April 24, 2004

NOTHING LEFT TO CHANCE:

Swelled Heads (Jim Holt, April 25, 2004, NY Times Magazine)

Did a jaw mutation really ''cause'' the enlarged brains that make us human? Darwin himself, curiously enough, suggested just the opposite: first we acquired our bigger brains, then our smaller jaws. The expansion of the brain, he theorized, occurred in tandem with the spread of hunting and tool-making. After all, a meal of meat takes intelligence to obtain, and it also provides rich protein for hungry brain tissue. And once we became meat eaters, we could afford smaller jaws, since meat needs less chewing than nuts and plants, especially if you're clever enough to tenderize it over a fire and cut it with a blade. Moreover, a knack for fashioning weapons makes a powerful muzzle less important. As our ancestors ''gradually acquired the habit of using stones, clubs or other weapons for fighting with their enemies,'' Darwin observed in ''The Descent of Man,'' ''they would use their jaws and teeth less and less. In this case, the jaws, together with the teeth, would become reduced in size.''

Since those words were written, evolutionary theorists have come up with a bewildering variety of explanations for how natural selection might have produced human intelligence. Steven Pinker agrees with Darwin that hunting and tool-making had a lot to do with it, but he also cites the fact that our hominid ancestors were social creatures. Living in groups, they had to compete with one another with increasing shrewdness to further their interests. Such competition, the idea goes, might have set off a ''cognitive arms race'' that led to rapid growth in brain size. Another view, advanced by Geoffrey Miller, is that sexual selection explains the evolutionary push toward intelligence. The human brain, according to this hypothesis, is rather like the peacock's tail: a courtship device to attract and retain sexual mates. Wit, virtuosity and inventiveness are turn-ons, and those that have them end up producing more offspring.

The late Stephen Jay Gould, by contrast, said he believed that our lurch into intelligence wasn't really driven by anything at all. He held that random genetic drift caused a slowing-down in the emergence of adult features in each individual. In fact, humans, with their relatively big brain cases, small jaws and hairless skin, look like baby apes. The prolonged period of development before adulthood gives our brains a chance to grow to three times the size of an ape's. Much of this growth necessarily takes place outside the womb, since the female pelvis can barely accommodate the newborn's enormous head as it is. (The pain women undergo in childbirth is part of the price we pay for our big brains.)

The great mystery about all these competing mechanisms is why they should have worked only for humans. We are hardly unique in being a social species; bumblebees, parrots, dolphins, elephants and wolves also live in groups, but none of them have participated in cognitive arms races. We are not the only hunting species; lions show tremendous cunning when hunting zebras, but that cunning has not evolved into all-purpose intelligence. [...]

However we humans shimmered onto the scene, it seems important to our self-image that the appearance of Homo sapiens was somehow cosmically decreed -- either by divine will or as the inevitable culmination of a stately natural process. The very idea that we owe our existence as a species to a hitherto unnoticed mutation that need never have happened (and a mutation that weakened something, at that) might seem a blow to our dignity. But if we're a fluke, at least we're unique. Let the other apes gnash their powerful teeth in envy.


One of the innumerable similarities between Creationists and Darwinists is that genuine randomness is unacceptable to both. Evolution must have a purpose--God's, Nature's or both.

Posted by Orrin Judd at April 24, 2004 10:48 PM
Comments

This is a good example of the way in which Natural Selection is moving out of the hard sciences into the social sciences. Like much of economics or anthropology, it is now simply a series of stories we tell ourselves that fit the scant observed facts. These stories are perfectly plausible, but so are other stories that could be concocted to fit the facts. Which story gets taught says more about our contemporary preferences and biases than about the past.

Posted by: David Cohen at April 25, 2004 12:08 PM

Well, Natural Selection started in the social sciences then was misapplied in the hard, so it should migrate back where it belongs, right?

Posted by: oj at April 25, 2004 12:34 PM

Wrong. You misunderstand randomness, recursion, and statistics.

Posted by: Jeff Guinn at April 25, 2004 4:33 PM

But understand Darwinists.

Posted by: oj at April 25, 2004 5:01 PM

Not even that.

We are not the only intelligent species, only the most intelligent, in general, although there are some things that less intelligent animals can do that we cannot do nearly so well-- navigate without mechanical instruments, for example. Among the other intelligent species are hunters (dolphins) and vegetarians (gorillas).

So, if darwinists say, as they repeatedly do, that there is nothing special about us -- we are, as Peter said yesterday -- one end of a continuum; then on what ground do the antidarwinists keep saying, 'O, you really do think you're special'?

If there is a finite continuum there must be, as Jeff implies, somebody on the end. Nothing special about that.

Posted by: Harry Eagar at April 25, 2004 7:52 PM

Precisely. We're at the end oif the continuum. Ta Da! Darwin renders us.

Posted by: oj at April 25, 2004 8:00 PM

OJ:

Sequoia trees are at the end of a continuum. As are whales, elephants, and a particular kind of wasp, the name of which escapes me at the moment.

Tallest, biggest, biggest, smallest.

Variation of any quantity in natural history is not infinite; there must be end points. Darwin rendered neither them, nor us.

Posted by: Jeff Guinn at April 25, 2004 8:41 PM

Jeff:

Yes, Creation.

Posted by: oj at April 25, 2004 10:57 PM

But let's get back to large brains and small jaws, which nicely demonstrate science going out the window.

The implicit assumption behind the small jaw/large brain story is that, as the excerpt says, large brains make us human. Huh? There's nothing scientific about that. In trying to make this small jaw mutation fit into natural selection theory, the fine edges are being sawed off.

First, while it might be nice to find one mutation that is responsible for increased intelligence and consciousness, such a simple explanation has been rejected by Darwinists for some time -- because there was no evidence for it. In other words, the story of the evolution of h. sapiens can be made to fit both one quick mutation, or a slow process of accretion.

Second, the implicit basis for this story is nonsense. There is no basis to believe that brain size has anything to do with intelligence, or that either have anything to do with consciousness. Other species have bigger brains and, within h. sapiens, intelligence and brain size are not correlated. As we don't know what consciousness is, and can't measure it, we have no idea if it requires a large brain. (Actually, the most recent research I've seen is focussed on the number of connections within our brain as the cause of consciousness, rather than brain size.)

So why the focus on brain size? I would guess that some Darwinists like the idea of our "humaness" being traced back to something seemingly unimportant, like jaw size. Of course, smaller jaws and larger brains are both contra-fitness mutations and it seems very unlikely that intelligence could have developed fast enough to overcome those changes, so my wag is that intelligence preceded small jaws and big heads.

Posted by: David Cohen at April 26, 2004 7:58 AM

David:

That's the beauty of the theory though--because the mutation survived it must have conferred some advantage even if just one so tiny that we can't ken it. It thus spread to the entire population of men everywhere, men who welcomed this slack-jawed cousin into their midst with open arms and sought to breed with him/her (you know how accepting we all are of the "other"). All you have to know it the outcome (the telos) of evolution and you can explain anything.

Posted by: oj at April 26, 2004 8:20 AM

Blue whales have the biggest brains. Elephants' brains are four times bigger than human brains.

Dolphin brains are 40% bigger than human brains and are even more wrinkly. But most of it is taken up with their sonar sense.

We already know that brain size alone doesn't equal intelligence in the sense that we mean 'intelligence'. But it probably helps. Humans have the biggest brains in proportion to their bodies.

Funnily enough, Neanderthals had bigger brains than modern humans.

Maybe a Neanderthal would be able to grasp that because you can explain how a process moved from point A to point B, you are not suggesting that the process knew it was going to point B, when it started out.

Posted by: Brit at April 26, 2004 8:49 AM

Brit:

Has the darwinism you adhere to pretty much abandoned the notion of fitness playing a role at all?

(BTW, why not take a break from evolution and treat us on another thread to your take on the Blair announcement of an EU referendum.)

Posted by: Peter B at April 26, 2004 9:13 AM

Brit:

You do know B.

Posted by: oj at April 26, 2004 9:36 AM

Correct. We do.

We also know what the weather is like today. And what the weather was like at any point you care to name in the last month.

And so...?

(tread carefully OJ. Think about it)

Posted by: Brit at April 26, 2004 9:47 AM

And so we can formulate a theory that will describe why we had the weather we had today.

Posted by: oj at April 26, 2004 10:02 AM

And...?

Look, here it is in the simplest possible terms:

Darwinists claim that evolution moved from point A to point B. But Darwinists DON'T claim that evolution moved from point A with the stated goal of arriving at point B.

That is what distinguishes non-telelogical Darwinism from teleological Intelligent Design.

Intelligent Design theorists claim that evolution moved from point A to point B. And Intelligent Design theorists DO claim that evolution moved from point A with the stated goal of arriving at point B.

So why are you arguing both that Darwinism is teleological, and that it is also wrong and ID right? Bizarre, eh?

(Actually I'll tell you why: because among your several confusions, you're confusing an argument that Darwinists are 'teleological' because they try to bend their theories to fit the observations; with an argument that Dawinism explains evolution teleologically. Which it doesn't, otherwise it would be ID, and you'd call it true.)

So can we at least agree about what we disagree about?

Posted by: Brit at April 26, 2004 10:12 AM

By the way, doesn't this quote reflect a complete misunderstanding of Darwinism:

As our ancestors "gradually acquired the habit of using stones, clubs or other weapons for fighting with their enemies, . . . they would use their jaws and teeth less and less. In this case, the jaws, together with the teeth, would become reduced in size."

Posted by: David Cohen at April 26, 2004 10:17 AM

Brit:

Intelligent Design doesn't require God to end at point B either.

Posted by: oj at April 26, 2004 11:06 AM

OJ:

That's true.

Though I suspect most ID theorists would argue that we've reached the end of evolution.

So that tends to be a practical difference between most Darwinists and most IDers, but it's not a necessary conceptual difference between the two theories, as you correctly say.

In fact, a theory can qualify as 'Intelligent Design' if it resembles Darwinism in every single way...except that it claims that someone or something initiated evolution with the aim of arriving at a particular point (could be now, could be somewhere in the future), or even just of moving in a particular direction.

A key feature of Darwinism is that it does not make this claim.

Posted by: Brit at April 26, 2004 11:29 AM

Brit:

So why didn't the unhinged jaw Man survive instead of hinged jaw Man?

Posted by: oj at April 26, 2004 11:44 AM

Couldn't tell you, mate. That's what scientific researchers are for.

Posted by: Brit at April 26, 2004 11:46 AM

Orrin/David

You guys are ahead of me in this area. Would I be going too far by suggesting darwinism (the random, directionless version)seems to have become an effort to use scientific laws, classifications, principles and evidence to prove chaos.

Posted by: Peter B at April 26, 2004 11:48 AM

Peter:

It's not science at all, just a philosophy that applies Adam Smith and Malthus in an attempt to remove the Creator from Creation.

Posted by: oj at April 26, 2004 12:12 PM

Peter:

I'm not, or at least don't consider myself, anti-Darwin. Darwanism is a nice attempt to reconcile the fossil record and captures a dynamic that undoubtedly plays itself out in nature. For the 19th century, and without an understanding of the mechanism of genetic inheritance, Darwin did a good job of showing how biological diversity is possible without direct intervention by G-d. As Harry suggests somewhere on the site, the record is there; it can't be any insult to G-d to try to understand it.

I think, for example, that OJ focuses too much on speciation, which isn't necessarily that big a deal and could easily result from random mutation and isolated populations.

I have the following problems with Darwinism:

Now that we have a better understanding of how traits are passed down, natural selection is trivial.

Given the limits Darwin faced, mutation was always a black box -- it was a given, not explained by the theory, which depended upon mutation being rare. Nonetheless, lots of Darwinists insist that Darwinism has implications for the mechanics of mutation, when Darwinism has nothing to say about that.

Darwin was influenced by Malthus. We now have a much better understanding of population density than Malthus did, and it turns out he was wrong. As a result, natural selection just isn't as fine a sieve as Darwin expected. (Note that his commitment to Darwin requires Harry to defend Malthus, which is exactly the opposite of the position I would expect him otherwise to take.)

Darwin can have nothing to say about the creation of life. There's lots of hand waving here, about churning oceans, and primordial soup, and the effect of tides and heat, etc., but there is no reason to believe that the mechanisms of natural selection have anything to say about turning random amino acids into life.

Darwinism relies too much on long periods of time as the solution to all questions.

Some speciation is just very unlikely (though over long periods of time, not impossible). I'm particularly bothered by the great variation in the number of chromosomes among species. Although parents with different numbers of chromosomes can mate, having them breed true, having their children find mates who breed true, etc., is highly unlikely. (Of course, they had lots of time . . .) The problem is that this requires things that are very unlikely to happen millions and millions of times.

And yet, other things happened only once. For example, we have yet to find any life that can't be traced to one creation event. Why should this happen once, and other things, just as unlikely, happen constantly.

None of this can disprove Darwinism, which is, I suppose, one of its problems. It is too malleable to be useful. After all, here we are, and Darwinism will always end in our being here. Add in that Darwinists are allowed to rely on the occurence of speculative, low-probability events for which there is no direct evidence, and you end up with a story, not a theory.

Finally, and this is admittedly subjective, I dislike the presumption of some Darwinists (none of our friends, here, of course) that believing in Darwin makes them better or smarter than other people, captured as we are in our superstitions. Darwin's achievement, for his time, was great. Believing in his theory today, though, is hardly a badge of courage or an intellectual feat. That many of those Darwinists misunderstand the theory and its implication -- as our friends here do show -- is simply the cherry on top.

Posted by: David Cohen at April 26, 2004 12:57 PM

David:

Thanks very much. The reason I asked was I was struck by your comment about darwinists being attracted to a mundane explanation for the brain. But I also note Brit uses the word "process" a lot and I have been trying to get my head around using that word to describe something purposeless, random and directionless. Of course they will point to weather, but weather doesn't turn off and on and it does have an element of predictability and pattern that they seem to be denying to evolution. It clearly isn't random.

I guess the other source of my mental gyrations is the concept of fitness. As you say both the jaw and brain seem contra-fitness, but so does just about everything else about man's putative evolution. It takes quite a tale to conjecture about what natural forces led to a slow naked biped that can't smell or navigate, can't see at night and is built for endless birthing problems. But if you posit chaos you can do it.

Posted by: Peter B at April 26, 2004 1:41 PM

David:

Finally, someone comes up with some coherent objections to Darwinism. Figures it would be you.

Regarding your problems: That Darwin had nothing to say about mutation makes his theory incomplete. And Darwinists can insist there are implications for mutation. For example, if there were, say, 3,000 genetic differences between chimps and us, instead of around 300, Evolution would be holed below the water line. The fossil record is clear about when humans branched off from our last shared ancestor with the chimpanzees. Even before the genome project, rates of genetic drift were known well enough to realize what the genetic difference between chimps and us had to be.

You are absolutely right about Darwin and the origin of life. It surprises me so many critics get this one wrong.

Continental drift relies on even more time than Evolution does--slow, and/or low probability events take a lot of time to happen. Why is that a problem? Besides, not all time periods are particularly long. Flightless birds evolved on isolated Pacific islands in far less than eons.

Your comment on chromosomal variation is, to me, the single biggest unknown remaining to Evolution. I suspect our notion of genetics is far too simplistic/mechanistic; the answer is a material one, we just haven't figured it out yet.

I think you miss the mark with things happening once, and constantly. If enough throws of the dice allowed life to arise, once initial conditions were met, once every 10,000 years, then by the time the second chance came around, the field would already be taken.

There are ways to disprove Darwinism--the number of mutations between us and chimps would have been a great opportunity. Unfortunately, God neglected to leave the red herring.

Excellent post, David.

Peter:

You are right, fitness does have a whiff of tautology about it. But I think you assume too much by concluding that jaw and brain seem contra-fitness. Let's take as stipulated that they are: did God keep giving us a leg up despite our manifest shortcomings?

Or were their shortcomings just compensated for by gains in other areas, so that there was a net, however slight, increase in the ability to survive and reproduce? Remember, fitness isn't absolute.

Posted by: Jeff Guinn at April 26, 2004 8:51 PM

David/Jeff

Good posts. I’ll try to address some of David’s points without repeating Jeff’s admirable responses.

Firstly, as a general point, finding 'problems' with Darwinism is a good thing. All good scientific theories can be refined, and elements rejected or added. Opponents might call this ‘moving the goalposts’, but I’d call it ‘learning.’

Mutation: it’s true that Darwin didn’t know about the specific mechanisms of genetic mutation. But he correctly thought that the object of selection is the phenotype – that is, the developed, unique, individual animal, its characteristics and behaviours. Some decades ago, some Darwinists shifted into speculating that the genotype was the object of selection. This view is now rejected, and it’s accepted that Darwin was right all along. Do you see the implications of this for your comment? Maybe that’s for another thread…

Incidentally, not only are mutations rare, but beneficial mutations are even rarer.

Chance and unlikelihood:
You say: “Some speciation is just very unlikely (though over long periods of time, not impossible).”
I’m not quite sure what your point is here. Maybe I’m missing the mark, but beware the logical fallacy of thinking that because something looks unlikely, it somehow ought not to have happened in an undesigned universe. If everybody on Earth spends all day tossing a coin, the chap who gets 200 heads in a row may think he’s special - “I’m the Chosen One!” he might cry – but he’s not thinking straight. Everyone around him is producing an equally unlikely series of results. His just looks pretty.

More importantly, you have to realise that while mutations at the genetic level are indeed random, selection at the level of the phenotype is not actually ‘random’ at all, but massively determined by the environment.

For evidence, see ‘convergent evolution’. This is where species not closely related genetically – ie. very far removed from a common ancestor - independently acquire similar characteristics, because they inhabit a similar environmental niche. A striking example is the African aardvark, which is genetically unrelated to the South American anteater, but looks just like it, having evolved the same tools – long sticky tongue, few teeth etc - to eat ants. More obvious examples are whales and dolphins – which look like fish, but aren’t.

And winged flight has evolved at least three times quite independently (bats, birds, insects).

I don’t really understand your comment: "Although parents with different numbers of chromosomes can mate, having them breed true, having their children find mates who breed true, etc., is highly unlikely."

Is that a problem for Darwinism , or just genetics in general? Can you elaborate?

The usefulness and the evidence:
You say: "Add in that Darwinists are allowed to rely on the occurence of speculative, low-probability events for which there is no direct evidence, and you end up with a story, not a theory."

I think you’re off the mark here. The evidence is there in abundance. Not only do biogeography, fossils and the genome project support Darwinism as evidence, but Darwinism explains why there are like they are, and has predicted that things will be as they are, and they’ve turned out to be so. Which makes it pretty useful.

Posted by: Brit at April 27, 2004 5:53 AM

Brit:

Thanks. Can you elaborate on your comment that while genetic mutations are random, phenotype selection is not? Seriously, no baiting. I am having a conceptional difficulty with that one. Isn't that the opposite of the linguistic development you say is analagous to evolution, where individual changes are not random but the overall development over time is?

Still hoping for your thoughts on the EU referendum.

Posted by: Peter B at April 27, 2004 6:43 AM

I mean conceptual. Coffee, please.

Posted by: Peter B at April 27, 2004 6:44 AM

Peter

Ok, the question is: "is Darwinian evolution random?".

And the answer is: depends how you look at it, and what you mean by 'random'!

First, genetic mutation itself is completely random. So you cannot predict how a genotype will mutate.

But, selection of the 'phenotype' - that is, which developed animals will survive and reproduce and which won't - is not really random in the same sense at all, because it is determined by their particular environment.

So a random mutation at the genetic level might produce a rabbit with a deformed leg, or a blind rabbit (the phenotype). But it's highly predictable that that phenotype will not survive and reproduce in its environment (it can't run away from predators very well, for example). So it will be selected against, you might say, non-randomly.

But of course environments themselves and changes in them are hard to predict. You might say ice ages, floods and earthquakes are random.

But that is all separate from another sense in which Darwinists talk about evolution overall: when he call it 'random' we're distinguishing it from the claim that it is 'designed'.

--------

So it is analagous to language, in that while individual instances of word-utterance conscious and deliberate, the overall development - which is the net effect of these utterances - is unconscious and just happens.

A fox catches a three-legged bunny because it wants a meal. It does not do it with the intention that bunnies in general are selected in favour of having four legs, because he wants future generations of rabbits to be four-legged!

Likewise, your kids utter certain slang words for skateboards and computer software and text messaging that mean nothing to you. When they grow old these words might have become acceptable for printing in the Times. Your kids don't have this change in the language in mind when they utter these words, but it will just happen.


-----


(EU referendum - it's a good thing. Because the answer will be no. The politics of the U-turn are odd though. It makes sense for the next election, but after that how will Blair deal with defeat?)

Posted by: Brit at April 27, 2004 7:12 AM

Peter:

What Brit means is that at the level of the genome, replication is non-deterministic, and process failures in the replication happen in the same way that radioactive decay does. For a sample of a given size, it is possible to say statistically what the decay rate will be, but impossible to say which atoms will decay. Same way for genetic replication. Similarly, for mutations.

Whether through mutation, or just normal variation across a population, the environment is not equally friendly to all. A good example is the Middle Voyage of Africans to the Americas. The mortality rate was high, but it was lower for those who could resist dehydration better. Because part of the dehydration resistance bell curve distribution was chopped off several hundred years ago, African Americans today are more prone to hypertension than they would otherwise.

In my view of linguistics as analagous to evolution, changes in vocabulary, spelling, and grammar are essentially random. But whether a particular change "sticks," or not, has to do with whether it is fit enough to propagate. That is where recursion comes in.

Also, despite having a pretty good record of English, one can only say in hindsight what changes succeeded, and often can't say why. I'm not sure that argues for Intelligent Design as an explanation for linguistic change over time.

Posted by: Jeff Guinn at April 27, 2004 7:25 AM

Brit:

" determined"

See, that wasn't so hard. It's just a form of determinism leading to higher levels of fitness, thus teloeological.

Posted by: oj at April 27, 2004 7:46 AM

Jeff/Brit:

Thanks for your responses. Let me see if I can give them the responses they deserve.

I still think that you underestimate the implications of the ways in which mutation actually happens for Darwinism as conceived by Darwin. Consider the passage I quoted above:
As our ancestors "gradually acquired the habit of using stones, clubs or other weapons for fighting with their enemies, . . . they would use their jaws and teeth less and less. In this case, the jaws, together with the teeth, would become reduced in size."

Because Darwin did not understand the mechanism of genetic inheritance, he could assume that use would have some direct effect on the genotype; that is, that as we used our teeth and jaw less, our children would have smaller teeth and jaws. This has at least two pretty significant implications: first, it uncouples mutation from natural selection, leading to Peter’s questions; second, it greatly expands the time necessary for the evolution of the human race, which was again lengthened when the fossil record showed long periods of equilibrium punctuated by short, dramatic bursts of speciation.

Thus, we have a loosening of both sides of the Darwinian process. In fact, natural selection is not as powerful a force as Darwin assumed. “Fitness” describes not one possible genotype, but any number of possible phenotypes. Brit says that phenotypes are massively determined by the environment, but this does not seem to be the case. Frankly, survival is, if not easy, than not quite the constant battle that 19th century romantics, including Darwin, assumed. It turns out that, most of the time, ever faster lions are not driving gazelles to be ever faster, themselves. Rather, lions are “satisfied” eating the old and the sick gazelles, the ones that are not going to have any effect on the future genotype.

At the same time, mutation is independent of natural selection. The mutations that arise (as opposed to survive) are not shaped by what would be useful to the species.

My problem with relying on low probability events is that it is like the old joke about the economist on the desert island who assumes a can opener. It has become an all purpose explanation for anything in the theory that can’t be directly explained.

(Jeff – I don’t understand your point about continental drift. It is slow, but it is not random and, once the mechanics are understood, it is intuitive. When the plates start moving randomly, or reverse themselves, then we’ll have a problem.)

Brit – I don’t think my problem with chromosomal variation is s problem with genetics. As I say, it can happen. Rather, my problem is how many times it would have to happen. I understand your point about the one man in six billion who gets 200 heads in a row, but would you bet with him on the 201st toss? Or would you suspect that something had its thumb on the scale?

I have more to say, but now I have to get the kids to school.

Posted by: David Cohen at April 27, 2004 7:54 AM

Grow up, OJ.

Posted by: Brit at April 27, 2004 7:56 AM

Brit:

So, I win?

Posted by: oj at April 27, 2004 8:09 AM

Brit:

But are your three legged and blind bunnies really good illustrations? The genetic mutation that caused those may well be random, but is there any connection at all to the development of a phenotype? If two blind or lame bunnies mate, they don't produce blind or lame offspring, at least not necessarily.

Posted by: Peter B at April 27, 2004 8:10 AM

Peter:

Maybe not - it's a good illustration if you get the point.

The genotype is the specific genetic makeup of an individual (the DNA). It 'codes for' the phenotype: that is, it carries instructions for how to build the phenotype - which is the sum physical and behavioural characteristics of the developed individual.

Genetics in a very small nutshell: Genes are self-replicating - when offspring are made, copies of the genes are made. Occasionally small mistakes are made in the copying process (mutation). These mutations will themselves by copied in the genotypes of future offspring, should the phenotype reproduce. (That's 'inheritability').

So let's suppose a mutation (mistake in the copying process) in the genotype of a bunny codes for the creation of a fifth limb - some grotesque disfigurement.

If the resultant unfortunate phenotypic bunny suvives long enough to find an unfussy mate, there's a good chance that its own offspring will have these horrible appendages too.

Of course, what will probably happen is that the slowly hobbling bunny will be gobbled up before it can find a mate who doesn't turn her nose up.

In which case the phenotype of the five-legged rabbit will have been selected against. It's not necessary that it will be, but it's unlikely that generations of rabbits with this particular mutation are going to become prevalent in rabbit populations.

Other mutations might do though. Most mutations will be either detrimental or neutral (that is, confer no benefit or handicap on the phenotype). But some, such as stronger hind legs, might. That's the basic notion of gradualism.

The point being, that properly speaking, the phenotype in the environment is the object of selection. There's still a lot of randomness and unpredictability involved - environments change randomly, predators themselves die out etc.

But it is not 'purely' random in the sense that mutation at the gene level is.


OJ:

"Win?" We're not even playing the same game.

If it amuses you to take one single word out of context and pretend that my conception of Darwinism is the same as yours, that's up to you.

Posted by: Brit at April 27, 2004 8:37 AM

Brit:
Brit:

Thanks again. But doesn't there have to be a distinction made between the kind of mutation like wings or blue eyes that actually leads to changes in the phenotype (i.e. reproduces predictably as part of normal breeding) and those that are more what we see as disabilities or freaks of nature? Again, two congenital deaf mutes can produce perfectly normal children. How do you distinguish?

Posted by: Peter B at April 27, 2004 8:52 AM

Peter:

My example is a deliberately broad over-simplification. In reality, genes are complicated, and they interact with each other in complicated ways.

Some genetic characteristics do not manifest themselves in the phenotypes of every generation, but can lie 'dormant' only to pop up now and again, as I'm sure you know.

I'm not sure what you mean about a 'distinction' - do you mean practical (some are more likely to become prevalent than others), aesthetic or what?

That might be context-dependant. An exceptionally tall person is as much a 'freak' as a very short one - but he might make a great basketball player and be considered successful. Of course, if he's a coalminer it might be a 'disability'.

And of course, sometimes deformities might not be an impediment to reproduction at all. Take the Hapsburg Jaw - generation after generation of hideous freaks. No woman would have looked twice at Carlos II if he'd been a peasant. But being King has its advantages...

Posted by: Brit at April 27, 2004 9:11 AM

Brit:

Out of context? It's your point. Survival is deterministic.

Posted by: oj at April 27, 2004 9:13 AM

David:

You certainly ask good questions. I’ve had to have a good think.

Your first point I think can be condensed to: was Darwin himself not really a 'Darwinist'?

Or, since he didn’t know the mechanism for genetic mutation, was he in fact no different to Lamarck?

Well, I think it's fair to say that Charles Darwin was more Lamarckian than modern Darwinists. That is, he did think that some acquired characteristics could be inherited. But he also acknowledged that he needed genetic inheritance, and that his theory would be incomplete if no mechanism for such could be found.

Since we’ve learned about DNA etc, we’ve chucked the Lamarckian idea out the window. 'Modern Synthesis' is the combination of Darwin's theories – natural selection, common descent etc – with modern knowledge of genetics.

(But wait, to further complicate matters, check">http://en.wikipedia.org/wiki/Epigenetic_inheritance">check this out: Epigenetic Inheritance!)

None of which is an attack on modern conceptions of Darwinism.

Let’s interpret the sentence: "gradually acquired the habit of using stones, clubs or other weapons for fighting with their enemies, . . . they would use their jaws and teeth less and less. In this case, the jaws, together with the teeth, would become reduced in size" in a Modern Darwinist way.

A Modern Darwinist might not put it this way, but if he did, it would just be shorthand for saying: "over time, in the trade-off between the benefits (whatever they are) of having smaller teeth and the benefits of having big teeth, the increased use of tools would tip the balance in favour of small teeth, and, over time, you would expect smaller teeth to become more prevalent. This might happen relatively quickly in some isolated populations, which then might come to dominate and supplant other populations with big teeth."

I’m making the details up, but you see the principle?

Darwinism has changed since Darwin.


----------------------

"'Fitness' describes not one possible genotype, but any number of possible phenotypes. Brit says that phenotypes are massively determined by the environment, but this does not seem to be the case."

Yes to the first sentence, no to the second. Which phenotypes survive is massively determined by the environment. That's why the OBJECT of selection is the phenotype, not the genotype. That’s also why your sentence:

"At the same time, mutation is independent of natural selection. The mutations that arise (as opposed to survive) are not shaped by what would be useful to the species."

is entirely correct.

-------------

Next:
"Frankly, survival is, if not easy, than not quite the constant battle that 19th century romantics, including Darwin, assumed. It turns out that, most of the time, ever faster lions are not driving gazelles to be ever faster, themselves. Rather, lions are 'satisfied' eating the old and the sick gazelles, the ones that are not going to have any effect on the future genotype."

First, let’s not get carried away with lions and gazelles. That example was designed to explain the principle of gradualism. But you’re right. There are numerous conservative factors in evolution, as well as change-mechanisms. Gene flow (see Wikipedia for definition) is an incredibly powerful conservative factor. Which is why when speciation happens, it happens relatively quickly to isolated populations (which still isn’t overnight, you understand.)

Punctuated equilibrium is not the divisive factor opponents of Darwinism portray it to be. The arguments between Darwinists are really only over the relative degree of importance of gradualism and punctuation in speciation. The notion that most Darwinists rely on gradualism alone to explain speciation is a strawman.

Posted by: Brit at April 27, 2004 10:34 AM

Well, there's no chance I'm not going to get dragged off onto a tangent, so I might as well enjoy it.

I may not be sure what Brit means by "massively determined". If a mutation is incompatible with survival, it will not survive. But lots of mutations and lots of phenotypes are not inconsistent with survival. There is a certain type of Darwinist, and every single evolutionary psychologist, convinced that they must hunt down a reason for every single difference between any two members of a species. Sometimes, most of the time, it's just going to be that nature couldn't care less.

Equally, many mutations, even if beneficial, won't actually make it into the species. Let's say, for example, that little ESP baby was on the Titanic. Oops. That is, in a sense, determined by the environment, but not on any grounds of fitness.

Posted by: David Cohen at April 27, 2004 2:26 PM

David:

Does every mutation though have just this one ur instance? why don't ESP mutations (or whatever) go on all the time and then survive or not? Don't two individuals with the mutation have to mate? Why don't those without kill the mutant? And so on and so forth...

Posted by: oj at April 27, 2004 2:40 PM

Well, here I was already to type out a long response, only to discover Brit has discussed the points perfectly.

David:

My point about continental drift was that it is bloody slow. So slow that only the most sensitive measurements could discern the difference over the course of human history. Since there is no privileged time scale, the fact that Evolution (absent extinction) is discernible only over extended time is simply not an argument against the theory.

At the risk of being pedantic, continental drift is random, but not recursive.

But what is more interesting about continental drift is that any parcel of land on the planet has probably been through about every climate zone there is. That there is any terrestrial life at all means life had to adapt to those changes--there are plants in the desert, and in Maryland, but they are scarcely the same. What process, other than environmentally selective survival and recursion, explains that fact?

Your point about the impact of sheer happenstance is good one, and one that should be far more prominent than it is. I find it kind of interesting to consider how various parts of the system might have interacted to produce the outcomes we see. For example, women have features and proportions reminiscent of children (higher voices, lack of facial hair, head size/shoulder width ratio). Why is that? Well, possibly because way back in the day, women with those variations gave a sufficiently greater impression of vulnerability than their less childlike sisters, so that their men stayed around more to protect their genetic investment. Which led to differential survival success for the offspring. Recursion led to what we have now.

Fairy tale? Perhaps. Probably. But you just can't do that kind of speculation with ID.

OJ:

That is why evolution happens most quickly among small, isolated populations. Just like with language.

Posted by: Jeff Guinn at April 27, 2004 8:07 PM

Jeff:

You're wrong about continental drift--it's easily measurable on a very short term basis. Evolution, as you note, has never been measured because it hasn't occurred during at least recorded history.

Your little schtick about women is the kind of just so story that makes y'all so precious.

Posted by: oj at April 27, 2004 8:20 PM

OJ:

I'm not wrong about continental drift. Absent very sensitive measuring equipment, it isn't detectable short term.

And Evolution has occurred during recorded history. Extinction is just as much part of evolution as speciation is.

My little schtick was part tongue in cheek. But even at that, it is far more interesting than "on account of because," which is all ID amounts to.

Posted by: Jeff Guinn at April 27, 2004 10:38 PM

Jeff:

I posted the piece here earlier about how easy it's become--you can actually measure NYC and LA drifiting apart. The plates move--oddly enough--as fast as your fingernails grow. Plenty observable.

Extinction has nothing to do with Darwinism. Everone knew extinction occurred. After all, where were the dragons?

ID is Darwinism, it just substitutes God for Natural Selection. I'm equally dubious of both.

Posted by: oj at April 27, 2004 10:57 PM

David:

Everything in your last post is correct and consistent with Darwinism - because nothing in Darwinism insists on absolute 'fitness' all of the time.

Here it is in black and white: Fitness is not perfection.


OJ:

"ID is Darwinism, it just substitutes God for Natural Selection."

Not if you want to use the definitions as everybody else uses them. ID can include natural selection AND God.

If you want to have special OJ definitions, fine.

Funnily enough, the two key elements in ID are "Intelligent" and um..."Design". Which are two of the things not included in Darwinism.

Posted by: Brit at April 28, 2004 4:39 AM

OJ:

My post said that absent sensitive measuring equipment, continental drift is not detectable over human time spans.

Until the, oh, 1950s or 60s, the whole concept was derided as nothing more than special pleading about coincidentally shaped coastlines.

After all, since people began making maps, there was no detectable continental drift.

Accurately dated fossils from the coastlines of Africa and South America showing contiguous, then divergent evolution, was the first conclusive evidence of continental drift.

Posted by: Jeff Guinn at April 28, 2004 8:09 AM

Jeff:

It's not particularly sensitive equipment and the drift is significant. These measurements prove drift and therefore make it utterly unlike Darwinism.

Posted by: oj at April 28, 2004 8:17 AM

OJ:

I agree. Measurements prove continental drift, hence plate tectonics.

Just like measurements prove genetic drift, hence Darwinism.

You are finally getting it.

Posted by: Jeff Guinn at April 28, 2004 6:17 PM

The plates moved an inch last year, as per measurement. What evolved?

Posted by: oj at April 28, 2004 9:04 PM

The AIDS virus. Antibiotic resistant bacteria. The SARS virus.

Undoubtedly there were a few extinctions.

Tiny changes, no doubt. As would make no difference at all. Just like an inch of continental drift.

Posted by: Jeff Guinn at April 28, 2004 10:28 PM

That's the best you've got?

Posted by: oj at April 28, 2004 10:32 PM

It is exactly on point.

You have repeatedly said evolution does not occur, since none has been observed during human history.

That is also completely true about continental drift. How much has occurred during human history? None.

OK, that's not completely true, since the advent of extremely sensitive measuring equipment, we have observed extremely small changes--the 1" movement of an entire continent. But before then (then being about 1980)? It all relies on fossile evidence of various kinds, and vast swaths of time.

The changes I noted above are tiny. Just like 1" of continental drift. So why is fossil evidence and eons okay for the latter, but not the former?

Posted by: Jeff Guinn at April 29, 2004 7:25 AM

Jeff:

We've been measuring continental drift since the 50s at least and it occurs every day of every year.

We've been measuring change within species for thousands of years. Wolves are now poodles. We've been measuring speciation via Natural Selection....never.

Posted by: oj at April 29, 2004 8:13 AM

OJ:

So does Evolution--which, BTW, is more than speciation. That you have failed to acknowledge any evolution that has occurred in the last vanishingly recent period of natural history is an excellent example of arbitrarily assigning some preferred rate and quantity on phenomena that could not possibly care less about your preferences.

Extinction, by the way, is also an example of Natural Selection.

Now, given that virtually all species that have ever been are extinct, just where do you suppose the ones that are alive today came from?

Posted by: Jeff Guinn at April 29, 2004 9:01 PM
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