I enjoyed the post. It makes a correct and extremely important point about the fallacy of teleology. I have come to identify teleology with natural law theory, which has dominated Western civilisation for the last two millennia. Both Marx and Spencer (!) quickly identified the major contribution of Darwin’s _Origin of Species¬_ as putting the boot into teleology. Alas, they were a bit over-optimistic. Alas (2), I fear that your enthusiasm to make this point has led you astray. In the post, you condemn formulations which are at worst ambiguous or a legitimate figure of speech. I read the handout you refer to at https://www.stem.org.uk/system/files/elibrary-resources/legacy_files_migrated/35875-Y6Evolution-DarwinsFinches.pdf, and see little wrong with it. The story told is a good one, which entertains while instructing. It is true that some of its formulations are not inconsistent with a teleology, but so what? – you can’t do everything in a handout. To be specific: “the finches had to evolve beaks which could take advantage of the food supplies available to them … different finch populations evolved to eat different food sources.” There is nothing wrong with this, and you do not make out a case that there is. Birds have “distinctive beaks adapted for their specific diet.” Ditto. And so on. True, if you interpret “having to” as a compulsion, then it’s wrong; if you say populations evolve *in order to* exploit varied sources, then it’s wrong; if you think “perfect adaptation” literally exists, rather than constituting an – in context – legitimate hyperbole, then it’s wrong. If you think that evolution happens for a reason – an ‘in order to’ reason, rather than a ‘because of’ reason – then you are wrong. Evolution is not forward-looking and does not have a goal. But your strictures go way beyond this. You claim that it is ‘obvious’ that “individuals can’t adapt to an environmental need”. I say that it is obvious that they do, all the time. Take your example of meeting potential mates – individuals spend extraordinary time making themselves look and smell attractive, and learning the appropriate language and behaviour to make themselves seem cool. We absolutely do not adopt the stoicism of *simply* accepting the hand we were dealt. What do you think “*working* with what you’ve got” is doing, if not adapting? Your parable of the crossbills in the supermarket falls flat. “Did any of these birds adapt to the foods they ended up eating?” you ask. Yes, clearly they did. Firstly individuals adapted by specialising where they had advantage, absolute or relative. Secondly, newly learned habits of unwrapping cheese, etc, will be passed on by cultural evolution, thirdly, the frequency of helpful genes to each population will rise, fourthly, helpful mutations will be conserved. You know all this: why are you denying it? You seem to imply that inefficiencies are evidence of failure of evolution. They are not. There are trade-offs involved. The *best* trade-off will generally involve a bit of inefficiency here and a bit there. You summarise the problem thus: “Is a crossed beak the result of (1) divine intervention, (2) an evolutionary adaptation to the environment, or (3) did crossbills just get dealt a bad hand… and they’re struggling to do the best that they can with what they have?” The 1st 2 options I recognise. The 3rd is more problematic. It seems to be just an instance of (2). “Struggling to do the *best* one can with what one has” sounds like a good definition of adaptation. This reminds me of the idea of ‘satisficing’ put forward in economics as an alternative to optimisation: it should not be forgotten that satisficing might be optimal.
Thank you for your thoughtful reply. I enjoyed it very much. Basically, we do not disagree. There are, however, differences in the way we are using some terms, e.g., "adapt"... I understand your definition but it is a bit different than mine.
You also understand the standard evolutionary hyperbolic language for what it is, explanatory conveniences. I agree. However, many people (including many of the people with whom I interact in academia) don't take the nuanced view that you do. As I mentioned at the end of the essay, there are a host of recent popular articles rife with teleological "just so" stories about human behavior. None of these consider the basic points that I brought up here, in the crossbill essay. My goal in writing this essay was to encourage people to re-examine how they think about evolution rather than to teach them how they should think about evolution. I appreciate the fact that you shared your intellectually vigorous and thought-provoking response!
Overall the article seemed a bit quibbly to me and for a bit obscures the point you seek to make. But still it was interesting as it forced me to dredge up my memories from genetics and populaton classes. Nuance language is certainly the key here. I think for many people, the simplified version of Darwin's Finches works reasonably well and really doesn't hurt much - if the wording is chosen carefully. Saying the birds "need to adapt" etc. is misleading.
For those delving deeper into genetics or population studies, requires a more exact discussion. Hence, we make clear, the birds don't adapt because they need to. Each animal needs to survive but many don't. Rather its my understanding that birds surviving to reproduce successfully had some fortuitous genetic advantange, that, as commenter Andrew says, was conserved and perpetuated in subsequent generations. The genetic advantage is likely totally random. Unsucsessful genetic changes die quickly. Apparently the crossed bill is one such lucky genetic accident and the birds diverged into another species. It is interesting to note that crossed bills have evolved in several different far flung species as a solution to a common challenge - great example of convergent evolution.
From this, we can go farther discussing whether the genetic accident is a gradual thing or occurs suddenly. I think I've seen some literature in the last few years where evolution may really occur in sudden "jumps" vs the concept of gradual evolutiin that I grew up with. I wish I could put my fingers on citations.
The introductory photo caught my attention as each winter I enjoy hosting common and white winged crossbills at my feeder. It is fascinating how they make short work of sunflower seeds that the nuthatches have to hammer open. I have not been able to see how the chickadees open them - I still wonder. I have also watched crossbills tear apart spruce cones and their bill adaptation is amazingly effective on tight spruce cones. We host pine grossbeaks too that also quickly munch the sunflower seeds with their powerful beaks. We had one chickdee showing the overgrown upper bill (forget proper term) that projects past the lower bill and hooks down like a skinny hawk's beak; they struggle a bit and greatly benefit from the neighborhood feeders. This bill abberation is being seen in other northern species besides chickadees and appears to be a disease, not a genetic shift https://blog.nature.org/science/2020/10/06/deformed-beaks-what-we-know-about-an-alarming-bird-disease/ . I look forward to more articles.
Here are a few responses to your excellent comments:
1. I think for many people, the simplified version of Darwin's Finches works reasonably well and really doesn't hurt much –
FRP: Well, in the overall goings-on of the cosmos, it doesn’t hurt. It only hurts in the sense that it’s misleading and incorrect. Every day I work with students, instructors, and read articles aimed at influencing policy that misunderstand this basic point. Take a look at some of the articles that are referenced at the end of my piece, especially those that appear in Quillette.
2. … birds surviving to reproduce successfully had some fortuitous genetic advantage, that, as commenter Andrew says, was conserved and perpetuated in subsequent generations. The genetic advantage is likely totally random.
FRP: Yes, that’s basically true. But you have to ask yourself why you’re calling something and “advantage”. That’s an assumption that people make when they see a characteristic in an organism. The crossed bill is not necessarily an advantage. There’s never been any thorough empirical examination of that contention. The birds eat a lot of things besides pinecones, and the crossed bill exists in animals that don’t eat pinecone. If a bird has a facial deformity and can still have sex, that doesn’t imply that the deformity can be seen as advantageous. It may just be a pain in the neck.
Say, by the way, put your finger on your upper lip and feel for that little indentation under your nose. What's the evolutionary advantage of that? Everyone's got it so it must be advantageous..... Otherwise it'd disappear. I'm sure I could make up a great just-so story about how it diverts mucus from your runny nose around the sides of your mouth so you don't re-infect yourself with viruses when you have the flu. "Cavemen" that had this little indentation were healthier than those who didn't, and so they had more kids. That's why the trait got passed down to us But the story would be total baloney, right?
3. Unsucsessful genetic changes die quickly.
FRP: Depends what you mean by unsuccessful. My guess is that you’re using the circular argument: If the animal dies, it was unsuccessful… How do you know it was unsuccessful? The animal died. You know, like the tautology, “survival of the fittest.” Disadvantageous mutations don’t just disappear from the population. Think of cystic fibrosis, achondroplasia, cancers, Huntington’s Chorea, and so on.
4. … crossed bills have evolved in several different far flung species as a solution to a common challenge - great example of convergent evolution.
FRP: Nope, nope, nope. What’s the common challenge? It certainly ain't helpin' the Swiss chicken! Even if you find some common challenge, you can’t just grow something as solution to a challenge. This is the whole point of what I was saying. You’re making an assumption about what’s going on in the world and then fitting everything into the assumption… In this case it's that mutations happen as solutions to things. Stuff just happens. If you can make it work long enough to have sex, some of your kids are going to have the same stuff.
5. … gradual thing or occurs suddenly.
FRP: The crossed bill was a rapid change due to a mutation in what's called a switch gene.
6. I have also watched crossbills tear apart spruce cones and their bill adaptation is amazingly effective on tight spruce cones.
FRP: You are correct; they manage the closed cones well but there's still slower, overall, than straight bill finches according to the experiment I mentioned.... but I wish you'd quit calling it an “adaptation.” Well, even if you don’t quit, I’d still have whiskey with you… But, please remember, it’s not an adaptation to your birdfeeder. It’s a genetic mutation that has functionality in certain situations. If you caught all of your crossbills and put them in a grocery store, they'd probably figure out how to open cheese packages (or something). But that does not make the crossbill an adaptation to cheese packages!
I thoroughly enjoyed the exchange…. Okay. The first whiskey is on you.
Thanks for the reply. "intellectually vigorous and thought-provoking response" How kind! But obviously this is projection and really applies to your initial post. I look forward to future posts. BTW, I am currently reading David Haig (forward by Daniel Dennett) (2020) "From Darwin to Derrida". V good so far: you might enjoy it. Highly relevant to the issue.
I enjoyed the post. It makes a correct and extremely important point about the fallacy of teleology. I have come to identify teleology with natural law theory, which has dominated Western civilisation for the last two millennia. Both Marx and Spencer (!) quickly identified the major contribution of Darwin’s _Origin of Species¬_ as putting the boot into teleology. Alas, they were a bit over-optimistic. Alas (2), I fear that your enthusiasm to make this point has led you astray. In the post, you condemn formulations which are at worst ambiguous or a legitimate figure of speech. I read the handout you refer to at https://www.stem.org.uk/system/files/elibrary-resources/legacy_files_migrated/35875-Y6Evolution-DarwinsFinches.pdf, and see little wrong with it. The story told is a good one, which entertains while instructing. It is true that some of its formulations are not inconsistent with a teleology, but so what? – you can’t do everything in a handout. To be specific: “the finches had to evolve beaks which could take advantage of the food supplies available to them … different finch populations evolved to eat different food sources.” There is nothing wrong with this, and you do not make out a case that there is. Birds have “distinctive beaks adapted for their specific diet.” Ditto. And so on. True, if you interpret “having to” as a compulsion, then it’s wrong; if you say populations evolve *in order to* exploit varied sources, then it’s wrong; if you think “perfect adaptation” literally exists, rather than constituting an – in context – legitimate hyperbole, then it’s wrong. If you think that evolution happens for a reason – an ‘in order to’ reason, rather than a ‘because of’ reason – then you are wrong. Evolution is not forward-looking and does not have a goal. But your strictures go way beyond this. You claim that it is ‘obvious’ that “individuals can’t adapt to an environmental need”. I say that it is obvious that they do, all the time. Take your example of meeting potential mates – individuals spend extraordinary time making themselves look and smell attractive, and learning the appropriate language and behaviour to make themselves seem cool. We absolutely do not adopt the stoicism of *simply* accepting the hand we were dealt. What do you think “*working* with what you’ve got” is doing, if not adapting? Your parable of the crossbills in the supermarket falls flat. “Did any of these birds adapt to the foods they ended up eating?” you ask. Yes, clearly they did. Firstly individuals adapted by specialising where they had advantage, absolute or relative. Secondly, newly learned habits of unwrapping cheese, etc, will be passed on by cultural evolution, thirdly, the frequency of helpful genes to each population will rise, fourthly, helpful mutations will be conserved. You know all this: why are you denying it? You seem to imply that inefficiencies are evidence of failure of evolution. They are not. There are trade-offs involved. The *best* trade-off will generally involve a bit of inefficiency here and a bit there. You summarise the problem thus: “Is a crossed beak the result of (1) divine intervention, (2) an evolutionary adaptation to the environment, or (3) did crossbills just get dealt a bad hand… and they’re struggling to do the best that they can with what they have?” The 1st 2 options I recognise. The 3rd is more problematic. It seems to be just an instance of (2). “Struggling to do the *best* one can with what one has” sounds like a good definition of adaptation. This reminds me of the idea of ‘satisficing’ put forward in economics as an alternative to optimisation: it should not be forgotten that satisficing might be optimal.
Thank you for your thoughtful reply. I enjoyed it very much. Basically, we do not disagree. There are, however, differences in the way we are using some terms, e.g., "adapt"... I understand your definition but it is a bit different than mine.
You also understand the standard evolutionary hyperbolic language for what it is, explanatory conveniences. I agree. However, many people (including many of the people with whom I interact in academia) don't take the nuanced view that you do. As I mentioned at the end of the essay, there are a host of recent popular articles rife with teleological "just so" stories about human behavior. None of these consider the basic points that I brought up here, in the crossbill essay. My goal in writing this essay was to encourage people to re-examine how they think about evolution rather than to teach them how they should think about evolution. I appreciate the fact that you shared your intellectually vigorous and thought-provoking response!
Overall the article seemed a bit quibbly to me and for a bit obscures the point you seek to make. But still it was interesting as it forced me to dredge up my memories from genetics and populaton classes. Nuance language is certainly the key here. I think for many people, the simplified version of Darwin's Finches works reasonably well and really doesn't hurt much - if the wording is chosen carefully. Saying the birds "need to adapt" etc. is misleading.
For those delving deeper into genetics or population studies, requires a more exact discussion. Hence, we make clear, the birds don't adapt because they need to. Each animal needs to survive but many don't. Rather its my understanding that birds surviving to reproduce successfully had some fortuitous genetic advantange, that, as commenter Andrew says, was conserved and perpetuated in subsequent generations. The genetic advantage is likely totally random. Unsucsessful genetic changes die quickly. Apparently the crossed bill is one such lucky genetic accident and the birds diverged into another species. It is interesting to note that crossed bills have evolved in several different far flung species as a solution to a common challenge - great example of convergent evolution.
From this, we can go farther discussing whether the genetic accident is a gradual thing or occurs suddenly. I think I've seen some literature in the last few years where evolution may really occur in sudden "jumps" vs the concept of gradual evolutiin that I grew up with. I wish I could put my fingers on citations.
The introductory photo caught my attention as each winter I enjoy hosting common and white winged crossbills at my feeder. It is fascinating how they make short work of sunflower seeds that the nuthatches have to hammer open. I have not been able to see how the chickadees open them - I still wonder. I have also watched crossbills tear apart spruce cones and their bill adaptation is amazingly effective on tight spruce cones. We host pine grossbeaks too that also quickly munch the sunflower seeds with their powerful beaks. We had one chickdee showing the overgrown upper bill (forget proper term) that projects past the lower bill and hooks down like a skinny hawk's beak; they struggle a bit and greatly benefit from the neighborhood feeders. This bill abberation is being seen in other northern species besides chickadees and appears to be a disease, not a genetic shift https://blog.nature.org/science/2020/10/06/deformed-beaks-what-we-know-about-an-alarming-bird-disease/ . I look forward to more articles.
Good afternoon!
Here are a few responses to your excellent comments:
1. I think for many people, the simplified version of Darwin's Finches works reasonably well and really doesn't hurt much –
FRP: Well, in the overall goings-on of the cosmos, it doesn’t hurt. It only hurts in the sense that it’s misleading and incorrect. Every day I work with students, instructors, and read articles aimed at influencing policy that misunderstand this basic point. Take a look at some of the articles that are referenced at the end of my piece, especially those that appear in Quillette.
2. … birds surviving to reproduce successfully had some fortuitous genetic advantage, that, as commenter Andrew says, was conserved and perpetuated in subsequent generations. The genetic advantage is likely totally random.
FRP: Yes, that’s basically true. But you have to ask yourself why you’re calling something and “advantage”. That’s an assumption that people make when they see a characteristic in an organism. The crossed bill is not necessarily an advantage. There’s never been any thorough empirical examination of that contention. The birds eat a lot of things besides pinecones, and the crossed bill exists in animals that don’t eat pinecone. If a bird has a facial deformity and can still have sex, that doesn’t imply that the deformity can be seen as advantageous. It may just be a pain in the neck.
Say, by the way, put your finger on your upper lip and feel for that little indentation under your nose. What's the evolutionary advantage of that? Everyone's got it so it must be advantageous..... Otherwise it'd disappear. I'm sure I could make up a great just-so story about how it diverts mucus from your runny nose around the sides of your mouth so you don't re-infect yourself with viruses when you have the flu. "Cavemen" that had this little indentation were healthier than those who didn't, and so they had more kids. That's why the trait got passed down to us But the story would be total baloney, right?
3. Unsucsessful genetic changes die quickly.
FRP: Depends what you mean by unsuccessful. My guess is that you’re using the circular argument: If the animal dies, it was unsuccessful… How do you know it was unsuccessful? The animal died. You know, like the tautology, “survival of the fittest.” Disadvantageous mutations don’t just disappear from the population. Think of cystic fibrosis, achondroplasia, cancers, Huntington’s Chorea, and so on.
4. … crossed bills have evolved in several different far flung species as a solution to a common challenge - great example of convergent evolution.
FRP: Nope, nope, nope. What’s the common challenge? It certainly ain't helpin' the Swiss chicken! Even if you find some common challenge, you can’t just grow something as solution to a challenge. This is the whole point of what I was saying. You’re making an assumption about what’s going on in the world and then fitting everything into the assumption… In this case it's that mutations happen as solutions to things. Stuff just happens. If you can make it work long enough to have sex, some of your kids are going to have the same stuff.
5. … gradual thing or occurs suddenly.
FRP: The crossed bill was a rapid change due to a mutation in what's called a switch gene.
6. I have also watched crossbills tear apart spruce cones and their bill adaptation is amazingly effective on tight spruce cones.
FRP: You are correct; they manage the closed cones well but there's still slower, overall, than straight bill finches according to the experiment I mentioned.... but I wish you'd quit calling it an “adaptation.” Well, even if you don’t quit, I’d still have whiskey with you… But, please remember, it’s not an adaptation to your birdfeeder. It’s a genetic mutation that has functionality in certain situations. If you caught all of your crossbills and put them in a grocery store, they'd probably figure out how to open cheese packages (or something). But that does not make the crossbill an adaptation to cheese packages!
I thoroughly enjoyed the exchange…. Okay. The first whiskey is on you.
Thanks for the reply. "intellectually vigorous and thought-provoking response" How kind! But obviously this is projection and really applies to your initial post. I look forward to future posts. BTW, I am currently reading David Haig (forward by Daniel Dennett) (2020) "From Darwin to Derrida". V good so far: you might enjoy it. Highly relevant to the issue.
I'll read it... thx!
There's a pdf floating round on the WWW.
Well, thank you very much… that's quite a compliment!