The Problem of Predictive Equivalence

In the previous section I described the argument that many biologists have endorsed for thinking that the hypothesis of evolution by natural selection is more likely than the hypothesis of intelligent design. This argument considers the observation that organisms are often imperfectly adapted to their environments and construes the design hypothesis as predicting that organisms should be perfectly adapted. This version of the design hypothesis presupposes a very definite picture of what God would be like if he existed.

Actually, in the previous section Sober was primarily concerned with creationism. This is made rather obvious by the chapter title. It’s as if he was writing about Creationism and then Intelligent Design burst on the scene and he had to change things up to make it appear as if the two are the same. But what’s a philosopher of biology to do?

The point here is to demonstrate how evolutionary arguments are in fact theological rather than scientific. This is admitted by a major philosopher of biology. This OP was motivated at least in part by claims by Rumraket that the genetic code ought to be perfect if it was designed. Arguing that it’s not perfect, therefore it’s not designed. To quote Sober, “This version of the design hypothesis presupposes a very definite picture of what God would be like if he existed.”

What does this have to do with actual science, if anything?

Why do biologists (and Rumrakians) require the foil of a perfect designer God in order to make their case for evolution?

What reason do we have to believe that an intelligent designer would ensure that her organisms were perfectly adapted to their environment?

What reason do we have to believe that natural selection leads to organisms that are imperfectly adapted to their environment?

196 thoughts on “The Problem of Predictive Equivalence

  1. phoodoo: Rumraket: The populations are not large enough and they will not persist for long enough for all the best possible combinations of allele to arise and fix in any population.

    The best combination, huh?

    Yes. To say that it is the best possible one, is not to say that it is perfect and without flaw. I was talking from the perspective of reproductive success. I am saying that given some constraints, there is going to be some combination of alleles that give some organism from some species the highst attainable fitness, and any possible genetic deviation from this combination of alleles, is going to result in lower reproductive success.

    Given some genome of arbitrary length, and some static environment, there’s going to be some theoretical combination of alleles that it the best possible arrangement for that environment for the species in question (there might even be several of an equivalent fitness). But the combinatorial space of those alleles is so incomprehensibly vast that it is extremely doubtful that any natural or experimental population will ever happen to come upon that combination.

    And were it even to obtain in an individual by sheer luck, or be designed by God, it couldn’t persist because of genetic drift. No amount of being good at outrunning lions, fighting infectious microorganisms and attracting mates, is going to matter when a meteor lands on your head.

  2. Neil Rickert: Good question.

    Presumably, one measures adaptiveness in terms of the ability to achieve a purpose.People who deny a role for purpose should not be talking about adaptation.

    For that matter, people who talk about copying errors can only do so if they presume a purpose.Otherwise there are no copying errors.There’s just stuff that happens.

    Evolutionary biology is riddled with teleology.And biologists tend to be in full denial mode about this.

    This, roughly speaking, is why I say that I am not a Darwinist.

    No, I haven’t suddenly become a creationist.Organisms evolved.But the Darwinist account has problems.

    I understand but I don’t agree. There isn’t anything you can’t extend this kind of thinking to. The ground I walk on is “for holding me up”. The lava that comes out of the volcano is “for heating the surrounding air” and so on.

    The purposes you speak of seem to me no different. We can speak in those terms, but what we’re doing is importing purpose to the entities in question. Purpose is not to be found in the things we speak about, it is only in our heads as an idea we hold about other things.

    I’ve done this analogy several times before. A person might craft a screwdriver and intend to use it as that, a screwdriver. To drive screws with. But is this intention found anywhere in the screwdriver? Nope. It’s in the crafter’s head. The screwdriver might be well suited for the crafter’s intentions, but it can serve just as well as a stabbing weapon, or a sex-toy, or a door stopper or what have you.

    But the screwdriver doesn’t change if it is used for something else (disregarding wear and tear). It doesn’t take on new, or replace previous properties it didn’t have before. The screwdriver remains the same. It is the people who use it that change. They change in what they do with and intend for the screwdriver. So the purpose was never in the screwdriver, it was in the user’s heads and never left.

    Even were there a *great intender* (I understand that this is not what you’re saying) behind everything in evolution, it would still not mean that any evolved entity “had purpose”. The only place purpose could be found would be in the head of the *great intender* behind it all. There would still not be any purpose in the muscles of the Gazelles legs.

    You might say they’re for propelling the gazelle forward, but I might say it’s for feeding lions, or beetles when it eventuall dies. And none of us could ever show that the other one was wrong. Because there isn’t anything we could point to about the Gazelle’s muscles that would settle which of us was right.

  3. Rumraket: Yes. To say that it is the best possible one, is not to say that it is perfect and without flaw. I was talking from the perspective of reproductive success. I am saying that given some constraints, there is going to be some combination of alleles that give some organism from some species the highst attainable fitness, and any possible genetic deviation from this combination of alleles, is going to result in lower reproductive success.

    Given some genome of arbitrary length, and some static environment, there’s going to be some theoretical combination of alleles that it the best possible arrangement for that environment for the species in question (there might even be several of an equivalent fitness). But the combinatorial space of those alleles is so incomprehensibly vast that it is extremely doubtful that any natural or experimental population will ever happen to come upon that combination.

    And were it even to obtain in an individual by sheer luck, or be designed by God, it couldn’t persist because of genetic drift. No amount of being good at outrunning lions, fighting infectious microorganisms and attracting mates, is going to matter when a meteor lands on your head.

    Well, I think you brought up several issues that are important.

    First, there never would or could be a static environment. Even if there was only one species, let’s say its man, man still has to eat something. So, it will always either consume another species, or even if we invented food in a lab, one man is going to want to take it from another. One man is going to want to keep the females for himself. Another man is going to want all the resources, so there is no best. Best at running is not best at lifting. Best at wrestling, is not best at singing. Best at beating someone over the head is not going to be best at avoiding pneumonia. So the premise is flawed.

    Furthermore, there always has been, and always will be luck. Its probably the biggest determinant to which wildebeast gets eaten (obviously big, fast wildebeats also get eaten, if they just happen to walk in front of an alligator) , or to which birds get to mate. Two birds, one tree, you will probably mate. Two trees, one bird, you won’t, bad luck.

    And its even more complicated than this. There really is no such thing as YOU as a separate entity. You are a whole community of microbiomes. Its luck, its temperature, its your first exposure, it becomes you, and you become it. The microbes that you are first exposed to never leave you, and everyones is different. So even if you had a genome that you thought was “the best” , its totally dependent on what environment you throw it in. Prior to you being born, there is no combination that can be set to “best”.

    Its asking the question, what’s the BEST way to survive. That is a meaningless question. What’s the best way to win a football game? That which wins is best.

  4. phoodoo,

    Furthermore, there always has been, and always will be luck. Its probably the biggest determinant to which wildebeast gets eaten (obviously big, fast wildebeats also get eaten, if they just happen to walk in front of an alligator) , or to which birds get to mate. Two birds, one tree, you will probably mate. Two trees, one bird, you won’t, bad luck.

    How significant a role does luck play? Can you quantify it?

    E.G. in each generation the number of individuals who would have been the fittest but did not survive to breeding age due to luck was X percent?

    What is X? If it’s the “biggest determinant” it must play a significant role, more so then actually being a faster or slower runner as per your example.

    And, of course, if you can’t say how big a % it plays how do you know it plays a significant % at all, other then fevered hope and imagination for your favourite “just so” story.

  5. phoodoo,

    So even if you had a genome that you thought was “the best” , its totally dependent on what environment you throw it in.

    So it’s almost as if when the environment changes then the various versions of the genome compete against each other to see who can survive best (barring luck, of course) in the new environment. Is that what you are trying to say? And presumably the one that survives BEST goes on to spread those variants in the population?

    Its asking the question, what’s the BEST way to survive. That is a meaningless question.

    Yes, because as we know the environment is always changing. So the “best” way to survive is also changing.

    Hmm, you’ll be one of us before the decade is out…

    Out of interest, what happens if the environment changes too fast?

  6. phoodoo,

    Its asking the question, what’s the BEST way to survive. That is a meaningless question. What’s the best way to win a football game? That which wins is best.

    Well, that’s not true is it? For example, we could collect all the strategies together we could think of to play football and test them against each other in a simulator.

    The team with the rule “stay away from the ball” would no doubt lose almost all of the games played against the “move to the ball and then kick in a random direction” team.

    But over time, playing those strategies against each other, we’d quickly find that the question “what is the best way to win a football game” is not meaningless at all. We’d find a collection of strategies that we’d label “the best”.

    Otherwise why do football teams have managers if there is no “best” way to win at football?

    https://howtheyplay.com/team-sports/Top-10-Best-Football-Managers-In-The-World

  7. phoodoo: What’s the evolution explanation for giraffes necks? Tell us the right thinking.

    I guess I’ll comment on this.

    The traditional picture is that natural selection acted to optimize the giraffe to its environmental niche by giving it a long neck for feeding on the higher leaves.

    As I look at it, a niche where the organisms eat the high leaves is a different niche from one where organisms eat the lower brush. So I don’t see this as optimizing for a fixed niche; I see it as migrating to a different niche. I divide up niche space more finely than the traditional picture.

    So there was an earlier population of grazing animals. This population was always exploring the boundaries of its niche, in an attempt to expand. And it was experimenting with change in the organisms, to allow it to explore other niches. One such experimental change allowed reaching higher. And that turned out to be effective, leading to the giraffe.

    Why pick the giraffe? It wasn’t picked. The same population was likely exploring other ways of changing niche, and some of those might have been just as effective. So we see a diversification, with multiple species that are descendants of an earlier population.

    This is subtly different from the Darwinian picture, but you will probably see it as not much different.

    Here’s the difference. I’m not afraid of using the word “purpose”. Darwinism wants to say that all is explained by a passive background process that is purposeless. I’m instead saying that there is foreground purposive process, where the “purpose” is survival of the population (or successor populations). So I see it as purpose driven. But it is a natural purpose, and not anything like the kind of purpose that religions want to call on.

    If “intelligence” means acting with a purpose (as Dembski suggests in a recent book), then this really is intelligent design. It is a process of continual redesign by the populations themselves. This is not what most ID folk mean by “intelligent design”. They want an external designer, whereas what I see is internal self-redesign.

  8. petrushka: Gould asserted the selection explanation was a just so story.

    Sounds reasonable but it still seems more useful start than an unknown designer decided to do it for some reason somehow.

  9. phoodoo: I will let Neil answer as to his own beliefs, but I am not just talking about learning new things, I am talking about the physical responses that occur.

    As far as I know, all such learning depends on feedback. The organism (could be you) is continually evaluating its own performance. And then, with a system of trial and error, it is acting in ways that improve its performance.

    Accentuate the positive; Eliminate the negative

    Darwinism is only “eliminate the negative”. That’s not enough. You also need “accentuate the positive”. And that requires some system of self-evaluation.

  10. Neil Rickert: Darwinism is only “eliminate the negative”. That’s not enough. You also need “accentuate the positive”. And that requires some system of self-evaluation.

    Competion within the population would be a mechanism to do that.

  11. newton: Competion within the population would be a mechanism to do that.

    Population density regulation is critically important there. Critics of evolutionary biology who say that natural selection only eliminates less-fit genotypes and does not increase the numbers of more-fit genotypes forget that the whole population produces an excess of offspring, and then is trimmed down to near the carrying capacity by density regulation. So the numbers and frequency of fitter genotypes do grow.

  12. Rumraket: I understand but I don’t agree. There isn’t anything you can’t extend this kind of thinking to. The ground I walk on is “for holding me up”. The lava that comes out of the volcano is “for heating the surrounding air” and so on.

    I thought I had replied to this. It looks as if I closed the browser tab without posting.

    For the way that I am using “purpose”, the lava example would not work.

    If the volcano were measuring the air temperature, and adjusting the lava flow depending on whether the air temperature had reached its target, then we could say that warming the air is the purpose of the lava flow. But without that kind of feedback and behavior adjustment based on feedback, then I’m not going to use “purpose”.

  13. Joe Felsenstein: Population density regulation is critically important there. Critics of evolutionary biology …

    I should add that I do not consider myself to be a critic of evolutionary biology. I’m criticizing only the Darwinian story which puts too much emphasis on natural selection and not enough on “accentuate the positive”.

    Natural selection is often described as shaping the biosphere. I use the cookie cutter analogy. The cookie cutter shapes the dough into the form that we want. But it only works because the dough is being pumped through the cookie cutter. For biology, it is biological reproduction that does the pumping.

    To me, “natural selection” is a “tail wags the dog” kind of explanation.

  14. Joe Felsenstein:
    Just to attempt an answer to the question of where the quote comes from: Elliott Sober’s Evidence and Evolution, page 109.

    I don’t own a copy, but did this by indirect means by web searches.I might be wrong but that is a best guess.

    Thanks. I haven’t read a ton of Sober, but what I have read I’ve liked.

  15. Rumraket: I’ve done this analogy several times before. A person might craft a screwdriver and intend to use it as that, a screwdriver. To drive screws with. But is this intention found anywhere in the screwdriver? Nope. It’s in the crafter’s head. The screwdriver might be well suited for the crafter’s intentions, but it can serve just as well as a stabbing weapon, or a sex-toy, or a door stopper or what have you.

    But the screwdriver doesn’t change if it is used for something else (disregarding wear and tear). It doesn’t take on new, or replace previous properties it didn’t have before. The screwdriver remains the same. It is the people who use it that change. They change in what they do with and intend for the screwdriver. So the purpose was never in the screwdriver, it was in the user’s heads and never left.

    In this example the thinking creativity of the designer precedes that of the physical screwdriver. And we can get an idea of the thoughts of the designer by examining the designed objects. I say objects because you only considered the screwdriver and disregarded the screw that goes along with it. Things must be looked at in context.

  16. Joe Felsenstein: Population density regulation is critically important there. Critics of evolutionary biology who say that natural selection only eliminates less-fit genotypes and does not increase the numbers of more-fit genotypes forget that the whole population produces an excess of offspring, and then is trimmed down to near the carrying capacity by density regulation.So the numbers and frequency of fitter genotypes do grow.

    I’d like to know which critics do you say claim that natural selection does not increase the numbers of more-fit genotypes?

    I have previously stated that natural selection changes the ratio of different traits within breeding populations.

  17. Neil Rickert: As far as I know, all such learning depends on feedback.

    I have no idea how a learning systems makes muscles grow stronger and bones denser when you use them more. I have no idea how our bodies because more tolerant to alcohol or drugs , if we use them more.

    I don’t know what trial and error and feedback you are talking about, and how that translates into a genetic trait that becomes inherited.

  18. CharlieM: In this example the thinking creativity of the designer precedes that of the physical screwdriver. And we can get an idea of the thoughts of the designer by examining the designed objects. I say objects because you only considered the screwdriver and disregarded the screw that goes along with it.

    Some creativity involves a new use for an existing object in which case the screwdriver exists first.

  19. newton: I am still pondering how one uses a screwdriver as a sex toy.

    Carefully ,I guess

    Its an object which is usually long and thin which is bulbous at one end and you have to think about it?

  20. newton: Some creativity involves a new use for an existing object in which case the screwdriver exists first.

    A bit like the creative use of the pentadactyl limb.

  21. CharlieM: A bit like the creative use of the pentadactyl limb.

    Right like Landscape Arch , design is not necessarily a linear process

  22. newton:

    I am still pondering how one uses a screwdriver as a sex toy.

    Carefully ,I guess

    CharlieM:

    Its an object which is usually long and thin which is bulbous at one end and you have to think about it?

    Remind me never to borrow Charlie’s screwdrivers.

  23. CharlieM, to Joe:

    I’d like to know which critics do you say claim that natural selection does not increase the numbers of more-fit genotypes?

    Neil just did:

    Darwinism is only “eliminate the negative”. That’s not enough. You also need “accentuate the positive”.

    He’s clearly wrong about that, as Joe explained.

  24. Neil Rickert: Darwinism is only “eliminate the negative”. That’s not enough. You also need “accentuate the positive”.

    Eliminating the negative is relative. Therefore, if a better allele comes along, the less good but once-common allele will tend to be the negative that ends up being eliminated.

    Glen Davidson

  25. newton: Right like Landscape Arch ,design is not necessarily a linear process

    Not really alike. One is caused by extrinsic, physical forces acting on a static structure, the other is intrinsic, dynamic, living forces reacting to external conditions.

    And I’d say that the variations of pentadactyl limbs are more of a radial process than linear.

  26. GlenDavidson: Eliminating the negative is relative.Therefore, if a better allele comes along, the less good but once-common allele will tend to be the negative that ends up being eliminated.Glen Davidson

    Extinction creates an empty niche. An opportunity. A species on the edge of that newly empty niche can expand in numbers to fill that niche.

  27. Glen:

    Eliminating the negative is relative. Therefore, if a better allele comes along, the less good but once-common allele will tend to be the negative that ends up being eliminated.

    Right. So one way to fix Neil’s statement is to change it from this…

    Darwinism is only “eliminate the negative”. That’s not enough. You also need “accentuate the positive”.

    …to something like this:

    Selection by itself only eliminates the (relatively) negative. That’s not enough. You also need to generate the positive, which is where variation comes in.

    Variation is what generates the positive. Natural selection accentuates the positive by selectively eliminating the negative. That’s Darwinian evolution.

    It makes perfect sense. Neil’s objection is bogus.

  28. CharlieM: Not really alike. One is caused by extrinsic, physical forces acting on a static structure, the other is intrinsic, dynamic, living forces reacting to external conditions.

    Both are shaped by external conditions.

  29. CharlieM: And I’d say that the variations of pentadactyl limbs are more of a radial process than linear.

    How so?

  30. CharlieM: Its an object which is usually long and thin which is bulbous at one end and you have to think about it?

    It is the sharp pointy end which makes me wonder about the suitability.

  31. keiths:

    CharlieM, to Joe:

    I’d like to know which critics do you say claim that natural selection does not increase the numbers of more-fit genotypes?

    Neil just did:

    How right you are, so he did.

    I, for one, have no problem agreeing that natural selection increases instances of what is already present in the population.

  32. keiths:

    Variation is what generates the positive.

    Alan:

    Nonsense. Variation is random.

    What a dumb thing to say, Alan.

    Flint:

    Why can’t random variation sometimes generate an improvement?

    Alan:

    It often does.

    Exactly. So my statement is correct:

    Variation is what generates the positive.

    This is Evolution 101. You’ve been involved in these debates for more than ten years. How can you not understand that variation is what generates the positive mutations that selection favors?

  33. CharlieM: I’d like to know which critics do you say claim that natural selection does not increase the numbers of more-fit genotypes?

    I have previously stated that natural selection changes the ratio of different traits within breeding populations.

    CharlieM may never had made that claim, but it is quite common. It is common also among evolutionary biologists, though they discuss fertility in addition to viability, where it is easier to see that natural selection can increase the fertility.

    Also, evolutionary biologists don’t go on to try to persuade their audience that this shows that natural selection cannot increase favorable traits.

    When made by creationists and ID supporters, it is intended to persuade the audience that natural selection does not work to improve adaptation.

    I’ve heard the point made by them here many times. Perhaps someone could help me by finding exampled.

    In the meantime, here, is an exampleof this from various outside creationist and ID-supporting sources:

    From “News” at Uncommon Descent, March 26, 2016, Denyse O’Leary quoth, quoting someone else here

    A friend writes to note what philosopher of science, John Elof Boodin (1869-1950), had to say about natural selection:

    The principle of natural selection is indeed an important contribution to biology. But it is a negative, not an architectonic, principle. It does not explain why variations appear, why they cumulate, why they assume an organization in the way of more successful adaptation. Organisms must, of course, be able to maintain themselves in their life environment and in the physical environment, in order to leave descendants and determine the character of the race. But that is all natural selection tells us. It does not explain the traits and organization of organisms nor why they become well or badly adapted to their specific environment.

    (A little consideration will show that this Boodin fellow was wrong about saying that natural selection cannot explain why adaptations cannot “cumulate”). It explains why they rise in frequency, and when originally occurring in different individuals, can become combined into the same individual.

  34. CharlieM:

    How right you are, so he did.

    I, for one, have no problem agreeing that natural selection increases instances of what is already present in the population.

    Yes. Variation is what gets positive mutations into the population in the first place. Once they’re present in the population, selection increases their relative frequency.

  35. Joe Felsenstein,

    It does not explain why variations appear, why they cumulate, why they assume an organization in the way of more successful adaptation.

    Do you agree with this especially the fist sentence, “It does not explain why variations appear”?

  36. keiths:
    .How can you not understand that variation is what generates the positive mutations that selection favors?

    I suppose that technically, variation is not what generates mutations, it’s mutations that generate variation. Variation is a result, not an agent.

  37. colewd:
    Joe Felsenstein,

    Do you agree with this especially the fist sentence, “It does not explain why variations appear”?

    I agree with it. Mutation proposes, selection disposes.

  38. keiths:
    CharlieM:

    Yes. Variation is what gets positive mutations into the population in the first place.Once they’re present in the population, selection increases their relative frequency.

    In “Dance to the Tune of Life”, Denis Noble mentions a paper where they describe an experiment in which they disable the flagellar system of bacteria. Within four days the population has managed to restore the flagella. They do this by using mutations to find a different regulatory network to the original. This is a good example of the population using random mutations to achieve a desired outcome.

    The mutations could indeed be random but the random variations are used in a way that is directed in a similar way as that used by the immune system.

  39. colewd:

    (Boodin, via O’Leary): It does not explain why variations appear, why they cumulate, why they assume an organization in the way of more successful adaptation.

    Do you agree with this especially the fist sentence, “It does not explain why variations appear”?

    I agree with these sentences in part. But I already expressed my disagreement with the “cumulate” part (does it mean increase in frequency? Or why successive mutations that increase in frequency come to be accumulated? Unclear!)

    The part about “assume an organization” is just plain unclear. Perhaps it’s some kind of escape hatch for saying he is only referring to really really complicated adaptations.

    And the last sentence, while technically OK, makes it sound like there is some big mystery as to why mutations occur. They will happen in any non-perfect replication.

  40. Flint,

    I suppose that technically, variation is not what generates mutations, it’s mutations that generate variation. Variation is a result, not an agent.

    No, the word ‘variation’ can be used either to refer to a process or to the result of that process. The same is true for ‘mutation’.

    Variation (the process) produces variations (the result), and mutation (the process) produces mutations (the result). And since mutations are a form of variation, we can say that mutation (the process) produces variations (the result).

    Note, however, we that we don’t use the plural when referring to the process. So this statement of yours…

    …it’s mutations that generate variation.

    …is incorrect. Mutations are themselves variations. They don’t cause variation (the process)*; they’re the result of it. They don’t cause variations — they are variations.

    So my original statement is correct, and your revision of it is not.

  41. CharlieM,

    In “Dance to the Tune of Life”, Denis Noble mentions a paper where they describe an experiment in which they disable the flagellar system of bacteria. Within four days the population has managed to restore the flagella. They do this by using mutations to find a different regulatory network to the original. This is a good example of the population using random mutations to achieve a desired outcome.

    The mutations could indeed be random but the random variations are used in a way that is directed in a similar way as that used by the immune system.

    I haven’t read the paper yet, just the abstract, but I can’t see why you think the evolutionary process that restores motility is “directed in a similar way as that used by the immune system.”

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