Philosophy Discussion Forums | A Humans-Only Club for Open-Minded Discussion & Debate

[Steve3007]

Seagull:

I agree that evolution progresses too slowly to be able to see it happening over just a few generations. But it's still possible to look at the mechanisms that cause it and analyse the extent to which those mechanisms do and don't exist at a particular instant in evolutionary time. It is possible to observe the existence, or otherwise, of pressure (a static phenomenon) without necessarily being able to observe the movement that is caused by that pressure (a dynamic phenomenon). This is, in fact, how we know about evolution, and other very-long-term processes, at all. We occupy an instant in cosmological/geological/evolutionary time and therefore see a snapshot of the universe. But we can extrapolate a lot from that snapshot.

Obviously, in the human societies of the last 4000 years or so, life is still hard, death is still common and therefore evolutionary pressure does still exist. Hence my use of the quotes around the word "stopped". But the point of the research cited in the OP was to propose that in pre-historic times it was even harder and that it was this extreme hardness, existing over a much longer period of time than 4000 years, which was largely responsible for the current evolutionary state of our brains.

[A Poster He or I]

In the last 2 decades, research in neurophysics and the other cognitive sciences has provided significant evidence to suggest that much -- possibly even most -- of the evolutionary pressure on humans since even before homo erectus has not been the pressure of brute survival but rather the capacity for symbolic processing (Nadeau & Kefatos' The Non-Local Universe provides a comprehensive synopsis of these findings as a quick source). In other words, those hominids with the greater capacity to utilize the rudiments and evolving forms of what would become language were favored in the struggle to survive. It makes a lot of sense when you think about it: tribes with greater capacity to communicate symbolically could employ better strategies for hunting, resolving internal conflicts, and passing vicarious experience (knowledge) to new generations, all of this favoring survival. It is considered by many scientists the most plausible explanation for why human brain size increased so dramatically in such a short time, since only humans have complex language and language processing involves almost every part of the brain.

In this light, human evolution since Neolithic times appears to be most fundamentally a continuum of evolving sophistication in information processing. It then becomes easy to imagine that evolution has not "stopped" at all, and that indeed the pressure to assimilate and be fluent with information technology may even be increasing, not stopping. For example, the so-called "digital divide" is nothing short of evolutionary pressure in action since it potentially contributes to the kind of social stratification that alters the distribution of genes in the species.

[Wilson]

Today there's no logical reason to think that we will continue to get smarter. Maybe even the opposite, since the smarter you are, the fewer kids, in general. And bright and less bright people in developed nations, at least, all seem to live long lives. Evolution doesn't point toward increased intelligence, increased strength, increase athleticism - what we think of as desirable qualities - unless said qualities are helpful in surviving or reproduction.

I think increased intelligence was extremely helpful in promoting survival in hunter-gatherer times, as A.Poster said above, and I'm pretty sure that indeed was what drove our development of increased brainpower and conceptual abilities. Remember that in those times humanity was mostly in relatively small groups - probably averaging between 20-50 individuals. And there were probably a lot of shared genes within each groups, because families tended to stay together. So some groups naturally were a lot smarter than others, and those were the ones that tended to survive. And the groups with better abilities to cooperate also survived better - and cooperation is facilitated by empathy, a sense of being a part of a group - us vs them, altruism (where an individual might sacrifice himself for the group or tribe), and a moral system which valued others within the group. So intelligence and empathy and cooperative tendencies were all selected for.

Here's a puzzler, though. Most girls today don't seem to be as attracted to the brainy types as much as to the brawny, more physically dominant boys. Shouldn't evolution have led women to be sexually attracted to thinkers rather than athletes? A couple of possibilities. Maybe in those days the girls didn't have as much to say about who they lay with as they do today. Or maybe the strong men were just as important to the survival of the group as the brainiacs - or more so. Or maybe the innovations and benefits that came from the smart guys were of value to everyone in the tribe, not just the inventors themselves of a better way to trap large game, to build a safer home, to fight an invading army, to protect against predators, or whatever. Still, you'd think evolution should have made us relatively bright contributors to a philosophy forum more objects of carnal desire than we are.

[Steve3007]

Poster (and addressing/re-iterating some of what Wilson said):

Interesting points about the importance of symbolic processing to survival. Obviously we can see the extraordinary result of that evolution right here in the conversations we're having. I'm staring at a glowing 12 inch screen with some black wiggly lines on it and, bizzarely, I see them as symbolizing the thoughts about some subtle and interesting philosophical ideas in the brains of other people thousands of miles away. I try telling that to my cat and she just looks at me like I've finally lost it. (But, then, she always looks at me like that.)

And, strangely, when I'm not procrastinating on philosophy websites, like many other people in my society I spend my days drumming my fingers on little plastic squares to generate loads more black squiggly lines. That seems to result in someone giving me reasonably large chunks of another abstract concept called money. I can then use that abstract concept to get non-abstract things like food, clothes and a house.

Incidentally, I googled that book you mentioned: "The Non-Local Universe" and saw that (as the title suggests) it's main theme is physics experiments which seem to demonstrate non-locality. Does it have a section on the evolution of the capacity for symbolic processing in humans?

Anyway, regarding your point about the "digital divide" being a modern continuation of the evolution of symbolic processing: as Wilson points out, in our societies at least, the material success resulting from the ability to master such things doesn't seem, any more, to translate directly into reproductive success. To put it more bluntly: Nerds don't necessarily have more children! (I have only two.) This seems to be part of a broader pattern in our societies of the de-coupling of intellectual/material/social success from reproductive "success".

I think, in our societies, as Wilson says, it's perhaps possible to see trends in which material success leads to fewer offspring. I think perhaps an underlying reason for this is that the more materially secure we become the less we see the necessity of having a large family as an insurance policy and as a status symbol. We like to think we have our material and intellectual status symbols instead. (As well, of course, as the fact that materially successful people often simply regard themselves as too busy to have lots of children.)

As a particularly vivid example, it's always struck me as interesting to consider the "reproductive success" of recent US presidents in this context. How many children, on average, do, say, Reagan, Bush, Clinton, Bush and Obama have? No more than the western average, I think.

But they're supposed to be the most powerful people on Earth. They should have hundreds! Hundreds of children with the "Got what it takes to be president" gene. I guess there's always the possibility that there are lots of secret illegitimate children (at least with Clinton, if not any of the others). But I guess you have to go all the way back to Kennedy to get to a president who seems to have behaved in the way that big powerful tribal leaders are "supposed" to behave (from an evolutionary standpoint) i.e. using his power and influence to allow him to have sex with pretty much any female of reproductive age with a pulse.

[A Poster He or I]

I feel you two, Steve and Wilson, may have missed my point. If indeed the primary evolutionary pressure on humans has been the need for successive generations to be ever-the-more information-savvy, then the fact that "nerds don't get to procreate any more than less-intelligent people" is beside the point. The point is that the nerds (more broadly, the creative contingent of humanity) have fashioned across the centuries an environment that has reached a point nowadays where the information-savvy have de facto priority over the less-information savvy when it comes to social interaction, and that means the potential for distribution of their genes.

Intelligence per se, is incidental. It is aptitude (and opportunity) with information that allows individuals to be most socially interactive. An underpriveled ghetto-child who grows up computer-illiterate is not likely to find a potential mate via match.com. An unemployed person who can't leverage the internet in their job search, can't provide business references reachable by telephone or email, and has no computer skills, is more likely to remain unemployed and less likely to be an ideal prospect for a potential mate.

[Steve: the Nadeau/Kafatos tome is mostly a philosophical extrapolation of Bohr's Principle of Complementarity (they are big believers in the Principle of Complementarity, as am I). As such, the book goes beyond physics into biology, Darwinism, Cartesian dualism, and psychology. I mentioned the book only because it has a chapter that serves to summarize some of the neurophysics findings I alluded to, in case anybody wanted source material for my claims].

[Wilson]

The point is that the nerds (more broadly, the creative contingent of humanity) have fashioned across the centuries an environment that has reached a point nowadays where the information-savvy have de facto priority over the less-information savvy when it comes to social interaction, and that means the potential for distribution of their genes.

Poster, I'm not sure you're quite clear on how evolution works. The nerds have greater potential for distribution of their genes? What does that mean? Potential doesn't cut it with regard to sending your genes forward, it's actually the old in-out, in-out leading to babies.

The actual driver of evolution is not survival, exactly, it's the number of fertile offspring. Survival is only important because you can't procreate from beyond the grave. Survival is a necessary but not sufficient condition. If an ugly, stupid, crippled person on continuous flow nasal oxygen has ten kids and a handsome, athletic, Nobel-prize winner has one, the former will have a greater say in the quality of the next generation than the latter, regardless of internet access.

[A Poster He or I]

Wilson,

It will help if you actually read my post accurately. The sentence reads: "the nerds...have fashioned across the centuries an environment that has reached a point nowadays where the information-savvy have de facto priority over the less-information savvy when it comes to social interaction, and that means the potential for distribution of their genes." You seem to have ignored the clause which I've now colored for your convenience. I hope this will make clearer to you that my point has nothing to do with how often a nerd can get coitus. It has to do with how people in general get access to coitus by their ability to socially interact in an information-intensive environment. Such ability is partially contingent upon the assets they can employ, many of which distill down to how savvy they are with information.

Your point about the ten kids of a cripple having a greater effect on the next generation than the single kid of a Nobel laureate is short-sighted. The Nobel laureate's child is more likely to have priveleged circumstances that will allow him to be far more selective in his/her mating choices, ensuring offspring which in-turn are priveleged to maintain a higher degree of interaction with an information-rich environment. Your point about numbers is irrelevant for long-term species survival. The long-term requires adaptability. If the trend toward information-savviness continues, evolutionary pressure will favor offspring best predisposed toward maintaining and expanding the information infrastructure which the species relies upon for survival. A Nobel laureate's child is more likely to get the college education than all ten of the cripple's children getting college educations.

[Obvious Leo]

In the last 2 decades, research in neurophysics and the other cognitive sciences has provided significant evidence to suggest that much -- possibly even most -- of the evolutionary pressure on humans since even before homo erectus has not been the pressure of brute survival but rather the capacity for symbolic processing (Nadeau & Kefatos' The Non-Local Universe provides a comprehensive synopsis of these findings as a quick source). In other words, those hominids with the greater capacity to utilize the rudiments and evolving forms of what would become language were favored in the struggle to survive. It makes a lot of sense when you think about it: tribes with greater capacity to communicate symbolically could employ better strategies for hunting, resolving internal conflicts, and passing vicarious experience (knowledge) to new generations, all of this favoring survival. It is considered by many scientists the most plausible explanation for why human brain size increased so dramatically in such a short time, since only humans have complex language and language processing involves almost every part of the brain.

In this light, human evolution since Neolithic times appears to be most fundamentally a continuum of evolving sophistication in information processing. It then becomes easy to imagine that evolution has not "stopped" at all, and that indeed the pressure to assimilate and be fluent with information technology may even be increasing, not stopping. For example, the so-called "digital divide" is nothing short of evolutionary pressure in action since it potentially contributes to the kind of social stratification that alters the distribution of genes in the species.

A very thoughtful and intelligent post. My congratulations on so immediately coming to the point.

In the simple Darwinian paradigm evolution is driven by death. In the case of an individual species the rate of evolution is entirely determined by its rate of reproductive success, which is inversely proportional to its mortality rate. Traditionally top-order predators have a low mortality rate for obvious reasons and thus they evolve very slowly. Crocodiles and sharks are an excellent example but humans are an excellent counter-example. The uber-predator that is us managed to evolve to the top of the tree of sentience with scarcely a natural predator to worry about. Except for one. Other humans.

Human intelligence evolved to the remarkable level we now witness in the blink of an evolutionary eye. Our brains trebled in size in less than 100,000 generations, an enormous phenotypic change never observed elsewhere in a higher order mammal. And yet evolution is driven by death. What could possibly have been killing off the clever homos in such extraordinary numbers to drive this phenotypic change?

Answer. We did it ourselves by eating the dumb ones. Human intelligence selected for itself and in evolutionary biology this is known as a self-reinforcing evolutionary loop. Poster gives a very concise summary of the mechanism for this process.

Regards Leo

[Wilson]

It has to do with how people in general get access to coitus by their ability to socially interact in an information-intensive environment.

Sorry, that's just wrong. If internet access led to more children, it would be true. But it doesn't. The ability to select better mates through internet dating or whatever would possibly improve the quality of their one child. And that child might contribute more to society. But what's ultimately important is the number of copies of one's genes passed on into the next generation. And obviously in my example the poor fellow breathing supplemental oxygen who is dumb as a post and mating with a succession of similarly afflicted women will have ten copies of his genetic material going into the next generation compared to the Nobel laureate's one. And there's social mobility, and maybe a couple of the poor fellow's girls are attractive, and they marry rich men. The genes of the next generation get all mixed together. You may not have heard this, but nerds tend to fantasize about beautiful girls, not nerdy girls, and somewhat vice versa, so the high IQ line doesn't stay pure. Without question the contribution to the gene pool of the next generation is much greater for the poor soul in my example. And for the most part that's what determines the direction that evolution is going to take.

Poster, if you're male, and you had the choice between Kate Upton (Sports Illustrated swimsuit model, presumably of average intelligence) and an ill-favored brilliant woman physicist, who would you go after? Evolution has given us urges and drives that have a lot more to do with physical attractiveness than mental attractiveness, unfortunately. You might end up with the physicist for her wit and personality, but more likely beauty wins the race. Not fair, not ideal, but that's the way we are constructed. (If you're female, you are probably less superficial than we men are, but physical attractiveness is still very appealing for you, too, I suspect.)

[A Poster He or I]

Sorry, that's just wrong. If internet access led to more children, it would be true. But it doesn't. The ability to select better mates through internet dating or whatever would possibly improve the quality of their one child. And that child might contribute more to society. But what's ultimately important is the number of copies of one's genes passed on into the next generation. And obviously in my example the poor fellow breathing supplemental oxygen who is dumb as a post and mating with a succession of similarly afflicted women will have ten copies of his genetic material going into the next generation compared to the Nobel laureate's one.

For some reason, you seem caught up in the immediate mechanisms of genetic transmission, whereas I am more interested in the OP's question of whether human evolution has stopped, a matter which requires a much, much more long-term assessment of species than the short-term willy-nilly maintenance of mere population numbers.

Let's consider the species' first information geeks: those mutant Homo Habilis with a penchant for rudimentary symbolic association just a little beyond the gesturing/posturing/vocalizing of their fellow animals. I'm certain that these "nerds" were outnumbered at least 10-to-1 by those unable to handle nascent linguistic associations. Yet in the end? Sheer numbers proved irrelevant. Those individuals with the alleles for larger brain mass capable of symbolic association survived while the smaller brains didn't for the simple reason of LONG-TERM ADAPTABILITY. The nerds of their era won out and the genotype for the entire species ended up with larger brains and the capacity for language.

And there's social mobility, and maybe a couple of the poor fellow's girls are attractive, and they marry rich men. The genes of the next generation get all mixed together. You may not have heard this, but nerds tend to fantasize about beautiful girls, not nerdy girls, and somewhat vice versa, so the high IQ line doesn't stay pure. Without question the contribution to the gene pool of the next generation is much greater for the poor soul in my example. And for the most part that's what determines the direction that evolution is going to take.

The purity of the high IQ line is irrelevant. The level of how "directly" high IQ is transmitted into the gene pool is irrelevant. Intelligence per se is irrelevant (there are a lot of very stupid individuals out there who are far more savvy with an i-phone than some very intelligent people I know).

You may not have heard this, but the direction that evolution is going to take is determined by how species--not individuals--ADAPT to their environment. Our species lives in an environment which has been rendered information-intensive by our very own actions as a species. So what actually is relevant is how successfully the species can maintain the information infrastructure it has created and to which it must continuously adapt to. I concede that this is far more likely to be achieved at the level of the lowest common denominator: base consumerism and rote, procedural maintenance. So fill the gene pool with as many unintelligent drones as you wish. If the environment remains stable, we'll all do just fine.

The trouble of course, is that the environment won't stay stable. Some rogue will up the survival stakes with new information technology and, once again, what was rote and standard procedure won't be good enough any longer for continued adaptation. Those priveleged to be educated in newer paradigms (the Nobel Laureate's child) will be sought after for their capacity to "spread" adaptability, since a thousand, a million, a billion individuals are of no survival value to the species if they are psychologically trapped in outmoded paradigms.

Poster, if you're male, and you had the choice between Kate Upton (Sports Illustrated swimsuit model, presumably of average intelligence) and an ill-favored brilliant woman physicist, who would you go after? Evolution has given us urges and drives that have a lot more to do with physical attractiveness than mental attractiveness, unfortunately. You might end up with the physicist for her wit and personality, but more likely beauty wins the race. Not fair, not ideal, but that's the way we are constructed. (If you're female, you are probably less superficial than we men are, but physical attractiveness is still very appealing for you, too.)

Again, the mechanisms of short-term phenotype propagation don't strike me as very relevant to the issue presented in the OP. The long-term survival of the entire genotype is what should be considered if evolution were truly to stop. That is where the issue is all about adaptability.

[Wilson]

Poster, are you simply saying that humanity will continue to advance technologically? Certainly that's true. But that's not evolution. To be honest, I'm a little confused as to what you believe the actual deep down mechanism of evolution to be, if it isn't, broadly, the number of offspring, which is the basis of Darwin's theory.

As I said earlier, our increased brain capacity came about because it aided survival in a time when survival was anything but assured. Those groups of hunter-gatherers which were less intelligent were more likely to die than those groups in which there was more innovation and cooperation. Since families tended to stay together, many genes were shared, and some groups were therefore considerably smarter and more creative and more empathetic and cooperative than others. Those groups cooperated in protecting the group against predators - human and animal. They cooperated in providing more food and better shelters for their group. They had individuals who were willing to sacrifice themselves, if necessary, to protect their families and other people in their community. Those were the groups which tended to live long enough to have more children, and those groups who were less cooperative and less innovative tended to die off, and their children with them. And the genome shifted.

The increased mental capabilities and social skills were what made survival more likely and sent their genes forward, and those same capabilities and social skills allow us today to do math and design software and build cathedrals and form governments. We are advancing technologically not because we are that much smarter than we were then but because of the cumulative effect of one discovery leading to more discoveries on top of it.

Long term survival of our species will not be threatened, and therefore our genome will not change very much, until we humans start dying like flies. When and if that happens, then evolution will kick into high gear once again and select out those individuals best suited for the new environment - and our genotype and phenotype will change much more quickly than it is changing now. And it may not be intelligence or creativity that is selected. It might be, but it might be increased resistance to radiation sickness, or better ability to handle starvation, or disease resistance. If it were disease resistance to a devastating plague, for instance, the intelligence of the next generation would likely not change all that much.

[Obvious Leo]

In the case of human evolution we need to think rather laterally. Nerds have always been a protected sub-group within human populations. Herodotus wrote of them, as did Plato, Plutarch and Confucius. By and large they were regarded as of lesser value in the hunt and in the fight but they earned their dinner by coming up with good ideas. It's not hard to see how this social evolution would have benefited us even more in the hunter-gatherer scenario, where it would have been the survival of the fittest tribe that drove the evolutionary agenda, rather than the survival of the fittest individual. The geek who comes up with a superior arrow shaft may be guaranteeing the reproductive success of his entire extended family and the genetic inheritance he shares with them. Our biological evolution was being driven by our social evolution and the first bloke who figured out that it was a good idea to build a fence to enclose animals rather than spending all day running around the tropical savannah would have had his genes passed on through his kin, even if he never personally got to throw the leg over.

Regards Leo

[A Poster He or I]

Poster, are you simply saying that humanity will continue to advance technologically? Certainly that's true. But that's not evolution.

You'r right. Evolution is the long-term change in the genome from all of the dynamical processes that affect it over time, one of which is technological advance. Would you deny that agriculture or livestock domestication directly impacted the human genome, for example? If so, you stand against scientific evidence that all three human blood types other than the original (type O) may have been mutations whose survival value was in direct correlation to the introduction of grains and dairy products into the human diet. Would you deny that the immune response in Caucasian populations to infectious disease was forever altered by the building of the first great cities? If so, you can come up with your own explanation of why Native Americans were so easily slaughtered by white men's diseases.

To be honest, I'm a little confused as to what you believe the actual deep down mechanism of evolution to be, if it isn't, broadly, the number of offspring, which is the basis of Darwin's theory.

I've never heard of Natural Selection being defined in so limited a fashion as the mere number of offspring produced. If sheer numbers are the basis for evolution, we must consider single-celled bacteria to be the most evolved life form on the planet, by orders of magnitude! No, Natural Selection implies ALL of the means whereby circumstance eliminates phenotypes from the gene pool and introduces new ones, not just numbers. And when I say all, that includes human will as an expression of Nature: all of the means we have introduced that affect--intentionally or not--our own populations: wars, vaccinations, incest taboos, pogroms, swamp drainage, state eugenics boards, etc., etc.

As I said earlier, our increased brain capacity came about because it aided survival in a time when survival was anything but assured. Those groups of hunter-gatherers which were less intelligent were more likely to die than those groups in which there was more innovation and cooperation. Since families tended to stay together, many genes were shared, and some groups were therefore considerably smarter and more creative and more empathetic and cooperative than others. Those groups cooperated in protecting the group against predators - human and animal. They cooperated in providing more food and better shelters for their group. They had individuals who were willing to sacrifice themselves, if necessary, to protect their families and other people in their community. Those were the groups which tended to live long enough to have more children, and those groups who were less cooperative and less innovative tended to die off, and their children with them. And the genome shifted.

Exactly. However, you stress increasing brain capacity and increasing intelligence as the basis for the shift in the genome. I consider that to be sort of putting the cart before the horse, myself. I agree with the neurophysicists who suggest that the basis for the shift in the genome was the evolutionary pressure to favor symbolic communication. To that end, those who could master the rudiments of language better than others had the survival advantage, and that corresponded to phenotypes with larger brain capacity. Perhaps we're saying the same thing, but I don't agree that increasing brain capacity PER SE was the evolutionary advantage. After all, humans do NOT have the largest brains on the planet, neither by volume nor by number of neurons. Rather, increasing brain capacity was concomitant with the real evolutionary advantage: language.

The increased mental capabilities and social skills were what made survival more likely and sent their genes forward, and those same capabilities and social skills allow us today to do math and design software and build cathedrals and form governments. We are advancing technologically not because we are that much smarter than we were then but because of the cumulative effect of one discovery leading to more discoveries on top of it.

Correct. And what allows the discoveries to be cumulative and synergistic instead of every generation having to reinvent the wheel? Language, or more broadly, information. It has now become the critical means of survival for humans as a species.

Long term survival of our species will not be threatened, and therefore our genome will not change very much, until we humans start dying like flies. When and if that happens, then evolution will kick into high gear once again and select out those individuals best suited for the new environment - and our genotype and phenotype will change much more quickly than it is changing now. And it may not be intelligence or creativity that is selected. It might be, but it might be increased resistance to radiation sickness, or better ability to handle starvation, or disease resistance. If it were disease resistance to a devastating plague, for instance, the intelligence of the next generation would likely not change all that much.

To repeat myself, intelligence is incidental. Adaptability is everything. The extinction of our species is only a matter of time unless humans foster their ever-evolving penchant for information processing and muster it into the means for proactively disseminating our genome either off-planet or into artificial technology that can survive Earth's next extinction-level event (e.g., the next comet strike, or the next eruption of the Yellowstone caldera). The geological record makes it clear that the average life of a species on this planet is only 4 million years. Yes, bacteria, fern, chambered nautilus are exceptions, but if humans are to prove an exception too, it won't be by the means used by those species. It will have to be via the means that defines us as a species so uniquely: information processing.

No wonder the nerd has such an esteemed function in society as Obvious Leo has cleverly pointed out!

[Wilson]

Evolution is the long-term change in the genome from all of the dynamical processes that affect it over time, one of which is technological advance. Would you deny that agriculture or livestock domestication directly impacted the human genome, for example? If so, you stand against scientific evidence that all three human blood types other than the original (type O) may have been mutations whose survival value was in direct correlation to the introduction of grains and dairy products into the human diet. Would you deny that the immune response in Caucasian populations to infectious disease was forever altered by the building of the first great cities? If so, you can come up with your own explanation of why Native Americans were so easily slaughtered by white men's diseases.

Agriculture and livestock husbandry and the building of cities profoundly changed the environment. Allowed many human diseases to flourish for the first time, and certainly resulted in evolutionary changes for protection against those diseases - again because those with protective mutations survived better than those without and therefore had more children. There's no question but that specific challenges to survival will tend to change the genome affecting the specific condition that is killing lots of people or making them sick. But most of the evolutionary changes regarding intelligence, problem solving, and personality were probably already in place. Also cities, for all their dangers, probably brought about a population explosion, which by itself would make evolutionary changes slower (except those to meet new threats, as I mentioned).

I've never heard of Natural Selection being defined in so limited a fashion as the mere number of offspring produced.

Well, it's not quite that simple, but almost. As I wrote before, "survival of the fittest" means that those best able to survive in the current environment will be able to procreate, and those that die, won't. Of course the offspring must be able to produce offspring. In Darwin's day discussions of sex were embarrassing, and discussions of survival weren't, so "survival" was the catch word, and as I said, survival is a prerequisite for procreation. Eunuchs, for example, couldn't affect the next generation's gene pool, even if they lived to a ripe age.

Natural Selection implies ALL of the means whereby circumstance eliminates phenotypes from the gene pool and introduces new ones, not just numbers.

Yes, but how are you postulating that that happens? You don't eliminate phenotypes without eliminating genotypes. Those mutations which are harmful to survival or procreation become less common; those which increase survival or increase the number of offspring become more common. It's simple. It's beautiful. It's evolution.

However, you stress increasing brain capacity and increasing intelligence as the basis for the shift in the genome. I consider that to be sort of putting the cart before the horse, myself. I agree with the neurophysicists who suggest that the basis for the shift in the genome was the evolutionary pressure to favor symbolic communication. To that end, those who could master the rudiments of language better than others had the survival advantage, and that corresponded to phenotypes with larger brain capacity. Perhaps we're saying the same thing, but I don't agree that increasing brain capacity PER SE was the evolutionary advantage. After all, humans do NOT have the largest brains on the planet, neither by volume nor by number of neurons. Rather, increasing brain capacity was concomitant with the real evolutionary advantage: language.

Languages and communication, tool building, social skills, and problem solving all required new and larger parts of the brain. Not just size but also improved functionality and architecture, I'm sure. Once again, all those things were important in facilitating survival in a very tenuous environment, and gave those with favorable mutations better chances to send their genes forward.

To repeat myself, intelligence is incidental. Adaptability is everything.

But if everyone is surviving - which is pretty much the case today in developed societies - then evolution slows to a crawl. That's because the mechanism for evolution - differential survival and procreation - is in hibernation until the environment becomes deadly. There's no need to adapt.

The extinction of our species is only a matter of time unless humans foster their ever-evolving penchant for information processing and muster it into the means for proactively disseminating our genome either off-planet or into artificial technology that can survive Earth's next extinction-level event (e.g., the next comet strike, or the next eruption of the Yellowstone caldera). The geological record makes it clear that the average life of a species on this planet is only 4 million years. Yes, bacteria, fern, chambered nautilus are exceptions, but if humans are to prove an exception too, it won't be by the means used by those species. It will have to be via the means that defines us as a species so uniquely: information processing.

That depends on what that catastrophe is. And evolution doesn't do anything proactively. It will wait until people start dying and then it will get to work. We, on the other hand, can do things proactively. Whether we will .....

[enegue]

Your point about the ten kids of a cripple having a greater effect on the next generation than the single kid of a Nobel laureate is short-sighted. The Nobel laureate's child is more likely to have priveleged circumstances that will allow him to be far more selective in his/her mating choices, ensuring offspring which in-turn are priveleged to maintain a higher degree of interaction with an information-rich environment.

But, of course, the child of the gangster will rob the child of the laureate of all his advantages, and the child of the Nobel chemist will take care of the issue of the ten crippled kids ever being able to procreate.

Cheers,
enegue