You said: "a smaller brain is not a disadvantage for survival". We can see that all kinds of people live around us. It isn't an Darwinian revelation.
Over the last 10,000 years, the human brain has shrunk about 10% in size.
I see. Those cave men needed big brains for spear-chucking, while small brains are the order of the day in our modern world full of modern medicine, high literacy, mathematics, astonishing engineering feats, etc etc.
Previously you said that a larger brain "little as a century or so ago was a death sentence for both mother and child" and now you say that 10,000 years ago people had larger brains. Did they also have advanced medicine? Maybe they worked on elliptic curves and classifying finite simple groups when they weren't using their big brains to chuck spears.
Or rather than postulate more tiresome Darwinian stories in an attempt to reconcile this contradiction, we can instead conclude that Darwinism is false, and your stories are not true.
the brain uses ~20% of the body's total energy intake. Under periods of starvation... a distinct survival disadvantage.
You're talking about a 10 percent difference in brain size, which amounts to 2% of energy intake. And this 2% is spread out over, as you say, 10,000 years, which at any time amounts to an imperceptible fraction of a percent. And you say it's a "distinct survival disadvantage". I don't believe your story.
I seriously doubt you've ever taken vector physics,
You may be right, I've long been hampered with the evolutionary disadvantage of not having a small brain. If only it were smaller, whole vistas of modern intellectual fields would become accessible to me: mathematics, medicine, computer programming... Maybe I would even do my own taxes too and not have to hire a small-brained accountant to help me.
the progress of evolution over time is very analogous to the movement of an object subjected to many forces, whose trajectory and speed is determined by the vector total of the applied forces. Many selective pressures act on a species, and the characteristics of that species reflect the vector total effect of all the selective pressures.
That's a really beautiful story. I can sit down and imagine all those pointy vectors. It reminds me of another really beautiful picture: Ptolemy's solar system, with all those lovely epicycles and the equant point and all that. Except for this very important difference: there were, at least back then, some good reasons to believe what Ptolemy was saying.
they compare science to religion in order to "bring down" science tells me that they have a very low opinion of religion,
How about comparing Darwinism to Marxism or some other psychotic 19th century ideology? Would you have less of a problem with that?
You really did not do well in reading comprehension in school, did you? I already explained in some depth about this: reread my post #59 and get back to me when you can demonstrate that you actually understand it.
I see. Those cave men needed big brains for spear-chucking, while small brains are the order of the day in our modern world full of modern medicine, high literacy, mathematics, astonishing engineering feats, etc etc.
I see that you know very little about how pre-historic humans survived. They had survival challenges that modern humans cannot imagine. Compared to many of the predators and the prey that filled their world, they were small, weak, and had no built-in weapons--soft nails, tiny teeth. They had to survive by making weapons and by outwitting other animals. If they couldn't outwit predators, they became food. If they couldn't outwit prey, they starved. They were nomadic, so they had to be observant and remember where to go and how to get there from season to season. And so on. They had survival challenges that most modern people cannot even imagine--and most modern people would not survive in that environment.
Previously you said that a larger brain "little as a century or so ago was a death sentence for both mother and child" and now you say that 10,000 years ago people had larger brains. Did they also have advanced medicine? Maybe they worked on elliptic curves and classifying finite simple groups when they weren't using their big brains to chuck spears.
It looks like you are as unaware of the fact that women commonly died from childbirth complications prior to modern medicine as you are unaware of the survival challenges of prehistoric humans. As with many evolutionary traits, there are opposing forces at play here. In the prehistoric environment, the smarter children--those with larger brains--were more likely to survive and pass their genes to their offspring. But if the brain size of those offspring was too large, they would not be able to exit the birth canal, and both mother and child would die. So survival was a balancing act between big enough and not too big. The specific survival disadvantage of large brain size was only recently negated through modern medicine.
Or rather than postulate more tiresome Darwinian stories in an attempt to reconcile this contradiction, we can instead conclude that Darwinism is false, and your stories are not true.
Still trying to denigrate science by comparing it to something which you hold equally contemptible, religion? Tsk, tsk. I already know you dislike science, but do you have any respect for the institution of religion at all?
BTW, your inability to understand that multiple forces are at play and that the final outcome is the result of the vector total of those forces does not negate any scientific observation. These vector forces affect everything we do--they are hardly unique to evolutionary biology. For example, your kids want to go to the amusement park every day and you say no, because chores need to be done and you can't afford daily visits, so you compromise with one visit per month: that is an example of vector forces at play.
You're talking about a 10 percent difference in brain size, which amounts to 2% of energy intake. And this 2% is spread out over, as you say, 10,000 years, which at any time amounts to an imperceptible fraction of a percent. And you say it's a "distinct survival disadvantage". I don't believe your story.
You don't strike me as the type who enjoys intellectual activity, and you have already demonstrated a distinct dislike of science, but here is a nicely written article that explains many of the factors influencing brain size. Brain shrinkage did not result only from the switch to a civilized life style, other forces were also at play. Remember, evolutionary change is the result of vector forces. Remember, too, that evolution works at the level of population, not individuals, and that 10,000 years is a really short time when considering evolutionary time scales. BTW, your inability to understand concepts does not invalidate them.
You may be right, I've long been hampered with the evolutionary disadvantage of not having a small brain. If only it were smaller, whole vistas of modern intellectual fields would become accessible to me: mathematics, medicine, computer programming... Maybe I would even do my own taxes too and not have to hire a small-brained accountant to help me.
Let's see... you just stated that you have to hire someone to do your taxes for you, presumably because you have no desire to devote brain resources to understanding the tax code yourself. Lucky for you, someone else has devoted *their* brain resources to understanding it, so you still get the benefit of that knowledge.
Obviously, in the absence of survival challenges, we have plenty of brain-power to spare to devote to specialization. I doubt I would survive long left on my own in the savannah, but I can certainly survive in my present environment--with the pay I earn from doing scientific research, I buy everything I need to survive.
How about comparing Darwinism to Marxism or some other psychotic 19th century ideology? Would you have less of a problem with that?
*You* are trying to pass science off as a religion, not me. That comparison of science to religion (to try to make science look bad) comes straight from the creationism literature--which you appear to know quite well. No, you don't actually have to quote reams of nonsense from Answers in Genesis, Discovery Institute, or any of the other crackpot creationism websites for me to recognize their influence on your discussion. Since I have no reason to denigrate the scientific profession, I have no need to compare it to something I find despicable--which would *not* be my religious faith, in any case.
In closing, let me say that no matter how much you claim to be incapable of understanding the complexities of biological science, or how many times you profess not to "believe" scientific evidence, that evidence won't go away. Your belief is irrelevant to scientific progress, and trying to convince a scientist (me) that science isn't real has absolutely no effect whatsoever. Science *will* keep advancing, just as it always has.