of its dreariness, and ID provides the “miracles” that God somehow fails to perform today.

    Glen Davidson

  37. Allan Miller:
    Actually, re-reading, I concede to phoodoo that I got it wrong. He was not actually talking of the salmon and the anteater/aardvark being convergent at all.

    This concession and apology were made far easier by the calm, reasoned and gentlemanly fashion in which phoodoo pointed this out to me. An example to us all, I think.

    I am glad you noticed what a gentleman I was Allan, because originally I was going to say something really dickish, like:

    Allan Miller: Gah, that’s even worse. When you flail, you really give it a good go

    But then I decided, no no, I should take the high road, like Allan, er, like some people would.

    But I really am proud of you for recognizing a calm reasoned reply when you write, I mean see, one, Allan.

    Gah!

  38. phoodoo: Well then just make up a story about it.

    That’s what evolutionists always do.It always works.

    Not only evolutionists, teleology is a story .A designer who creates something somehow is another.

  39. Does punctuated equilibrium pose any challenge to gradualism? Some people would say no, but Gould says yes.

  40. Mung:
    Does punctuated equilibrium pose any challenge to gradualism? Some people would say no, but Gould says yes.

    What is the ID position, either way is as likely or unlikely, there is really no way to know?

  41. In fact, Darwin’s antipathy to Kelvin was idiosyncratic and based on the strong personal commitment to gradualism so characteristic of his world view.

    – The Flamingo’s Smile. p. 131.

    Some things never change.

  42. All along we have looked for the expected pattern: slow, steady, progressive change. And all along we have found instead a pattern of sporadic change.

    – Niles Eldridge & Ian Tattersall

    Makes you wonder whether the evolutionists here have ever actually picked up and read a book on evolution.

  43. But the crucial point to Simpson’s argument was this: Whereas the gaps between species and genera involve sufficiently minor amounts of anatomical change so that typical patterns of rather abrupt appearance of descendants necessitates no modification of standard neo-Darwinian theory, the gaps between higher taxa are another matter. If, Simpson argued, we invoke gradual adaptive modification at rates customarily observed between species and genera to explain the evolutionary origins of whales and bats, we would require scores, and in some cases even hundreds, of millions of years. Clearly this is impossible …

    – Macro-Evolutionary Dynamics. p. 23

    Impossible. lol. Clearly.

  44. Mung:
    “Gradualism sometimes works well.”

    – Stephen Jay Gould

    heh

    I think Gould is very glad gradualism doesn’t always work, or most of us would never have heard of him. He is that famous slogan writer, right?

    “Hmm, I need to come up with a name, to disguise another one of the problems with Darwinian evolution… Modern Synthesis? No, I don’t like the ring of that, save that one. Neutral Drift? Nah. I got it, PE, like PE class! What starts with P? Punctual Evolution? I like Punk music. I got it, Punk Equality! Mmmm, maybe too political, let me keep thinking.”

  45. phoodoo,

    But then I decided, no no, I should take the high road, like Allan, er, like some people would.

    You’d already decided to be an ass in your very first post to me, to which that was a response, so fuck off.

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