Today we are going to talk about some things that are not very pleasant. So be of good cheer. The things I am going to explain will probably be the worst you hear all day. Everything else will seem a lot better by comparison.

I am going to explain a force that may urge you or people around you to do things that you would not in good conscience tolerate. Once you understand how that force works, you will be in a better position to do what you want to do, to avoid doing evil by seeing its mechanism.

Evolution is a process. It begins with a closely related population. Within this population there is inheritable variation. Members of the population will have offspring, some members more offspring than others; one of the reasons for the differences will be the inheritable variation. Because of this, the new generation of offspring will, on average, be very slightly different from the parents. I do not believe evolution accounts for all life; after all it does not account for genetic engineering. On the other hand, it is the process by which farmers breed plants and animals, so there is no question that it happens.

Now there are those who will say evolution is not happening to people. Consider four things that may affect your reproductive success; in other words, four things that can get you killed. There are your genes, there is the environment, there are your choices and there are accidents. Both genes and the environment, that is society, are subject to evolution. People say we are not evolving because we have this society. Nice, but the society produces inheritable variation; parents teach children. Besides, look at the other two things. You can make choices that get you killed As humans, we have the chance to make more choices than other living things make. On the other hand, wild animals are much more subject to lethal accidents - famine, disease, falls - than humans in a society. So yes, we are evolving, and very rapidly; genes play a larger role and chance a lesser role in our reproductive success than they do in wild animals.

As we have discussed before, when two populations are separated, they will evolve independently in different directions. When they are brought back together, if absolutely no evolution has occurred, they become the same population again - say if only ten minutes has past. If they have been separated a long time, they will not be able to interbreed at all. In between, they may be able to have offspring, but the offspring themselves will have a reduced average fertility. There will be individual variations, but since humans are not very fertile anyway, any reduction is serious. Humans are subject to hybrid infertility.

Today we will talk about how hybrid infertility has affected human evolution, including the evolution of our personalities. Like it or not, our personalities are largely genetically based. And even if they were not, society itself is subject to evolution and follows much the same laws as genetics.

In the motion picture "Zorba the Greek", the title role is played by Anthony Quinn. Zorba is a rather silly man, but Mr. Quinn plays the role with high seriousness; Zorba is heroic in an existential way. At one point the employer taunts Zorba with his lack of patriotism. The man explodes that he has fought, killed, bled and raped women for his country. For Zorba it is no joke. It is part of the job, the least pleasant part. I will try not to use the "r" word, but you will know what I am talking about.

What you already know, or should know, is that evolution is the process by which 1) Information stored in an organism, described as a set of "genes", causes the organism to grow and develop. 2) Slight differences in the genes of closely related organisms causes inheritable variation. 3) This inheritable variation produces a difference in the reproductive success of the different organisms. 4) This difference produces s change in the frequencies of the different genes in the next generation. If you don't think it happens, explain why farmers can breed animals and plants successfully. If you think it accounts for all life, explain why scientists can do genetic engineering successfully.

Well, then, on the surface of it the behavior of soldiers seems quite mysterious. Having fought their way into a village or town, the soldiers promptly and at some risk to their own health begin to try to try to have forced intercourse with the women of the defeated town.

It does no good to argue that males are just like that. Any male's notion of what is attractive has been honed meticulously by evolution; it serves an apparent purpose. If a female is very old, very young, very ill, pregnant or a sister, the male by and large will simply not have a sexual interest in her. Evolution, whether genes or culture - it really doesn't make any difference - tells him that this may be a poor choice of mate. And if the woman IS a potential mate, his first priority if he is a decent sort of man (as I think most are) is the avoid alarming of offending her.

The women in a defeated town are just as likely to be of child bearing age and to be reasonably healthy, but what about their genes? Their men just lost the fight. They are, in the only sense that is immediately obvious, INFERIOR. So if evolution is a process of getting "good" genes and getting rid of "bad" genes, then the logic would seem to be that the victorious soldier should keep his better genes. After all, the history of warfare is such that fights are repeated again and again. Even if he will not have to fight these people again, his children or grand children may.

And then think about the women of the vanquished town. These invaders have just defeated their men folk. Obviously the invaders have good genes. The women by rights ought to be attacking the soldiers, lying in wait for them, springing on them from behind, dragging them off into the bushes. But no, the women try to run away.

How very odd.

What is going on is this. I said that evolution is the process by which the frequency of genes in a population changes under selective pressure. I did NOT say, and you should NOT THINK, that his means getting good genes and getting rid of bad genes. By and large, there is NO SUCH THING AS A GOOD GENE or such a thing as a bad one. It all depends on the context.

Consider the American Bison. Suppose, just suppose, one of them developed mutation that caused its legs to be only just long enough to let him clear level ground. He would not be able to negotiate uneven ground. He could not run. He could not turn effectively. But otherwise he would be healthy, big and strong. This would be a bad gene, right? It would mean that he could not live except on level ground with lush grass, and it would mean that he was vulnerable to predators. This would be a bad gene that evolution would get rid of, right?

Maybe.

Or maybe the bison that has this mutation lives on a bison farm. The farmer is overjoyed. Bison mean tastes good and is wholesome, and you get a lot of it on one animal, but these beasts are very difficult and dangerous to deal with. Ah, but with short legs. It would make them a lot easier to raise. The farmer breeds for the same trait. In a few years the offspring of that one animal outnumber all other bison. O there are some wild types still around, as many as ever, but the ones that are safe to handle are now feeding the world. In terms of evolution, the mutation is a spectacular success.

Genes aren't good or bad except in a particular context.

It is a general principle of the plant and animal kingdoms, that when two organisms mate that are different, their offspring - called a hybrid - may or may not survive, may in many ways be superior to either parent, but usually will have reduced or absent fertility.

Sorry. That's the truth. No, I can't prove it in humans. It would be unethical, cruel and frankly impossible to do a controlled scientific experiment. But it is true, and is the unrecognized force that drives men at times to do such things as attack the women of a defeated town.

Now you see why evolution decrees that it must be done. If the victors can only make enough of the women pregnant, if they can only manage to have the next generation be largely hybrids, then for generations to come, the fertility of their ancient enemy will be reduced. Wars will be more easily won. In the end the other tribe, nation, city, whatever may be completely wiped out.

It is genetic warfare. Think about it. It works. It works even if the people doing it do not know why.

But it is only a reflex. It does not only operate against an enemy. It is notorious that during the first few months at college, promiscuity and illegitimacy among the students is very high. Then the "girls learn to protect themselves" and things become a bit more normal. Well, maybe it is all a matter of females who have never heard that males can be aggressive and treacherous. But look at it from the male point of view. They are new on the scene, too. THEY GO INTO SOLDIER MODE, victorious soldier mode. After they have their feet on the ground, after it feels like home, they will begin to act more like the decent human beings they generally are.

Need more proof? What does a woman in a war torn town look like? Starved for starters. Exposure to the elements produces sunburn or suntan and chapped red lips. Chronic stress causes hormones to be released that cause the skin under the eyes to turn dark. When a male sees that set of clues, something inside him reads "attack me."

So if a woman wants to be attractive, what does she do? Study music and art? Learn a foreign language or a sport? Hang out at the museum or library? Lots of them diet, put on lipstick, put on eye shadow and get a suntan. The woman turns herself into a war hag. And men notice it and are drawn.

By raping some or the woman of a village, an army can routinely do harm to that village over the next few generations. That is why it happens. Nobody wants it. Evolution simply decrees that it will happen - unless of course we understand it and decide to stop it.

It gets worse. Evolution need not even wait for war to force people to do things they would find it impossible to live with if they understood them.

First a little very basic pathophysiology. In humans as in other mammals, the developing fetus is carried in the body of the mother. This gives it an excellent environment in many ways, but does prevent the fetus from doing things like eating and breathing. Functions like these are handled by the mother. The mother then sends nice clean nutritious blood to her uterus. Schematically, it looks like this:… The fetus is attached to the wall of the uterus by an organ called a placenta. The fetus gets a hold of nutrients and oxygen and gets rid of wastes by circulating its own blood trough the placenta, which acts as a kind of filter. Things like oxygen usually pass readily across the placenta; red cells do not. But the placenta is not perfect, and there is some leakage of red blood cells across to the other circulation. If it crosses from the fetal to the maternal circulation, it is subject to being destroyed by the mother's immune system.

I suppose just about everyone has heard of the immune system and knows that it is very complex. The body is exposed to some material that the body interprets as being foreign, and the body after a time is able to attack such material and generally destroy it. If the fetus and the mother have different blood types, then any blood cells that leak across are promptly destroyed, and that is the end of that. Their numbers are too small to be of great consequence.

I suppose you know that blood comes in types A, B, AB and O. These letters refer to specific sites on the blood cells called "antigens." If you have type A antigens, you have type A blood or type AB if you have both antigens. If you have neither antigen, you have type O blood. Commonly, when people refer to blood types, they refer to "A positive" or "A negative." This refers to another antigen we call the Rh antigen. If we were being consistent in our notation, we would simply add the Rh antigen in the same form as A and B; we would have: A, B, AB, O, ARh, BRh, ABRh and Rh. However, since the Rh antigen is much weaker than A and B antigens, simply being told that a person had B type blood would not tell you if he had B negative or B positive but the person reporting hadn't thought the weak Rh antigen worth mentioning.

But it can be very important.

If a few fetal blood cells that leak into the mother's circulation have no difference except that the fetus has the Rh antigen and the mother lacks it, then weak though the antigen is, it will elicit a very effective response from the mother. She will produce enough antibodies so that they will cross the placenta in the other direction and destroy the perfectly normal cells that are circulating quite properly within the fetus. The first pregnancy usually presents no problem because it takes time for the mother's immune system to respond. But the next and later fetuses will typically suffer anemia.

This disease, called Rh incompatibility, will occur only if the mother is Rh negative. If she has the Rh antigen herself, her body will not respond as if it is a threat. The disease will occur only if the father is Rh positive; the fetus has to get the gene for making the antigen from somewhere. The fetus that suffers will always be Rh positive, and it will always have one gene for not making the antigen (an Rh-negative gene from the mother) and one gene for making the antigen (an Rh-positive gene from the father.) Since the death of fetus removes one of each gene from the gene pool, Rh incompatibility is not rapidly eliminated from a population.

The anemia from Rh incompatibility produces such things as, a rapid heart rate of the fetus as it tries to supply is tissues with oxygen with insufficient numbers of red cells, dilation of the fetal heart as it is overwhelmed trying to pump so much, edema of the tissues as the heart fails (hydrops fetalis), discoloration of the skin from the contents of so many red cells being dumped into the circulation (kernicterus), and brain damage as the red cell contents and their metabolites soak into the brain and poison it, and death.

If you ask your friends, you will probably find a number who have had this happen to people they know or are related to. Once the condition starts, it continues essentially inexorably. Within living memory, in the United States, this single condition caused more death and disability than all other known genetic diseases combined. At least in some states most, yes most, of the people in institutions because they were incapable of living independently, mostly they were there because of Rh incompatibility.

Imagine the horrible drama of birth in those conditions. The couple tries again and again to have a baby. Each time the pregnancy lasts as long as a normal pregnancy, each labor is as difficult, and each time it is obvious at a glance that the bloated, spastic, discolored baby will never walk or speak.

And yet there was never a private campaign or a public attempt to educate people. Bright, educated people did NOT KNOW what science knew, that they needed to make sure they had compatible blood types before they married in the expectation of having children.

People have a lot of fun sniggering about incest and about parts of the country where people kept track of their relatives, so that people knew if they were distant cousins. Medical researchers had glamorous easy careers wandering around chatting with folks about their family trees and recording the oddities that seemed to occur with inbreeding. Yet all the ill effects of inbreeding combined (and they do exist) were not a patch on the disaster of Rh incompatibility. Yet there was never a warning I have ever heard of.

Even among doctors, all you seemed to hear of was, "Those Rh negative women and their babies." You seldom heard of those Rh-positive fathers and their babies or those doctors who had the facts but never bothered to tell anybody.

Modern medical science can prevent the condition. The mother can be given shots that prevent her from developing the antibodies. Even surer, people can get their blood typed and simply be sure to marry those with the same type. The advantage of the last way is that, even if modern medicine were to vanish, as long as people used knowledge of their ancestral blood types, the disease would recur to a more limited degree. Yet even now, there is no educational program. "And I only am escaped alone to tell thee."

It was all unnecessary. Had it not been for cross breeding, the nightmare would never have occurred. Just being smart was not enough. Goethe, the great German poet and probably one of the most educated and intelligent men of his time watched child after child of his own die. The notorious infant mortality of bygone years - yes, some of it was poor hygiene. But many died of cross breeding. And mothers died too, after attempt upon attempt to prove that they could have at least two good babies. If you have tears left after you have wept for your sins, weep for those people, too.

Unnecessary? Nay, it should have been impossible. Is not evolution there? Should evolution not have stepped in and prevented this? Perversely, evolution seems to have conspired with the disease.

If you look at the right map, and I'm sorry, you'll have to trust me on this one or else search through about the last eighteen years of Scientific American, if you look at a map of the distribution of blood types around the world, you can see where people with Rh negative blood live: they live everywhere. However, any place you go in the world, there are more Rh positive than Rh negative people.

Since mixing the genes kills babies, it is assumed that we were at one time in pre-history, we were all one kind. Those experts who have looked at the map say that the distribution of blood types and their frequencies makes those experts believe that the original blood type was Rh negative, and we are seeing late stages of Rh positive wiping it out.

Since Rh incompatibility eliminates equal numbers of positive and negative genes, the spectacular success of the Rh-positive type begs for explanation. Perhaps they were better at fighting, hunting and resisting diseases or whatever. However, there is no evidence whatever for such accomplishments. Perhaps it is because nobody has looked, but at least there is nothing I know of.

What I do know is that those populations that maintain relatively high Rh-negative gene frequencies tend - just tend - to be of European decent. That in itself only means that the first Rh positive population probably turned up elsewhere, and it means it was already well established by forty thousand years ago, because the original population of Australia has a very low incidence of Rh negative, and they have been cut off from the rest of us for about forty thousand years until well into historical times.

So how are Europeans different on average from the rest of the world? That question may be a little too hard to answer. But how do they LOOK different? Surely it is possible to ask that question. And the answer has to be that they are less densely pigmented in the eyes, skin and hair. Maybe it is because they live in a cold climate, but Patagonian Indians and Inuit Eskimos have lived where it is cold and are not all that pale. Or perhaps you disagree with my observation. As long as it is because you own observation is different (and not just because you want it to be different) well and good. Ignore this next bit. But if your observation is akin to my own, and if you accept from the Patagonian and Inuit experience that such things change slowly, then it seems plausible that there has long been a correlation between fair people and Rh negative blood.

Mull that over before deciding to accept it. Because if you do accept it, the idea may haunt you all the rest of your days. Because I have a second observation: people have a fascination with the image of a dark handsome man and a fair woman.

You can see that combination around here a lot. You see it on the street. You see it on television. You see it on the covers of paperback romances. The image of the dark man and fair woman is ROMANTIC. "You will meet a tall, dark, handsome stranger" is the standard cliché for immanent romance.

And this fascination is not some reaction against racism or against the atrocities of the Third Reich of Germany and the rampant race hatred of those days.

The English poet and artist Blake used the image. Saw something spiritual in it. By now you probably see where this whole thing is leading. Try not to gag. It is not a matter of economics, with darker men showing their upward financial mobility by marrying a blond trophy wife from a family with old money; the Ottoman Turks, rich beyond the dreams of avarice, prized blond peasant women for their harems.

The Minoan civilization of ancient Crete routinely portrayed in their art men as being darker than women. I have seen a painting from ancient Egypt showing the sky goddess and the earth god. We have reversed the sexes since then, with Mother Earth and the man with the white beard in heaven, but we agree on the colors. Their sky goddess is as pale as the underlying papyrus could portray her thousands of years ago, the earth god very dark.

The concept of the dark male and fair female is culturally a very robust image and has been thought attractive for eons.

But it would seem impossible. How could any culture accept mating between dark males and fair females since historically that has always entailed an increased risk of Rh incompatibility and the horribly dead babies that causes?

Imagine a valley, very long but only as wide as one farm. There are two tribes; one lives at either end of the valley. They meet in the exact middle. One tribe is Rh positive and one tribe is Rh negative. An Rh-positive man living on the farm next the middle marries the Rh-negative woman who has the adjoining farm. They pool their resources, making a single farm. Then they start to have children. One child lives. The rest die. After many years and many pregnancies the woman dies. The man now controls what was her land. He lives to marry again. Their child carries a substantial chance of having Rh incompatibility problems and statistically can be written off; in a primitive society a motherless child has no chance. The final result is that a farm that was in Rh-negative hands is now in Rh-positive hands.

Details have varied, but it looks as if it is that process that has resulted over scores of thousands of years and with unthinkable human heartbreak, suffering, disease and death … has delivered the entire planet into the hands of us who are Rh positive. O, did I mention? I am Rh positive myself.

Far from stopping it, evolution was right there cheering the process on. You see this strategy was so successful that any community that employed it more often expanded more rapidly.

Because be haven't lived in a narrow valley. Rh positive has been advancing along a broad front.

Ignore the Rh-negative population; they were dying out anyway. The effect was on the Rh-positive population. Any cultural or genetic prod that encouraged the male to take an Rh-negative wife was favored by selective pressure. Those who did so flourished, or at least their genes did. Those who did not, fell by the wayside.

And how did he know how to find an Rh-negative mate? Look for the blond. It was as easy as that. So over geological times, partly by culture and partly by genetics I am sure, the reflex got welded into the population.

And he feels very good about it, this Rh-positive male. He fully expects his family to approve - as indeed they should from an evolutionary standpoint. He expects the rest of the world to approve. It does not trouble him that there was a more appropriate mate who must now spend her life without him, nor that there was a more appropriate mate for the wife, also now doomed to disappointment. It does not trouble him that the children they will have will not look like her - her whom he believes to be the ultimate beauty. Even without the Rh question, he has done something destructive, but he is sure he has done the right thing.

Because in his heart, there is this force he cannot quite put his finger on, but it is as strong as anything is in his life. And this force tells him he must, at all cost, gain this woman as his mate.

Well, of course there is a force there. It is the force of a hundred thousand years of evolution, and it is telling him to murder her and her children in a way where he will get away with it and get the land. It seems inconceivable that he would do it knowing the cause, the true cause of his feeling. If he was crazy enough to murder that many people that horribly and do it deliberately, society would never have tolerated him.

So he is working in good faith, doing what he thinks is right. He is following his inner urge. He only does not know what the inner urge is all about.

And of course by now it is a total rip off. The man is being cheated of his life as much as she is. She is not going to die; nor are her children. By now Rh types are so mixed up that there is no way to tell in an individual case (although there are still trends) by looking at a person what their blood type is.

But the instinct, if that is what the force is, goes on. It urges him to do something that once would have accomplished the death of a woman and her children, deaths his conscience would not tolerate him causing. But there is still harm, because even with Rh incompatibility under control, and even if it stays under control forever, there is still the problem of hybrid infertility that he is giving his offspring, for no other reason than that his ancestors killed their own families.

It gets worse.

Consider two groups; we will call them Montagues and Capulets. They live near each other. Obviously, this is an unstable situation, but to understand the point, we will assume there are no wars, famines, plagues, population changes, religious conversions, technological advances, outside influences or new ideas.

Now suppose we arrange that Montagues that like Capulets more be here, closer to the Capulets. And Capulets who like Montagues more are closer to the Montagues. Also the Capulets that hate Montagues are way over here, while Montagues that hate Capulets are way over there.

Now you can see what is going to happen. These people and these people like each other and are going to have a tendency to intermarry. Their children will, we will presume because of inheritable variation, share the parents' attitudes. Then because of hybrid infertility they will pretty much die out.

So, and this is the important point, the average for each group will shift away from liking the other clan toward intolerance and hatred.

Because look at these people who are interbreeding. Maybe you think I am about to say that they are baby-murdering scum. But no, that is not what they think of themselves. They are your hopers, darers, trusters, lifters, dreamers, risk takers, problem solvers. They are willing to open their hearts, to try something new, to defy society's pathetically inadequate but very real rules against intermarriage.

These are not people you want to lose. These are not people you can afford to lose from your society. But you will lose them.

If you do not like bigotry, if you do not like war, if you do not like race hatred, if you do not like intolerance pay attention. THIS is what causes these things. You need not look for a devil, for evil humans, for a sinister plot, for a plan to cheat honest laborers for the value of their efforts. Intermarriage between different groups, THAT is your enemy. That, by the inexorable working of natural law, is what produces societies that are willing to do terrible things.

Look at France. She is self-consciously a great liberal and intellectual power. Look at her history: The Gauls used to burn people alive. The Romans brought in blood sports. Not so long after the Romans, there was the genocidal crusade against the Cathars, then the slaughter of the Templars. Later there was the massacre of the Huguenots and then the terror with the guillotining of the aristocrats and most recently all the clerks and office boys of the Vichey government were murdered and tossed into the Marne. Most of those things were done by the duly constituted civil authorities of the time.

Germany: in the nineteenth century she surpassed even France as the worlds center of science, philosophy, enlightenment and social progress. Then suddenly they all seemed to go crazy and started killing everybody.

What is wrong with us humans? Why, despite our best efforts, can we not establish a consistent pattern of decent logical behavior?

There is an answer. The answer is that every time we start to make progress toward mutual trust and understanding, our purest and best marry outside their own close circle, die out because of hybrid infertility, and leave the rest of us staggering along with whatever ideas the nastiest of us have.

Thank you.

I hope you sleep well tonight.