Evolving Thoughts

For every philosopher

Cicero-absurd.jpgIt’s an old joke: the one rigid and true law of economics is “For every economist, there is an equal and opposite economist”. But the joke was anticipated by Cicero back in the Roman times: “”There is nothing so absurd but some philosopher has said it.”[1] I would like to recast this as:

For every philosopher, there is an infinite number of equal and opposite philosophers.

Fortunately, the vast majority (an infinite number) of these absurd philosophers are merely potential or possible philosophers. We don’t need to debate every one of them, or take all their views to heart when arguing for our own views, so long as we do take to heart those that are actual and plausible. Even that is a hard task to undertake…

1. De Divinatione 58:119

Humor Philosophy Truisms

Related Posts

Evolution

On the origins of creativity

I’m not a very creative guy. I had an idea back in the 1970s, but I managed not to do anything about it in time for someone else to do something with an almost identical idea. I think I dodged a bullet: once you come up with one great idea,…

Read More
Epistemology

Evolution and truth

[Reposted from my first blog. I’m avoiding writing anything useful.] One of the problems in having a philosophy related blog is that ideas are hard things to generate on demand, so often you need someone to raise the problems for you to think about. Being naturally (and preternaturally!) lazy, I…

Read More

Comments (57)

  1. There is in fact a whole line of philosophers that have generally been ignored by mainstream biologists for decades. I am referring to those philosophers (and working biologists) who have raised the tautology argument against natural selection. Some attempts have been made by Gould and a few others to address these concerns, but the responses are, frankly, implausible. See the Stanford Encyclopedia of Philosophy’s entry on Adaptationism, in which Orzack and Sober, two working biologists, describe how they found after an extensive literature review only four papers that adequately present an adaptationist argument. Four papers in over 100 years. And this assumes, charitably, that we can in fact make coherent predictions about fitness that don’t simply look tautologically to reproduction rates to determine “fitness.”

    Gould’s responses are even more lackluster, in his 1976 response to Bethell’s paper and in his 2002 book The Structure of Evolutionary Theory, in which he essentially dismisses the tautology argument with a wave of the hand.

    Wilkins addressed the tautology argument in a number of blog posts, but the solution he came up with was, again, implausible because it relied on extraneous features that perform no function.

    This is a major major problem for natural selection as the primary agent of evolution and it really needs to be addressed.

    1. And this assumes, charitably, that we can in fact make coherent predictions about fitness that don’t simply look tautologically to reproduction rates to determine “fitness.”

      Philosophers who proclaim that the usual descriptions of natural selection are tautologous are a bit like mathematicians who look at a computer program containing the line “X = X + 1” and proclaim that this is contradictory.

      The error in both cases is mistaking a dynamic description for a static one. The X on one side of the equal sign is not the same thing as the X on the other side. The program says (in a non-contradictory way) how they are related. The reproduction rate (fitness) in one generation is not the same thing as the reproduction rate in the next generation. The theory of NS says (non-tautologically) how they are related.

      2. “Philosophers who proclaim that the usual descriptions of natural selection are tautologous are a bit like mathematicians who look at a computer program containing the line “X = X + 1? and proclaim that this is contradictory.”

        Mathematicians probably wouldn’t know the etymology. In early programming languages I think that “x=x+1” (or “x++” for that matter) would have been “set x equal to x+1”

        PR

        Poor Richard’s Almanack 2010

    1. Posky, both your examples are inaccurate. No mathematician would wrote x = x + 1. They would write y = x + 1. Your example is indeed contradictory b/c the first rule of logic is that x cannot be not-x at the same time, and x + 1 is indeed not-x.

      As for NS being tautological, it’s not “just” philosophers (those pesky folks who demand that reason actually prevail in science) who have made this claim; it’s also many august biologists such as T. H. Morgan and C. H. Waddington, as Tom Bethell describes in his 1976 article:

      http://www.stanford.edu/~joelv/teaching/167/Bethell%2076%20-%20Darwin's%20mistake.pdf

      There are generally two responses to the tautology argument: 1) Gould’s response: we can determine “a priori,” based on bioengineering principles, what fitness is, and then test such predictions (this is also described by some as the “propensity interpretation” of fitness); 2) ignoring the problem.

      The problem with the Gould/propensity approach is that it’s been incredibly bad as a predictive theory, as Orzack and Forber write about in the SEP entry on adaptationism.

      So we are left with either: 1) a very bad theory that has almost no empirical post hoc support and makes really inaccurate predictions, or; 2) a logically empty theory that can’t, by definition, tell us anything about the natural world.

      This is not a good situation to be in for the key theory of evolution.

      2. Yeah, and besides, nobody writes “x=x+1”, they just write “x++”. Did someone hear a whooshing sound just now?

      3. I’d normally write “INC A” but not because of my mathematical training.

      4. A population of bacteria is exposed to an antibiotic. The only survivors are those who are to some degree resistant, and the next generation consists solely of their descendants (or replicants).

        Another bacterial population is raised on artificial media. At some point a mutation occurs which enables one bacterium to metabolize a nutrient present in the media which its predecessors could not. It grows and reproduces more rapidly than the rest and becomes the dominant strain.

        Due to a mutation, a human youth is born with blue eyes. Many members of the opposite sex find this trait attractive, mating opportunities abound, and within a few generations this trait becomes widespread.

        Perhaps I’m missing the point, but I don’t see anything problematic in any of these scenarios.

      5. Bad Jim, let’s look at your first example.

        A population of bacteria exposed to an antibiotic. Obviously what you describe occurs (or antibiotics wouldn’t work and bacteria wouldn’t develop resistance to antibiotics), but the problem arises in saying “natural selection led to the new resistance.” This is a problem b/c the statement is empty. All it’s saying is that a new resistance arose and including the phrase “natural selection” serves no purpose. It’s saying “A = A,” the essence of tautology. When one absorbs this feature of the language of natural selection one can use it to parse any description of natural selection similarly and we realize that any way natural selection is described descends into meaningless statements of A = A = A = A.

        Here’s a recent example from an essay by Francisco Ayala: “Natural selection – i.e. differential multiplication – can accomplish adaptation because a favorable mutation that has occurred in one individual may thus spread to the whole species in a few generations…” Let’s parse this sentence. “Natural selection,” “differential multiplication,” “favorable,” “adaptation,” “may thus spread,” are all ways of saying exactly the same thing: more offspring are produced in some situations. Even more simply, all these phrases say, essentially: there is some biological change occurring. Ayala’s sentence says A = A = A = A = A. It is, thus, true but unhelpful as a theory of evolution.

        To be a theory of evolution, it must say something about WHY, in general terms, certain genotypes and phenotypes spread. And natural selection is certainly not that theory.

        Fodor and Piatelli-Palmerini make the case that natural selection should be called “natural history” because all it consists of is a series of case studies about particular instances. And if this is the case there is no general theory of natural selection there is “only” natural history. I put only in quotes b/c this may in fact be the best we can hope for. We may never have a general theory of evolution, but, instead, a series of detailed case studies. And that’s probably ok. But we shouldn’t pretend that natural selection is a general theory of evolution when it’s not. We should acknowledge that it’s a logically empty phrase and instead adopt a different term such as natural history or “natural evolution,” to distinguish it from theistic or other approaches to the evolution of life.

        Your second example is essentially the same as your first, as is your third, in terms of my response.

        To wrap up, some biologists have said it’s expecting too much to have natural selection be a predictive theory. I would hope most biologists would expect more of the crown jewel of their field. And if this is the case, let’s not just sweep these issues under the rug. Let’s address them head on and find a better approach that either is predictive (at least more predictive than our current theories) or acknowledges that biology is simply too complex to have predictive theories beyond very controlled circumstances like those in a petri dish.

      7. No mathematician would wrote x = x + 1. They would write y = x + 1. Your example is indeed contradictory b/c the first rule of logic is that x cannot be not-x at the same time, and x + 1 is indeed not-x.

        I think the mathematical notation would be x_(t + 1) = x_t + 1

        The x_t and x_(t+1) are not the same thing; just as taking the means of parent and offspring generations is not estimating the same value twice, but two different values.

        Genetics gives us a distribution of the relations between x_t and x_(t+1). Natural selection is a particular model for those relations, given that the components in x_t meet certain conditions.

        The extrapolation from x_t to x_(t+i) is a matter of mathematics, based on the relation between x_t and x_(t+1). Like any extrapolation, its relation to real examples depends on certain assumptions.

        How any of this is a tautology is lost on me.

    2. J. J. Please see my response to that post. I hope you’ve read Fodor’s book and not simply given in to the agenda-driven dismissals of the book. I don’t agree with everything they write, but they raise some very powerful points. Their “intensionality” argument (not to be confused with “intentionality”) is a more generalized, but thus more obscure, framing of the tautology argument.

      I think they did themselves a disservice by poorly explaining some of their key arguments. Nevertheless, the book is a powerful indictment of many crucial concepts in today’s evolutionary biology.

      1. You don’t think biologists can predict which phenotypes will be more fit in a give environment – is this your concern?
        It is pretty easy to show that observed fitness is not equal to expected fitness for a given individual, but on average those individuals with the higher expected fitness have higher observed fitness. What happens to any given individual can be very different than what happens to a population.
        You might want to look at the work over the past 30 years by David Reznick and his colleagues on guppies in Trinidad.

      2. Michael, there are some limited cases where predictions have been borne out, but see the SEP entry on Adaptationism where Orzack and Forber conclude after an extensive literature review that literally only four papers meet their criteria for an adequate adaptationist case study.

        You write that “on average those individuals with higher expected fitness have higher observed fitness.” Can you send me some citations? I think the reality is actually very limited to no success in making predictions about expected fitness (based on observed reproduction rates to confirm such predictions), but I’m always open to new data so please send it along if you have it.

  3. I’ve always liked,
    “If all the economists in the world were laid end to end, they wouldn’t reach any conclusion.”
    George Bernard Shaw

  4. Johannes Vilcinsonus scripsit*:

    We don’t need to debate every one of them [absurd philosophers], or take all their views to heart when arguing for our own views, so long as we do take to heart those that are actual and plausible.

    Who is “we”? For the “we” that is working scientists, naturalists etc., “we” can manage without any explicit philosophy, just getting on with the job, staring up telescopes, down microscopes. and along other tropes.

    Whether “we” should though… is that a moral(ly) philosophical argument?

    1. Thank you for telling me what my Latin name is; but couldn’t it be something simpler?

  5. Re selection as tautology:

    Fitness of some character value is a predictive measure, reproductive success (or failure) the outcome that tests the prediction. [At least to this layperson.]

    Biology need not use philosophical methodology in a philosophically consistent way (though biology might benefit if it did; depends). It’s sufficient if they use it in a biologically consistent way (which is done; e.g., bad Jim’s examples). Same goes for math and computer programming.

    Funny (?) aside: I usually read quietly, but when I got to the word “tautology” in Tam Hunt’s comment, I said “oh no” and got up to fix myself some coffee.

      1. John, have you sipped the latte yet? I’m still waiting for a substantive response to the essay I sent you and my comments above 🙂

      2. So, when do you reach for your Scotch? When for your beer? 🙂

        Sorry for my long and technicalicious gibberish below. I blame it on life-long schooling in German sentence construction and insufficient exposure to philosophy of biology.

    2. Ben, if you argue, as you do, that we can make predictions about “fitness,” thus following the Gould/propensity interpretation of fitness, I’d ask you to review the literature and see how good such predictions have been. As Orzack and Forber write in their SEP article on adaptationism, such predictions have been incredibly bad. So, as I write above, we either have a very very bad predictive theory of a logically empty theory.

      Orzack and Forber have argued for many years now for an Adaptationism Project, akin to the Human Genome Project, to put some flesh on the very skinny bones of natural selection as the key agent of evolution. They’ve failed to gain funding for such an effort or arouse much interest in the idea more generally. Thus the problem remains.

      I think, being fair (and as someone trained in evolutionary biology during my undergrad years, for what that’s worth, as well as being an avid reader of biology for decades), that the best way we can say of natural selection is that it is a speculative hypothesis that remains in limbo as an actual theory until a whole crapload more work is done to flesh it out.

      2. Part of the problem is reconstructing historical causation – why does organism x have trait y? Many biologists are using comparative methods as an approach (see for instance Brooks and McLennan Phylogeny, Ecology and Behavior chapter 5 or more mathematical approaches by Ted Garland and Emilia Martins come to mind).
        The experimental approach more easily shows natural selection occurring and many of these studies have been repeated in the lab and field. I find it surprising that Orzack and Forber cite none of these studies. I get the feeling Orzack hasn’t looked at the literature since he wrote his paper with Sober almost 20 years ago. Not even a cite of Endler’s Natural Selection in the Wild from 1986. Take a look at the 30 years David Reznick has worked on guppies, the work of Hopi Hoekstra on mice, Peter and Rosemary Grant just to name a very few.
        I think you are selling biologists way short.

      3. Thanks, and sorry for the late reply.

        To clarify (perchance to confuse?): I wasn’t meaning “predictions about ‘fitness'” so much as predictions about the reproductive success of some organismic feature observed in the experiment. In my view [again, lay perspective], talking about the fitness of some character value is like establishing a measure for the success/failure of the experiment, based on past experience (including past reproductive success, but not exclusively so). Once the hypothesis is safely stated (“on average, the population mean for character x will shift [or will have shifted] from value x_i to x_j, iff we made the right assumptions about what constitutes fitness for the period of observation”), you can test it. The test may well fail to support your assumptions about what constitutes suitable character values.* Then your predictive measure was off. [That at least was what I meant with “predictive measure” above.] Fitness provides a measure for observing historical changes; it does not constitute the objects of the changes themselves (those would be the organisms, and their group’s statistical properties).

        *Failing may be due to misjudging the character and its evolutionary relevance entirely (perhaps because it is extremely useful taxonomically), or to misjudging the selective advantage of a particular subset of the character value range. I think “adaptation arguments” are more precisely about the latter, and I wonder whether the tautology only applies to the former types of statement.

        Again, all of the above goes with the disclaimer that IANAPOB. (I am not a philosopher of biology, just a measly music historian interested in the history of biology.) Cheers.

      4. Thanks for the leads Michael, I’ll follow up on these. And please send more if you have them. But see my response to Poor Richard below for a generalized response that I think is fair given the current state of evolutionary biology.

      5. Ben, you are right in your suggested approach. The problem is that I believe, based on what I have surveyed of the literature thus far, that such predictions about fitness (the propensity interpretation of fitness, as opposed to observed fitness in terms of reproduction) have been very inaccurate. So this suggests that even if we accept the logical validity of the theory, the empirical foundation of the theory is currently on quick sand.

        Michael Fugate disputes this idea and I’m following up on his suggestions now to see if Orzack and Sober are unfair in their conclusions about the paucity of valid selectionist/adaptationist demonstrations for particular populations (they conclude that only four papers in the last 150 years meet their criteria, as they write in the SEP entry on Adaptationism).

  6. When I hear the word ‘tautology’ in any discussion of Darwin’s theory, I am reminded of the poverty of operationalism.

      1. Poor Richard – See the SEP entry on operationalism at
        http://plato.stanford.edu/entries/operationalism/
        for a more critical discussion than you find at Wikipedia.
        Claims about the tautologous character of the concept ‘fitness’ concern the semantic properties (“meaning”, if you prefer) of the concept. In this context, it’s the common equation of fitness with reproductive success that generates problems. It’s the semantic version of operationalism that I think is impoverished, not the perfectly legitimate methodology of “operationalizing” terms/parameters of models on which experimental science depends.

  7. Tam wrote: “To be a theory of evolution, it must say something about WHY, in general terms, certain genotypes and phenotypes spread. And natural selection is certainly not that theory. “

    Are you suggesting that variation is neutral as to fitness or competitive advantage or that the correlation is unexplained ?

    PR

    Poor Richard’s Almanack 2010

    1. Poor Richard, I’m saying that “fitness” and “survival [with implied reproduction]” are either the same thing (thus tautological) OR that our Gouldian “a priori” notions of fitness are so bad that the predictions of the theory are very very bad.

      The Gould/propensity interpretation, which argues that there are a priori bioengineering principles that we can deduce in localized circumstances with respect to particular species and, presumably, individuals, is perhaps the only way out of the trap. But as I’ve written elsewhere in this thread, the predictions made thus far under this approach have been very bad so we have little confidence in this approach at this time. Michael Fugate has suggested some additional avenues for investigation, which I will look into soon, but I think we can make some broad valid conclusions at this point:

      1) We have very little evidence accumulated over the last 150 years for the validity of the non-tautological framing of natural selection as the key agent in evolution.
      2) We should try to gather vastly more evidence from case studies of particular species and populations, but this becomes “natural history” instead of “natural selection” because it is highly unlikely that any generalized bioengineering principles will reveal themselves in this inquiry.
      3) This is the case because we may think we know what constitutes “fitness” for a given population, in terms of phenotypic change, but given that there are umpteen factors at work in every situation we will find, upon testing of our hypotheses, that we are extremely bad at figuring out what does in fact lead to greater reproduction in a given population.
      4) More generally, when we think it through, we realize that the so-called a priori bioengineering principles that are nothing more than an amorphous set of ideas at this point will almost surely be very mammal-centric and anthropocentric, at least at first, which surely can’t qualify as general principles of natural selection.
      5) But here’s the heart of the problem: consider the morphospaces available to organisms: they are literally infinite. We have a very finite number of actual morphs on our planet, but to create a general theory of biology that rests, as Gould argues, on a priori bioengineering principles (such as “faster is better,” or “”bigger is better,” or what have you) requires that we have far more knowledge about the possible morpospaces of the species that occur on our planet.
      6) In sum, it seems clear that NS is either logically empty or a highly provisional hypothesis about why species change. The phrase “natural selection” means literally nothing in itself. If there is any hope for the theory, it will be the a priori bioengineering principles that form the meat of the theory, not the empty phrase “natural selection.”

      1. I would endorse some version of the propensity interpretation of ‘fitness’. In other words, fitness is a function (in the mathematical sense) of adaptive capacities to survive and reproduce. The degree to which these capacities are realized by an individual is determined by the environmental circumstances encountered in the course of the indiviudal’s existence. I don’t think it likely that there is a unique function that covers all the contingencies of all the environmental interactions of all the organisms that will ever exist. But nor do I think the theoretical value of the concept of fitness depends on there being such a universal function.

      2. bob koepp, if NS is to be a general theory (and not simply “natural history”) my points 1-6 above apply in full force to your comment. If you retreat to the position that NS shouldn’t have to be a general theory, it seems that it again becomes “merely” natural history and is thus not a theory at all, but a series of case studies that are interesting and illuminating in each instance, but do not collectively constitute a theory of anything.

      3. Tam – I’m not sure what you want in the way of a “general theory.” It’s obvious that natural selective processes are not the only factors in evolution — there’s also (at least) drift. And that’s enough to counter your claim that “saying “natural selection led to observed phenotypic change X” is an empty statement. It tells us nothing other than saying “observed phenotypic change X happened.” ” Among other things, it tells us that drift was not the cause of the change in question.

        If, on the other hand, your complaint is that many purported selectionist “explanations” are no more than just so stories, I agree. Many selectionist stories are no more than plausible conjectures about how things might have happened. The plausibility often rests on rough and ready ideas about what Gould referred to as “engineering principles.” But don’t burden him with the absurd notion that these engineering principles are arrived at a priori.

      4. Bob, I’m aware that practically all biologists also acknowledge genetic drift as an agent of evolution. And see Jablonka and Lamb’s Evolution in Four Dimensions or Fodor and P-P’s What Darwin Got Wrong for rather long lists of other possible agents of evolution.

        But my point is stronger than that: I’m saying that the statement “natural selection cause x” is not saying anything at all. It’s equivalent to saying simply that the change x has been observed. It tells us nothing about the how or why. We need the “a priori” engineering principles to be fleshed out way way beyond what we have today in order to have a theory of natural selection as an agent of evolution (the “how” and the “why”). And I’ve been putting “a priori” in quotes b/c Gould actually used this phrase in his 1976 rebuttal to Tom Bethell’s essay on the tautology argument. Here’s the link:

        http://www.stephenjaygould.org/library/gould_tautology.html

        I agree with you that Gould’s suggestion is absurd – how on earth could we know a priori what such principles are? I don’t think he really meant a priori, but, rather, that we could discover such principles through assiduous investigation of each situation.

        But then we’re back to my assertion that this set of principles, necessarily particularized to each population, becomes “natural history” and not a general theory of evolution by natural selection.

        And we may have to simply accept that. A small ray of light presents itself with the possibility that an Adaptationism Project (which Orzack and Forber call for) could flesh out these principles to the point that we could make some general conclusions about various types of phenotypic changes in relation to differential reproduction. And that may eventually be deserving of being called a theory of evolution by natural selection. But if this is even possible, it’s many decades away.

      5. Tam – Despite my pointing out that saying a thing evolved by natural section rules out alternative evolutionary processes, you persist in your claim that citing natural selection as a cause of x is “equivalent to saying simply that the change x has been observed.” Do you also claim that saying drift caused x is equivalent to saying simply that x has been observed? If so, do you accept the inference that natural selection is equivalent to drift? If not, what’s the relevant difference that makes drift an informative concept while the concept of natural selection is claimed to be empty?
        I’m still not clear about what sort of general theory you want. John Wilkins has mentioned the view that the idea of natural selection provides a schema which gets filled in on a case by case basis to provide explantations for a variety of phenomena. In other words, the “theory” of natural selection is a family of models of selective processes. What more in the way of theory is needed?

        1. If he’s taking the FAPP line, he wants a theory that specifies exactly what entities evolve, down to the physical specifications, and a predictive model that allows us to assert what the future will be like, down to the actual organisms and parts that will exist. In short, he wants a theory that doesn’t exist for any special science.

  8. Is the alleged problem merely that selection is not teleological?

    the problem arises in saying “natural selection led to the new resistance

    Well, yeah. Natural selection is not the hand or mind of god, it’s a description of the result of a long chain of circumstance. If there hadn’t been any resistance in the existing bacterial population, there wouldn’t have been any survivors.

    Selection is the market’s verdict, not the author of the work in question.

    1. That seems to be the Fodorian objection: there’s no intentionality. Of course, if you think intentionality itself is a phantom, then that objection evaporates.

      1. John, are you sure you mean “intentionality” and not “intensionality”? These are very different terms and Fodor focuses on the latter and explicitly disavows any role for intentionality in evolution (see the very last sentence of their book).

        1. No, I meant intentionality. They seem to want the principle of natural selection to be about the world in ways that the principle should specify ahead of time. I think this is a statement about a general theory, not the principle, and that their requirements for a theory are too strict. Their final sentence merely suggests that they do not think the theory of NS provides intentionality because it is not intensional; that is, because it has no inherent definitional content (or, as they say on page 155, nomological content) it cannot provide an intentional context. They may be right about that; my view is that doesn’t matter, because no formal theory does this, contrary to what FAPP assert. All theories require interpretations, in the mathematical sense of something like “Let x be the thing or process Y”. Once you do that, the rest follows fine; it’s just a schematic for an explanation that we fill out in every case with an interpretation.

    2. Bad Jim, I’m not arguing anything about teleology here. I’m arguing, rather, that saying “natural selection led to observed phenotypic change X” is an empty statement. It tells us nothing other than saying “observed phenotypic change X happened.” We need to understand WHY changes happened if we are to have a general theory of evolution. And at this point all we are saying when we say that NS caused something is that we are assuming there is a natural explanation and not a supernatural explanation. This may be helpful, but it’s not deserving of being called a theory.

      1. Tam wrote: I’m arguing, rather, that saying “natural selection led to observed phenotypic change X” is an empty statement. It tells us nothing other than saying “observed phenotypic change X happened.”

        As a layman the nuance of your objection may just be lost on me, but rather than NS saying “change X happened” for no apparent reason, I thought NS says the environment reinforces variations positively or negatively by things like predation and the amount of food, moisture, light, etc. available in a given habitat. If the fox catches the rabbit, the fox (aka nature) has selected the rabbit–albeit negatively.

        What is tautological about that?

        Poor Richard’s Almanack 2010

    3. bad Jim, please see my reply to bob koepp directly above. I’m not suggesting we need any teleological influence. Rather, I’m saying that the statement “natural selection led to x” is not saying anything at all. In other words, it gives us exactly zero insight into the how or why change x came about.

      To focus on your example of bacterial antibiotic resistance, we can certainly say that some of the bacterial population survived the antibiotic deluge. And we can make some hypotheses that are testable as to how and why the various bacteria survived, which would require, if we chose to dig deeply, a number of biochemical and molecular analyses. But saying, in general terms, that “natural selection” led to the survival and thus selection of some of the bacteria tells us nothing in itself. It requires the much deeper analysis of the particular circumstances of the bacteria and the antibiotic to figure out the hows and whys.

      And when we do this over and over, we will have many detailed case studies that may eventually be deserving of being called a theory of natural selection. But we’re decades from that point now.

      The problem becomes more apparent when we change your example a bit and try to make predictions about which bacteria are likely to survive the antibiotics and how many offspring are likely to result from those survivors.

  9. Tam Hunt, nobody says “natural selection led to X”. You’re missing the point. Natural selection is simply the result of the differential reproductive success of various phenotypes in various environments.

    When you say “We need to understand WHY changes happened” you are, as far as I can tell, thinking teleologically, trying to discern an underlying purpose, or at least a general principle driving evolution. There doesn’t seem to be anything like that. Phenotypes change as the result of mutations, any given environment favors certain phenotypes over others, and environments change, sometimes abruptly.

    1. bad Jim, please see my latest reply to bob koepp above. I’m not suggesting we need any teleological influence. Rather, I’m saying that the statement “natural selection led to x” is not saying anything at all. In other words, it gives us exactly zero insight into the how or why change x came about.

      To focus on your example of bacterial antibiotic resistance, we can certainly say that some of the bacterial population survived the antibiotic deluge. And we can make some hypotheses that are testable as to how and why the various bacteria survived, which would require, if we chose to dig deeply, a number of biochemical and molecular analyses. But saying, in general terms, that “natural selection” led to the survival and thus selection of some of the bacteria tells us nothing in itself. It requires the much deeper analysis of the particular circumstances of the bacteria and the antibiotic to figure out the hows and whys.

      And when we do this over and over, we will have many detailed case studies that may eventually be deserving of being called a theory of natural selection. But we’re decades from that point now.

      The problem becomes more apparent when we change your example a bit and try to make predictions about which bacteria are likely to survive the antibiotics and how many offspring are likely to result from those survivors.

  10. Tam Hunt, your replies fall short of passing a Turing test. Why, after I stated «nobody says “natural selection led to X”», do you write «Rather, I’m saying that the statement “natural selection led to x” is not saying anything at all.»? It’s like talking to a wall.

    In the hope that any remaining readers are not robots, I’ll make one last comment.

    It would be hard to predict the future of a colony of bacteria without foreknowledge of the introduction of antibiotics, of the future of dinosaurs without foreknowledge of an incoming asteroid, of the future complexion of northern Europeans before the innovations of blond hair and blue eyes. (Why wasn’t the reaction Ick! Albinos!?)

    Selection is an accounting of the result of the interaction between live things and their environment. It enables prediction under certain restricted circumstances and provides a general explanation for the remainder of phenomena. It’s quite a bit like gravity, which describes precisely the orbits of the assorted detritus in the vicinity of the sun, and explains to some degree the aggregations of dust and gas that became the sun and the planets, the Kuiper belt and the Oort cloud, but concedes much of the particularity to chance.

    1. bad Jim, I’m still getting the hang of this particular forum’s posting methodology so my last response to you was actually posted further above and then re-posted below.

      So a few more responsive points: 1) Almost all biologists I know would indeed say “natural selection led to x.” They don’t mean by this that there is a force or an agent that reaches in and effects the change. Rather, they mean that the theory explains the observed change. So “natural selection” is a theoretical explanatory construct. And what I’m saying is that in its current form, it is NOT an adequate explanation of anything. Rather, we need particularized case studies to explain the observed changes in each situation – which may allow some predictions of expected reproductive differentials for those populations and species we know a lot about (which is essentially what you say above, so I think we’re on the same page on this one).

      2) Natural selection differs from gravity because gravity is itself a force and there is a “theory of gravity” that we use to explain observations. The theory of gravity is deserving of being called a theory b/c it allows us to make very specific predictions that are generally accurate (there are some anomalies with respect to general relativity, our current theory of gravity, but that’s beyond the scope of the present discussion). Natural selection is nowhere near the level of gravity in terms of being a predictive theory.

      3) Last, my point about predictions with respect to natural selection doesn’t require that we have any particular prescience about future events, as you suggest with your examples of antibiotics and asteroids. Rather, I’m saying if we were to apply antibiotics to a given bacterial population we should, based on a theory of natural selection deserving of being called a theory, be able to make meaningful and generally accurate predictions about how the bacteria will respond to the antibiotics. And I don’t believe we can, at this point, because biology is extremely complex, even at the level of bacteria in a controlled environment. So natural selection is at best a proto-theory, and at worst logically empty. Again, I think the best resolution for this impasse is to reduce natural selection to natural history and accept that that is probably the best we’re going to get in evolutionary biology because it is some much more complex than physics or chemistry.

      4) Last, I would ask you how we could possibly falsify natural selection as a theory? And if we can’t falsify it, is it deserving of being called a theory?

      1. Just something peripheral that occurred to me on #2:

        Gravitation, as far as I understand it, is not a “force” but a property of spacetime and its interaction with the masses, momenta, and energies in it. “Force” is definitely a Newtonian concept in origin (first derivative of momentum?) and I’m not sure how valid it is in the Einsteinian world view.

  11. Tam Hunt,

    The statement you’re arguing to be void is something like “natural selection led to x” (where x is a differently composed character pool, I guess). What do you mean by the verb “lead” there? It does have a faint by-taste of entelechy to it. (And Darwin was quite displeased with his coinage because it implied intent on the side of some selecting agency. That’s why he later favored (also with qualms) “survival of the fittest”).

    Also, your statement that natural selection would reduce to natural history doesn’t seem too bad to me. Nat. sel. is simply one way in which natural history occurs, apart from all the others.

    As for teleology: obviously there’s a telos to the process; producing offspring capable of again producing offspring. Anything beyond that is unlikely to matter.

  12. Ben, two points: 1) I’m not suggesting that natural selection, to be a useful or valid theory, must have any conscious agency or entelechy. Rather, I’m suggesting that for it to be a useful theory, in the way it is thought to be a useful theory, statements such as “natural selection resulted in phenotypic change x” should actually mean something. As it is now, the only thing such a statement means is that we are assuming that natural causes led to the observed changes and not supernatural ones. We need to fill in Gould’s a prior engineering principles to a far higher degree than we have today to be able to make such a statement and have it have any meaning.

    But it sounds like we may be on the same page after all due to your second paragraph in which you state that you are fine with natural selection framed better as natural history. I would go a bit further than your statement, however, in that I would argue it makes no sense to say that natural selection is “simply one way in which natural history occurs.” Rather, natural selection reduces to natural history and we thus jettison the phrase “natural selection” as empty.

  13. Tam Hunt: again, sorry for the late reply (other stuff intervened).

    I’m still not on board with your complete reduction of selection to history. Quite possibly, future biologists (or philosophers) will find new means of defining selection phenomena in such a way that they are fundamentally the same as drift, but until then “selection” provides a convenient handle for changing population compositions not due to chance. (Aside: chance is not a supernatural cause.) At the least, the concept selection allows biologists to formulate hypotheses that are stabbing at the “engineering principles” a posteriori, and since hypothesis formulation is an enjoyable activity, I doubt that biologists are going to abandon the concept anytime soon, unless a better one comes along.

    I’m guessing that a re-formulation of natural historiography (which seems to be what you’re driving at) will come along not too far into the future, and one which would collapse drift- and selection-phenomena in some way. I’ve been batting around a few ideas, but they’re both a bit uninformed [IANAPOB] and on the back burner due to other projects haunting me.

    At any rate, I’m not too worried about the “tautological” nature of selection explanations, since they do give us some insight into the relations of biota. Once I’ve formulated my Grand Unified Theory of Random Evolution & Selection (GUToRES), I’ll send our esteemed host and copy and see how high I score on the biology crackpot index. 🙂
    [A physics blog I was reading in the late 90s had a crackpot index for papers in relativity; I’m not sure whether there’s yet one for evolutionary biology; if not I’ll be happy to inaugurate its use. (-: ]

Comments are closed.