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Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Dec. 27 2002,00:08    From an ISCID thread: Cornelius G. Hunter wrote: Quote I don't think we have scientific reason or evidence to believe complex systems such as echolocation or the DNA code could have evolved. Hmm.  I don't think that we have scientific reason or evidence to indicate that echolocation is due to anything other than evolutionary processes. There are several different approaches to biosonar.  The examples of bats and odontocetes are pretty sophisticated, but those of oilbirds and honey badgers are relatively simple.  Even humans can use hearing for directional cues, as several aids for the blind demonstrate. So I'd like to know what, specifically, puts the dolphin biosonar system (the one I'm most familiar with) outside the scope of evolutionary process. Wesley Edited by Wesley R. Elsberry on Dec. 27 2002,00:08 -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Dec. 27 2002,08:22    Cornelius G. Hunter wrote: Quote I am not familiar with the dolphin's biosonar, but I am somewhat familiar with human-made radar and sonar systems. For those who may not be familiar with the bat's echolocation system, we should briefly explain that it maps out objects around it as small as a mosquito by sensing the echoes of its own squeaks. Its squeaks are well beyond the range of human hearing and are emitted at up to 2,000 times per second. Next it determines both range and direction to the mosquito by sensing the echo while filtering out echoes from the squeaks of nearby bats. Anyone familiar with today’s sonar or radar systems knows the immense complexity involved with such systems: the problems of sensing the echo in the presence of the transmitted signal which can be billions of times stronger, of filtering out spurious signals such as echoes of older transmissions, of combining the echo information with knowledge of your own motion, and so forth. Yet the bat’s detection abilities are superior to those of the best electronic sonar equipment. Evolution, on the other hand, has been shown to be able to make rather limited modifications to multi cellular organisms. These might include resistance to pesticides, minor morphological changes (eg, beak size and shape), more major morphological changes in the case of breeding (eg, dogs), coloration, etc. My list here (off the top of my head) is not close to being complete and I do not want to short-change evolution, but I trust I'm not missing anything too significant. My point is merely that, relative to the sorts of changes required to create a biosonar system, the observed evolutionary changes are rather minor. It is also worth noting that the observed evolutionary changes are made possible by a complex cellular machine that evolution cannot explain, aside from speculation. I think it is fair to say that there does not exist empirical evidence supporting the claim that biosonar systems could have evolved. I would say it is, as you put it, "outside the scope of evolutionary process," at least the known process. The idea that it evolved likely arises from a prior commitment to the truth of evolution rather than biosonar systems appearing to have evolved. It is probably worth exploring the question of whether it is at least a reasonable conjecture that such systems could have evolved? Personally, I would require any such attempt to include a fairly detailed explanation of the steps involved, where each step (i) consists of changes of the type and magnitude that are empirically observed, and (ii) confers increased fitness, or is reasonable for us to imagine given what we know about population genetics and neutral mutations. Also, I would require that the mutations required, in total, pass a likelihood test. That is, given (i) the number of bat populations and the number of years available, and (ii) the immense design space involved, is the evolutionary pathway anything more than astronomically unlikely. I feel these requirements are reasonable, and I have not seen any explanation that comes close. And I do not think it is because they are trivial and therefore taken for granted. In fact, correct me if I am wrong, I suspect we do not even have all the details of the bat's system so as to know what the required mutations are in the first place, let alone their individual effects at each step in the process. This appears to be a classic argument from incredulity.  It echoes early reactions against Donald Griffin's discovery of echolocation via ultrasound in bats, where is was considered inconceivable that such lowly creatures could have technology which was then new to human technology. I'm going to discuss dolphin biosonar for two reasons.  The first is that dolphin biosonar is the sort I am most familiar with.  The second is that Hunter's claim was about biosonar generally, not limited to bats in particular. The first issue to note is that the receiving system in dolphins need not be considered to be out of reach of evolutionary process.  I'm going to use human auditory performance as a becnhmark, since humans are a well-studied non-echolocating mammal with fairly generic capabilities.  One piece of evidence concerns the performance of humans given a biosonar task.  A study by Fish et alia (1976) demonstrated that human divers could perfrom about as well on a target discrimination task as did the dolphins, when the humans were given the dolphin biosonar signal shifted into the range of human hearing.  This indicates that even a rather general mammalian auditory system (as seen in humans) is sufficient to the task of deciphering biosonar information.  It also indicates that the general mammalian auditory system is an adequate starting point for an evolutionary process ending in biosonar capability. What changes to the general mammalian auditory condition must occur to derive a dolphin-like system?  Either of two parameters in cochlear construction will extend frequency response on the high end: increase the stiffness of the basilar membrane or reduce the width of the basilar membrane.  This falls into the category of "minor morphological change".  Dolphin cochleas have slightly fewer turns than in humans, but a bit over double the variation in width along the basilar membrane.  The minimum width of the dolphin basilar membrane is a bit less than a third of that of the human basilar membrane. Neurologically, dolphin basilar membranes have about the same numbers of inner and outer hair cells as seen in humans.  There are some differences in the brain, though.  The auditory cortex in dolphins is enlarged relative to that seen in humans.  Dolphins and bats each have lost the lateral superior olive, a structure implicated in coordinating eye movement with auditory cues in humans.  Dolphins are known to process clicks differently than tonal stimuli; this is something that is not seen in humans.  Dolphin evoked potentials show a faster response to click stimuli than to tonal stimuli. Psychoacoustics also demonstrate differences in quantity rather than quality between dolphin and human hearing.  Johnson's 1968 study on temporal auditory summation in dolphins showed that dolphin and human time constants were close in the range of 0.5 to 10 kHz.  Critical ratios are similar for dolphins and humans, although critical bandwidths are larger in the dolphin than in humans by a little more than double.  For frequency discrimination, dolphins perform similarly to humans, but at a higher frequency range.  Dolphin sound localization capabilities are also similar to those in humans. I still don't see any show-stoppers in what we know about the dolphin receiving system's characteristics. That leaves the transmitting system for possible show-stopping adaptations.  I think I'll write a post on that separately. Wesley -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Dec. 27 2002,08:34    Archived post from the ISCID thread: I'll keep my comments here brief since the issue of biosonar is pretty tangential to the thread topic. Hunter's reply lacks the specificity that I requested.  The objection seems to be raised in a general, rather hand-wavy way.  I'd also caution against trying to take cues from human technology for whether particular tasks are difficult for biological systems.  As we know from computer science, many tasks that are easy for animals are difficult for computers, and vice versa.  The application of accurate mathematics is a snap for computers, but hard for humans.  Machine translation of human languages is a classic case of something that is easy for humans (who have both of the relevant languages), but has turned out to be very tough for the computers. I've taken my continued discussion of biosonar in dolphins to  another thread so that I won't be cluttering up this thread with it. Wesley -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Dec. 27 2002,10:36    Cornelius G. Hunter wrote: Quote I'm not sure how I could have been more specific. I discussed the fact that the evolution of biosonar systems is significantly beyond the observed and known evolutionary process, I discussed the complexity of the process in general, and I laid out the requirements for establishing the reasonableness of the hypothesis. I gave 3 specific requirements: (i) lay out steps which are of observed type and magnitude, (ii) steps must not degrade fitness, and (iii) mutations required must pass a likelihood test. What more could I provide, especially given the lack of specificity in the available evolutionary conjectures on this hypothesis? Am I supposed to derive hypothetical evolutionary scenarios for you and then find point out their weaknesses when no such scenarios exist in the first place? If you find my response "hand-wavy" then you must find evolution to be far more so. One way to be more specific, overlooked by Hunter, would be to name an adapatation necessary to dolphin biosonar and present an argument as to why it could not arise via evolutionary process.  This specific form of argument is notable by its absence from Hunter's discussion.  While I disagree with Bill Dembski's mode of argument and conclusions concerning the E. coli flagellum, at least he made an attempt at a specific argument in that case. It is nowhere near a "fact" that "the evolution of biosonar systems is significantly beyond the observed and known evolutionary process".  Begging the question is not a valid argument.  I've already pointed out simple examples of biosonar, which even if we agree to disagree concerning the examples of dolphins and bats remain as an impediment to the scope of Hunter's claim. I'm not the one making universal claims about what is not possible.  That would be Hunter.  So far, though, I haven't seen anything that would cause me to think that the biosonar of dolphins poses a difficulty for evolutionary process.  Nothing in Hunter's discussion so far changes that. Quote Obviously, conjectures about the future can work both ways, and what we are left with is our current list of evidences and analyses. These do not bode well for evolution. I think that we will have to agree to disagree on that conclusion as well.  It looks like a non sequitur to me. Charles Darwin wrote: Quote Any one whose disposition leads him to attach more weight to unexplained difficulties than to the explanation of a certain number of facts will certainly reject my theory. Wesley Edited by Wesley R. Elsberry on Dec. 27 2002,10:43 -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Dec. 28 2002,09:38    From an ISCID thread: Cornelius G. Hunter wrote: Quote Wesley: Respectfully, I think it is important to be clear and consistent on who is making what claim. Let me clarify that my position on the evolution of biosonar systems and macro evolution in general is that such evolution is unlikely and does not constitute a good scientific theory. I am not making a universal statement as you suggest. In fact, my comment which you originally responded to, and which you quoted in your first post was that: quote: -------------------------------------------------------------------------------- I don't think we have scientific reason or evidence to believe complex systems such as echolocation or the DNA code could have evolved. -------------------------------------------------------------------------------- It is not clear to me how you concluded that my claim is that such evolution is impossible. It is worth pointing out, however, that this amounts to a shifting of the burden of proof, and is a common mode of argument. In fact, it seems that in every extended discussion of this sort I am, at one point or another, asked to provide evidence that evolution is false (as though the theory is true until proven false), or more commonly, as here, am told that this is my claim and that I've failed to support it. This is so common, it is not surprising that Darwin used it: quote: -------------------------------------------------------------------------------- If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. – Darwin, Origin -------------------------------------------------------------------------------- Darwin allowed that if the skeptic could find a complex organ that evolution could not produce then the theory would be disproven. But it would be impossible for a skeptic to prove that evolution could never create complexity, for that would be tantamount to proving a universal negative. You write: quote: -------------------------------------------------------------------------------- One way to be more specific, overlooked by Hunter, would be to name an adapatation necessary to dolphin biosonar and present an argument as to why it could not arise via evolutionary process. -- Wesley -------------------------------------------------------------------------------- It is ironic that, on the one hand, while I am not making a universal claim you criticize me for doing so, but then on the other hand you suggest this is what is required for me to criticize evolution effectively. What you suggest is, of course, precisely the requirement that Darwin laid out, and it places the critic in an impossible position. And importantly, it makes science vulnerable to any idea that cannot be falsified. You write: quote: -------------------------------------------------------------------------------- It is nowhere near a "fact" that "the evolution of biosonar systems is significantly beyond the observed and known evolutionary process". Begging the question is not a valid argument. -- Wesley -------------------------------------------------------------------------------- It would help me if you could point out how I was begging the question, as I certainly try to avoid fallacious arguments. I thought I was merely pointing out the facts of the situation when I said that : quote: -------------------------------------------------------------------------------- My point is merely that, relative to the sorts of changes required to create a biosonar system, the observed evolutionary changes are rather minor. … I would say it is, as you put it, "outside the scope of evolutionary process," at least the known process. -------------------------------------------------------------------------------- How is this begging the question? You write: quote: -------------------------------------------------------------------------------- I've already pointed out simple examples of biosonar, which even if we agree to disagree concerning the examples of dolphins and bats remain as an impediment to the scope of Hunter's claim. -- Wesley -------------------------------------------------------------------------------- I'm not following here. Can you clarify what you see the implications are of the simple examples of biosonar? I like your quote from Darwin: quote: -------------------------------------------------------------------------------- Any one whose disposition leads him to attach more weight to unexplained difficulties than to the explanation of a certain number of facts will certainly reject my theory. – Darwin -------------------------------------------------------------------------------- In other words, we need to consider all the factors, such as the explanatory power, supporting evidence in addition to the problems. I could not agree more. In fact, it is the many problems with the positive evidences, as set forth by evolutionists, which caught my interest originally. The problem of complexity is less interesting as it is fairly obvious. --Cornelius Pointing out a sentence that does not contain a universal claim doesn't exculpate one from defending a universal claim made elsewhere.  Here's one from Hunter: Quote I think it is fair to say that there does not exist empirical evidence supporting the claim that biosonar systems could have evolved. That's a universal claim.  It's also a negative claim, which means that if any evidence exists which supports evolvability of biosonar, the claim is false. So Hunter's universal claim is false, because there does exist empirical evidence that biosonar systems could have evolved.  I've already mentioned the simple systems of oilbirds and honey badgers, which Hunter has thus far avoided taking up.  I've also gone into some detail concerning comparing the dolphin receiving system with that of a general non-echolocating mammal, Homo sapiens.  These represent empirical evidence that biosonar is not "beyond the scope of evolutionary process". I can understand Hunter's haste in trying to frame up a critic in an attempt to avoid the consequences of making such an egregiously false claim.  However, I'm not the type to take those sorts of shenanigans lightly.  Hunter's claim that no evidence exists to support the evolvability of biosonar is one that he bears the burden of proof for.  It may have been unwise of Hunter to put himself in the position of proving a universal negative, but he has no one else to blame for it. Perhaps the reason that sooner or later Hunter gets called upon to prove evolution false is simply that he makes such claims, and critics naturally call upon Hunter to either support or retract them. The "sorts of changes required to produce a biosonar system" are "relatively minor" and fully within the scope of evolutionary process, as far as I can tell.  Hunter's statement is begging the question because he is taking as a fact something that has not been established.  I suppose Hunter could respond that that is merely the use of a false premise instead, but in either case his argument is hosed. Simple examples of biosonar imply that Hunter's claim that "no evidence exists" to support the evolvability of biosonar is simply wrong.  If evolutionary process can explain simple biosonar, Hunter's universal is false.  Further, the facts of dolphin biology do support the possibility of dolphin biosonar being derivable from a generalized mammalian condition. Hunter's response to the Darwin quote I provided seems not to touch the issue identified by Darwin. Wesley Edited by Wesley R. Elsberry on Dec. 28 2002,09:46 -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Barbarian Posts: 3 Joined: Jan. 2003 (Permalink) Posted: Jan. 10 2003,12:01    Quote The application of accurate mathematics is a snap for computers, but hard for humans. I wonder how a baseball player, using cues about the sound of a bat hitting a ball, and a split-second sample of the early trajectory of the ball, is able to instantly compute the subsequent path of the ball so as to run to that spot and catch it. Yet it seems effortless.     Maybe brains work better than we think?

charlie d Posts: 56 Joined: Oct. 2002 (Permalink) Posted: Jan. 10 2003,12:33    Hi Barbarian: There are actually several papers published on the physics and psychobiology of ball-catching (your taxpayer money at work!.  Here's a rather famous one in Science from a few years ago: Quote How baseball outfielders determine where to run to catch fly balls. McBeath MK, Shaffer DM, Kaiser MK. Science 1995 Apr 28;268(5210):569-73 Current theory proposes that baseball outfielders catch fly balls by selecting a running path to achieve optical acceleration cancellation of the ball. Yet people appear to lack the ability to discriminate accelerations accurately. This study supports the idea that outfielders convert the temporal problem to a spatial one by selecting a running path that maintains a linear optical trajectory (LOT) for the ball. The LOT model is a strategy of maintaining "control" over the relative direction of optical ball movement in a manner that is similar to simple predator tracking behavior.

Tom Ames Posts: 238 Joined: Dec. 2002 (Permalink) Posted: Jan. 10 2003,13:00    This just in: Quote Fly Ball or Frisbee, Fielder and Dog Do the Same Physics By YUDHIJIT BHATTACHARJEE When a dog goes after a sailing Frisbee — now racing, now turning, head cocked skyward — it looks like nothing so much as an outfielder chasing a fly ball. The resemblance is impossible to miss. Now researchers say it is laden with deeper similarities. The scientists, at Arizona State University, had previously shown that outfielders navigated by keeping the ball's image moving along a straight line against its background. Now, after a study involving a cheerful springer spaniel, Dr. Dennis M. Shaffer and his colleagues say that dogs use the same instinctive arithmetic, and they say that the similarity, while not unexpected, could shed light on questions about instinct and learning. Of course, neither dogs nor baseball players use the strategy consciously. Continued at New York Times web site (requires free subscription). -------------- -Tom Ames

Wesley R. Elsberry Posts: 4966 Joined: May 2002 (Permalink) Posted: Jan. 10 2003,13:03    Barbarian wrote: Quote Maybe brains work better than we think? And I wrote before: Quote As we know from computer science, many tasks that are easy for animals are difficult for computers, and vice versa.  The application of accurate mathematics is a snap for computers, but hard for humans.  Machine translation of human languages is a classic case of something that is easy for humans (who have both of the relevant languages), but has turned out to be very tough for the computers. I certainly had no intention of giving anyone the impression that brains were incapable of solving difficult problems.  In context, I think that it was clear that I was making a case that the class of problems which is easily solved on von Neumann architecture computers is not exactly the same as the class of problems easily solved by brains, and that the latter class is not empty. Wesley -------------- "You can't teach an old dogma new tricks." - Dorothy Parker

Barbarian Posts: 3 Joined: Jan. 2003 (Permalink) Posted: Jan. 10 2003,13:18    Yes, and my comment was partly tongue-in-cheek.   However, I am not suprised to learn that trajectory tracking behavior in humans is not a straightforward mathamatical analysis, but rather a modification of neural systems useful in predatory behavior. Not what you would expect from a designer.   But rather typical of evolutionary processes.

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