While many ID proposals are based on introducing teleonomy into evolution, I wanted to ask the question as to whether or not evolution, even by a Darwinian definition (i.e., natural selection and materialism) was already teleonomic.
The reason I ask this is because all sorts of things that Darwinian evolution has trouble explaining gets thrown into the basket of “sexual selection”. Basically, the reason why an organism evolved feature X was because that feature was selected by mating. In other words, the other organisms appreciated feature X, and therefore copulated and reproduced more with organisms showing more and more of feature X.
I find this interesting, because, especially if taken materialistically, this gives a teleonomic direction to selection, something that Mayr attempted to rule out.
Think of it this way. If one is a materialist, then what is determining the desires of the organism? It is the organism’s genetics! If the organism is desiring a mate, that’s because its genetics is telling it to do so. If an organism sees mates with feature X as being more desirable, that means its genetics are telling it to do so. Therefore, the organism’s genes are, in a very direct way, directing the selection process themselves.
Mate selection, under materialism, seems to me to definitely fall under the umbrella of teleonomy. And, since it governs a large component of the evolutionary process, it seems that one must then say that to a large extent the evolutionary process is teleonomic, even under Darwinian terms.
I’m curious to your thoughts on this. I am not aware of this idea being discussed in the literature, but if someone has papers or links to other discussions of this, I would love to see them.
Allan Miller,
Are there dumb people and smart people Allan? Fat people and thin people? Ones with genes resistant to lung cancers and ones with genes susceptible to lung cancers? Gay people and straight people? People with red hair and people with black hair? Yep, there sure are Allan.
And ANY “expected value” you would have to give to different genotypes would have to include calling ALL of these types fit, by virtue of the fact that they exist and have existed, and continue to exist. You have no criteria for calling them unfit.
There Allan. That wasn’t so hard.
Having read the OP, that portion of the comments posted by people who are not on my ‘ignore commenter’ list, and a small number of comments posted by people who are on my ‘ignore commenter’ list, I have one question for johhnyp.
Bluntly: So what?
Less bluntly: What difference would it make if Darwinian evolution genuinely was “teleonomic”, as opposed to Darwinian evolution not being genuinely “teleonomic”?
Are there any questions which would be investigated by a researcher who works from the proposition that Darwinian evolution is teleonomic, and yet would not be investigated by a researcher who doesn’t take that proposition into consideration? Okay, in principle I can see that any questions that have direct bearing on The Designer Of Darwinian Evolution would be investigated by the former and nor by the latter. But in practice, we have researchers who do, indeed, accept the proposition that biology requires a Designer for something or other… and not even one of those researchers is, in fact, doing any research into questions that have direct bearing on The Designer. Indeed, it’s not at all uncommon for ID proponents to respond, when asked specific questions about the Designer they invoke, that questions about the Designer are not matters of science, but, rather, are matters of theology!
So… um… what difference does it make whether or not Darwinian evolution qualifies as “teleonomic”?
cubist,
Nope, it makes no scientific difference at all. There’s no difference in the hypotheses formed, procedures whereby hypotheses are tested, etc.
phoodoo,
That is not correct. The expected value (ie fitness) of a genotype bears no relation to its current frequency. You are simply wrong. Post after post after post wrong. (I realise people would probably rather I shut up so that you do).
The criterion for calling any genotype ‘less fit’ than another is its expected value – ie the mean offspring numbers accruing to carriers vs non-carriers. That’s definitely not their averages in the current population, as you would have realised by now if you’d really read up on ‘Expected Value’ – The Concept.
Do you understand what ‘a reference’ is? You have simply wibbled a bit more, mercifully in less excitable fashion than usual, over some rather debateable ‘genotypes’.
Take obesity. There might be a genetic component, there might not. OK, let’s say there is. Do you think the presence of both genotypes in the population means that they are equally fit? If that is the case, you have not understood one goddamned word (I knew that anyway, of course).
I’ll say it again: the differential between two genotypes is the mean offspring numbers accruing to carriers vs non-carriers. That’s not their current status in this population. Perhaps I should call this ARGUMENT #1 to save me typing it out for the 50th fucking time.
So, what are the mean offspring numbers of the obese genotype vs those of the skinny genotype? No idea? Me either, but this means you have not supported your ‘opposites are equally fit’ contention, since you have not determined the differential. Obesity or skinniness may be the fitter genotype, they may be neutral with respect to each other, or there may be some frequency dependence. But you can’t declare them equally fit just because they both exist. Existence and fitness are not the same thing. Not even close.
Of, course it is difficult to measure fitness in people for ethical and practical reasons. Not so in fruit flies and flatworms. You can measure the differentials and then pit them together in replicate populations. Pick a published non-human example to support your case, that anyone uses current status to infer fitnesses for competing alleles. Don’t just waffle some more.
Allan Miller,
Wait, what do you mean Allan? Do you mean the mean offspring number after they already have offspring, or the ones someone predicts? Does it matter who is predicting?
phoodoo,
No-‘one’ need be involved. Are you sure you understood the expected value concept? Or, indeed, have actually read any of my last several posts before launching off into some excitable fantasy? A genotype has an expected value before it has any offspring, and with no-one ‘expecting’ anything, just as a brand new die has an expected value before it has rolled once. I’m sure I’ve said this, and not just once.
Of course not. You are just being silly for the hell of it. As more (finite) trials are made, the actual value is ‘expected’ to converge on this value. You seem to deny that any differential between two types could possibly exist until someone has measured it – or, until they have actually competed for some undefined time. Which is like saying that two runners cannot be different in their basic speed, or two people cannot be of different height, until someone has measured it in some way. Which would be a stupid position to hold.
Schrodinger’s fitness. It’s nothing until I measure it.
Allan Miller,
You mean you can determine who is the fastest runner before someone has run? How would you do that exactly? Past performance?
Then the better runner is the one you predicted to run better or the one who actually ran better?
phoodoo,
Why would you need to? I mean, for there to be a differential in the first place? You seem fixated on measurement, as if this is the only thing that causes anything to happen.
There is no need to measure a differential in mean output for it to exist and have causal power. 3.8 billion years of evolution took place without anyone wishing to or needing to measure the many differentials. Where one existed, the type with the higher value would tend to fix more often (though it hardly comes with a guarantee, for typical selective differentials).
There would be an expected value of total wins/losses for A vs B over a notional infinity of trials, before they had ever competed. You obviously have no way of knowing what this is if you have no stats on them (though there’s nothing to stop you gathering stats, of course). One race is clearly not enough to determine who is the ‘fitter’, just as one instance of a genotype is not enough – detrimental alleles can drift, even unto fixation. Although the one that won one race is clearly more likely to be the fitter, unless the differential is marked one run is not enough to show it.
Once you have some stats, you can make predictions, but of course this is not a guarantee (which is how bookies make their money).
You can easily measure gene fitnesses outside of a ‘population’, by just getting the types to breed without restriction. Having measured their absolute fitness, you can put them through their paces in real contests. All that happens in populations in the wild is that preliminary measurement step has been omitted. It is hardly necessary for the contest to take place that anyone know the fitnesses first, or later for that matter.
But there is not just one race. An endless succession of novel alleles is produced and filtered. The Law-of-Large-Numbers ‘expectation’ (that word again) is that descendants are progressively and continually enriched in advantageous alleles, and impoverished in detrimental, even though individual beneficial alleles are easily lost, and detrimental ones (a bit less easily) fixed.
You might not believe it capable of much, but it is wrong to say that fitness can only be retrospective. The differential (which may be zero) is there at the start.
In what way did you get the impression that anybody here uses “naturalism” as something like a description, instead of a position that you follow as a guide?
I don’t actually have that impression.
Sounds interesting.
In other words, it’s reducible at least to animal anatomy, with some socio-linguistic fluff on top.
It would be useful if you specified what kind of socio-linguistic explication you have in mind. Searle’s “institutional facts”?
Then your original distinction between “stance” and “proposition” came from nowhere and is going back to where it came from. Once again I mistakenly assumed that you actually meant something when you said stuff. I will do my best to not repeat the mistake.
That’s not right. The distinction was my explanation of “I don’t know what it means to say that naturalism is true or is false” (here).
Allan Miller,
Allan, are you not paying attention to your own writing? Is fitness the “expected value” or the actual value. Look how hard it is for you to own this concept. How can you measure gene fitness by getting them to breed, if the definition of fitness is the “expected” value and not the actual value? By testing the actual value? And then by testing the actual value you create the expected value?
As Mung said, the great thing about a circle is it never ends.
If you have a race and you give a higher expected value to one runner over another, and yet the runner with the lower expected value always wins, who is the fitter? You answer seems to be, well, after we run a thousand races then we get the expected value! Oh brother. So then you adjust the expected value so that the one who always wins gets the higher expected value. Then they begin racing again, but the one with the higher expected value has pulled his hamstring, and can’t run, so he keeps losing to the one with the lower value. Who is fitter?
Its one or the other Allan. The fitter one is either the expected fitter one, or the actual fitter one. Which is it Allan.
I can tell you why you can’t answer this clearly. Because they are the same dam thing! The one you expect to have a higher value is the one who you measure to have the higher value. As soon as you test them, the one that has the ACTUAL higher result becomes the one you EXPECT to have the higher result.
A circle never ends!!
Holy shit, don’t accuse me of being the confused one Allan. I got it perfectly.
I can almost see how one might have that impression, but that’s not at all what I was getting at. What I said was
In saying that intentionality evolved from older kinds of animal cognition, I am thereby precisely saying that is not reducible to those older kinds of animal cognition.
There are three inter-related features of intentionality — the kind of conceptually articulated understanding distinctive of normal mature human beings and expressed through various “symbolic forms”, as Cassirer puts it — that interest me.
The first is that each of us can understand him or herself as occupying a distinct embodied and encultured perspective on reality that differs from that of everyone else. The second is that each of us can understand him or herself as nevertheless also and at the same time beholden to standards of correctness of both believing and acting. The third is that each of us also understands him or herself as having an interest in getting reality right.
That is to say, human thought is constitutively — and all the same time — subjective, intersubjective, and objective. Each ‘leg’ on the tripod depends on the other two. (Postmodernism tried to dispense with objectivity, but it’s quite clear by now that that can’t work.)
Given that intentionality is at work in both thinking and talking, we can ask, “is the intentionality of thought conceptually prior to that of talking, or is the intentionality of talking conceptually prior to that of thinking?”
Here I side with Sellars against Chisholm: the intentionality of talking is prior to that of thinking, because (a) we can understand the intentionality of thought as an internalization of the intentionality of talk over the process of psychological and linguistic development and (b) we cannot understand the intentionality of talk in terms of the intentionality of thought because that would make the intentionality of thought sans talk a utter mystery. (The long argument for (b) is in Sellars’s “Empiricism and the Philosophy of Mind”.)
I would also stress that I am talking about animal cognition, not — as you substituted — animal “anatomy”. Anatomy is the study of structure, and as such, anatomy is what we learn (mostly) from dead animals. Cognition can’t be studied in dead animals, because (on my view) cognition is pervasively physiological in character and ecological in function. Cognition is the unity of perceiving and acting.
What I’m doing then, is proceeding along a two-pronged approach that is both ‘top down’ and ‘bottom up.’ Working ‘from the top down’, I am interested in theorizing about the most general features of normal mature human cognitive activity — as expressed in science, art, philosophy, religion, and so forth — using the tools of epistemology, philosophy of language, philosophy of mind, and phenomenology. Working ‘from the bottom up’, I am interested in theorizing about the dynamics of animal cognitive activity, as described and explained in neuroscience, cognitive ethology, developmental comparative psychology, and ecology. The two directions are unified within a general paradigm informed by liberal naturalism and the extended synthesis of evolutionary theory.
Searle is an interesting case for me. I think he is quite badly wrong in some interesting ways. Searle thinks that intentionality is a single kind of accomplishment — there’s no room in his view for anything like “animal intentionality” — and he thinks that intentionality is a power of the human brain. My view of intentionality is not brain-bound, and I do think that there is animal intentionality.
I do share Searle’s general thesis that intentionality is biological, but I do so by way of Sellars’s and Brandom’s insistence that intentionality is social and linguistic. What need to be understood in biological terms is sociality and language. And that is done, I think, by stressing the coevolution of languages and brains/bodies over the four (or so) million years from the australopithecines to modern Homo sapiens (though a rather punctuated rather than gradual process).
Rather than claim that intentionality is a power of the individual human brain, as Searle does, I want to claim both that intentionality is constitutively socio-linguistic but also that our unique cognitive powers are embedded in and transmitted through unique forms of sociality and language which evolved as part of an ecological niche that is unique among primates: cooperative foraging.
In cooperative foraging, each member of the group makes a specific contribution to meeting the caloric and nutritional requirements of the group as a whole.
This requires specialized local ecological knowledge (where the right sorts of tubers and nuts are to be found, when the best times for hunting are, the differences between poisonous and non-poisonous frogs, which kinds of wood make the best spears), the ability and willingness to cooperate between groups and within groups (one group collects turtles and nuts, another group tracks deer), and active transmission of knowledge from generations.
And the co-evolution of language and brains is really important here, especially if we take seriously what’s called niche construction. The difference is that whereas beaver dams are physical constructed niche, intentionality is a cognitive constructed niche.
The next big phase of my project is to get clear on the differences between human conceptually articulated intentionality and more primitive animal intentionality. I have some pretty good ideas (I think they’re good) about how to proceed but I need to put in the hard work and see how others respond.
I know you are one busy guy but here was some previous discussion that I hope you might get chance to revisit here.
Sure! I think Tomasello’s Cultural Origins of Human Cognition is fantastic but he walks back from some of his stronger claims in A Natural History of Human Thinking.
In COHC he puts all the emphasis on the evolution of human intentionality, whereas in ANHHT he allows that great apes display a kind of intentionality that he calls ‘individual intentionality’. I think he’s on the right track here but I’d be concerned about the conceptual coherence of ‘individual intentionality’ if one is persuaded of largely neopragmatist theses about intentionality (as I am). But COHC is much more comprehensive. I’d recommend both!
Oh, and Tomasello’s new book on the evolution of morality was published a few days ago!
I haven’t read much De Waal except for Primates and Philosophers, but I think they are asking different questions. De Waal seems interested in the evolution of affectivity and emotion, and Tomasello more interested in cognition and understanding. But I haven’t yet come across any systematic comparison of their approaches.
This is completely wrong Phoodoo. Nothing in evolution suggests that populations relative to a given “optimally fit” group won’t survive. In fact, given that there are many organism characteristics and dynamic environments, no one characteristic can ever define fitness.
As Allan has noted repeatedly, “fit” groups will reproduce statistically greater numbers than those that are less fit, but that does not mean that the less fit won’t reproduce at all. Your characterization above is erroneous Phoodoo.
Kantian Naturalist,
Thanks for that. I’d already downloaded the Kindle extract of COHC and I’ll push the boat out and get both. The Ape and the Sushi Master by Frans Waal has a biological perspective on the evolution of culture but I’m enjoying it, even though it might be a bit dated, 2001, and pitched at a “popular” level.
Alan Fox,
If you feel up to tackling a less “pop” and more “scholarly” take on the evolution of culture, you might consider Not By Genes Alone: How Culture Transformed Human Evolution. I haven’t read it, but my friends who work in the evolution of culture have recommended it very highly.
You know, Phoodoo, I like your scenario above. It can be used to very clearly illustrate the error in your thinking.
Try this – instead of asking the question about only two runners, why not try your thought experiment using 100 runners against another 100 runners. Or better, how about a million runners against a million runners. Now compare expectations. You now have a million runners with a higher expected value (more fit) running against a million runners with a lower expected value (less fit). What are the odds that all (or even most, or even some) of the fitter runners pull hamstrings or get wiped out by meteorites before the race? What are the odds that some of the less fit runners experience some sort of catastrophe?
See, evolution applies at the species level, not at the individual level. Individuals get knocked out of the various evolutionary races all the time regardless of fitness, but on average populations with given fitness are far to large to feel much effect from such random events. So using relative fitness of populations has extremely high predictive value and accuracy.
If your goal is to make the top-down and bottom up meet in some sense, do you think that will involve explicating the top-down in terms of the bottom up (what I think can be roughly called the Dennett-Millikan take on Sellars), or the bottom up in terms of the top-down (Brandom’s take).
I suspect you have to pick one if you believe they are going to meet.
In another post, you say that Okrent and Rouse directly address issues with naturalizing intentionality which Millikan and Dennett dismiss as unimportant. Does that include the Swampman objections, or are your referring to something subtler. If so, is it easy for you to provide a rough sketch of how they do deal with Swampman-style objections?
Finally, the following recent nature article on concepts from physics being directly used in biology might interest you. I think these sorts of examples challenge an “every science is independently done” viewpoint if it is taken too far.
The Physics of Life
Robin,
How do you decide who the most fit runners are?
I think that getting the top-down and bottom-up approaches to converge will require assigning a priority to neither. I think of the top-down approaches as “explicating the explanandum” and the bottom-up approaches as “explicating the explanans”. But sometimes we find that the reason why our explanations are unsatisfactory is that the explanandum was insufficiently characterized. So it really does need to be a reciprocal adjustment of each in light of the other.
To be honest, I’ve never really known what to do with the Swampman objection, or with thought-experiments like that in general. What I had in mind was an argument from Okrent for the conclusion that goals are logically prior to functions, so we can’t stop at merely the level of functions (contra Millikan), and also an argument from Rouse that intentionality needs to be conceived in social and linguistic terms (here Rouse is building on Haugeland’s existentialist criticism of naturalism).
Very interesting! Thank you!
Composite of a specific set of characteristics such lean calf and thigh muscle length, leg to upper body length ratio, upper body strength – particularly shoulders and upper back, lung oxygen absorption efficiency, oxygen diffusion efficiency, hematocrit, etc.
I see. So the composite of the characteristics that you mentioned are what you deem as fit, it that correct?
Now suppose we take ONE individual, and we give him a very high score on your composite, and another individual who doesn’t get a high score on your composite, and we have these two individuals race. And the one with the lower composite score wins. But we don’t just do it 1 time, we do it 100 times, and the one with the lower composite score wins every time.
In such a case, who is the more fit runner?
phoodoo,
Sure I am. You evidently are not.
It’s the expected value. The expected value in probability is the assumed long-run mean of an infinite number of trials. If you do a finite number of trials, the more you do, the more you appear to converge on a value. The value on which you converge is the ‘expected value’. If you throw a die once, you can only get 1,2,3,4,5 or 6, with equal probability on a fair die. That evidently gives you little info on the expected value (3.5 for a fair die). Throw the die some more and you start to build up a probability distribution. The more throws you do, the less the mean varies. Plot the values and you find the variance getting smaller and smaller. The centre of this variance is the expected value. It was there at the start. Your repeats found it.
The mistake you are making is to fail to recognise that a given run through a population is a finite trial, not an infinite one. If a new allele with a high mean fitness (whether measured or not) gets sat on, that is a very likely result when the allele is rare. But its expected value is still high (in the example). You can’t say it was of low fitness, if you haven’t even got close to a convergent value. It’s akin to throwing a die once and claiming that the expected value was the result of that one throw.
This is a measurement problem, not a problem of causation. But you can measure fitnesses by taking examples of the genotype and allowing them to breed, outside the population. The more replicates you do, the more the real value will converge on the actual value. That’s how to measure fitness. You don’t need to do it in the population. One run through a population is not an accurate guide to fitness, and hence is not used as such, despite your repeated assertion.
Yeah, that’s the great thing about this circle. You will continue to misunderstand this till the end of time, and I may or may not continue to explain it. Fitness is a very well established concept in biology, yet somehow it’s wrong. There is a fair chance, don’t you think, that you may simply be misunderstanding?
Clearly then, you haven’t got the right expected value. If you run repeats and find A always beats B, each repeat provides confirmation that your actual value is converging on the expected value. The more races you run, the higher your confidence in this convergence. More closely analogous to fitness (because differentials tend not to be so wide), you will get A winning x% of races and B winning y%. After one race, you have one data point. After two, 2 and so on. The more races you run, the more confident you can be that your actual value is closing in on your expected value. But the first race is evidently not enough, which is why no-one says that one population is enough to show which was the fitter.
One run through a population, for alleles fairly closely matched, is not enough to determine which alelle has the higher expected value, because there is a strong influence from chance. But the more runs you do – the more alleles you generate – the more surely will the fitter fix and the less fit go extinct. It’s the Law Of Large Numbers.
Of course. Because the theory can’t be wrong by definition!
phoodoo,
Allan,
Thank you for finally admitting what we have known all along.
Your theory can not be falsified. If it could, we would just simply change the numbers.
I’m afraid it’s not just your understand of evolution that is lacking, but science in general.
Richardthughes,
Patrick, Kindly move Richard’s post to guano. We don’t want to encourage his trolling by forgetting the rules just for him.
Not what I “deem as fit”; they are the defined characteristics for runners. If you want to address some other type of behavior, there will be other characteristics as defined by that discipline.
Again, viewing individuals against individuals is meaningless – evolution works on populations, not individuals.
That’s a rather meaningless question as it illustrates a misunderstanding of actual biological fitness.
Sorry Phoodoo, but the falsification of evolution is not contingent of your (mis)understanding of expected value. You don’t understand science or evolution. This is a statement of fact, not an assessment of your character. Others are free to do this themselves based on the evidence you leave such as reviewing papers you haven’t actually read.
What’s the defined characteristics for surviving best and and passing on ones genes?
Incorrect Phoodoo. The issue is that you don’t seem to understand the theory. One instance of any event has no effect on evolution because individual events get diluted by the collective events of the population over numerous time frames. This is what you don’t seem to address in your example.
So go back and look at millions of runners against millions of runners against millions of runners and ask your question again.
Good environmental fit and a healthy slice of luck, I’d say.
phoodoo,
Of course it can. But if you had some reason to think the expected value of A was bigger than B, yet B won every race, you have either made an error of measurement, or the expected values have changed. This has nothing to do with your broader theory (which in this example amounts to the pretty uncontroversial claim that there is a differential in their likelihood of beating each other, which may be zero).
phoodoo,
Which theory? The theory that A is faster than B can readily be falsified. If you ‘just change the numbers’ you aren’t really gathering data in a very respectable way, are you? The theory that A is taller than B can be falsified. You don’t just change the numbers. The theory that genotype A is fitter than genotype B can readily be falsified. By measurement, in all instances.
Be more specific: surviving best in what environment and against what competition at a minimum. What threats are being faced? What resources are available? What do the organisms do in general? And so forth…
This again illustrates the error in your position: you are attacking an incomplete strawman. Evolution doesn’t posit anything about “surviving best”; fitness is a measure of specific population dynamics under specific environmental conditions. Unless you address those, your questions are meaningless.
Allan Miller,
I guess you missed it, so let me refresh your memory. Evolution predicts that the fittest genotypes will out-compete lesser genotypes over time, and this is how selection weeds out the bad, and advances the good. Its the great strainer you talked of earlier. Some people call it natural selection-perhaps you have heard of it.
So the question is, is it really true that the fitter genotypes survive and breed better than lesser types, or is it really about luck, timing, circumstance which determines what lives and what does. Hm, its an interesting question, that it would be great to get to the bottom of, in the interest of science, and data and all that you know.
Oh, wait, you have just explained to us, its not an interesting question in science afterall apparently. Because you have just admitted that it has to be true, because it can’t be falsified by definition of what is fit. A circular impossibility of falsification.
So truth seekers, don’t waste your time. It HAS to be true.
Robin,
How would you go about measuring that then, in order to test the theory that the best genotypes win in the long run?
Phoodoo, when Vegas takes all your money is it luck or good game design?
You don’t understand science.
Easy: you measure the relative survival rate of organisms with given genotypes in given environments and compare that to the estimated difference between organism fitness values.
Robin,
Then if they don’t match NS is false, or if they do match NS is false?
If they didn’t align statistically, then NS would be in serious doubt. Fortunately, all such measures so far show an incredibly accurate correlation.
Robin,
Oh great, so this has been done extensively in the real world then? Perfect. Can you please show us some of those examples?
phoodoo,
That’s correct. When types compete, that with the higher mean offspring number will tend to increase faster than that with the lesser. This is pretty non-controversial. Do you expect the opposite to happen?
And you think no-one has ever verified this proposition … ?
That’s not correct. Unfalsified does not mean unfalsifiable. It just happens (on investigation) to be true. Genotypes with higher mean fitnesses (mean offspring numbers) do increase faster than those with lower. Kind of as you’d expect, but the counter-intuitive opposite could be true, on investigation. It just isn’t.
‘truth-seeekers’ who are determined that it not be true could do some empirical investigation instead of bloviating fallacies on the ‘net.
Here are the basic possibilities (yet again) governing 2 types, and 2 sub-possibilities for their long-run population effect:
1) There is no net differential between their fitnesses (mean reproductive output).
— 1a – this results in both types remaining in the population for ever
— 1b – this results in one type eliminating the other with an approximately equal chance for each.
2) There is a net differential between their fitnesses (mean reproductive output).
— 2a – this results in both types remaining in the population for ever
— 2b – this results in one type (usually but not always that with the higher mean) eliminating the other.
It turns out that 1b and 2b are the situations in nature. 1a and 2a could have been the case. They aren’t.
The only situation in which NS could be deemed inoperative is if there is NEVER a differential in reproductive output. In that case, everything would be genetic drift (which is still evolution, just not by NS). So you’d have to ask yourself if it is plausible that there is NEVER a difference in net reproductive output between two genotypes. How would you check this? It’s certainly not impossible; it’s not forbidden by any assumed circularity in the definitions. It can be measured.
Measure a few genotypes and determine whether they NEVER have a differential between their mean outputs, or that differentials exist but never have a causal effect on genotype frequencies – that all genotypes, everywhere, are only governed by ‘luck’ in real populations. That NS does not, in practice, exist. Good luck.
https://scottburgessecology.wordpress.com/research/
https://www.researchgate.net/publication/269936355_Deconstructing_environmental_predictability_Seasonality_environmental_colour_and_the_biogeography_of_marine_life_histories
http://www.evolutionary-ecology.com/abstracts/v16/2936.html
http://www.evolutionary-ecology.com/abstracts/v16/2912.html
http://www.evolutionary-ecology.com/abstracts/v16/2913.html
http://www.evolutionary-ecology.com/abstracts/v16/2915.html
http://www.evolutionary-ecology.com/abstracts/v16/2916.html
That’s a good start. Enjoy!
Robin,
Not a single one of these cut and paste diversions does as you claimed. Gee, what a surprise.
We are back to the start. A theory that says the ones who have the most offspring, are the most fit, and the ones who are the most fit have the most offspring. Unfalsifiable. Uninformative. Unimaginative.
Surprise surprise.