Today I was guest lecturing in a journalism class, and the topic was the definition of truth in science and in philosophy (as opposed to, or in similarity with, what journalists think about the matter). In preparing my notes, and going through various concepts of truth, I of course had to (briefly) consider the idea of “revealed” truth – as in truth told to us directly (in a manner of speaking) by a deity.
Of course, the very notion of revealed truth is in fact a logical fallacy. See, truth revealed by a supposedly supernatural entity is a particular case of argument from authority. In elementary logic, arguments from authority are a classical example of fallacy, because there is no independent reason or evidence supporting the statement alleged to be true, other than somebody telling you that it is true.
It's important to note that just because a statement is logically fallacious, it doesn't mean it's not, in fact, true. For example, suppose I am taking a certain medicine. If someone asks me why I'm taking the medicine and I respond “because the doctor told me,” I am committing the fallacy of employing an argument from authority. Still, the doctor (who, unlike me, is trained in medicine) is probably right.
Plato, in the Socratic dialog known as Theaetetus, makes the same distinction. He acknowledges that someone may be right as a matter of chance, but he maintains that true beliefs only constitute knowledge if they can be justified rationally, i.e., if one can account for why one holds a certain belief (without falling back on the argument from authority).
This is exactly what makes discussions with creationists so frustrating. They wish to argue their position, thus squarely putting themselves in the camp of rational argumentation. However, when their “logic” is trumped, they use what they seem to think is the ultimate ace up their sleeves: “well, I believe it because it's in the Bible.” But that is an argument from authority, a logical fallacy, and therefore no justification of one's belief (in the broader sense of informed opinion) at all. One has to pick: either engage in rational arguments and face the consequences, or retreat into faith and admit the irrationality of one's position.
Rationally Speaking: an archived blog about science & philosophy, by Massimo Pigliucci
This discussion is a bit over my head, but I ran across this quote today and thought it to be, in a way related. I'll just let
ReplyDeleteProfessor Pauling speak for me.
It is sometimes said that science has nothing to do with morality. This is wrong. Science is the search for truth, the effort to understand the world; it involves the rejection of bias, of dogma, of revelation, but not the rejection of morality.” -- Linus Pauling, Scientist for the Ages (oregonstate.edu)
I did not go virtually a day in college that I did not have some creationist standing on the corner telling me I'd be going to Hell for my pursuit of secular knowledge.
ReplyDeleteThe conversation stopper I employed was thus;
"Do you believe in faith?"
"Yes."
"Well, God spoke to me in a dream, he told me anyone speaking about God on the corner was full of sh!t."
There's really no retort if you accept faith.
From the Nizkor site on fallacies to which you linked:
ReplyDelete"An Appeal to Authority is a fallacy with the following form:
1. Person A is (claimed to be) an authority on subject S.
2. Person A makes claim C about subject S.
3. Therefore, C is true.
"This fallacy is committed when the person in question is not a legitimate authority on the subject. More formally, if person A is not qualified to make reliable claims in subject S, then the argument will be fallacious. [emphasis mine]"
If this is the case, then your example of taking a medicine because the doctor told you to do so is not really an example of a fallacy, because the doctor is "qualified to make reliable claims" on the subject of medicine.
That would mean that the problem of with quoting the Bible as an authority relates to it not being qualified to make reliable claims, not to the mere act of quoting from it.
J.J.,
ReplyDeleteI stand by my original example. I don't care how good an authority is, to appeal to it and nothing else isn't an argument at all. Again, as I said in the post, that doesn't mean the authority in question is wrong, but one has to be conscious of the fact that one is not building a rational case, just delegating it to somebody else.
Massimo Pigliucci: "I don't care how good an authority is, to appeal to it and nothing else isn't an argument at all. Again, as I said in the post, that doesn't mean the authority in question is wrong, but one has to be conscious of the fact that one is not building a rational case, just delegating it to somebody else."
ReplyDeleteAll that is saying is that arguing on the basis of a qualified authority is defeasible reasoning that does not have the certainly of a conclusion from pure logic. The same can be said of inductive or abductive reasoning. Calling these fallacies muddies the waters and fails to distinguish between reasoning processes that lack perfect certainty but are good heuristics in practice and reasoning errors that shouldn't be used at all.
J.J.,
ReplyDeletewell, we might just have to agree to disagree here. I don't see how "I'm thinking X because Y told me so" constitutes any reasoning at all.
Massimo Pigliucci: "I don't see how 'I'm thinking X because Y told me so' constitutes any reasoning at all."
ReplyDeleteThat's because there is a hidden premise that goes unsaid. To put in syllogistic form, the reasoning goes something like this:
Major premise: What Y says is true.
Minor premise: Y says X.
Conclusion: X is true.
The argument is valid, but its major premise is in practice impossible to obtain. What can be done in practice is to soften the major premise, so you get something like this:
Major premise: What Y says about subject Z is true the vast majority of the time.
Minor premise: Y says X about subject Z.
Conclusion: X is probably true.
This argument is valid, and as seen in your example with the doctor, works well in practice. Of course, the conclusion does not guarantee that X is true, which is the downside.
Of course, fundamentalists tend to use the first syllogism, where the major premise is "What Y says is true," and they do it without securing the major premise, so the argument is valid but false.
Interesting that quote that J.J. got from the site. Until now, I'd thought that the argument from authority was just "X is true because Y said so", regardless of the expertise of Y on the matter.
ReplyDeleteBut after seeing that excerpt from the site, I noticed we frequently do it like that. It's like "Einstein said SVO languages must be the first to evolve, and Einstein was a genius". Everybody will point out that Einstein probably knew doodle squat about linguistic typology. Now if someone said "Einstein said that your mass varies depending on your speed", not many people would challenge that on the basis of expertise.
Now, which one is right, what's the "official" definition of "argument from authority"? I still think my earlier version was better, regardless of heuristics we might apply regarding expertise. If one says "Einstein said your mass varies deppending on your speed because he's proven so in such and such scientific publications, with everything independently confirmed by lots of physicists in the community, and nobody has yet been able to contradict him", then I think it's no fallacy. You might say the whole "proven in publications, verified, not contradicted, etc." was part of the hidden premises. But I think this is a bit different from the example J.J. gave, since it's not some generic "Einstein is good in physics, therefore all he says in physics is true".
Now, regarding the deity part of it all. Well, I'm an agnostic atheist, but I'll somewhat disagree that saying "god said so" is an argument from authority. Sure it came from some authoritative source, so to speak. But logic can't apply to the supernatural, because logic is about the natural world, what do you guys think? I mean, a human authority is fallible. A deity is not - at least the ones fashionable and most popular these days. The fact that deities do not exist does not change this. If they did exist and were omnipotent, then whatever they say must be true by definition. Am I missing something in my reasoning?
J
J
ReplyDeleteIt's not so much "God said so" as it is "The Bible said so" or "St. Visionary said so".
Massimo,
ReplyDeleteI would love to have the creationist(I.D.) vs. evolution debate on your site. I promise I will only argue from a logical view. No using authority (either side) as a premise for truth. I find this is done just as much with evolutionists as it is with creationists. I find most people accept evolution as truth without knowing anything about the process, just because it is accepted by the scientific community. This is perhaps the best example of "revealed truth" there is.
You have a lot of intelligent commenters on your site, would make for some interesting debate. Although I am not a creationist in the typical sense. I am just an evolutionist gone bad, because of the holes in the theory.
"I am just an evolutionist gone bad, because of the holes in the theory."
ReplyDeleteJim, you do realize that that's a logical fallacy in itself, right? It's an example of non sequitur. Just because a theory or explanation is incomplete, it doesn't follow that it is not true. Moreover, it certainly doesn't follow that another explanation (the Intelligent Designer did it -- which is not an explanation unless one says who/what/how) is true just because the currently accepted theory is wrong.
Massimo,
ReplyDeleteI agree with your statement that just because I believe evolution is not true, that does not make I.D. true. Fact is I don't know exactly what I believe.
I do believe that micro- evolution is true (i'm sure you have heard other I.d.ers say the same). I can even accept that man came from ape or chimp or other primate (since we have no body part that they dont have this would just be micro-evolution). I just need someone to explain (mechanicaly) how a complex feature such as the human hand or eye, or all the mechanisms for child birth evolve from a series of mutations. Keep in mind that we need not discuss genetics or any part of the actual chemical processes at work. I will concede that they are all capable (since I dont have the intellect or knowledge to understand it all). So for argument sake I will concede that any mutation is possible (within reason of course, a whole human hand will not be a mutation). I just want someone to explain in detail how a hand formed. The answer is usually that there is no way we can know those events givin we were not there to witness them. I say that we should at least be able to come up with a senario (true or not) on how the hand could form. Such as : the first mutation of the hand was one single finger (no knuckle just one strait appendage), and this was an advantage because the enviorment changed, so that only the creature with this appendage could survive because it was able to dig insects out of some kind of hole in the ground. So the rest died out and just the mutated lived on. then the next mutation is such and such. Making up a story like this should be easy (true or not) given we can control the enviorment and each individual mutation. Problem is, not only is it not easy, its not possible. Especially for things like childbirth. Where unless the whole process mutates at once it does not have any benifit (you would have to find another advantage of breasts that has nothing to do with childbirth. You would have to find another advantage of ovaries that has nothing to do with childbirth. You would have to find another advantage of a uterus that has nothing to do with childbirth. Not only would you have to find these advantages, it would have to be such an advantage that the members of the species without the mutation would die prior to reaching an age of reproduction.
When I make this arguemnt that it is impossible for the enviorment to cause such advantages, usually someone tells me that I dont know enough about biology or geology or whatever field of science. I argue that it is not even about biology or any field of science. Its really just about actual mechanical advantages that muct be brought about by changes in the enviorment. Anyone can understand these advantages. Even given millions of years and infinate changes in enviorment (however that could be achieved) its not possible.
A couple of good books about evolutionary explanations of complexity are: Jablonka & Lamb's "Evolution in Four Dimension," and the very recent "The Plausibility of Life," by Kirschner and Gerhart. See also M.J. West-Eberhard's "Developmental Plasticity and Evolution."
ReplyDeleteMoreover, be careful with claims like "it is impossible that..." It turns out that it is very difficult to actually show that something is impossible, unless it contradicts the laws of logic.
Finally, again, incomplete explanations don't invalidate the general picture. We don't know how to reconcile quantum mechanics with general relativity, but no physicist thinks that we therefore ought to conclude that either (or both) theories are wrong.
Massimo,
ReplyDeleteThankyou, for your book recommendations. I will read "The Plausibility of Life" this weekend and get back to you. Although I have read a number of books on the subject (from Darwins "Origions of the species" to some of Goulds books and others) and have yet to see a good explaination for my delemma. I will honestly keep trying. I am afraid my mind is getting more and more closed on the subject(not by choice).
My arguement is often refered to as the complexity arguement(as you stated). To me it is more of a simplicity arguement. What mechanical advantage does the womans breast play besides providing milk for the young. Its that simple, there is no other imaginable advantage to a device that turns food into babys milk(enough so the woman that dont have it cant even get to reproduction age). Thats to say that a breast could mutate all at once (which it can't). There has to be some advantage to every part that makes up the breast individually.
You say to be careful making claims of impssiblilty. But since you can't evolve something like child birth without having all the parts in place to give birth to a child. And since all the parts of child birth had to evolve for other advantages. By definition, this is impossible.
Its kind of like the old saying "what came first the chicken or the egg". I can say it impossible to have one without the other. You will have to say that it can evolve with an extreemly high degree of complexity(but you dont have to prove any part of this compexity). But enviorment does not have that kind of compexity. They have to be simple mechanical advantages. evolution has the burden of proving how the chicken arrived without the egg or how the egg arrived without the chicken. I don't have the burden of proving why it can't work. Although I think that I have.
"You say to be careful making claims of impssiblilty. But since you can't evolve something like child birth without having all the parts in place to give birth to a child. And since all the parts of child birth had to evolve for other advantages. By definition, this is impossible."
ReplyDeleteThis is the current ID argument from irreducible complexity. It has been shown to be fallacious on philosophical grounds (see, e.g., Shanks, N., and K. H. Joplin. 1999. Redundant complexity: a critical analysis of Intelligent Design in biochemistry. Philosopyh of Science 66:268-282) and on biological grounds (see this article by Ken Miller: http://www.millerandlevine.com/km/evol/design2/article.html)
Ask a blind person if a barely functional eye is better than no eye at all.
ReplyDeleteFor a very good popular treatment on this issue check out Richard Dawkins "Climbing Mount Improbable" - the analogy he uses is that, yes, it seems improbable to leap from no eye to human eye in one step, this would be like jumping up a 1000' cliff face to the top. But notice that around back of the cliff there is a slope that one can climb by small increments - ratcheting the value of a structure upwards (adaptation to local environments / condition only) will get you to the top eventually.
This is the current ID argument from irreducible complexity. It has been shown to be fallacious on philosophical grounds
ReplyDeleteFallacious on Philosophical grounds? What the heck does that mean? This is hardly a philsophical debate. To me this is one of the biggest problems with the whole debate. Everytime I ask this question (many times now). I get pointed to books and articles, read many of them, and still don't get an answer. I never get an answer from the people I actually debate with (not attacking you personally). I find everyone believes evolution because someone else knows why complexity isn't an issue. This goes back to your origional blog. Just tell me why my arguement is fallacious on philosophical grounds. Don't refer my to a higher authority.
I tried your link on the bottom and can't get it to work, found the website but cant get to the exact link.
Derek you said,
Ask a blind person if a barely functional eye is better than no eye at all.
It has nothing to do with the blind persons will to look astectically pleasing. Its a matter of "does the blind persons non-functional eye give him some advantage to survival that other blind people without an eye don't have and therefor end up dying before they have a chance to reproduce."
As far as your analogy with the mountain, I get it, evolution happens in small steps. Not one big step. This is my issue in the first place! Each small step has to have a mechanical advantage in its enviorment in order to survive. We can all see how the eye is a great advantage. The animal without the eye perhaps can't find the food as quickly and the animal with the eye wins out every time. But can you see where just having the eyelashes without the eye would help the animal win out? Or just having some eye socket without a working eye would help the animal win out. Can you think of any mutation that involves an eye helping an animal win out unless that animal can see?
Just soemone please tell me why an eye socket without a working eye (socket would have to come first, right) could somehow be an advantage in its enviorment. tell me that hte animal stored food in its eye sockets so the other animals couldn't have any. At least that would be a start.
Massimo, I apologize for my tone, just that I have been down this road many a time. You can point me in any direction you want, but the answer is not there.
Jim,
ReplyDeleteI'm sorry but I have to refer you to published literature, I simply don't have the time to repeat for the nth time what plenty of other people have said before. That's what libraries and bookstores are good for.
Yes, the idea of irreducible complexity is problematic philosophically, because it makes a claim of impossibility that simply cannot be substantiated. There is no way to show that a given phenomenon is impossible to explain by any natural means, simply because there may be natural mechanisms that are as yet undiscovered and could explain the phenomenon.
The link to Miller's article (which is http://www.millerandlevine.com/
km/evol/design2/article.html), however, shows that even the more modest version of Behe's claim is bogus. It's simply not true that natural selection cannot build complex structures over time.
Of course, if you are waiting (as it seems from what you write) for a minute-by-minute account of the entire evolutionary process, you won't ever be satisfied. But that's true for many scientific theories besides evolution. Try to get a physicist to give you a full account of what goes on in your living room -- at the quantum level...
Jim,
ReplyDeleteconsider this:
One illustration of the power of Natural Selection is that of "evolvable hardware", where evolutionary algorithms are used to design things. (Google it for more information). One experiment at the University of Sussex in England used reconfigurable chips to design a logic circuit that could distinguish a particular audible tone. After about 5000 permutations, they ended up with an astonishingly efficient design. What's more, the researches didn't know how it worked. It didn't seem possible, yet it did work.
If this kind of sophistication can be achieved after only 5000 permutations, what kinds of things are possible after countless trillions of permutations churning along countless trillions of simultaneous paths? Given that, it seems to me, the complexity we see in the biological world should come as no surprise.
You can get text books on genetic algorthims as used in computer science - it may help your understanding.
As for women's breasts, one theory I'm familiar with (I think I read it in the Naked Ape by Desmond Morris) has to do with sexual mimicry. As our ancestors transitioned to bipedalism, breasts began to substitute for buttocks - a traditional sexual signaling feature in apes and primates. At any rate selection of females with slightly fuller breasts over thousands of generations led to the dominance of genes that build such breast tissue. I believe that a remarkably small percentage of the population (<3%) actually has to be selected for in order for traits to eventually encompass an entire population. Similar sexual signalling motivations are said to be responsible for fuller pink lips and the phenonema of blushing.
One thing to note about evolution is that traits are rarely evolved indepently -- instead many social, biological and environmental conditions are involved in complex interactions that slowly give rise to new features/traits.
Alan
Yes, the idea of irreducible complexity is problematic philosophically, because it makes a claim of impossibility that simply cannot be substantiated. There is no way to show that a given phenomenon is impossible to explain by any natural means, simply because there may be natural mechanisms that are as yet undiscovered and could explain the phenomenon.
ReplyDeleteYou say it cant be substantiated. I am telling you it is. Rather than get into the human organs required for child birth. I am going to over simplify again. You dont get a chicken without an egg and vise-vera. It is impossible through any type of selection or mutation to achieve this unless the whole chicken mutated at once from another animal.
To say that there are natural processes that are undiscovered to account for evolution, is just saying we know evolution is true, we just don't know why yet.
One time I had a dabate with my brother about the age of the universe (my brother being quite religous believes the universe cannot be older than 6000 years). I told him that since we can see stars that we know are millions of light years away. It took that light millions of years to travel here. So by definition, The universe must be at least the same age as how many light years away the furthest star we can see is. He acknowledged on the surface that sounds true, but there may be properties of light and time we don't even understand yet. You are making the same arguement for evolution.
I guess I am waiting for minute by minute account for evolution. I think most people just believe that through a bunch of little changes you get a nice big change. I want people to realize that each part of a macro evololution such as an eye requires a primary part to have an advantage, a secondary part that has an advantage that needs the primary part and so on and so on. If the chicken and egg can get here by chance mutations than shouldn't we be able to make up a story (doesn't have to be true) to account for it, just to show it is possible. If we can't even make something up using every avalable tool of science and imagination, how can it happen by chance.
If you see a wrecked car on the other side of a retaining wall, you may say that it is impossible for the car to get smashed up and get on the other side of the wall without doing any damage to the wall. Then someone else can say that maybe the car hit a smaller sports car and jumped off the hood of the sports car and flipped over the retaining wall then landing without touching the wall. Point is that if it is possible then there has to be some way to imagine it, true or not. I want someone to make up an account of how the chicken evolved, true or not, just to show it is possible.
Alan said,
One illustration of the power of Natural Selection is that of "evolvable hardware", where evolutionary algorithms are used to design things. (Google it for more information). One experiment at the University of Sussex in England used reconfigurable chips to design a logic circuit that could distinguish a particular audible tone. After about 5000 permutations, they ended up with an astonishingly efficient design. What's more, the researches didn't know how it worked. It didn't seem possible, yet it did work.
I think you are more describing the process of how genes make mutations. As I stated, I am not argueing that mutations are not possible.
As for trillions of permutations churning againsts trillions of paths? perhaps in microbes, but not in any living animal. Take the human for instance. If we consider 20 to be average reproductive age, in one million years you would only have 50,000 generations. Look at everyone you know or have ever met. how many have substancial mutations of any kind (good or bad). I mean something that could even be considered an advantage. Lets just say that they are out there we just can't quantify them. It would take a very high percentage of people with meaniful mutations that are only advantagous in nature to change our species even given a million years.
As far as your description of breast formation. Thats all good to get breast from small to big(just micro-evolution). But you still havent made them produce milk (macro evolution). Unless you believe that came about in one mutation. The nipple, the mammory gland, producing milk is a very complicated process. How did natural selection bring milk production into the picture.
The whole process you descibed about breasts, is using only natural selection. Natural selection requires a thought process(the way you describe it anyway). What about plants, and other living things that can't actually select by thought. They require actual physical advantages that are so good the members that don't have it die out.
Jim,
ReplyDelete(hastily written comments follow):
With regards to evolvable hardware, I don't agree that it is analagous to genes making mutations, but to natural selection creating a working design, i.e. new organism.
With regards to trillions of permutations - that was in reference to the whole history of life, not just the brief snapshot in which humans exist.
Mutation rates are quite well quantified and in our mitochondria, for example, mutation rates have been used to verify movement of populations and correlate to archelogical evidence. Sickle cell anemia is a mutation that gave humans an advantage in fighting malaria for example. I'm not sure observing a useful mutation is even a viable concept. How does one know its advantageous in the tiny snapshot of time we live in, i.e. one or two generations. I'm not even sure that Natural Selection even operates on modern humans given that mate selection is not based on traditional fitness criteria and that we control so much of our environment as to all but eliminate selection pressure.
I think you might want to read "Genome" by Matt Ridely. It is not about evolution, but one cannot help understand evolution a bit more as the story of the genome unfolds. It is very accessible and written for lay people.
Another resource that addresses your central concern is at www.talkorigins.org (though it will take some time to review all the materials)
They have a section on "irreducible complexity" and in that section a link to "29+ examples of macro evolution."
There is no need to continue debating me, I believe that site will plenty of evidence for you to mull over.
Good Luck,
Alan
One last recommendation:
ReplyDeleteIn "River Out of Eden" by Dawkins on pages 77-83 he describes research conducted by Nilsson and Pegler who used computer models to show how a "camera eye" can evolve from a simple "photo cell" in less than half a million years (assuming one generation per year). This accounts for the fact that the "eye" has evolved independently over 40 times with many different designs.
Also starting on page 84 a fascinating explanation is given on how the honey bee dance evolved - something previously thought irreducibility complex.
These might give you insights into the questions troubling you.
Let me try a different (but same) arguement. If it is changes in the enviorment that cause changes in species, why is this not a testable theory. Why can't we take species that have fairly rapid reproductive age like a fly or mosquito or ant. Put them in a contolled enviorment (such as an ant farm) change the enviorment in as many ways as we can think of using thousands of ant farms. Try some with gradual changes. Try some with rapid changes. We should be able to force evolution (at some level). You will probibly argue that we would need millions of years. But by definition, evolution happens one single mutation at a time (a collection of these supposedly brings out a macro evolution such as a eye), but we should be able to force mutations with sudden enviorment changes, that are more than just color changes. If it is not possible to do this then how could evolution respond to real changes in the enviorment. Do we think that real enviormental changes are something that happens with the species in mind?
ReplyDeleteWe also should be able to selectivly breed mutations to design anything we want. If Chance mutations can bring forth something like an eye, and if we have any understanding of the process whatsoever, then we should be able to easily selectivly breed macro evoltions. Or is chance smarter than intellect?
I appreciate the fact you guys are trying to point me to different resources to find the answers to these questions. Don't think I haven't done my share of research on complexity. I have been through the Talk Origions web site extensivly and done my share of reading on the subject. The answers are always more philisophical than specific. I can argue that anything is possible reguardless of how improbible.
The reason I picked this piticular blog to get into this is because I wanted to show how that it is the evolutionists that tend to use revealed truth just as much if not more than the creationist. You guys have done nothing to explain the issue at hand except to tell me to read other material, which tells my that you believe in evoltion without actually understanding the process yourselves. I understand why. How can something be so mainstream science and not be true? It must be true. I know you guys are thinking that I am a creationist. I truely am not. Although I leave the possiblilty that intelligent design is possible. I don't even go to church. I really am a evoltionist gone bad. I think we can think of evoltion through thought experiments just like Einstein did for relativity. Try to imagine what enviormental changes could accomplish. Try to imagine ice covered ground where there used to be savanna. Try to imagine what mutations could get a zebra through that and able him to survive. It all doesn't add up. Nature is extreemly delicate. As we have proven as we tread this planet and change the enviorment around us. We watch as we destroy the frail species around us. They don't change, they die. And the changes we make as humans are nothing compared to what mother nature has already accomplished as far as changing the enviorment.
There may be an explaination for life that we haven't even thought of yet. I think many people are afraid to question evoltion because they think that makes them religous. Yes, I am a Christian, but I would have no problem accepting Christ and evolution. Fact is I did for many years.
"Why can't we take species that have fairly rapid reproductive age like a fly or mosquito or ant. Put them in a contolled enviorment (such as an ant farm) change the enviorment in as many ways as we can think of using thousands of ant farms. Try some with gradual changes. Try some with rapid changes. We should be able to force evolution (at some level)."
ReplyDeleteIt has been done, many times. Indeed, my students can show you natural selection in action, changing populations both in the field and in the lab, any time you'd like. In some cases people have also been able to replicate the speciation process (in plants, insects, and even vertebrates).
But I'm sure somehow all of this isn't what you are looking for.
btw, since science works by competition among theories, what _exactly_ is your alternative, and why do you think it explains things so much better than evolution?
It has been done, many times. Indeed, my students can show you natural selection in action, changing populations both in the field and in the lab, any time you'd like. In some cases people have also been able to replicate the speciation process (in plants, insects, and even vertebrates).
ReplyDeleteKeep in mind Massimo that I am concedeing that micro-evolution is real. Can you show me a result where your students managed to create something that wasn't already there, as macro-evolution claims?
btw, since science works by competition among theories, what _exactly_ is your alternative, and why do you think it explains things so much better than evolution?
Massimo, this is where you are more than correct, and I fail. I have no competing theory. I guess for the time being, I just have to side more with I.D. I really just want people to know that it truely is not for religous reasons. As I said before I honestly don't know what I believe. Believe it or not many times I argue from the evolutionist prospective, when I am talking with a creationists. Guess I usually am just the devils advocate.
More than anything I just don't want people assuming that evolution is fact. the way science uses it today, fact of evoltion is assumed by pretty much every scientist. As long as this continues, I feel whatever the truth is, it won't be discovered. There may be some magical bond between I.D. and evolution (I realize I am not the first to say this). Never the less Massimo, I realize by not having a theory of my own to defend and just saying evolution is not true, is poor science at best.
I thank you (and Alan) for your debate. I will be back to visit you blog frequently, keep up the good work. Lets all keep in mind that revealed truth is a logical fallacy.
Jim,
ReplyDeleteThanks. One last comment. I do not "believe" in evolution or natural selection. I merely accept them as the best explanation presented thus far and will continue to do so until new evidence arises.
Also one critical distinction (you probably already know this). Evolution is different from Natural Selection. The former is the observed phenomenon and the latter is the theory of a mechanism used to produce the phenomenon.
Evolution is scientific fact. Where "fact" (as in all science) is defined (as articulated by Gould) is:
"confirmed to such a degree that it would be perverse to withhold provisional assent." The operative word being "provisional". I think we can all agree to that.
Natural Selection is more provisional and scientists acknowledge they still working to form a complete understanding of the mechanisms of evolution. I have no doubt that future scientific work will refine our understanding of Natural Selection or find perhaps augmenting theories. Time will tell.
Until then, in the absence of any competing "scientific" evidence, I also give Natural Selection my provisional assent.
(Even if God is responsible for Natural Selection and hand tweaked the mutations, it is still Natural Selection from a scientific viewpoint)
Thanks again,
Alan
Evolution is scientific fact. Where "fact" (as in all science) is defined (as articulated by Gould) is:
ReplyDelete"confirmed to such a degree that it would be perverse to withhold provisional assent." The operative word being "provisional". I think we can all agree to that.
I still have to refute that evolution is not confirmed to any degree whatsoever. I don't believe that evoltuion explains anything since we have no Idea how anything evolved. We just say things like this animal let to that amimal because they have similar anatomy or appearence. But it doesn't actually explain how or why using any detail whatsoever.
To me the key words in Goulds definition of fact is "confirmed to such a degree". what has been confirmed to any degree? In prior comments in this debate, Massimo campared evolution to other theorys such as relativity and quantum mechanics. The reason these can be treated as fact is because we have "confirmed them to such a degree". to confirm relativity, atomic clocks were put on the space shuttle and compared to atomic clocks on the earths surface. A prediction was made on what the difference would be between clocks. The prediction was confirmed. same with quantum mechanics. predictions can be made and confirmed. This is what makes them a "provisional" fact. Evolution does not meet that same criteria as these theorys for this reason.
Jim,
ReplyDeletewhat on earth are you talking about? Evolutionary theory, for example in the guise of population genetics, has made countless predictions about selective forces, changes in gene frequencies, fitness of organisms to different environments, and even long-term trends in the fossil records. And countless of these predictions have been empirically (either experimentally or observationally) confirmed. To claim otherwise seriously distorts the scientific facts. If you want examples, again, just pick up any textbook on evolution, for example the one written by my colleague here at Stony Brook, Doug Futuyma.
I suspect that your skepticism derives from a misunderstanding of the nature of historical sciences (as compared to the physical ones -- though please note that astronomy is entirely historical and observational, and yet nobody has questioned its status as a science). If so, this paper by Patricia Cleland would do much good: Cleland, C. E. 2001. Historical science, experimental science, and the scientific method. Geology 29:987-990.
what on earth are you talking about? Evolutionary theory, for example in the guise of population genetics, has made countless predictions about selective forces, changes in gene frequencies, fitness of organisms to different environments, and even long-term trends in the fossil records. And countless of these predictions have been empirically (either experimentally or observationally) confirmed.
ReplyDeleteSelective forces, Changes in gene frequencies and fitness of organisms to different enviorments are:
1. Could be processes of only microevolution
2. When you speak of predictictions made, you are talking about experiments leading to prediction. example: by changing the waters alklinity we noticed the gold fish had a change in gene frequency of such and such. Then use this info to make a prediction of what will happen if waters alklinity is raised. It is really just obsevational micro-evolution.
As far as making long term predictions in the fossil record. How in the world could that be accomplished? I't wouldn't matter how much info you could attain. that prediction would be literally impossible due to unpredictable factors.
I am just asking for one prediction that would validate Macro-evolution. Predict that some where in the world (any species) we will see some mechanical hardware that was not previously there
Jim Fisher,
ReplyDeleteWhat you are asking is nearly impossible, and I think you know that. Due to the stochastic nature of evolution, it is hard to make predictions about when and where individual species will evolve. Does that refute evolutionary theory? No. Just like quantum mechanics is not considered refuted because it cannot predict when an individual uranium atom will disintegrate. What counts is that both the theory of evolution and the theory of quantum mechanics are the best theories currently available, despite their many imperfections. Live with it.
Cheers
Ido
Ido,
ReplyDeleteYou are correct I do know it is impossible to predict any evolutionary outcomes. I am a little suprised missimo is saying it has been done. But shouldn't one prediction be that we (even in one lifetime) will witness a significant mechanical change in some species. Not a simple micro evolution, which only involves size, shape and color. A real piece of macro evolution. We don'thave to predict what it will be , but shouldn't we witness something somewhere. There is supposedly millions and millions of macro evolutions. But we can't witness even one real tangable mutation (not micro) that has a benifit.
Jim Fisher,
ReplyDeleteI have the feeling that if I give you an example of speciation that has been observed, then you will repeat that it’s an example of micro-evolution. Speciation doesn’t necessarily require big changes in the way organisms look. Big changes take big time. Scientific progress these days is measured in units of 3 or 4 years, because that’s how long it takes to complete a PhD thesis. Why don’t you specify more precisely what it takes for an evolutionary change to be considered “macro”?
Although it would be difficult to actually witness a mutation, how about a mutation that changes the bird flu virus into a virus that can infect humans and spread airborne from human to human? That virus would have a clear selective advantage (greater survival in air) and we could sequence its DNA to see what mutation had occurred.
Best wishes
Ido
Jim,
ReplyDeleteI have to agree with Ido. I'm not sure there is a separate thing as "macroevolution" -- its just microevolution over a long period of time.
I'm having trouble imagining any new "hardware" that wouldn't appear as microevolution given an arbitrary snapshot of time.
How long have mammals been around? 120 million years according the latest evidence. I would argue that all distinctions between a rodent and a human are microeveolutionary changes -- we pretty much have all the same parts, just in different geometrical arrangements.
Therefore to observe the type of "macroevolution" you suggest may take 500 million years plus. Other than bacteria which are not very complex, what organisms (even fruit flies) reproduce so quickly as to allow any kind of laboratory experiment that would show such a change in our lifetimes.
Even then, how could you possibly know you were introducing the right selection pressures. In an experimental environment you would be limited to just a few selection pressure options whereas nature had countless of pressure operating in complex interactions.
Finally, I think you discount just how technical the field of biology is. I know next to nothing compared to a trained molecular biologists doing research in the field. There is not a mass conspiracy to convert all biologists into Darwinists. I know that's a bit of argumentation from authority, but if you believe in televisions, CD players, computers, airplanes and anti-biotic then there has to be some acknowledgement that the very methods that have led to the discovery of the science behind those technologies cannot suddenly be invalid with respect to the cornerstone of modern biology. Newton's theories were not invalidated by quantum mechanics, just augmented. In the same way (as I said earlier) refinements and new knowledge may augment the gaps in Natural Selection/Evolution, but to say that "evolution explains does not explain anything since we have no idea how anything evolved." is a bit of a stretch.
Here is a posting (admittedly about observed microevolution) about a very interesting experiment that also involves some advance topics such as polygenic and polyphenism . See if reading this can you appreciate a little more of the rigor that is applied to evolutionary science and how much it is backed up by molecular biology: http://www.pandasthumb.org/archives/2006/02/evolution_of_a.html
In this experiment scientists "directly observed the evolution of a complex polygenic, polyphenic trait by genetic assimilation and accommodation in the laboratory. This is important exploration of mechanisms of evolution—shows that evolution is more sophisticated than changes in the coding sequences of individual genes spreading through a population, but is also a consequence of the accumulation of masked variation, synergistic interactions between different alleles and the environment, and perhaps most importantly, changes in gene regulation."
Jim,
ReplyDeleteFYI - To see the full URL above you have to view the comment in the "permanent link" mode.
Alan
P.S. - why do allow myself to get drawn into these things :)
Alan, Ido
ReplyDeleteYou make a great point that I can just right off any variation in nature as micro evolution. Since the definition of a macro evolution is supposedly the sums of many micro evolutions then how can a macro evolution be witnessed? Valid arguement.
So first let me give my definition of a micro and macro mutation. To me the difference is about weather or not something new is created. If it is truely new then we can consider it a macro evolution. So first a proper definition of micro evolution. This is my personal definition (from doing thought experiments). I dont know what the scientific definition is but my own definition is
Micro evolution is changing only the size, shape or color of an exsisting mechanical feature. For example, humans have breed many types of dogs by selecting specific features of the dog and changing their size, shape or color. But the end result is that every dog has the same exact mechanical body parts reguardless of how different they look from each other. No breed of dog has gills to breath under water. No degree of breeding and selection could give a dog gills. You could change their enviorment so that they must swim 18 hours a day. But you still will never get gills on a dog. Now in fairness, you will perhaps say that it would take millions of years for a dog to develope gills and just the right enviormental changes. My arguement is that the total gill isn't the only macro evolutiuon. Each part that makes up the gill could be considered a macro evolution. If you can get just the slit opening, I will give you that this could be considered a macro evoltion (as long as the slit could serve as some purpose). The slit can't just be some genetic defect. It must be a genetic defect and serve purpose or else it wont make it on all dogs of that species.So the definition of macro evoltion is a mechanical change that does not involve just size, shape and color. It must be something new. You can't get eyes, lungs, hands, feet. By just changing size, shape and color of single celled animals. Somewhere, somehow there must have been drastic mutations that resembled fingers and knuckles to form a hand and each one of these drastic mutation had to serve as a great advantage by itself. ther must a been millions and millions of them through out the history of nature and for every one that worked there must have been 10,000 that didn't work. Why don't we see any of these mutations now? (not micro mutations, Macro!)
Hi Jim,
ReplyDeleteHere's the problem I have with your current argument: Let's say we did have what appeared to be observable species change in the form of transitional mutations (which is what I think your looking for, but please correct me if I'm wrong). The ID'er/creationist could easily argue that what we are observing is not really species change. Because, let's face it, both komodo dragons and polar bears have four limbs; that doesn't mean that they have an evolutionary connection. And they could easily keep pushing the criteria further and further up in order to keep rejecting evolution (as they have with the fossil record.)
So the question is: what would we have to observe in order to accept so called macroevolution has taken place?
Personally, I think you can observe these changes in nature. Consider the platypus, an egg laying mammal, or the relatively recent fossil finds of dinasours with feathers, which now show a clear connection between them and modern birds. The common ID/creationist response has been exactly what I mentiond in a previous paragraph.
Noah
So the question is: what would we have to observe in order to accept so called macroevolution has taken place?
ReplyDeleteMy point is, in order for macro evolution to work there has to be an abundance of macro mutations in nature. The platypus has looked the same throughout recorded history. In order for macro-evolution to be possible there should be observable physical mutations (micro and macro) constantly even if they are not part of a whole complicated mechanical devise (such as a hand) Such as: in order for a hand to come about through evolution. There must a been a first major macro mutation (perhaps just the palm) that somehow gave the peticular member of that species some advantage that was so great only him and his offspring could survive. The rest of the members of the species either must die out (for not having this piticular mutation) or get seperated. For every one of these macro mutations there should be thousands of others that are useless and mean nothing(since chance mutations are responsible for the process). we should see these strange physical mutations constantly, even if they don't present an advantage (for every one that presents an advantage there should be many that don't).
Combine the fact that we very rarely see physical macro mutations in nature. How the heck can a species respond to an enviormental change.
Let me give an example of micro evolution (you have probibly already heard) that is made up.
A species of horse like animals lives in the savanna and feeds off of grass. Suddenly there is a drought, and all the grass dies out. There are a couple of horses that have rare gene mutation that makes their necks unusually long. These few members can reach the leaves in the trees and manage to survive eating leaves. The rest slowly die out. Now the species gradually gets replenished by the longer necked members. This is an over simplified thought experement showing micro evolution is possible. But nothing new was created the animal already had a neck, it just changed by either size, shape or color. In order for micro evolution to be possible we should see an observable variation in all species components involving size, shape and color. This is true, every person we know has different size shape and color appendeges and features.
In order for macro evolution to be possible we should see a huge variation in actual gross mutations. For example (hand again) one guy has an upside down palm at the end of his arm. One guy has a sideways palm at the end of his arm- and so on. Then for some reason the guy who has the palm the right way has some enviormental advantage. Again,I am over simplifing with a thought experimant. But never the less in order for macro evolution to be possible, there should be a huge number of macro mutations observed in nature, in order for chance advantages in the changed enviorment to bring out usefull ones. This is absolutly nessisary for macro evolution to work. Yet we dismiss the absense of these mutations and replace it with philsophical reasons why we don't have to see them.
Yes if you drop thousands of matches on the floor over and over they will form letters and maybe even words, but youhave to have the matches. We dont have the physical mutations required for macro evoltion.
Yo Jim,
ReplyDeleteTwo comments. First, major discrete “innovations” are relatively rare. As Alan argued, all mammals are at least morphologically (let’s ignore behavior for now) topologically equivalent: you can imagine how one mammalian species changes by a continuous transformation into another (like your giraffe example). Second, it’s quite conceivable that even major innovations evolve quite gradually. The standard example is the eye, and even though I think nobody knows what sequence of mutations has transformed an eye-less ancestor into a descendant with eyes, people have come up with plausible scenarios, where each additional mutation yields a benefit. Your favorite example is the hand, but it’s not so hard to see how a hand (or paw) evolved from the fins of the first fish that spent part of their time on land (such fish still exist). Such relatively small mutations have been observed many times (also in humans).
To summarize: (1) Big beneficial mutations are probably rare. (2) They might be of minor importance.
You say its not so hard to see how a hand could evolve from a fin if the fish walks on land. although the fish knows he is walking in land, his fin doesn't know nor can he think to put a mutation on his fin for the next generation. So lets say that the first mutation is a bump on the bottom of the fin which gives that peticular fish a traction advantage while walking on land. We can all see how that would be an advantage. And perhaps this fish beats the other fish to the food and eventually the fin with bump on bottem members of the species end up replacing the whole population. My delemma is that evolution does not know to put the bump right on the bottom of the fin. So there would have to be thousands of fish with bumps in all different spots on its body, until one day a fish appears with one one the bottom of its fin. This is the chance end of it.Not only would there have to be thousands of fish with bumps but also every other concieveable macro mutation (all different shapes and sizes) would have to cover the fish for one of the right shape and size to end up in the right spot (on the bottom of fin). This is why I say if macro evolution were true we would see all species covered with macro mutations. Evolution cant think, it happens by chance. In order for it to work the numbers would be so vast nature would be an ugly monster. In oreder to get the palm at the end of your arm it would have to appear at every concievable part of your body.
ReplyDeleteJim,
ReplyDeleteYou say: “In oreder to get the palm at the end of your arm it would have to appear at every concievable part of your body.”
The mechanics of development suggest that palms would not be equally likely to show up at any position of the body. However, there are well-known mutants of fruit flies that have legs on their heads. Does that qualify?
Ido kind of stole my point. But here goes anyway. The bump might be more likely to appear at an extremity, since the mutation might affect the production of a protein. Instead of "stop right now", you get "hang on just a second longer, now STOP at once!"
ReplyDeleteWhat I get from my reading is that we should think of the genome as a recipe book, rather than a blueprint.
So much for my history/English major two cents worth.
P.S. "Argumentation cannot suffice for the discovery of new work, since the subtlety
of Nature is greater many times than the subtlety of argument. "- Francis Bacon {English 401}
ok, sounds like a lot of ground was covered but Jim still sees a gap between observation and theory. I commented earlier on the human eye. I said "ask a blind person if a barely functional eye is better than none at all" - Jim missed my point.
ReplyDeleteJim wants to know how one can get from no eye to complex human eye? This would be a 'macromutation' right? Well, complex eyes and other complex structures don't appear fully formed. They also don't appear in useless intermediates - every intermediate HAS to be useful or it wouldn't be selected, right? (all the intermediates that are not useful don't get selected and thus don't /rarely get fossilized or seen by biologists)
So no, we won't see eye sockets appear 'waiting' for the eye to evolve! We will see, and we do see, lots of species with light-detecting organs that don't do much more than detect light and dark. These are simple eyes - not image forming.
This was my point - the blind person doesn't want a barely functional eye in order to appear normal, he wants a eye that, say, detects light and dark, rather than no eye at all. There MUST be some functionality to the intermediate stage (which I think Jim knows...).
Thus theory predicts that macromutations aren't common because most things we consider huge, complex and 'macro' actually are the result of countless micromutations - all with functionally useful intermediate stages.
As such we would only see micromutations in nature, and the end result would be complex human eyes (and note that this type of eye evolved at least twice, if not more - vertebrates, cephalopods, and cubozoans (box jellies)).
Wow, nothing like a bit of good ole evo x ID to fire up the comments section.
ReplyDeleteJim,
Glad to see you are actively looking for information. I have a few comments, some more examples, stuff like that.
First, you got to think again when you say something to the effect that "people just take what the scientists say as true, therefore fallacy". Not that it's wrong in principle or for most people, but remember Massimo IS a scientist, and in the field of evolution, so he's not simply "taking what scientists say as gospel". He's seen a lot of the original research and he's doing his share of it, I'm sure. As is the case with other people who hang around this blog (me included).
Now to some specific examples about evolution. You complained about predictions and long term fossil records, how would it be possible. First, prediction here does not only mean things that will happen in the future (like future fossils), but mainly things we will discover in the fossil record someday. With that in mind, consider this:
First, a bit of simplified geology in case it's needed. The soil we walk on is ground rock, generated over time by forces of erosion (water, wind, etc). With time, soil piles up, and the older the soil, the deeper it will be, I think you will agree. And, with pressure and temperature, this soil becomes rock - sedimentary rock. Now, some organisms which happened to die and get buried in such sediment, will stay there, and become fossils. So, it's easy to see the same principle applies here: the deeper the fossil is located, the older it is.
So here goes a prediction of long term fossil trend for you: you won't ever find a precambryan (>500 mi years old) rabbit fossil (I think Richard Dawkins came up with this "challenge" to anti- evolutionists, but could be somebody else). You can look as hard as you want. Why is it so? Because rabbits (and mammals before that) evolved from reptilian ancestors much more recently than that. Another similar prediction for you, which I just made up: you won't find a fossil ape among dinosaurs. Same reasoning.
Micro and macro. Don't get so caught up on this terminology, it's misleading, I think. As somebody already pointed up, what looks "macro" now is just a lot of "micro" piled up over geological time - and all intermediaries disapeared, contributing to the effect. Mutations are mutations, no micro or macro.
But then you will repeat your charge of "how good is half an eye/mammary gland/reproductive system/hand/whatever?" Here, the problem is that, again as other pointed out, you take the current product as the only possibly functional version, anything less wouldn't work (irreducibly complex). Of course nobody can give you the minute-by-minute movie of things evolving (and if you insist evolutionists do so, please also ask the IDers to give you a the same for their "alternative"), but here goes one example as illustration: ever heard of those "funny" mammals from Oceania, the equidna and the platypus? They lay eggs, like our reptilian ancestors. A little bit more modern are the marsupials, like kangaroos and opussums: they give live birth, but the thing is a tiny embryo whose only capability is to crawl up the mothers fur and get inside a pouch, where a tit will feed them for the rest of their development. Kinda clumsy, but way better than laying eggs. Not consider another step "up" in the effectiveness of the process: the "pouch" stays inside, and the feeding comes straight from the maternal blood, so the embryo only has to leave the mother when it's pretty much complete - some of them go right away running and feeding. Can you see how a less sophisticated system could gradually change to something that seems impossibly complex, but is actually the result of many small optimizations (which we can't see because we don't have many of the intermediary states present anymore)? And keep in mind that some snakes, for example, don't use external eggs anymore - they hatch inside the mother. Is this going to become something similar to the mammalian system, or something completely different in mechanism, we can't say. But I think you get the point.
Staying with the platypus and equidna, and now looking at the mammary gland problem: they also give us good clues about what happened. These animals literally sweat milk over an area of the mother's abdomen, and their babies lick it (mammary glands are modified sweat glands). Again not very efficient. But it does not take a revolution to imagine these many little glands getting closer together in some animals, making the process more efficient - concentrate the milk in a smaller area, less loss, better baby survival.
Another thing I do have to say: evolution IS a scientific fact. You seem to confuse, as is common, evolution (change over time, as seen in the fossil record or in gene pools, for example), with the mechanisms that acted during evolution (like natural selection, genetic drift, exaptation, etc.) There is no doubt that evolution happened. What we're working on is the mechanisms. By the way, there must not be some functionality/ advantage for every single little thing that happens - there are more mechanisms involved than natural selection, and neutral or even slightly disadvantageous traits can survive for a long time in a population.
Last but not least, you sometime said that the environment drives the species to adapt. That's a common misinterpretation too. There is no directing involved. What environmental changes do is eliminate organisms that didn't have some pre-existing characteristic that is now advantageous.
There are many other examples and explanations that came to my mind as I read your questions, but I've already written way too much (as is my habit).
I hope I helped at least a little bit.
Cheers and keep learning
J
Ido said...
ReplyDeleteJim,
You say: “In oreder to get the palm at the end of your arm it would have to appear at every concievable part of your body.”
The mechanics of development suggest that palms would not be equally likely to show up at any position of the body. However, there are well-known mutants of fruit flies that have legs on their heads. Does that qualify?
These two comments contradict each other, but yes a leg showing up on a flies head does in a way qualify. What I am looking for is not so much a complete complex item appearing somewhere else on the body (although this happening does go against my argument), but the first step of a complex (like the bump on the fin) appearing in every concievable spot of the body at some point in time until it becomes an advantage somewhere.
Lily,
I still dont understand why the bump doesn't have to appear everywhere because it might affect the production of a protein? Chance dictates a mutation. If it survives or not depends on if it has a mechanical advantage. Thus any mutation should appear thousands of times before it is used.
Derek,
You are hitting the nail on the head. I have read the summary of parts of the eye evolving. And does sound practical for each part. except that each part (which was a considerable change)just happens to form only at the eye. So it the eye started with just light sensing cells (which would still need a connection to the brain, so that connection by itself needs some advantage without the light sensing cells), anyway, 'lets just say it starts with light sensing cells. For them to appear on the human head by chance. then they should appear all over the body at some point prior and after. As should every piece of every macro evolution. Like I said for it to mathmatically work nature would be an ugly monster.
i,
My comments were in no way directed at Massimo (had no idea who he was when I came across this site through a link). Let me say, that so far you have given an excellent arguement with your examples. First, about not finding newer species in older strata. I can't refute this. This is the single best arguement for evoltion to date in my mind. Unless I argued that I.D. is an ongoing process from God, which I will not. Although it is possible, and I wont leave out that possibilty, one could argue that ID. should predict that new species will suddenly appear if this is true.
I still disagree that macro is just a sum of micro's (per my own definition). Micro just being the change in size, shape and color (which we witness), cannot be responible for a complex feature. We can say a macro (such as hand) can be a sum of smaller mutation, but each of those mutations has to be new features.
I am not looking for a minute by minute account for evoltion, I understand this is impossible. But I am saying wwe should be able to make something up (for minute by minute) to show that it is possible (does not have to be accurate). Although I have seen this done with objects (like the eye) I still found leaps that don't explain why these mutations only find there way to the eye and not the rest of the body. Like I said, dropped matches can find there way to make letters and numbers, but for every letter there are thousands of matches that do nothing.
Great example with the kangaroo and possum. I curious why you say it is better than laying eggs? In some ways the Kanagroos process could be considered an advantage over human reproduction. Since the kangaroo is pregnant for much less time developing its embrios on the outside would make her more mobile. Point being it doesn't seem intermetery. Still has all the componets of mammel reproduction (perhaps more).
You say there doesn't have to be an advantage for every little thing that happens. I can't argue that(since it defends my point). But I can argue that not only does there have to be an advantage to evey component of a complex feature, but for every one that is an advantage there should be thousands and thousands that are not advantagious.
I apologize for not responding sooner, I am ususally not on from Sunday to Tuesday. I really want to thank eveyone for their comments. Very intellegnet, and I am being swayed back and forth.
Jim
ReplyDeleteI'm not sure if I'm going to answer any of your questions directly in this comment, we'll have to see where it goes. I just wanted to tell a story.
I've always been interested in evolution. When I was a teenager (50's-60's), I did some reading on it. There was a penguin book by John Maynard-Smith, and some books by Julian Huxley, which I devoured.
Then I stumbled on another kind of book, which threw me for a loop. It was Creative Evolution, by Henri Bergson. He wasn't too fond of either Darwinism or Intelligent Design (he called them Mechanism & Teleology; incidentally, he lumped the two together since he regarded Teleology as a mechanical tinkering from the outside). He thought that neither of them did justice to the organisms ability to respond creatively to things around them, and proposed a kind of creative force he called the élan vital. He offered the eye as a sort of test case for his hypothesis. The human eye and the octupus eye are two complex structures that are very similar but unrelated to each other. What could explain this convergence, if not some creative internal force? The whole thing was expounded with tremendous intelligence, I thought.
Years later, when I retired, the first item on my agenda was to do some reading, particularly to find out more about this whole evolution thing. I went to the bookstore and came out with Daniel Dennet's book Darwin's Dangerous Idea. More a book of philosophy than biology. He relates Natural Selection to computer science, artificial intelligence, etc. He presents life as a sort of game of design, in which the right moves have to be found to keep the game going. For example, Metabolism: "If you want to live, you gotta eat". Some moves are so important that they have to be considered "forced moves"- as for example, eyes for a moving animal.
So here are two versions of the evolution of eyes. One philosopher says its élan vital, the other said it's such a good idea it's almost necessary.
But here's the thing. There's a gene called the pax-6 gene that biologists think is implicated in the development of eyes in all the instances where eyes have developed- over 40 of them. This is a surprising fact that neither philosopher was in a position to predict. But it sure seems to answer a lot of questions. Hence my Bacon quote earlier.
Anyway, back to the bump. I don't think it's a question of an individual species. Why is there a bump on the finger, and not somewhere else? Probably because Nature has been working on the bump question for millions of years. Let's say a creature of a few hundred cells develops a protuberance which can stir up the water and hence draw food toward it. This is advantageous, and is passed on to descendant species. Maybe in one of these species the protuberance gets longer and the critter can actually move itself in the direction of food, which is a greater advantage. Now the bump is locked in. Not much point in having a bump on some other part of the body because the bump we already have is working so well. The new bump will be washed out in a few generations. But the original bump has gotten more sophisticated. It starts to become curved on the end, sort of cup-like, good for swimming. All this is passed along to descendant species. Then in some species the bump becomes thicker and sturdier, and the organism can sort of lift itself up in shallow water to ingest oxygen. Then it loses its cup like quality the better to plant itself with, and later the bump becomes a leg and foot, etc.
Similarly the eye: just a light sensitive patch in some simple animal that enables it to detect the presence of danger, but as it grows more complex a certain pathway is preserved and handed down. This pathway is like a recipe that is followed by every embryo in developing an adult eye. Same with the bump. But if the bump changes it's because the recipe is altered slightly, do this longer, add more influence from this other gene, say a thickness gene. If a new bump developed on some other part of the body it would have to compete with the already functioning bump and would get nowhere.
I have a feeling that someone with greater scientific leanings could explain all this in about two sentences.
Mostly what I'm saying is that for a feature to develop on one part of the body, there is no need for constant experiments all over the body, since the site for that particular feature was probably established a long time ago, and is embodied in a particular pathway. It is this already successful pathway that is the subject of further modification.
Enough for now.
Lily,
ReplyDeleteCreative Evoltion sounds facinating. I will surely give it a read. I have tried myself to put them together without any sucess. Its funny, I watch discovery science channel quite often. Love those Dino shows (makes me feel like a kid). They always say things like "mother nature then designed a" or "evoltion decided that the species needed a". My wife and I always laugh that they think it Ok to give evoltion personal qualities. If only there could be some way of giving intelligence to evoltion and keep it in a naturalistic view. It would perhaps be accepted. But what could that be? when the definition of naturalistic is - made or changed without artifical means. And since we all accept intelligence as artificial, it can't happen.
I wonder do most evoltionists believe in God or a creator for the universe in general? Or do they feel that Naturalistic causes just keep going backward in time forever?
I think you lost me a little on the bump thing. but I think what your saying is that the reason that a bump for the fin would not be all over the body and only appear on the fin is because the information was already there from a previous mutation that happened much earlier. For this to work all features would have had to start its evoltion back when it was just those few hundered cells. The eye would have had to start prior to it being an animal already, as well as every other feature.
Jim
ReplyDeleteI guess I was suggesting a building block approach,e.g.,once a limb has developed, the question becomes what can the limb be used for or adapted to- flying? swimming? walking?
As for Bergson, I did mean to suggest that a better understanding of control genes, like the Hox genes and Pax-6, might eliminate any need to postulate some such quasi-mystical entity as the élan vital. By the same token, Dennet's reasoning on "forced moves" may be true as far as it goes, but it certainly makes more sense if it can be combined with actual knowledge of how things work.
Jim,
ReplyDeleteLily's bump explanation was very good. If it lost you then go back and read it over and over.
I had much the same thought in that the basic genetic blueprint for limbs goes way, way, way back in evolution and whether its a wing, a fin or a hand is a result of an abundance of micro evolutionary changes.
As Lily explained the formation of limbs may have started out as a simple feature, but once established and encoded the genome had momenentum in direction of modifying limbs that already existed (no matter how simple, i.e. a bump)
In math we would say it had degrees of freedom in the direction of improving the limb because the genome had committed in that direction, but once the basic plan or recipie for 4 limbs had been established then adding a new limb say coming out of the middle of the dorsal section would have required radical macro changes of the type you (for good reason) cannot fathom.
To me, it still boils down to incremental changes. The whole idea of limbs may have been radical at one point, but need not have started out as much more than a bump (again as Lily quite brilliantly explained)
Alan
Jim,
ReplyDeleteOn your other comments: Ascribing intelligence to evolution is always done in the anthromorphic sense. I usually try to avoid such language myself precisely because I think it confuses people.
I have not read about Creative evolution, but it strikes me as fanciful unless it is asserting that the animal's intelligence and resulting behavior contributes to the resulting selection and advancement of certain traits. But this does not contradict standard scientific evolution.
Finally, your question about whether there is purpose in the Universe is a complex and interesting one that may never be answered. An excellent discussion of this can be found in the last chapter of Paul Davie's "The Fifth Miracle". Being agnostic, I don't necessarily rule out the existence of a pantheistic or deistic creator or even some undiscovered "laws" that makes the Universe biased towards the creation of life (and intelligence?). However, the scientific method must assume a naturalistic viewpoint. The rest falls in the domain of philosophy or theology. What if our whole Universe existed as a science experiment in the lab of someone in another Universe? How could we ever know? It is a question beyond science which exists to explain the world we do know. If science finds real indisputable proof of an intelligence tampering in evolution, then there will at least be evidence to further what now remains a philosophical/theological discussion.
So, for most people there is no necessary cognitive dissonance occurring between the naturalistic viewpoint of the tool of science and our speculations about the ultimate nature of the Universe. Those speculations range from positive atheistic materialists to the many forms of Deism/Pantheism (totally accepting of science) to those folks with specific religious beliefs, i.e. Christians who believe evolution was God's tool.
Alan
Your right Alan, lily's explaination is very good. I did need to read it several more times. I am very slow to absorb things. Although I am sorry that I still can't get over the complexity issue. At the same time this fin allowed the creature to raise himself above the shallow water, lungs would be needed and other features. So you would need simultatious mutations in single members of the species. And each one of these simultatious mutations would have to have its roots back when it was just a few hundred cells. As well as to get feet from the origional bump you would still have the mathmatical issue of mutations needed to get the toes and other parts of the feet. There should be thousands of other members with the bump and toes all over the place, unless you can explain every single part of the complex foot having its mutational roots going back to when it was just a few hundered cells. My point is some where evoltion needs the capability to just create totally new features that dont trace back millions of years or it would be severly limited as to what could be accomplished.
ReplyDeleteJim,
ReplyDeleteThere was something I was trying to find on the Web, but could not. I will just have to describe it for you. From Ernst mayr's book What Evolution Is, pg.26, Fig.2.7:
It shows a human's arm, a cat's leg, a whale's fin, a bat's wing (a mole's digging apparatus is also mentioned in the text). What is quite stunning is the common body plan of all these limbs: ulna, radius, humerus, carpal, digits (5), are all present, though proportioned differently, and with different coverings as it were. Now I realize this still leaves us with the problem of where the body plan came from in the first place. But the point I want to make is that this seems to be an instance of Natural Selection at work (NS is generally considered to be the source of adaptation)- and not just for trivial differences in size, colour & shape. The basic body plan has already done most of the heavy lifting, so I don't think it's too much of a stretch to say that Natural Selection is responsible for these structures, especially since we can observe its more limited effects in experimental and current natural settings.
I've also been thinking of those eyeless fish found in the utter darkness of caves. The eye structures are present but are buried under the skin of the fish, so they are not functional. I cannot think of any explanation for this that does not involve natural selection. Either NS is totally absent because sight does not matter in that environment, or NS favours the sightless fish because it is too costly to maintain eyes in the dark (perhaps they require an excessive amount of vitamins, for example). Funny, it is usually possible with design issues to entertain the logical possibility that God did it, but here no! because it does not make sense to say that God designed something that did not work. But the real point I want to make is this: if this is what happens when NS is not operating, then it must be that NS is like the air we breathe. We may not appreciate it, but we cannot live without it. Is it possible that NS is the necessary condition of every adaptation, every function that we see, even though its presence is normally hidden, and only exposed sometimes, as with the eyeless fish?
It is all too easy to trivialize Natural Selection.
As for the body plan, I don't know much about it, but the so-called HOX genes are involved, I suppose.
Lily,
ReplyDeleteAs far as your example with eyeless fish being the result of natural selection, I have no issue with that. This is just an example of loosing something not needed. I will give you another example (i am sure many people have thought of but I never read). Many of us humans get our wisdom teeth removed due to recurrent infections and other reasons. Since humans have the technology to enable us to remove these teeth and survive, we will never evolve a finer species that has a perfect mouth. Looking at the mouth of most primates, they protrude much further than our own mouth, allowing it to hold more teeth without issue. So if humans did not have the technical advantage of modern medicine. We would perhaps evolve into a species with either less teeth or a smaller mouth that can handle the same number of teeth more effiecently. But to me this, as well as sightless fish is still examples of micro evolution.
As far as your point of differnt animals having features with five digits. This is a very good arguement for natural selection. I guess the question from my prospective is - Is the five digits better from a design standpoint, even for someting like a fin? Or is this actaully an example of natural selection. Either way it does not solve the complexity from origions issue (as you stated).
Another example similar to the fish you spoke of is the snake. It still has remenents of digits from a hand or foot. I read about it in one of my evoltion books (not sure which one). But they show a picture of the skeleton of a snake (not sure which species, could be all?) that has extra bones where legs would be if it walked like many reptiles.
unfortunatly most (all) exapmles we have of natural selection being a process of evoltion involve loosing rather than gaining. I need to see how we gain, since we origionated supposedly from micro.
Jim
ReplyDeleteI don't want to get bogged down in this, but I still have a couple of points to make.
1. I don't believe the bat's wing etc. are what most people have in mind when they speak of micro-evolution.
Usually the refrain goes: "Sure there was evolution, but the dog is still a dog, etc.". These adaptations are a mammal-wide
group of phenomena. The changes were not directly observable, as is sometimes the case with lengths of beaks or thickness of coats of fur, but the relationship is fairly obvious. The adaptations themselves are rather major. If you insist on calling them micro, then they must be macro-micro, as opposed to micro-micro. The fact that they are elaborations of the same body plan shows how evolution
works, by modification of existing structures. As for the body plan itself, it has its own history, probably involving control genes
and gene duplication, etc. The reason I thought the example was compelling was that the changes were rather major, and yet it was no stretch to see that they were fairly straightforward adaptations.
2.I'll bring up another one: the development of the mammalian inner ear. mammals supposedly evolved from reptiles, but the reptile has a simple ear structure, with a complicated jaw structure. The mammal has the reverse. And yet there is a good series of fossils showing the development of mammalian inner ear bones from reptilian jaw bones. The functioning of the ear is saved harmless through the whole process. But there is a problem with the jaw. The hinge has to move! But sure enough there are intermediate fossils showing a double-jointed jaw-bone. What is interesting about this scenario is that, without the fossil evidence,
you and I would probably not believe it. Which is a point worth pondering.
If you want to read more about the reptile's jaw, you can find a good account, with drawings, on Talk Origins, 29 evidences for
macro-evolution, Part I.4 Here is the link.
Dawkins spoke of arguments made from Personal Incredulity. For me the above examples balance any Personal Incredulity
that I may feel. Personal Credulity? perhaps.
Lily,
ReplyDeleteYou are awesome to keep going with me on this. I am printing out your link right now so I can ponder it while I am working (I am a group leader in manufacturing, so I read it while I walk around the floor and people think I'm looking over machine data or something). I have read this some time ago, but it has been a while. I will post back in a few.
Lily,
ReplyDeleteOn the surface this looks like an excellent picture of transitional species. But I still would have to understand why each fossil change has an advantage over the previous one. The end result is perhaps a better ear. Perhaps the mammal can hear better than the reptile, so it is a better hunter. But why did the very first change take place? On figure 1.4.3 it shows each transitional species. Look at the very first one on the bottom (Primitive synapsid), Then this turned into the Dimetrodon. Why? what was the advantage here? The changes between the two are just geometric and dont appear to have any real purpose. And back to my origional point. To get this change in geometry from a mutation, there must have been thousands of other geometric mutations that did not have this advantage (unless evolution can think), whatever the advantage is supposed to be, but there must be one.
On the other hand, what else could the explaination be, besides this is an evoltuionary progression? I would have to say that these are just all seperate species. If I say that then I am not explaining why it appears to be a nice smooth transition.
Then on the other hand I could still argue this to be micro since nothing new was created, the whole progression just reuses exsisting parts and litrerlly changes them by size and shape. I know I am a broken record but I still want to see how the orgional parts form from one celled animals. Or how one celled organisms formed from microbes and so on.
Jim,
ReplyDeleteLily gave you a nice example how something new (the mammalian inner ear) probably evolved, with several examples of intermediate fossils backing up the hypothetical history. Such intermediate forms were predicted by standard evolutionary theory before they were actually discovered. I would say that’s quite a feat, even though it’s not solid proof. Surely you realize that nobody can answer all your detailed questions about the specific function of each form. Again you argue that this is yet another example of micro-evolution since “nothing new was created”. But new things were created here. There was no inner ear before. I could use the same line of reasoning to prove that humans have never invented anything new. Name me a human invention, something really “new”, and I will argue how it is just a minor modification of something pre-existing, a micro-invention.
Ido, Lilly,
ReplyDeleteYou are right, if I just keep saying this is micro, when supposedly something new was created, then I am really being lame ass (seriously). Also, I am being too demanding about particulars that can't be known when asking for each advantage. I will agree with that.
You almost have me sold, but I need the one last thing
Looking at the first transition (same example I pointed out before), look at the quadrate. It changes severely. I was asking for the advantage of this change. You guys say we can't know what every advantage was. I will buy that. But we agree their must have been some advantage even though the actual function of the quadrate did not change (as unlikely as that is, I will buy it). My point is that the geometric change between the two parts is huge (especially on the second transition of the quadrate). In order for that change to take place by random mutations there must have been thousands of other mutations that did not work in order to get that one change that did work. There must have been every imaginable geometric configuration to the quadrate and all but that one, did not work. This is where I say nature would have to have a super high mutation rate to make this change (so much we could constantly witness it). You could argue that there are many mutations between these two fossils so they are much more subtle changes that is why we don't see the mutations (non-beneficial ones) constantly. But if the changes were so subtle then how could they have a real advantage in the environment to make them survive? This is kind of a paradox. Do you guys see my point?
Where are all the mutations that don’t work? If you say they are just the tiny variations that we witness every day, then how could any present an advantage. There has to be something significant to allow it to replace the species. And if it is significant enough to allow it to replace the species then there should be many more significant ones that don’t work. Evolution does not know which way to go. It is by chance. To hit the lottery you must play a lot of tickets.
Jim
ReplyDeleteIt's me again, but I'm done fighting. Before I retire from the thread I thought I might explain to you my reasons for being interested in evolution in the first place.
I had a moment of Personal Incredulity several years ago while watching a TV program. Here's what I saw. A sidewinder was scuttling at speed across the sand. It saw its prey, its favorite food , a gopher, struck at it, and missed. The gopher dove into its burrow. The snake shuffled its entire body into the sand, except for the end of its tail, which was left sticking up. Now this little piece of tail just happened to bear an uncanny resemblance to the gopher's favorite food, a certain type of grass. Gopher comes out of his hole for a nibble. You can guess the rest. What blew my mind was the delicate interplay between the three species, and the different orders of structure and behavior- appearance of grass, habits of gopher, instinct of snake. Moreover, the snake used his little trick appropriately, even though he was presumably hard-wired to do this [not so sure of the hard-wired part anymore]. Did this imply that evolution was somehow intelligent? Of course I thought of Bergson.
I still don't have a natural understanding of what went on here. I have heard of the three books that Massimo recommended, and feel part of the answer might lie there. Perhaps this summer I can get my son to borrow them from his university library.
It's easy to write off evolution when dealing with these things, but that would be hasty. Something I read in Dawkins' book The Selfish Gene told me to be cautious. On page 60-61 he describes Rothenbuhler's experiments with bees who clear the hive of diseased larvae. An apparently smooth, purposeful action is actually controlled by two different genes, which exhibit the robust characteristics of Mendelian inheritance. How could it happen? I don't know, but it did. So I have come to the point where I believe the best way to come to an understanding is simply to learn more about evolution, rather than fight it. Bergson is a dead end,and so is ID.
Anyway, that's what I'm trying to understand. The reptile's jaw, etc. doesn't bother me so much. Perhaps the mutation doesn't happen to the jaw, but to the recipe for making the jaw, and this might limit the kinds of mutations it can have. But I said I was done fighting! Cheers.
Lilly,
ReplyDeleteI hope you don't feel we were fighting. Your example of the sidewinder makes me look to I.D. but in all fairness other examples make me look to evolution. I have yet to make up my mind and don't know if I ever will. I do believe there is a creator to the universe, is evoltion one of his processes? I don't know yet. If someone can explain the issue of the missing mutations, I will probibly buy into it. I realize I have much more to learn about evolution (especially at the micro level), and I will continue to read. Thank you all for humoring me.
My Favorite Quote - We dont understand 1/10th of one percent of anything - Ben Franklin
Hi Jim
ReplyDeleteI was just being humorous when I said fighting. I just felt that we probably weren't going to say anything new, so it was time to retire. I'm continuing my researches. Best regards.
It is certainly a logical fallacy. Of course, it could be argued that the authority of God is of a different nature than human authority. But this still does not justify such arguments being used in public debate or rational argument. Even if God exists and, as such, we should take him at his word, this could not be a basis for rational discussion unless it was a) proved beyond doubt and b) accepted as a social norm (not or, and.) It's funny, if you just got rid of the I.D. folks, there wouldn't be such a debate going on with this whole science/religion thing. But they insist on stepping into scienctists turf....they deserve what they get, ie. Dawkins.
ReplyDeleteK. Feuerbach
"It turns out that it is very difficult to actually show that something is impossible, unless it contradicts the laws of logic."
ReplyDeleteMassimo,
So, would you agree with Michael Martin that the Judeo-Christian concept of God contradicts the laws of logic and is therefore logically impossible?
I am inclined to agree that the Judeo-Christian concept of God comes close to a logical impossibility. At the very least, it's fraught with loads of inconsistencies.
ReplyDeleteThat's what I'm inclined to think as well. :)
ReplyDeleteOn a technical note, what's the difference between inconsistencies and contradictions?
ReplyDeleteSeems to me that inconsistencies are less troublesome than downright contradictions. One can resolve inconsistencies more easily than contradictions (in fact, often inconsistencies are left unresolved because one assumes that not all the pertinent information is available). The contrast is sharper in the case of contradictions.
ReplyDelete