MS. DIANE REHMThanks for joining us. I'm Diane Rehm. John Horgan is a longtime scientific American writer. He also teaches a course called War and Human Nature at the Center for Science Writings at Stevens Institute of Technology. He's just published a book intended to challenge assumptions about the inevitability of war.

MS. DIANE REHMThe title of his new book is "The End of War" and John Horgan joins me in the studio. We welcome your calls, comments and questions, 800-433-8850. Send us your email to drshow@wamu.org. Join us on Facebook or Twitter. Good morning to you, sir, thanks for being here.

MR. JOHN HORGANThanks for having me on.

REHMMy pleasure. You come from a military background, but you've never served in the armed forces. Tell us about your family.

HORGANWell, my grandfather served in the Navy during World War I and he re-enlisted when he was in his early 40s and fought in World War II. My father went to Annapolis in the early 40s and also fought in World War II on a destroyer. So, yeah, I grew up with playing with guns that my father had brought back from Japan after World War II.

HORGANI grew up in the Cold War era. When I was in high school, I was eligible to be drafted in the Vietnam War so war has always been a presence in my life. It's something that I've always thought about. I've worried about both for personal reasons and then eventually for professional reasons, once I became a science journalist. I started doing a lot of research on the roots of war and so forth.

REHMYou drew a high number in the Vietnam War so you were not drafted?

HORGANYes. And by the time I got that high draft number, I'd already decided that I wasn't going to fight. The Vietnam War seemed crazy to me. It just seemed -- I couldn't see the justification for Americans going around the world to fight these people. The justifications seemed too obscure to me and thinking about the Vietnam War also led me to think about war in general.

HORGANI've always had this kind of visceral, emotional response to war as something that was not only wrong morally, but also just really stupid, this really primitive behavior, this kind of relic of our past that we must find a way to get past. And I finally have written a book to try to express that attitude and suggest to people that war is a problem that we can solve.

REHMWar is a problem that man created?

HORGANYes.

REHMOr not?

HORGANWell, so one of the motives for writing this book was my realization some years ago that the vast majority of people, including, I'm sure, the vast majority of your audience out there, are extremely fatalistic about war. A lot of people think of war almost as an act of God, as this kind of primordial force whether it's from original sin or from our genes. We've always fought war and we always will.

HORGANIt's a permanent part of the human condition. And that actually does not stand up to scrutiny. Science actually has told us that war is a quite recent behavior. It really only started emerging 10 to12,000 years ago.

REHMThat seems pretty long ago.

HORGANExcept that there are some scientists and an anthropologist named Richard Wrangham at Harvard University is a very prominent proponent of this point of view. He says that war is millions of years old, that war goes back even before the origins of the homogeneous to our common ancestor with chimpanzees.

HORGANThere are other scientists who say that war goes back at least to the beginning of the Stone Age, about two million years. So compared to those estimates saying that war only emerged about 10,000 years ago, that is quite recent.

REHMSo as I understand it, what you want to do is start a conversation about why we fight and how we can stop.

HORGANThat's right. So the first attitude that I want to challenge is the idea that war is a manifestation of our biology and particularly innate male aggression. And if that was true, maybe you would see war going back hundreds of thousands or millions of years ago, but as I said, war is quite recent. Also once war started emerging and spreading around the world, and it did quite rapidly, then the question is how persistent is it?

HORGANIf war is really biological in the same sense that, for example, language is biological, then you would expect to see it fairly constantly through human history. But the fact is that war is a very sporadic behavior so there are some societies that become very militaristic for a while and then they stop fighting. They get sick of war and some of them become virtually pacifistic. So you have to have an explanation of war that explains this immense variability.

REHMTell us about the surveys you carried out since the invasion of Iraq in 2003.

HORGANYou know, the first time I carried out, I started asking people in a kind of formal way about their attitudes towards war. It was when I gave a talk at a local church in my community in Garrison, New York, in 2003. I think it was about a month after the U.S. invasion of Iraq and the priest, this Episcopal priest who is a friend of mine, Frank Geare (sp?) said, come and talk to my parish about war. Maybe tell us what science says about war.

HORGANSo I gave a talk on whether war is in our genes and I reviewed some of the findings that I talk about in my book and I tried to give a very optimistic view of war, saying that war is a cultural phenomenon, that culture can help us transcend and surely we will end war some day. And everybody was kind of looking at me skeptically and I said, okay, tell me how many of you think that someday humans will stop fighting war once and for all? And virtually nobody put up their hands.

HORGANAnd this is a very kind of liberal, dovish, green community so I was really surprised. And I carried out that survey many times since then and in many different venues. I survey all the students I've taught since 2005 at the engineering school where I teach. I've surveyed people in Europe, in Switzerland when I gave a talk there, recently in New York, in California, all over the place, young, old, liberal, conservative, male, female, virtually all...

REHMThey all think war is inevitable?

HORGANThat's right. And the problem with this attitude is, I think, that that fatalistic point of view has consequences. It leads us to think that we must always maintain a strong, military presence because there are bad people out there who are going to attack us. In some cases, we have to carry out preemptive strikes to prevent these bad people from hurting us.

HORGANBarack Obama -- I'm a huge fan of Barack Obama. I voted for him in 2008. When he accepted his Nobel Peace Prize, of all places, in 2009, he actually...

REHMRead what he said.

HORGANYeah. So here's a direct quote from my book. "Obama declared, war in one form or another appeared with the first man." That's a scientific statement and it's wrong. He added, "we must begin by acknowledging the hard truth. We will not eradicate violent conflict in our lifetimes." So it seems to me that Obama's coming very close to saying, we've always fought and we always will. This seems to me to be an extraordinarily bleak, pessimistic statement coming from a leader of whom I expect vision and optimism about how we can solve this problem.

HORGANAnd the irony is that we're actually living in a period when violence is really -- military violence is really low, especially compared to the 20th century. The number of international wars has really declined dramatically since World War II. The number of people who die annually in war is only a tiny fraction of what it was in the first half of the 20th century for example.

REHMBut, you know, if you look around the world now, you can say the U.S. has gotten out of Iraq. We just heard from the Department of Defense that we may begin to get out of Afghanistan earlier than we had planned. At the same time, you've got Syria. You've got Nigeria. You've got parts of Africa where people have begun to think that war is the only way that they're going to be treated fairly. It does seem as though when one area stops fighting, another area erupts so the question becomes really back to the president's statement. Does war inevitably push men and women to take up arms?

HORGANThere has been a war, I think, in some places of the world -- pretty much for all of human history there has been war occurring somewhere and if you read the headlines of a paper pretty much any day, you're going to hear about wars around the world, acts of terrorism, terrible armed conflict and so forth. But people should know the signs are really good right now. This kind of violence is decreasing.

REHMJohn Horgan is an optimist and the author of "The End of War."

REHMAnd if you've just joined us, John Horgan is a science journalist. He's director of the Center for Science Writings at Stevens Institute of Technology. He's written a new book. It's titled "The End of War," a title that I'm sure many of us would like to see become a reality. He's talking about surveys. He's done research. He's done his family, both his father and his grandfather deeply involved in the Second World War.

REHMAnd if you'd like to join us, 800-433-8850, your email to drshow@wamu.org. Here's an email, "One word for your guest regarding the wars around our world, profit." And here is another email, "Two words, Adolph Hitler." So two different issues, profit and the ambitions of one man.

HORGANI'll use the profit question or statement or challenge to talk about what is a very common reason cited for pessimism about getting rid of war and that it's sometimes called resource competition. So, you know, if it's not just biology then the question is well, why do we fight? And a very common theory is that there are always too many humans for the available resources, whether its land or water or game or oil and so forth. And that's why we fight. We're fighting between the haves and have-nots. That's what Mark's thought was the primary cause of war.

HORGANSo again, that's a scientific theory that can be tested. And what happens when you look at war historically, there are some wars that have been fought over resources or too many people, too little to go around. But there are many wars that aren't. And the anthropological literature is pretty clear on this. In fact some of the populations that are most widely dispersed, tribal people, for example, the Yanomamo in the Amazon, and that have the most abundant game are the most warlike. They're ferocious. It's almost as though they're well fed, they're healthy and so they engage in war as a kind of sport.

HORGANThe fact is that there's really no good explanation. There's no real single factor that explains why we fight.

REHMBut more recently, you've got President Eisenhower talking about the military industrial complex. Does that not go to the issue of profit?

HORGANThe military industrial complex represents people who, I think, exploit the fact that there is war, that their societies engage in war, rather than perpetuating war themselves. At least, that's how I like to think of it. There have been periods right after the First World War, for example, when, you know, we had a gigantic military apparatus. And then, we dissolved it very rapidly because we saw no further use for it. And we took those resources and we put it toward building schools, building highways and those sorts of things.

HORGANI think that if we have the right political leadership and if voters realize that this is in their self interest, any kind of pressure from military defense corporations or the armed forces themselves to perpetuate war, to keep the defense budget very high will really dissipate very rapidly.

REHMWhat about the ambitions of a single man with one vision, such as Adolph Hitler?

HORGANI think the reason why -- here, I guess I'm really showing my pessimism even more. We've seen what happens when a nation follows an Adolph Hitler or a Saddam Hussein or, you know, these charismatic violent madmen. It's catastrophic for the followers of those people. There's a real sea change, I believe, in the way that people view war that's taken place because of World War I and World War II.

HORGANA hundred years ago you had prominent intellectuals, political leaders who could still talk about wars as kind of glorious sport. Teddy Roosevelt really glorified war in that way. People don't talk that way about war, very rarely anymore. And it's because we see now war as a necessary evil, as something we have to do to protect ourselves and to take care of bad guys who are out there in the world. So there has been this kind of moral progress in how we see war because of Adolph Hitler in part. And because of, you know, the mass slaughter that we've seen in the 20th century.

HORGANSo I think now the challenge is to get past even this period where we think we still need to rely on armed forces on lethal organized violence to take care of even people like Gadhafi or like Assad. You know, some of the -- you know, the violent strongmen who still are out there in the world. What I'm hoping for -- and I don't really have any particular solutions myself -- but, you know, there's smart people out there who I'm sure can imagine ways that we can resolve a problem like Syria or like the one that we had in Libya without using more violence.

HORGANViolence is the problem. We've got to find a way to solve those sorts of problems without more violence.

REHMI wonder whether seeing the casualties and the injuries coming home from both Iraq and Afghanistan will help us really in ways that we had not as fully seen before understand the reality of what war leaves behind.

HORGANI certainly hope so. You know, we're in this sort of weird situation where I think every sane person wants war to end. And 100 years ago, you couldn't necessarily say that. But today, I think it's true. You know, you take a poll and ask people, leaders, common citizens. They recognize the horror of war. They recognize that it is this great moral evil. And yet, they still have this fatalism about ending it. How can it be that we all want to end war and that we can't solve it? So I think one of the first steps is to get rid of the idea that it's unsolvable and collectively try to imagine ways to get past it.

REHMThere was a statement, conclusions by a group of scientists who drafted UNESCO Seville statement in the late '80s. What did that say?

HORGANWell, the Seville statement was a reaction of some prominent scientists to this idea that was emerging from some scientists that war is a very deep rooted biological behavior. That it's a kind of instinct that we are descended from killer apes. And these people were concerned that this was leading to the same kind of fatalism that I've been talking about. And actually, since the Seville statement came out in the 1980s, it's been widely ignored. And the scientific idea that war is biological has become even more popular. And the fatalism has grown and that's one reason why I'm working so hard to refute that idea.

REHMDo you think that the outlook on war would be any different if women were in charge?

HORGANI look -- so there are all these different solutions for war so one is creating a global government. Another is sort of getting rid of all weapons. Another would be solving poverty. And then there's the one that you just mentioned, which would be empowering women. And this is related to the theory that it's those men, men, aggressive men who are causing all the problems. And, you know, the problem is that since women got the vote in the United States and Europe it's not as though they are preventing us from going to war. There have been some women who have been quite hawkish.

HORGANI think Hillary Clinton is probably more hawkish than Barrack Obama is. So the idea that women are natural pacifists I think doesn't hold up any more than the idea that men are natural warriors. I think, you know, gender equality is something that we need to pursue for itself, but I don't necessarily see it as, you know, if we pursue gender equality then we will have war. We need to end war for the sake of ending war. We need to address it as this problem in itself because war -- the culture of war perpetuates war.

REHMAre there countries that have absolutely renounced war?

HORGANYeah, so this is another reason why I'm optimistic. And I think it's a proof of principle that war can be ended even by very complex societies. So obviously you had the case of Imperial Japan and Nazi Germany becoming virtually pacifist overnight. Now, they were forced to do so because they were defeated in World War II. But then you also have the case of Sweden and Switzerland, which renounced war about 200 years ago and have managed to stay out of wars pretty much ever since then.

HORGANThere's a wonderful -- the wonderful case of Costa Rica and Central America, which is, you know, this terribly violent part of the world. I went to Nicaragua in the '80s myself and saw firsthand just how violent it is. And yet right next to Nicaragua is Costa Rica, which went through a terrible civil war in the 1940s.

HORGANAnd then, the new government that emerged out of the civil war decided that, you know what, our armed forces don't seem to make us safer. They tend to be used by whatever regime is in power to maintain power. So the armed forces are actually hurting us. Let's dissolve our army and put those resources towards education and other things. And as a result on various happiness indexes maintained by scholars, Costa Rica ranks number one.

REHMAre you suggesting that the U.S. dissolve its military?

HORGANWell, I do have -- you know, I'm willing to take Obama's quality time. I do have a kind of action plan. The United States, I think, is both the problem right now in taking us to a world without war, but also potentially the solution. It's the problem, obviously, because we are very militaristic. We have this gigantic military as big as all other nations combined. But I think -- but, you know, we say we are people of peace and justice. I think we could show that by cutting our defense budget -- not eliminating it, let's say, but starting by cutting it in half, which would still make it much bigger than, for example, Russia's and China's combined.

HORGANWe could stop carrying out assassinations of people in countries with which we're not even at war with drones or Special Forces. You know, and violation of international agreements. I think we could just try to find when something happens, like Libya or Syria, we could be the ones who are trying to find nonviolent solutions to those problems.

REHMJohn Horgan. His new book is titled "The End of War" and you're listening to "The Diane Rehm Show." Course the problem is as we might begin doing that, that doesn't necessarily stop a shoe bomber from getting on a plane or a group trying to blow up the World Trade Center. I mean, as these things -- you sort of think one thing follows another.

HORGANI am -- first, I should say I'm not a true pacifist. In other words, I think -- you know, I think we need police. I think we will need some kind of minimal military force to protect us from, if nothing else, crazy apocalyptic cults that try to unleash, I don't know, biological or chemical weapons against us. I think it's always possible that there will be violent sociopaths out there that can do us harm.

HORGANI do think that as we rely less on violence that others will as well. But -- so I foresee some kind of future in which -- I don't know -- through the U.N. or so forth, there's an international police force that addresses problems like terrorism or outbreaks of violence by certain states against their own people. Although I certainly hope that will -- and I think it will decline as well. But I'm not so optimistic that I think we will ever have a world without any violence whatsoever.

REHMAll right. Let's open the phones. First to San Antonio, Texas. Good morning, Rob, you're on the air.

ROBHey, good morning, Diane. Thanks for taking my call.

REHMSurely.

ROBI wanted to mention this conversation is just shocking to me, the naivety that your guest is expressing. I literally left Afghanistan earlier this week. And to think that an uneducated people, the Afghans, that don't seek education and don't want education, we try to give them education, to think that people like that will ever be peaceful, that they are capable of talking on the same level that we are, having an intellectual conversation like this is just mind blowing to me. And you sound very sheltered to me, that you sit behind a desk at a university and have all these grand ideas.

ROBBut to me, it seems like the elites sitting there watching Rome burn and calling them barbarians, it's just -- yep, it's true, but at the same time, that's the real world we live in and it won't change.

REHMRob, first, thank you for your service. But what about his points, John?

HORGANWell, you know, there's some regions of the world where, unfortunately, people have grown up knowing nothing but violence. And they engage in these endless cycles of revenge, feuding and so forth. And, you know, some of these seem horribly intractable. The Israel, Palestine situation, obviously, is one of those and they look really bad. I think what makes me optimistic is that there are many cases through history where some of these intractable problems are resolved very quickly. Look at how peacefully the Cold War ended. In 1985, no one thought that would be possible.

REHMJohn Horgan. He's talking about his new book. It's titled "The End of War." Short break, right back.

REHMThose of you who've just joined us, John Horgan is with me. He's a science journalist and director of the center for science writings at Stevens Institute of Technology in New Jersey. His new book is titled, "The End of War." We're going to go back to the phones to Jennifer. She's in Creola, Ohio. Good morning to you.

JENNIFERHello, Diane, and hello, John.

REHMHi.

HORGANHi.

JENNIFERYou know, to start with, you should put in your book, war, what is it good for? Absolutely nothing. And I had written an article in the Columbus (unintelligible) because I was so upset about Frank Woolrich received no punishment for going to two houses in Iraq and killing 24 innocent Iraqi men, women and children. And one elderly person was in a wheelchair. Did you know that?

HORGANI think that was the case where the supposed ringleader was just acquitted. I think -- listen, I thought that verdict was hard to explain. On the other hand, I think the fact that the United States is identifying people who are involved in war crimes and trying them is a sign of progress. And it's a sign that we're trying to carry our wars out in a just fashion. And I think that's a necessary step toward recognizing that we would be better off not fighting wars at all.

REHMJennifer, thanks for calling. Let's go to Liz who's here in Washington, D.C. Good morning, you're on the air.

LIZHi, thank you for having me.

REHMSurely.

LIZI work at the Center (unintelligible) in Washington, D.C. And we talk with service members every day. We help conscientious objectors in the United States get honorably discharged and we are currently working on a campaign about moral injury and the increase of suicide in 2010 and 2011 actually out -- battle deaths, where more people die of suicide than they did in battle.

LIZAnd we think that it's because of these moral injury -- PTSD caused by moral injury is different than PTSD caused by war or some other dramatic event overriding your conscience in battle and doing something horrific causes you injury and now people are committing suicide. And I wondered if you had any insight on that.

HORGANI think -- I hadn't heard that phrase moral injury, but I have been reading, for example, about drone operators who are piloting drones from an office in Nevada and are pushing the button and killing somebody in Pakistan or Afghanistan. And some of these people are experiencing post traumatic stress disorder. I think, of course, that moral injury is a significant factor. One of the things I talk about in my book is findings from surveys of veterans of combat in World War II and Vietnam and other more recent wars that show the vast majority of men are very unwilling killers.

HORGANA lot of men in World War II fired away from the enemy deliberately because they didn't want to kill. This was a real problem and the army addressed it by intensifying its training so that men would kill automatically, like robots. That was what happened in Vietnam and it's thought that that might have contributed to the very high rates of post traumatic stress disorder coming out of Vietnam. And in the most recent wars as well, because we're not innate killers, because killing is very difficult for almost any normal person.

REHMHere's a Tweet, "What are the implications of war video games, both as natural impulse and possible use as an outlet for aggression?"

HORGANI have an 18-year-old son who is an avid player of extremely violent video games. He also plays in war games. He plays a game called Air Soft in which men dress up in uniforms and they have guns that look just like real combat guns and they shoot each other with BB's. And he's the nicest kid. He's just a young man. He's not mean. He wouldn't hurt a fly. I love war movies, I must confess. I love, you know, James Bond movies. I love...

REHMThat's hardly a war movie.

HORGANWell, I -- but even more realistic war movies.

REHM"Saving Private Ryan," I would call a war movie.

HORGANYes.

REHMOr "Platoon."

HORGANSo, I guess, what I'm saying is that I think that our response to fictional depictions of war, the fact that it excites us, arouses us, to me, is totally separate from the question of whether we want to be in a real battle.

REHMOkay, but your son is 18. Think about these young people from ages five, six, seven who see and participate in these war games online. I wonder whether that doesn't sort of minimize the idea of killing another person.

HORGANIt really worries me. I'm a First Amendment absolutist so I would never advocate, I don't know, censoring these kinds of violent videos. One encouraging fact is that the consumption of violent media has soared over the last 20 years even as crime rates, for example, and rates of international war have declined sharply.

HORGANI think it's possible that violent media can help perpetuate the idea that war is kind of cool and that might have some political consequences. But given the decline of violent homicide, violent crimes and of war at the same time as people are consuming all these things, it's not something that I'm really worried about.

REHMAll right. To Baltimore, Md., hi, there, Dave.

DAVEHi; wonderful program.

REHMGood.

DAVEAlmost too controversial -- John and Diane, nonviolence may be next to impossible and certainly, though, it's the first thing we should try and try again, but if you take the most difficult problem, Palestine and Israel, did you know the peace movements on both sides (unintelligible) . And I think one of the problems is the media just does not cover, like this program is doing, these very necessary and controversial issues.

REHMYou know, I have to point out, I love my cell phone. I use it a lot, but when we have call-ins on this program and your cell phone is not working well, it really does a disservice to the guest and all our listeners because I can't really understand everything you're saying. I'm missing part of each message. I realize that an awful lot of people these days don't even have land lines, but where you do, I would really encourage you to use a land line because your less than great cell phones are really working badly. Go ahead, John.

HORGANI just want to respond to one word that I did hear in that comment, the possibility of nonviolent behavior, for example, in Palestine and Israel. One of the people -- one of the scholars I talk about in my book is a guy named Gene Sharp, a political scientist who has written a series of books on the power of nonviolent activism. What he has tried to point out to people, and he provides abundant historical examples, is that if you are in a repressive, tyrannical regime, there's some injustice you want to change that there are all these things that you can do to bring about change.

HORGANSharp's work has had a profound impact on movements around the world. He was an inspiration for people in the Arab spring uprisings in Tunisia and Egypt. There are people in Syria, there are Palestinians also, who have used his work. Obviously, it's not successful in every case and the nonviolence is sometimes overcome with violence, but I urge people to check out Sharp's work. It's easily found online and he has just shown that, in many cases, it just works. And if you can use nonviolence to bring about social change, chances are that you will have a less violent and more just regime afterwards.

REHMWhat do you think we can learn from Japan and Germany during the second World War, the most violent countries?

HORGANI think one of the most obvious lessons that you draw from them is that we can change overnight. We can change so rapidly from being extremely militaristic and hateful and wanting nothing more than to dominate and destroy other cultures to being very peaceful. Not necessarily, you know, obviously Japanese and German cultures are still very ambitious and pursue their economic and -- but it just shows -- it's, again, a proof of principle and how rapidly we can change. I'll go back to the end of the Cold War, the end of Apartheid also, were largely nonviolent and they show that some situations that look so bleak and intractable really can be resolved very rapidly if people have the will.

REHMAll right. To Charlottesville, Va., hi, there, Tami. Tami, are you there? Gone. How about to Pete in Toledo, Ohio? Good morning, Pete.

PETEHi, Diane, I love your show. I'm on a cell phone. Am I coming in okay?

REHMYeah, you sure are. Thank you.

PETEI'm sorry?

REHMYes, go right ahead.

PETEOkay. Really, my point is I'm all against war. I think it's useless, but how can you argue that we aren't genetically inclined towards war when it is known that chimpanzees engage in war?

HORGANOkay, I'm glad you brought that up. I've got a whole chapter on chimpanzee violence and what it says about human violence. This is work done by somebody I already mentioned, Richard Wrangham, an anthropologist at Harvard and some others. Over the past 30 years or so, scientists have observed chimpanzees in a few isolated troops banding together and attacking -- ambushing, really, chimpanzees from another troop.

HORGANI think it's important to know that Jane Goodall was observing chimpanzees for 15 years without ever seeing one of these lethal chimpanzee raids. She, herself, thought that the chimpanzee raiding might be a response to her putting out provisions of bananas and so forth to the chimpanzee community that she was watching. You also should know that some chimp troops have never been seen engaging in this behavior. There is another chimpanzee species called the Bonobos, you may have heard of, that are nonviolent.

PETE(unintelligible)

HORGANSo the idea that this proves that human violence goes back millions of years just does not hold up.

REHMAnd you're listening to "The Diane Rehm Show." Here's an email from Texas that says, "In today's paper, there's a story about 73 dead at a soccer game in Egypt. The fight erupted when two groups stormed the field. The winners attacked the losers. We fight over almost anything."

HORGANRight. That was depressing and awful. I think that I try to distinguish between state sanctioned violence, that's what war is, and state sanctioned acts of genocide and some of these spontaneous outbreaks of violence like the kind you just described or bar fights or crimes of passion and so forth. Listen, I recognize that humans can be very aggressive and that sometimes our aggression is manifested as violence.

HORGANBut you should just know that in addition to rates of war related violence going way down over the last 60 years or so, rates of homicide, rates of all kinds of lethal violence have also diminished greatly over the past few centuries around the world. So things are actually getting better. Again, and this is, in part, because culture is helping us overcome some of these problems.

REHMAnd finally to Miami, Fla., good morning, Don.

LIZGood morning, Diane and John. I have to say, first of all, there are always exceptions to all patterns of behavior. But Mr. Horgan, I think I noticed in your discussion of male versus female behavior in war, I believe I detected some minimization of the issue of male involvement in war. War is predominantly, throughout history, a male pattern of behavior. It's just simply fact. And the physiology of aggressive behavior, there's a connection between androgen compounds like testosterone and aggressive behavior. It's well established.

LIZIt is also a fact that testosterone and related androgens fuel not only aggressive behavior, but also creativity, invention, construction and so on. And I wonder if it might be a good idea to try to show a way in a different direction for aggressive behavior through these other forms of behavior that are related to the functions of testosterone.

HORGANYou know, that's a good question. I've got a lot of -- I look at a lot of what I call pseudo solutions in my book to war. And one of them is a solution that was proposed by William James more than 100 years ago. Give young men dangerous, exciting things to do in a kind of public works program and that will solve the problem of war. Konrad Lorenz, a great biologist, also said more sports will help give us a cathartic outlet for our innate male aggression. The problem is that there's just no empirical evidence to support those sorts of theories. We need to end war because war itself is bad.

REHMJohn Horgan, his new book is titled, "The End of War." And let us hope that someday that will become the way of the world. Thanks for being here.

HORGANMy pleasure.

REHMAnd thanks for listening all. I'm Diane Rehm.