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. It depends on what you mean by “gradualism” — which you have not defined. It’s not a term that I normally use.

    Changes to the gene pool are gradual. However, meiosis allow new combinations which might be substantially different from what has been previously seen.

  2. Mung manufactures a “scientific controversy” with five tweets — no need for him to elaborate — and calls for disputation with the sixth. This is what the think tank to which he contributes, the Discovery Institute, advocates for public education in science.

    He follows a simple formula. Find a single contrarian scientist, and bury the fact that his view is atypical by pitting him against a single scientist stating the view of the vast majority of scientists.

    I call shenanigans. If you continue to play at propagandist, Mung, you’ll find me a exceedingly unfriendly guy.

  3. Neil Rickert: It depends on what you mean by “gradualism” — which you have not defined.

    I’m using the term as it is defined by evolutionists. If you have an issue with that take please it up with them. I could care less whether you use the term. Coyne uses it, and calls it one of the six components of evolution.

    Have you ever stopped to question that before now?

  4. Tom English: If you continue to play at propagandist, Mung, you’ll find me a exceedingly unfriendly guy.

    As long as you remain honest, Tom.

    What is it in my OP that smacks of propaganda to you? Asking folks for evidence? Do you really think Koonin is the lone voice crying in the wilderness?

    I hope you aren’t making plans to become keiths. That would truly suck.

  5. How is gradualism not an entailment of descent with modification when you factor in the known mechanisms of modification?

    Mung mocks YEC’s for being hyper-evolutionists, but his wild saltationist conjecture involves occasional single-generation-hyper-mega-mutationism, while ignoring the physiological difficulties involved in such a reproduction process.

    Let me remind you Torley is also sympathetic with this idea, in particular he claims the transition from invertebrates to vertebrates must have happened in a single generation. I kid you not. Those lancelets must have been shitting bricks

  6. Mung in OP: 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.

    This, in particular, I do not believe you believe. You know perfectly well that the notion of punctuated equilibrium originated with Ernst Mayr, as acknowledged by Eldredge and Gould. The “punctuation” of punctuated equilibrium is a period of gradual change. The meaning of gradual is not “slow on a geologic time scale.”

    I recognize the “they’re just as religious as we are” canard. I’ve seen what an important point it is in persuading state legislators to back “science education” bills deriving from model legislation drafted by the Discovery Institute. You tell them that what’s actually going on in science instruction is religious discrimination, and that their religious views deserve equal time. Most of them are smart enough not to say that in public. However, here in Oklahoma, we have a tractor-salesman-turned-senator who is in fact stupid enough to lay out his views, and publish them in a newspaper in his district.

  7. Being old enough to remember the punctuated equilibrium controversy of the 1970s and 1980s, let me provide a little perspective.

    1. Punctuationists such as Raup, Eldredge, Gould, Stanley, and Sepkoski argued that the pattern of change seen was stasis within species, and a burst of change in the daughter lineage at the time of speciation.

    2. For the mechanism of the bursts, they invoked species selection — species with desired adaptations being less likely to go extinct and more likely to give rise to new species. Long-term trends, they thought, were due to species selection.

    3. For many population biologists, this gave too much credence to selection at that higher level, while downplaying change within species for what, to them, were inadequate reasons. Individuals are born and die all the time, but extinction of whole species is a much less frequent event.

    4. Both camps invoked selection to explain adaptation, just at different levels.

    5. Although the evolutionary geneticists of the 1950s and 1960s had stressed smooth, continuous change, population geneticists in the 1970s and 1980s readily found that change could vary in rate by quite a bit without a need to invoke selection above the population level.

    6. There also was, and continues to be, controversy over whether the pattern of stasis is as complete as the punctuationists thought it was.

  8. Now I’m even more inclined to move to Oklahoma!

    But Tom, this isn’t about punctuated equilibria. Koonin’s claim that gradualism is false had nothing to do with that. My own examples in the “Eye” thread had nothing to do with that.

  9. I must be more devious then I ever imagined, lol!

    Even Neil manages to suss out that meiosis might be a challenge to the gradualist agenda.

  10. dazz: How is gradualism not an entailment of descent with modification when you factor in the known mechanisms of modification?

    The relevant question then would be what are the known mechanisms of modification and in what sense are they gradual modifications?

    I’d be interested in what you have to say along those lines.

  11. Mung: My own examples in the “Eye” thread had nothing to do with that.

    I’m afraid that I’ve let the real world get in the way of my TSZ reading (and writing).

    An OP should speak for itself, don’t you think? Whatever it is in the other thread that you think is relevant, you should have assembled in your new OP.

  12. Tom English: An OP should speak for itself, don’t you think?

    And I think it does. And you’re free to disagree. It’s almost as if this site were being hosted in the good old US of A!

    But to catch you up, I offered horizontal gene transfer, symbiosis, and whole genome duplication as examples. At which point the opposition fell silent, lol.

    Does evolutionary theory require gradualism, and if so why? Surely natural selection doesn’t care one way or the other.

  13. Mung: Koonin’s claim that gradualism is false had nothing to do with that.

    Maybe if you had given some hints of Koonin’s argument, this topic might make more sense.

  14. Tom English: I’m afraid that I’ve let the real world get in the way of my TSZ reading (and writing).

    You missed my best thread ever!!!???

    😉

  15. My apologies for trying to open a topic for discussion that didn’t depend on me setting out a contrary position that people could immediately attack. It would appear that this style of writing is out of character for me and it threw some folks for a loop. I try to be like evolution itself, unpredictable, ever changing, with no one quite sure of what it is.

    🙂

  16. Because when we find more complete fossil evidence of evolution, we then see “gradualism” (at least compared with what miraclists claim), like with the auditory ossicles of mammals.

    But then the genetic and cladistic evidence typically suggest fairly gradualistic change as well. And while hardly perfect, molecular clocks tend to agree with the other evidence in a meaningful way, which again fits best with relatively gradual changes.

    Glen Davidson

  17. Why does Glen put “gradualism” in scare quotes? Coyne didn’t put “gradualism” in scare quotes when he identified it as one of the six tenets of modern evolutionary theory.

  18. Gradualism may represent the most central conviction residing both within and behind all Darwin’s thought. Gradualism far antedates natural selection among his guiding concerns, and casts a far wider net over his choice of subjects for study.

    – The Structure of Evolutionary Theory. p. 148

    But why? Was it for scientific reasons? Was he allowing the evidence for gradualism to lead him in formulating his theory?

  19. Gould doesn’t use scare quotes either. Who the hell uses scare quotes when talking about gradualism, other than Glen?

  20. We often fail to recognize how much of the Origin presents an exposition of gradualism, rather than a defense of natural selection.

    – The Structure of Evolutionary Theory. p. 151

    Can we possibly forgive SJG for again failing to use scare quotes?

  21. Joe, I think I’ve established the centralilty of gradualism to evolutionary theory.

    If evolutionists such as yourself, Coyne, Gould, and Darwin, don’t define what gradualism means, why is that a failure to define terms on my part?

    It’s time to put on your big boy pants now and step up to the plate. You use the term “gradually” repeatedly in your book. Where did you define it?

  22. I’m not going to define what evolutionists mean by gradualism. And why should I? If gradualism is important to evolutionists, they will define it. As one of the six components of evolution, one would think evolutionists know what gradualism means.

    Or not.

  23. Gradualism does not mean, however, that each species evolves at an even pace.

    – Why Evolution is True. p. 4

    That’s awesome! Not much help though in figuring out what gradualism does mean.

  24. In the book The Fact of Evolution, gradualism doesn’t even appear in the index. Is that because evolutionists don’t understand what the term means, or is it because it’s not really a part of evolutionary theory after all. I’m no fool, I pick door number 3.

  25. Mung: Who the hell uses scare quotes when talking about gradualism, other than Glen?

    I stand corrected.

    Who the hell uses scare quotes when talking about gradualism, other than Glen and Joe?

  26. Tom:

    Mung manufactures a “scientific controversy” with five tweets — no need for him to elaborate — and calls for disputation with the sixth. This is what the think tank to which he contributes, the Discovery Institute, advocates for public education in science.

    He follows a simple formula. Find a single contrarian scientist, and bury the fact that his view is atypical by pitting him against a single scientist stating the view of the vast majority of scientists.

    I call shenanigans. If you continue to play at propagandist, Mung, you’ll find me a exceedingly unfriendly guy.

    It’s good to see Tom catching on to Mung. Better late than never.

  27. Mung: If evolutionists such as yourself, Coyne, Gould, and Darwin, don’t define what gradualism means, why is that a failure to define terms on my part?

    I know what Coyne, Gould and Darwin meant.

    I haven’t a clue what you mean by “gradualism”.

  28. Gradualism , as I read it in Goulds paper, was rejected and replaced by Punctuated equilibrium.
    This because the fossil record proved gradualism never happened. This is all about the fossils. (As usual in evolutionist hypothesis) The biology conclusions come after geological conclusions of deposition of fossils. Very important.

    Its a disaster to old time evolutionism. Thats why Gould is not fondly remembered today.

    The fossils showed creatures, in long timelines, never evolved.
    SO , plan b, it must be segregaterd populations from the great population that suddenly evolve into new populations by selection on mutations.
    Its the small, off broadway, population that is the source/origin , for important evolutionary change. Then the original population goes extinct.
    The small evolving population gradually evolves as it moves in smaller numbers, special envirorments, etc etc.

    Gould and company thought they were solving a problem, and thought they were making a accomplishment of note, to evolutionism.
    However in reality they highlighted the failure of the fossil record to show evolution as Darwin expected it could only be.
    They highlighted also evolutionism is not based on biology evidence but other disciplines.
    PE was a great thing for creationism.
    PE doesn’t help the problem of the total absence of evolutionary change in biology(in fossils).
    Its a last gasp to justify the invisible mechanism.

  29. Mung,

    Maybe he thinks Coyne is the lone voice in the wilderness.

    He may be right then. Is there ANYONE who still believes in Darwinism?

  30. Neil Rickert: I know what Coyne, Gould and Darwin meant.

    I haven’t a clue what you mean by “gradualism”.

    I think its another one of those secrets in evolution, like what do you mean by teleology, or random.

    What is the connection between evolutionists and Masons? Or Bohemian Grove?

  31. The interesting question to me is what koonin meant. Gradualism in what sense has been falsified? Having read quite a lot of his published work I’m sure he would give some examples. Can we get some context here?

  32. Rumraket:
    The interesting question to me is what koonin meant. Gradualism in what sense has been falsified? Having read quite a lot of his published work I’m sure he would give some examples. Can we get some context here?

    The relevant text is apparently this from p. 398:

    [Proposition]
    The variations fixed by natural
    selection are “infinitesimally
    small.” Evolution adheres to
    gradualism.

    [Postmodern Status]
    False. Even single gene duplications and
    HGT of single genes are by no means “infinitesimally
    small,” nor are deletion or acquisition
    of larger regions, genome rearrangements,
    whole-genome duplication, and, most dramatically,
    endosymbiosis. Gradualism is not the
    principal regime of evolution.

    Well, it looks like a strawman version of “gradualism” in the first place, yet hardly the saltationism/miracles of a Mung or VJT. I’m not sure where he got “infinitesimally small,” but that’s hardly what “gradualists” (at least whoever Mung’s babbling about) of today have been claiming. In any case, he’s not claiming a “non-gradualism” that relies on anything not well known in biology already.

    The pdf is here

    Glen Davidson

  33. phoodoo:
    GlenDavidson,

    Again more secret Bohemian Grove knowledge is needed to know what the evolutionists are referring to?

    Well it’s in a book, so it’s not really secret is it?

  34. Rumraket: Well it’s in a book, so it’s not really secret is it?

    There are Freemason books that reveal their secrets also…supposedly.

  35. Anyway now that we know what Koonin means it is easy to contrast with Darwin’s views on gradualism. With the exception of endosymbiosis, all of Koonin’s non-gradualist mechanisms are genetic, while Darwin spoke pretty much entirely about phenotypic changes, like limb-proportions, shapes and the like.

    If you take “intinitesimal gradualism” to apply to the genetic level, then sure it is false. But if you take it merely to apply in the sense envisioned by Darwin, it isn’t.

    In the other thread this excellent review by Theobald, of Darwin’s views on gradualism as contrasted with Punctuated Equilibrium sensu Eldredge & Gould, also gives some nice insights into what exactly Darwin meant by the term: All you need to know about Punctuated Equilibrium (almost).

  36. Mung: 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.

    I believe I’ve dealt with this back here.

    Mung:Because jumps would be indistinguishable from magic. And magic is unscientific.

    Rumraket: It has nothing to do with whether it “looks like magic”, it has to do with basic probability theory and it has to do with observation. Preferrably work by positing causes seen operating in the here and now, and smaller steps requiring fewer genetic changes are generally more likely.

    Mung:Why is it that evolutionists can accept entire genome duplication while at the same time claiming to having an aversion to big changes? It’s illogical.

    Rumraket:Because you have to look at the detail. Whole genome duplication leaves evidence behind.

    We might have a methodological preference for simpler and more likely explanations, but evidence can overrule that preference. Whole genome duplication leaves some very unambigous evidence behind: The whole genome exists twice. And when we compare multiple descendants from that putative ancestral whole genome duplication, we can even see how many of the extra genes are lost and degrade over time.

    Same goes for things like horizontal gene transfer, genomic rearrangements, endosymbiosis and the like. Many of these ideas were certainly fought intensely when initially proposed, because of that methodological preference for simplicity, parsimony, falsifiability and mechanisms observed to happen.

    But then evidence eventually managed to change the dominating views and all these mechanisms are now part of mainstream evolutionary theory.

    You’re right, there is an aversion to miracle-stories in science. Because they’re unobserved, hence exceptionally infrequent, and technically unfalsifiable. You could always, without exception, rationalize any historical pattern has having been created by a miracle.

  37. Mung,

    At which point the opposition fell silent, lol.

    If your arguments are so irrefutable, why don’t you publish a paper?

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

    Now that’s a bold claim. The evidence that small changes occur is, I would say, overwhelming. Whether they are the dominant mode is another matter (the genome says yes!), but there are sound theoretical reasons to doubt that large-scale single-generational changes are the norm. Not least in obligate sexual species, where the likely interference with meiosis argues against this being more common than a series of smaller steps.

    One would need to be careful to distinguish a change that resulted from many iterations of gradualism from a genuine ‘saltation’. These do occur – whole genome or whole chromosome duplications, which by their nature are distinguishable by those phylogenetic methods that Creationists don’t believe in. What the Creationist often seems to be thinking of, though, is something like a whale, where the ‘evidence’ of leaps is the (pretty inevitable) absence of fine grain detail.

    On a side note, Huxley urged Darwin to drop gradualism. It remains alive and well for evidential and theoretical reasons.

  39. Allan Miller: whole genome or whole chromosome duplications,

    Pretty sure I can guess the answer, but do these events produce descendants of a different species?

  40. Mung:

    Jerry Coyne writes that gradualism is one of the six tenets of “the modern theory of evolution” .

    Here he is referring to the gradual appearance of new species, genera, families etc. in the fossil record. Presumably, even if we had a complete fossil record, or had a time machine that would less us sample creature at 100,000 year intervals we’d still see the gradual appearance of these groups although it might be unusually rapid and geographically isolated.

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

    Koonin is referring to major events which occur in lineages such as symbiotic pairings, changes in ploidy, genomic rearrangements etc which are clearly all-or-none events. Koonin might be contrasting that with his incorrect assumption that originally all mutations where assumed to be point mutations in DNA.
    The mechanisms above certainly occur but they probably don’t create significant phenotypic changes, so gradualism is still valid.

  41. dazz: Pretty sure I can guess the answer, but do these events produce descendants of a different species?

    Sometimes. Allopolyploidy is known to do that from time to time. Usually not, though.

  42. RodW:
    Mung:

    Here he is referring to the gradual appearance of new species, genera, families etc. in the fossil record. Presumably, even if we had a complete fossil record, or had a time machine that would less us sample creature at 100,000 year intervals we’d still see the gradual appearance of these groups although it might be unusually rapid and geographically isolated.

    Koonin is referring to major events which occur in lineages such as symbiotic pairings, changes in ploidy, genomic rearrangements etc which are clearly all-or-none events. Koonin might be contrasting that with his incorrect assumption that originally all mutations where assumed to be point mutations in DNA. The mechanisms above certainly occur but they probably don’t create significant phenotypic changes, so gradualism is still valid.

    How does one GRADUALLY APPEAR?!
    Whats the state just before APPEAR?!
    In reality nothing in the fossil record appears but instead its a conclusion based on deposition claims. the fossil record only shows fossils in the ground. it says nothing by itself. another paradigm is needed in these matters. a non biological one. So the biology conclusions are not based on biology. Its not true science i say.
    Anyways.
    Gradualism was rejected by PE. They had too. the fossil record clearly showed fits and starts and never sly morphing as was expected by darwin and friends.
    Jowever in the NEW START they still don’t have fossils documenting it.
    right back to the problem.
    The fossil record just shows healthy creature types arrived and safe.
    PE is a last trench for evolutionism but in reality it crushes evolutionism if you think about it.
    ITs saying something didn’t happen. Yet it was always just a presumption something happened. PE attacks this presumption and not just a few conclusions.

  43. John Harshman: Sometimes. Allopolyploidy is known to do that from time to time. Usually not, though.

    Thanks John. For what I could gather that would involve hybridization of two different species

  44. Mung: The relevant question then would be what are the known mechanisms of modification and in what sense are they gradual modifications?

    I’d be interested in what you have to say along those lines.

    They are gradual in the sense, for instance, that no new complex structures, like the eye, can be created in a single iteration of descent.

  45. dazz: Thanks John. For what I could gather that would involve hybridization of two different species

    Correct. In fact that’s what the “allo” means in allopolyploidy.

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