Back to the T-rex, guys.
I think if you’re going to have a story about a T-rex chasing Adam and Eve, you need to add in that the poor thing’s arms withered when it wielded that sword. That way none of those sweet little children get sucked into evolutionary thought by asking “why would God make those arms so small?”
Just had to pop in to say…
My mother, the one who swears that I am demon possessed, saw this well-educated, intelligent man give a presentation at her church Wednesday night. And, surprise, surprise, not only did she think it was absolutely wonderful (to paraphrase her boundless enthusiasm) but now she desires to take a trip to visit the “museum.” So does my aunt, as her faithful sidekick. :rolleyes: If they do, I hope they forgo the souvenirs and perhaps bring me a rebel flag instead.
Yeah, I think I’m better off running for the Anti-Christ position after all.
So, would that be the opposite of the missionary position? 
CJ
Ducking and running for the hills!!!
I don’t follow your criticism here. The point is not whether you can conceptualize the environment in different ways. The point of natural selection is that we expect reproductive success to be non-random along particular common traits that some creatures in a population share and others do not. I don’t see how that is unfalsifiable. You can go out into the environment, study the populations, and find out whether or not this is going on from generation to generation: determine whether the various traits are found in successive generations in random or non-random patterns relative to other traits.
It there is no variation of traits in a population (i.e. error-free cloning), then there cannot be any natural selection. If the environment that the gene’s phenotype is placed in does not affect the reproductive success in any way, then there can be no natural selection. And if the traits that are favored in the surviving population are not heritable (and are likewise not subject to the Baldwin effect, which mimics Larmarkism in some respects), then natural selection will fail again.
Again, natural selection was defined by Darwin in Origin as the observation that heritable traits can lead to disparate reproductive success. Not “that which survives, survives.”
I guess I’m not following this debate on whether or not “intelligent design” and/or “natural selection” are falsifiable theories.
On the one hand, intelligent design is clearly a true explanation of many phenomena (even some living things), yet on the other hand, it does seem fundamentally unfalsifiable as an explanation for something’s existence. There are obviously a great many things which everyone agrees are the product of intelligent design–walls, bridges, aqueducts, stone monuments, and so forth. Even some living things are indisputably the products of intelligent design, at least in their present form–agricultural plants that can’t reproduce without human intervention; dairy cattle that produce far more milk than their calves need, which is then drunk by human beings , or chickens that lay enormous quantities of infertile eggs, for human consumption; or genetically-engineered bacteria that produce human hormones.
Now, while there are clearly things that are the product of intelligent design, other things, like random piles of rocks, don’t seem to be. But if one were to find a large pile of rocks sitting in the middle of a modern art museum, with a card on the wall that says “Installation #42: Intelligent Design. Granite, shale, and limestone”, you obviously wouldn’t start going on about how glaciers must have deposited these rocks in the middle of the Museum of Modern Art back during the late Pleistocene Epoch. However, even if you find a pile of rocks sitting in the middle of the woods, you can’t prove they weren’t put there by an especially avant-garde modern artist. You can never be absolutely certain that some intelligent designer(s) didn’t decide to simulate randomness or natural selection for his, her, its, or their inscrutable purposes. With regards to the biological world, except for a few obvious exceptions like dairy cows and small hairless dogs, if there is a designer, he seems to have gone to a lot of trouble to act exactly like natural selection acting to maximize reproductive success.
In general, with “intelligent design”, whether we’re talking about living things or stone tools, it largely seems like a case of “we know it when we see it”, which mostly works OK for practical purposes, but could be potentially problematic in such areas as SETI, paleo-archaeology, or dealing with Internet cranks who are convinced that Earth’s moon is littered with zillions of tiny “artifacts”.
Contrast this with natural selection: We can easily imagine living things which could exist, and which could survive in the natural world, which could not be the product of natural selection. Imagine a sheep-like herbivorous animal, for the most part much like any other ruminant, except for a couple of unique and peculiar features: One, this animal reproduces solely by parthenogenesis. Two, the females, in addition to parthenogenetically producing daughters to propagate the species, also periodically give birth to male offspring; although they appear anatomically capable of doing so, these males never show any inclination to mate with the females of their species. The females of the species are hardy animals with excellent survival instincts; they eat grasses, leaves, thistles, or in fact pretty much anything–rather like goats in that respect. They also have the usual herbivorous instincts to flee from predators or other dangers. Until they are weaned, the males do likewise. However, once weaned, they develop small stigmata upon each of their hooves and upon their foreheads. They also develop an apparently overwhelming instinctive drive to interpose themselves between predators and their prey: Whenever a lion or a leopard has cornered an impala or a zebra, if one of these males is around he will dash forward, distract the predator, and let himself be eaten instead of the intended prey. The males will even intervene and sacrifice themselves to protect predators, if for example a lone lion is cornered by a pack of hyenas, or a pride of lions is stalking a cheetah’s cubs. However, the males never intervene to save the lives of the females of their own species. (“Woman, what have I to do with thee?”)
Now, such an animal couldn’t possibly be produced by natural selection working on inherited traits; one way or another it would have to be the product of intelligent design, whether by the providence of God to serve as an allegorical sign and wonder, or as a prank by the gene-splicing monks of the Brethren of the Blessed Gregor of Brünn.
I suspect some of the “symbiosis worlds” you find in science fiction stories might also be impossible to get to via natural selection; not that natural selection can’t produce symbiosis, but you could probably design a planet full of self-sacrificing species which strive to cooperatively aid each other even at the expense of their own reproductive success. If such a planet were discovered, we might have to conclude it didn’t evolve via natural selection; either God or super-advanced aliens must have had a hand in the place.
So, we can hypothetically falsify natural selection, but we can’t ever truly falsify intelligent design.
Or what am I missing?
Possibly the fact that agents acting on the environment are themselves a part of the environment. Man and his progeny are still subject to natural selection despite that man can (or soon will be able to) engineer his own genes. Successfully adapted gene populations will continue to replicate with or without the intervention of outside agency. Natural selection does not determine what mutations will take place; therefore, whether mutations are random or devised has nothing to do with natural selection.
The reason intelligent design cannot be falsified is because it implicitly means supernatural intelligent design. The epistemology required to investigate it is analytic, not synthetic. The ID people are not positing that some design agent arose from nature. Natural selection, on the other hand, implies that nothing supernatural occurs. Natural selection cannot be falsified because it is a tautology. It cannot not happen.
Natural selection is a distinct process. It does not include everything that is.
A bird’s wing is the result of natural selection. However it came about–small dinosaurs running along the ground trying to catch bugs is a popular theory, I believe–there were relatively small, inheritable differences in the forelimbs of ancestral proto-birds; inheritable differences which give the proto-bird greater reproductive success (by allowing it to run and jump and glide more efficiently, thus allowing it to catch more food) are conserved, whereas other heritable differences are not.
This is not how an airplane wing is designed. Yes, the engineer himself is a product of natural selection, but Boeing 747’s did not come into existence by natural selection acting on small inheritable differences between different Boeing 707’s and 737’s until eventually you wind up with a 747. An airplane wing is the result of intelligent design–a completely different process from natural selection.
And in fact, although I certainly think they are being disingenuous about it, many of the more sophisticated intelligent design proponents do claim that ID doesn’t necessarily mean God. It could be space aliens.
You are now arguing that it necessarily must happen, in every instance. Yet, I have already shown you that not only can it “not happen”, it does “not happen”.
You seem married to the idea that Popper Must Be Right[sup]TM[/sup] on this topic, despite the fact that he, like you are now doing, applied his “unfalsifiable” label as a result of an incomplete and caricaturized understanding of natural selection. You stick to your “tautology” claim, even though it has been pointed out time and again that such is clearly not the case. I will even point it out for you again (in truly syllogistic form, even):
[ul][li]IF variations of a trait within a population have a genetic basis,[/li][li]AND some of those variations have greater reproductive potential (that is, those with such variations are more likely to survive and reproduce),[/li][li]THEN, over time, those variations will come to predominate in the population.[/ul][/li]
Clearly, then, natural selection can “not happen” in instances where traits are non-genetic (e.g., the aforementioned temperature-dependence of sex in crocodiles). Natural selection can also “not happen” if variations have no increased reproductive potential (e.g., slight color variations in many species). In such cases, the allele frequencies for those traits will vary from one generation to the next in a random manner, rather than in a directional or predictable manner.
Given the above definition, please point out the tautology within. Yes, “survival of the fittest” is tautological. But that is not the current working definition for natural selection. Perhaps it is time to update your thinking on the matter…?
Finch, I find your syllogism (slightly modified to make it a well-formed formula) to be a compelling argument. But I do not understand how it contradicts what I’m saying. In fact, it seems to agree with me and not with you. Are we misunderstanding one another? How is it, for example, that temperature dependence of sex in crocs not genetic? How is it that likelihood to survive and reproduce is not what natural selection is all about?
Well, by dint of it being falsifiable by a set of observations that are not mutually contradictory, or inconsistent. The set of observations
{“Variations of trait X in population Y are genetic in basis”,
“Some of these variations improve reproductive potential”,
“Over time, those variations decrease in frequency among the population”}
are not a model for Finch’s logical sentence, and would thus falsify the hypothesis. The set of observations isn’t inconsistent, it would merely be very surprising to obtain such a set. Since Finch’s sentence is therefore not modelled by all possible worlds, it can’t be tautological. I’m guessing that you feel the observations
{“Some of these variations improve reproductive potential”,
“Over time, those variations decrease in frequency among the population”}
could never, in fact, be made, if we define reproductive potential as the success with which an individual passes on his genetic traits. However it seems to me that that’s not what reproductive potential is; it’s simply a combination of lifespan and success in mating, which can be observed entirely separately from the observations of genetic variations.
You ask “isn’t likelihood of survival and reproduction what natural selection is about?”, but it seems to me that it isn’t, really*; it’s about the variation of frequencies of genetic traits. The likelihood of survival and reproduction is simply the proposed correlating factor by which these frequencies vary.
*IANAGeneticist, and all that jazz.
I would not be surprised if that is that case.
Consider the case with mammals, whereby the sex of the organism is determined by possession of particular chromosomes: XX becomes a female, XY becomes a male (leaving aside, for this discussion, numerous variations that might result in extra chromosomes, or transgenderism in humans). In crocodiles (and other reptiles), sex is determined during development, based on factors such as ambient temperature. Males and females are not differentiated genetically, but developmentally. That temperature dependence itself may well be genetic (I do not have information regarding that at my disposal), but the actual sex ratio that results is not determined by the DNA of the animals: a male’s DNA is pretty much identical to a female’s. Because of this, variations in sex ratios are not subject to natural selection; the trait of “sex” is not heritable.
Note that one theory postulates that it was just this sort of temperature-dependent sex that wiped out the dinosaurs: it got too warm, only females were produced, no mating could thus occur, and they all just kind of died out. Not saying I agree with that theory, I’m just throwing that out there.
Likelihood of surviving and reproducing is what natural selection is about, provided that likelihood is directly linked to one’s particular genetic variations. If the link is not there, then any one individual has about as much chance as any other one individual, so any selection will be essentially random in nature (that is, the nature of the selection will be random, rather than directed). For natural selection to occur, mating must be non-random, and both “winners” and “losers” must be determined by their particular variations. If one has (or, more correctly, if several individuals have) a variation that provdes a slight edge over rivals, then that variation will likely be preserved in the next generation, making that next generation slightly better at doing whatever it is they do than were their predecesors. Similarly, if individuals possess a variation which makes them less able than their fellows, then the frequency of that variation should decline in subsequent generations.
Depends on what ID actually says. If it says that all current alleles and distributions are the result of ID, it can easily be falsified (and has been) by observing evolution either experimentally or in the field.
But if it says that everything is just like evolution, except for a few specific instances, one of which is the origin of man, then it is impossible to falsify, since we will never know all speciation event over the last billion years or so.
Given the recent arguments from Badger and Finch, formulating and examining the issue deductively, I’ve no choice but to concede the point. I stand corrected. If indeed an experiment can be devised that allows for the possibility that well adapted species do not survive despite their genetic advantages, or alternatively that disadvantaged specied do survive, then natural selection is not tautological and therefore is falsifiable. Thanks to all who argued respectfully.
What does entire species surviving or not surviving have to do with natural selection? The point is not that entire species survive or don’t survive, but that if at least some slice of the species survives, we would expect that survival among the species would be non-random across the variation of heritable traits, and hopefully that we can tell a causal story about why these traits would have helped, on average, the individuals with them be more likely to survive.
I see. Thank you.
There is one last point (or nitpick, if you will) I’d like to make: if natural selection does not occur, there can be no such thing as a “well adapted species”. Adaptation is the direct result of natural selection over the course of generations. Thus, it could, indeed, be seen as tautological to claim that “well adapted species survive because of their genetic advantages” - their genetic advantages are why they are well-adapted in the first place, after all! This is why I was careful to phrase my arguments as only examining allele frequencies, and how those frequencies are altered (e.g., what is the cause of frequency changes) from one generation to the next. If they change as a result of environmental influences, and as such bestow an incremental advantage to one subgroup of the population, then that allele will flourish and its frequency in the population will tend to increase - the population adapts. If however, the frequency changes in a random manner, then natural selection is not occuring, and no adaptation results.
I would also like to apologize for my previous accusations of obtuseness on your part. Your perceived stubbornness was likely the result of an inability on my part to make my point clearly.
Which is that we need to find a way to transport large numbers of Black Israelites to the museum to protest.
As the Black Israelites (I’m not providing a link for feat that they will follow it back.) believe that Adam, Eve, Noah, and Jesus were all black, that all real Jews are black, and that there’s a massive conspiracy to hide these facts, they should find plenty of reason to be offended by the museum.
Just imagine them outside the museum, protesting with megaphones.
Yes, now that we’ve re-established that natural selection is not a tautology (and thanks for your enlightening posts, Darwin’s Finch and Apos, can we get back to our regularly scheduled denunciation.
I’m wondering if No Clue Boy ever wrote his email.
Yet again, Lib takes a controversial position, debates earnestly and respectfully and, after taking a long and hard look at what is left in the crucible, accepts that he is wrong (and even goes as far as, utterly unnecessarily IMO, apologising).
This is what this board is all about. I can think of very few here who would be so brave as to forward an opinion which lay outside the popular paradigm here, knowing that he might have himself a new one ripped by one as erudite in his field as DF, and ultimately admit so in so intellectually honest a manner.
Kudos, Lib.
That certainly makes sense. And I believe that that is what initially convinced me that it was tautological. It is a common mistake to presume that an implication is biconditional — a presumption I should not have made.
(Thank you, Sentient.)