Fisher’s Fundamental Theorem of Natural Selection: the death sentence for Darwinism
| April 4, 2008 | Posted by scordova under Darwinism, Evolution, Intelligent Design |
Consider the following claims:
Darwinism requires that the Fundamental Theorem [of Natural Selection] does not apply most of the time.
Walter ReMine
Biotic Message
and
a relative lack of natural selection may be the prerequisite for major evolutionary advance
Mae Wan Ho
Beyond neo-Darwinism
and
Concerning this theory [Darwinian evolution], I believe that we might question (or at least note) the following:
….
(10) The internal contradiction in its major theoretical cornerstone — Fisher’s fundamental theoremStanley Salthe
Analysis and critique of the concept of Natural Selection
and
many genomic features could not have emerged without a near-complete disengagement of the power of natural selection
Michael Lynch
opening, The Origins of Genome Architecture
Distinguished evolutionary biologist Michael Lynch recently published a much anticipated book, The Origins of Genome Architecture. Curiously, in this magnificent 494-page book, only an obligatory mention of the name of Charles Darwin was made. Darwin was mentioned passingly on 3 pages in the chapter entitled “GenomFart”.
It was also in this book Lynch demonstrated his great irritation with the advocates of Natural Selection (like Richard Dawkins). So great was his irritation that he gave the hard core Darwinists the ultimate insult, he likened them to ID proponents!
the uncritical acceptance of natural selection as an explanatory force for all aspects of biodiversity (without any direct evidence) is not much different than invoking an intelligent designer
Michael Lynch
The Origins of Genome Architecture, p 368
Why the disdain for Natural Selection? It follows beautifully from Fisher’s Fundamental Theorem of Natural Selection.
Lynch is one of the world’s foremost experts in population genetics. Population genetics is the sort of anomalous discipline in biology that has a rich tradition of mathematics, and one that commands both respect and disdain. Lynch himself points this out, “It is well known that most biologists abhor all things mathematical…”
What sort of things do population geneticists do? They mathematically describe the evolution of populations. They quantify the amount of natural selection going on in a population. If natural selection is like the notion of force in physics, then it only makes sense to attempt to quantify how much or how little of this “force” must be in operation.
A central figure creating the ability to quantify and measure the amount of selection acting in a population is R.A. Fisher. Fisher was a first rate mathematician, and his work is celebrated in ID circles as it led to the formalization of the Explanatory Filter and other means of complexity analysis.
But in addition to the groundwork Fisher provided for design detection, he has provided much ammunition for ID proponents in the field of population genetics. Make no mistake, Fisher is a Darwinist, hailed by Stephen Gould as a “patron saint”, so the irony is that he continues to be an unwitting hero for the ID hypothesis.
If his Fundamental Theorem of Natural Selection gave population geneticists the tools to measure the amount of natural selection in a population, what would happen if these sophisticated techniques demonstrated Natural Selection had to be next to non-existent for evolution to advance? Answer: Darwin’s theory would be formally disproved! And in fact that is the case, and it is only quietly acknowledged in the literature (as hinted by the quotations above).
How can we measure natural selection? Without going into the deep details, we conventionally assert selection exists if there has been a reduction in diversity in a population. For example, let’s say we have a population of fruit flies and apply a pesticide to the population such that only 1 in 1000 fruit flies survives. The diversity of the population is severely reduced, and we can assert the pesticide applies a very strong selection force on the population.
It’s actually a bit clumsy to use the fundamental theorem of natural selection to describe the strength of natural selection and the reduction of diversity. With some degree of gyration one can probably do it using Fisher’s Fundamental theorem. But the bottom line, according to Fisher’s fundamental theorem, as “fitness” increases, diversity must decrease! [I'll save the technicalities in the notes below and comment section.]
As an aside, Fisher’s theorem was controversial and misunderstood until the Creationist George R. Price reformulated it. The new version of Fisher’s Fundamental Theorem by creationist George Price can be found at Wiki here.
The Wiki biography comments:
[Price] thus clarified Fisher’s fundamental theorem of natural selection, which had caused some controversy and misunderstanding. He believed that this equation had been a gift from God, a miracle after a religious experience.
And given that Fisher’s theorem essentially destroys any hope of Darwinism being true, I would have to agree with George Price, that Fisher’s Theorem and Price’s reformulation was a gift from God. After Price’s renounced Darwinism and became a creationist, he managed to publish his ideas in the prestigious scientific journal Nature in the article, and The Journal of Theoretical Biology. It is noteworthy he published in the prestigious journal Science on Science and the Supernatural.
In Death of Altruist we read:
Price made his final revisions to “The Logic of Animal Conflict” the following February. In a cover letter, he explained to Maynard Smith that he had made a few changes to accommodate his newfound belief in creationism. “I think I found wordings that you won’t object to, and that won’t shock Nature’s readers by making them suspect what I believe,”
Ah the irony of it all!
But let me return to the issue of Fisher’s Fundamental Theorem, and particularly Lynch and Salthe’s observations. Recall Lynch wrote:
the uncritical acceptance of natural selection as an explanatory force for all aspects of biodiversity (without any direct evidence) is not much different than invoking an intelligent designer
I highlighted the word “diversity” for a reason. How does fitness improve according to Fisher’s Fundamental Theorem or Price’s Equation? Answer: by reducing diversity.
If we presume that all life descended from a single species and diversified, how can we logically argue that diversification happens through a process of removing diversification! Some may invoke things like allopatric (geographic) speciation or sympatric speciation where mutant forms are isolated somehow from the parent population, but is this not essentially a means of protecting new species from the culling effects of natural selection? It’s surprising the illogic of Darwinian claims has not been readily apparent!
Consider for example the problems of evolving a 3-chambered heart to a 4-chambered heart. The IDEACenter website has a wonderful treatment of the problem. See: The Vertebrate Animal Heart: Unevolvable, whether Primitive or Complex.
If we have species with 3-chambered hearts, how can species with 4-chambered hearts evolve? Let’s say a creature with a 3-chambered heart gives birth to a creature with a 4-chambered heart. This of course would be a saltational miracle in light of the fact a LOT of associated plumbing and developmental pathways have to be in place to make this possible. If the plumbing is hooked up in the wrong way, death results, no reproduction, no evolution.
But even granting this miracle set of mutations can happen, what role can selection possibly play? It has to allow both changes to exist simultaneously. If selection for the 4-chambered heart overtakes the population, then the 3-chambered hearts are eliminated (which is definitely not the case since reptilian 3-chambered hearts still exist). If selection for the 3-chambered heart takes place, then 4-chambered hearts are eliminated (which is clearly not the case since mammalian 4-chambered hearts exist).
Of course, one will argue that the two kinds of heart architectures might fall in separate niche’s (either geographically or via other means) and thus we prevent competition between the 3-chambered and 4-chambered heart. But competition is at the heart of natural selection. Thus I’ve demonstrated that in order for natural selection work, we have to prevent natural selection from working!
One of course would object and say that such saltations from 3 to 4 chambers violates Darwinian gradualism. Fair enough, but one is still confronted with the same problem. Let’s say one part of the population has pre-cursors to 4-chambered hearts and the other part of the population does not. For the 4 chambered heart to evolve, selection pressure has to be non-existent on the pre-cursors, exactly in the spirit of what Mae Wan Ho asserted: “a relative lack of natural selection may be the prerequisite for major evolutionary advance”. And if one thinks of it, this is actually a more forceful statement of the problem posed by irreducible complexity. But I save development of that brainstorm for another day…:-)
This contradiction between Fisher’s Fundamental Theorem and Darwinism has not been lost upon those I quoted above, and it has not been lost on those who research molecular evolution. In the 1960′s and 70′s, a problem emerged in trying to reconcile the existence protein polymorphisms (another word for “diversity”) and the “fact” of natural selection. Heated debates ensued, but the molecular quants like Jukes, King, and Kimura prevailed in putting forward the idea of non-Darwinian evolution for molecular evolution. See: Non-Darwinian Evolution and Neutral Theory of Molecular Evolution.
This fine tradition of “non-Darwinian” evolution has been quietly handed down and slowly extended to other domains of evolution, not just molecular. Lynch’s latest book is rich with Kimura’s math, and if one wishes to see the ID perspective on population genetics and Kimura’s math, I highly recommend Genetic Entropy by renowned Cornell geneticist John Sanford or Biotic Message by Walter ReMine.
And I close with this thought. Fisher’s Fundamental Theorem and its logical consequences cannot be properly taught in the School District of Dover Pennsylvania since Judge Jones ruled it unconstitutional to critically study the ideas of Charles Darwin. I’m grateful that the internet still provides a means for spreading the truth.
NOTES:
1. Walter ReMine has a wonderful exposition of Fisher’s fundamental theorem in his book Biotic Message. He explains Fisher’s Theorem by likening genotypes to bank accounts. Consider you have a portfolio of 2 bank accounts, one account starts with 10,000 earning 10% interest and the other starts with 10,000 at 5%.
The composite starting value of the portfolio is $20,000 with an instantaneous mean interest rate of 7.5% [ 7.5% = (10% + 5%) / 2].
However the mean interest rate of the portfolio will not be 7.5% forever, but will eventually move asymptotically toward 10% over time. The portfolio will thus become over-weighted and less diversified toward the more “fit” account bearing 10%. Fisher-Price describes the evolution toward an over-weighted portfolio.
How are interest rates related to the notion of selective fitness? This follows from Fisher’s Malthusian notion of fitness as is readily seen in this Wiki treatment Fitness
Wabs = N_after/N_before
Wabs = absolute fitness
N_after = number of individuals or money after selection
N_before = number of individuals before
For example, using the money analogy with an interest rate of 10% we can say a generational cycle is 1 year. Let
N_after = $11,000
N_before = $10,000
Wabs = 1.1 or a 10% increase
It can be see from the theorem it is a bit clumsy to actually apply it in terms of trying to analyze something like heart evolution, but I believe it is still correct, and I hope it suffices to at least get the discussion of these issues going.
2. I provided my take on Massimo Pigliucci’s review of Michael Lynch’s book in Michael Lynch: Darwinism is a caricature of evolutionary biology
3. To the formalists out there, I concede that reduction of diversity is formally only necessary, but not sufficient condition to assert the existence of selection since it is possible survival might be owing only to luck and not “fitness” as Raup pointed out in his book Bad Genes or Bad Luck! But Lewontin essentially pointed out (in Santa Fe Winter 2003) enforcement of this formalism would effectively discredit the concept of fitness and natural selection altogether! Kimura also shows the problem of distinguishing the effect of random walks from the effects of selection. Good luck often trumps good genes!!!!
4. A thriller movie actually W delta Z came out this year with Price’s equation as a central theme.
5. NAS member Masatoshi Nei is extending Kimura’s ideas to domains outside of molecular evolution. See: Prominent NAS member trashes neo-Darwinism
75 Responses to Fisher’s Fundamental Theorem of Natural Selection: the death sentence for Darwinism
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Haha, yeah, I suppose so (if having a PhD makes one “smarter than you”).
–Allen
nullasalus wrote (in #59):
As have I. That was one of my motivations in posting my blog on the 47 mechanisms for producing phenotypic variation. I remember my evolution professor at Cornell railing about precisely the same problem, and about the grossly mistaken notion that natural selection is the principle creative process in evolution.
Nothing could be further from the truth, of course. Natural selection produces absolutely nothing. It is an outcome, and is most emphatically not a “creative force.” The “creation” of new variation is what the “engines of variation” (the 47 different mechanisms) do, not natural selection.
The whole point to natural selection is that it preserves those variations that have the effect of allowing those individuals who have them to survive and reproduce more often than other individuals who have different variations. This is why Darwin preferred the term “natural preservation” to “natural selection”, as the latter sounded too active, as well as too “intentional.” However, he waited too long to try to change the terminology. By the time he expressed this opinion (in a letter to Charles Lyell; see http://www.darwinproject.ac.uk.....-2931.html), “natural selection” had become entrenched in the vocabulary of evolutionary theory.
On the other hand, natural selection is the explanation for why complex adaptations can evolve in surprisingly brief periods of time (e.g. 10,000 generations). Selection limits the possible range of variations in each generation to those that are closest to the forms that are already most adaptive.
Allen_MacNeill (55): “So the question really is, where does the information in the genome come from, and how much does it contribute to the actual phenotypes of organisms? How much of the “design” of an organism is provided by its environment? And can any of this be shown to be foresighted?”
Your posts are delightfully informative, as always. And these are good questions. However, there is a logical error in the following.
(15): “If, however, the processes by which variation are produced can be shown convincingly to not demonstrate foresight (i.e. that they produce characters that, when produced, are not necessarily immediately adaptive, but become so following a change in environmental conditions), then ID is unnecessary as an hypothesis for the origin and proliferation of adaptive characters in populations.”
This is assuming that all the new information comes from the engines of variation, with complexity only coming in the bottom-up fashion of being always preceded by a simpler ancestor. That might be so, but it also might not be so.
You mentioned a friend’s thought that “It’s all been downhill since the Mesozoic.” What if there is more “downhill” to evolution than even your friend supposed?
You acknowledged “Admittedly, we have a long way to go. We are only just beginning to understand how development is regulated, and the part that the environment plays in it. As we learn more about it, our models of how development and evolution are related inevitably change, to accommodate new research results.”
This leaves open the possibility of instances front-loaded development where it truly is “downhill” with the crest of a hill as a starting point. Notice that in such a scenario, it is not necessary for the engines of variation to demonstrate any “foresight” in the sense of reliably yielded immediately adapted variation. Nevertheless, the conclusion that “ID is an unnecessary hypothesis” in this scenario is false. One valid hypothesis is that the role of ID was at the point of front-loading the organism with the information, control mechanisms, and/or potential regarding development that makes the diverse variations we see possible.
In short, even though it may take no special intelligent intervention to roll downhill, employing variations that are not foresighful, that does not allow us to conclude that intelligent agency had no role, as you suggested. Rather, intelligence may be essential to getting to and starting from the top of a hill.
I agree this cannot be decided by speculation. Just wanted to point out that your list of possibilities was too short, with an important omission.
Allen_MacNeill,
In (15) (I know, this is late) you wrote a couple of paragraphs which I am still trying to decipher. In the interest of not quoting you out of context, as you warned about, (or at least trying), I will quote them in full (I see one of them was quoted by ericB in (63)).
The above apppears to be making two assumptions (among others). First, that we can study, in a given organism, the processes by which variation are produced, and that these can be identified with the processes whereby the organism itself was originally produced. The second is that if traits are somehow produced that are not adaptive at present, but become adaptive in a changed environment, this is somehow less indicative of foresight than the production of traits that are immediately adaptive.
Now perhaps I have misunderstood you, and If so I would appreciate correction. If not, the second point seems weak, and the first counterfactual.
Preadaptation seems to me to require more foresight than plain old ordinary adaptation. Adaptation can immediately be preserved and enhanced by natural selection, but preadaptation requires the preservation of traits that are not presently advantageous, and may even be presently deleterious, for some future advantage, and this foresight would seem to be a hallmark of intelligence. One could argue that if the adaptations are complex and specified enough, either one could be evidence of intelligence. But the reversal makes no sense to me. Putting a spare tire and a jack in a car takes at least as much intelligence as putting the original four tires on.
But that seems a minor quibble compared to the question that can be raised about the first assumption. What this seems to be saying is that the 47 (and counting) sources of phenotypic variation in a given organism necessarily account for all the variation needed to create it, or to modify it from some previous organism. I’m not sure that this is accurate. An example might illustrate the problem.
As you probably know, extensive attempts to take natural variations and artificially select them for the effect of a blue rose have uniformly resulted in failure. However, recently because of some careful gene insertions and manipulations, scientists have been able to produce a rose that can reasonably be described as blue, and that has no known counterpart in nature.
Now supposing that we are alien scientists exploring the earth after a disastrous epidemic has wiped out humankind, and enough time has passed so that the products of civilization (including records of what happened to make the roses blue) have disappeared, but the varieties of roses live on. Could we apply those 47+ kinds of phenotypic variation to the roses now (then) existing and explain how the rose became blue? Would we not be tempted to call it “lateral gene transfer” (meaning undirected lateral gene transfer)? And would we not be dead wrong? How could we possibly arrive at the correct answer to the origin of blue roses without allowing for the possibility of intelligent design?
Furthermore, imagine an island where blue roses were planted and survived because there were few natural enemies. We might observe the roses exhibiting many variants, and identify experimentally confirmable sources of variation until we were blue in the face, and still not be able to identify the correct reason why these roses differed from the vast majority of those on the mainland.
Part of the problem would seem to stem (ahem) from the assumption that all causes that have ever operated are now operating roughly equally to how they operated in the past. For intelligent agents, that may not be a valid assumption. Intelligent agents may very well create episodically, and they are not required to create when we want them to so that we can see how it is done.
I don’t see how your proposed way of determining whether ID is involved in present-day biology is either sensitive or specific. Perhaps you can clarify.
Gentleman,
This is wonderful discussion. I was en-route 16 hours yesterday, and it is good to be on my laptop again for a few minutes.
I see that DaveScot has posted a link to the paper by Lewontin which I mentioned in my original posting. I thank him for finding the paper in the first place since I could not longer find it on the net.
Lewontin’s paper was highly influential to Stanley Salthe and myself. It is technical, but wow, I learned so much from it. Lewontin was Gould’s colleague and also (along with Gould) a mentor to creationist Kurt Wise. When I asked Wise about Lewontin last year at Baraminology 2007, Wise spoke glowingly of Lewontin. It is easy to see why, when reading this paper…
Salthe considered this paper fatal to Darwinian evolution becuase it showed the difficulty of defining fitness.
Scroll to page 19:
http://tinyurl.com/4sjthv
To simplify:
In Physics the notion of force is measured in Newtons or Pounds. We can measure mass by the amount of pounds of force a gravitational field creates on object. The typical measuring device is a scale. I can even compare apples and oranges using a scale.
In math, if objects A and B and C have real values, we can say:
if A > B, and B > C, then A > C
( to put hard numbers, for example, consider A = 10, B =8, C = 5)
This is the Transitive Property of Inequality. In this manner we have a means of even comparing apples and oranges.
We can objectively say, one object has more mass than another. We cannot say the same about biological organisms with respect to fitness.
Lewontin demonstrated the difficulty of making such objective statements in defining fitness. For example, in sports competition we can’t make the following statement with certainty.
If team A beat team B, and if team B beat team C, then team A will beat team C.
Lewontin shows this difficulty with respect to the competition among varities, along with some very distressing situations where the defintion fitness varies radically with context. Thus Lewontin showed the difficulty in showing that fitness is anything more than a restatement of known statistics, and not a very good restatement at that.
If fitness cannot obey the transitive properties of inequality (which is so fundamental to properties in physics and chemistry, or practically any other scientific discipline except Darwinian evolution), trying to use this concept to make statements about the evolution of complexity become essentially incoherent.
We can compare apples and oranges in terms of their weight. Can we do so in terms of fitness? That’s the problem.
At best we can say the statistics may be evolve in a way analogous to a Darwinian model, or it may not. If things can evolve in a manner that is non-Darwinian, then the question is how much evolution is Darwinian, how much is non-Darwinian. I have suggested based on the channel capacity problem and Haldane’s dilemma, that even if fitness could be defined (which as Lewontin showed is a hopless quest in general), only about 2 bits ber 300 generation could be attributable to Darwinian evoltuion. That correlates to less than .1% of the human genome. The rest of the evolutionary story, 99.9% is non-Darwinian. That figure is already roughly accepted for molecular evolution (Kimura and friends). The question then is why shouldn’t that figure apply to just about everything else (which is Nei’s thesis).
I have suggested that Fisher’s theorem implies that selection actually has to be substantially relaxed to account for diversification, which will permit the evolution of complexity. The euphamism used by some to say this is “time-varying fitness landscapes”.
So, on many accounts, independent of ID, I don’t think the overwhelming majority of evolution can be Darwinian. Lynch’s irritation is so great, he practicallly faults Dawkins and Dennent (as well as ID folks) for making evolution a caricature by ascribing so much power to selection.
There are other naturalistic models for evolution that are non-Darwinian:
1. Brain Goodmans evolution via cooperation (rather than competition)
2. Saltationism, mutationism
3. neutral theory
Of course I have my ideas. My personal challenge is that it is hard to frame the answer in terms of direct empirical science. If God were readily apparent, I’d have an easier time arguing for special creation. ID on the other hand is at the doorstep of empirical science, but it is unfortunately still only and inference, it is not a direct empirical observation in the sense of observing mass or other physical quantities. The task is complicated because information and complexity (including specified complexity) is not a physical quantity.
And this relfects well on Cornell letting the best teachers teach independent of the letters after their name. The IDEA club there spoke highly of you and it is easy to see why. I think I would have very much enjoyed taking the classes you taught.
And from my perspective, your Evolution and Design class at Cornell where the Bill Dembski and Michael Behe’s works were studied critically was the best course of its kind anywhere.
scordova, (65)
I did what you suggested and scrolled to what was labeled page 19 of
http://tinyurl.com/4sjthv
and was unable to see how page 19 or the immediately surrounding pages demonstrated the difficulty of defining fitness. Could you please check the reference here and/or explain how the printed material makes your point.
Thanks
Dr. Giem,
My apologies for a bit of confusion. Lewontin’s essay begins on page 19, but his section on fitness begins on page 23.
On page 24:
In Fisher’s formulation fitness is growth rate. Thus bacteria are more fit than humans. Lewontin points out that these sort of notions are in conflict with Darwin’s notion of some sort of inherent biological property of what is “good”.
For example, in sheer numbers, the mammalian eye would be less fit than the insect type eye(s). This is problematic for explaining the evolution of the mammalian eye in terms of fitness scores. This problem I think is pervasive….How can we explaing eukaryotes if prokaryotes are more “fit”?
Lewontin wasn’t the easiest read, but each time I have re-read it I gain something more.
“It simply affirms that types
change in frequency.”
What causes these frequency changes?
scordova, (68)
I found out what I was doing wrong. The article you cite is found between pages 16 and 17, if you look at the bottom of the pages. My browser doesn’t give me precise PDF pages; instead I have to scroll down using the pages listed on the PDF. That of course threw me off.
It is quite a delightful article.
Jerry,
I recommend the examples in the article itself.
Frequency change can be due to:
1. Random Drift
2. Bad luck
3. Intitial density of population
4. Mix of population
Problematic is defining “fit” in the most general sense as we define mass or force or temperature in physics or even moles in chemistry. If one cannot do this, one has to question the difficulty of putting selectionist theories on par with the other sciences. I think the neutralist theories are at least framed in a way that puts them on a more sound footing scientifically (I say that as one who actually rejects mainstream neutral theory).
With respect to anti-biotic and pesticide resistance. The way we are able to argue for the presence of selection is repeated trials. If for example, one trait is observed in 100 petri dishes where anti-biotic resistence occurs and no resistance occurs in 100 petri dishes where the trait is absent, we can say a selectionist metaphor is applicable. In the absence of such repeated trials, how is it possible even in principle to argue selection was the cause or not. The only way I know how is to argue “not” through issues with population resources, as Kimura did using Haldane’s dilemma.
However form Fisher’s fundamental theorem alone, it’s kind of hard to argue eukaryotic evolution from prokaryotes since, in terms of Matlthusian reproductive fitness, prokaryotes seem more “fit”.
One might argue the exitence of allopatric (geographic) or sympatric niches to enable selection to work in selected isolated domains, but this seems like a special pleading. In such case, Goodman’s cooperative (versus competition) model would seem more accurate. i.e. a species develops ability to digest a different food source, thus it becomes sympatrically isolated without competing with the parent. The populations then live cooperatively together. This would accord well with symbotic and ecosystem evolution. I think Goodman is closer to the truth, but I say that as someone who personally disagrees with Goodman.
PS
by the way, I keep forgetting to list “self-organization” as a naturalistic theory. I consider that the main competitor to ID theories. I think Pigluicci of late is quite enamored with self-organization. So is Denton….
Especially problematic is the phrase “random with respect to fitness”. If fitness cannot be defined in general (except for special cases like antibiotic resistance), then how can we even say “random with respect to fitness”?
Sanford argues the difficulty with this becuase empirically speaking mutations on the whole do not seem random with respect to fitness. For example environmentally induced mutations (like radiation) seem to be statistically correlated against reproductive success, thus it is not random.
On the other hand we have adapative mutation which seem positively correlated to fitness. Ok, for another naturalistic theory, consider the work of James Shapiro (who seems privately favorable to Behe).
See Who are the Multiple Designers? James Shapiro offers some compelling answers
Thus there are observed non-Darwinian modes of evoltution, an I would argue they constitute 99% of the evolutionary modes present today and in the past.
I do believe in ID and even the more extreme hypothesis of special creation. The fundamental theorem of calculus was widely accepted as true even 300 years before it was proven. I think the case for special creation (if true) or ID might be in a similar boat. It may seem reasonable to many, but from a theoretical and empirical standpoint the proofs are not quite mature. Seeing these hypotheses put on a more solid foundation is my personal area of interest. Time will tell if ID proponents and their creationist cousins will be successful in these endeavors.
I read the Lewontin article. It is a fascination article and I am glad it was recommended. It celebrates fitness as an important variable in evolution, not discounts it.
In the examples on pages 24-26 it does not discount fitness but essentially says we do not know how to measure it. (Fitness may not be a single gene oriented concept by a gene network concept.) The examples used illustrate that varying environments and ecologies affect reproduction rates and measures the reproduction rates by variant. What can not be determined is what variables/networks determine the reproduction rates. It does not seem to be a random effect so it is variable related. So as the density of the population varies by the different species in the ecology, the reproduction rates vary by variant. What they cannot do is isolate the characteristics/networks within the species that are responsible for the varying reproduction rates when the various external variables are manipulated.
The article highlights micro evolution and why macro evolution may be impossible because the variation within the gene pool does not have the variation necessary to do anything really complex. It also defines novelty as trivial and only as changes not seen before. It is not what we usually mean by novelty.
I highly recommend that everyone read it and see if they come to the same conclusions that I did, which are different from Sal’s conclusions.
scordova: How can we measure natural selection? Without going into the deep details, we conventionally assert selection exists if there has been a reduction in diversity in a population.
So, according to the logic in the OP, how can Darwinian evolution produce diversity if by definition, natural selection decreases it?
Maybe this should be a question on “Are you smarter than a fifth grader?”
The most elementary formulation of evolution that I think anyone is familiar with always characterizes mutation and the like as the engine for producing variants, and natural selection as a culling factor. So what brilliant insight has been conveyed in the OP, or what oversight has been unveiled?
The word mutation is only mentioned once in the entire piece:
“But even granting this miracle set of mutations can happen, what role can selection possibly play?”
This is merely a passing comment in a discussion regarding the evolution of a four chambered heart, and it is that discussion I want to focus on now. The central insight of the author is that if a four-chambered heart appeared, and was superior and thus replaced through natural selection the three-chambered heart, it would be a reduction in diversity, as there would only be one type of heart (4-chambered) whereas previously there were two types.
But the logic of this utterly eludes me. From my perspective, a four-chambered heart is more diverse than a three chambered heart. It is certainly more complex, and I think ‘complex’ and ‘diverse’ or near synonyms.
From my perspective as a software engineer, an increase in fitness always entails an increase in complexity. (We’ll get to Occam’s razor in a minute.) Let’s throw a very instructive cliche into the mix here: “The devil is in the details.” Your original understanding of a problem is nearly always incomplete, so your original solution may be very neat and tidy and elegant. But as you start testing it in real world situations, you start encountering exception after exception after exception, and you have to go back and modify your original solution continuously to account for all these exceptions. This is not merely a result of bad planning – you can imagine consumer’s giving feedback, “but I want this feature or that feature”, or maybe modifications are driven by a need to keep up with competitors or new technologies. So despite Gould’s claim that evolution does not necessarily entail an increase in complexity, I would strongly disagree with that. (Do society, technology, laws, etc. get more or less complex over time?) In spite of all this it is certainly and obviously true that if you can ever take some big chunk of your software, and say, “Wait a minute, I could replace this 200 lines of code with 10.” Then by all means do it. This is apparently the brilliant insight of Occam. So complexity in an artifact is often an indication of a lack of planning and foresight.
By the end of this thread, Scordova is arguing that fitness is not even a meaningful concept:
So is scordova or Lewontin claiming that the concept of fitness among football teams is meaningless because the transitive property does not hold there (e.g. If team A beat team B, and if team B beat team C, then team A will beat team C. )
Certainly I don’t think Lewontin believes this (or other thoughts scordova credits to him) as I think the football analogy is scordova’s. But let’s examine the analogy for a minute.
If team A beat team B, and if team B beat team C, then it most certainly increases the probability that team A will beat team C (if that’s all you know about the teams).
If through tradition Michigan has Cincinnati on their schedule every year, and beats them nearly every year and Cincinnati plays East Toledo State every year and beats them nearly every year, then certainly it is highly probable that if Michigan played East Toledo State, Michigan would beat them. Maybe some think these observations are too simplistic for this forum or thread, but apparently they elude scordova.
But to continue with the sports analogy, Highly successful programs end up with teams from around the league snatching up all their assistant coaches and thus the strategies, schemes and plans of successful teams are disseminated around the league and persist for decades, long after these schemes are effective (e.g. “The West Coast Offense”). However The fact that fitness is certainly a meaningful concept in football does not imply that there is not also random genetic drift. You can have some obscure conference that for no apparent reason gets hot one year send a few teams to bowls, and then immediately descends back into obscurity. (Perhaps there’s a better analogy for genetic drift specifically, however.)
Here was the transitivity problem in Lewontin’s words:
In experiments involving competition of several genotypes taken two at a time, Dobhzansky (1948) showed lack of transitivity in fitness. That is, genotype A is more fit than genotype B in an experiment involving only these two genotypes, and B is more fit than C in two-way competition, but in three way competition C beats A.
But does this imply that fitness is a vacuous concept (Or does Lewontin think that – I don’t think so.)
In basketball, height is a huge advantage. In a one-on-one competition, even more so. But with five players on each side, throw an extremely quick but very short guard into the mix, and suddenly his height is not a factor. Does this make meaningless the concept of tallness or fitness? Hardly.
(And for the record, in response to a remark made by someone recently in another thread, I am one of those people that still believes the story of Noah’s ark is literally true.)
[...] Fisher’s analysis of the effect of gambler’s ruin essentially trashes his own theorem, Fisher’s Fundamental Theorem of Natural Selection. Fisher’s Malthusian notions of “fitness” in his fundamental theorem do not [...]