The Human Instinct: A Conversation with Ken Miller


Time and again, Ken Miller has debated creationists, intelligent-design advocates, and others who deny the reality of evolution. Now he’s shifting his focus. As one of America’s foremost defenders of evolutionary theory, he’s noticed a disturbing pattern among both proponents and deniers of evolution: “Too many people come away from [learning about] evolution with the idea that the evolutionary narrative demeans our species.”

In The Human Instinct: How We Evolved to Have Reason, Consciousness, and Free Will, Miller makes the opposite case—that evolutionary theory proves our special place among life on Earth—by pulling from biology, paleontology, philosophy, and neuroscience. What Miller has done, to paraphrase his editor, is write an evidenced-based pep talk for the human species.

Here, I ask Miller about the biggest ideas in his book, such as reconciling evolution with consciousness and free will, avoiding evolutionary overstatements, and tricks for maintaining friendships with ideological foes.

DJ Neri: I want to get into two major issues that you spend a lot of time in the book talking about: free will and consciousness. These are two big, challenging, and controversial questions. On free will, your argument seems largely to be in opposition to Sam Harris, who’s a determinist and believes that our sense of free will is an illusion. Could you explain in a simple way both why you think he is wrong and why you think this question is so important to answer differently from the way he’s answering it?

Ken Miller: Well, let me make it clear: I don’t claim for a second to have pinpointed the locus of free will within the brain, or to have come up with a neuroscience argument that can demonstrate free will. But I certainly don’t think anyone has come up with a perfect determinist point of view in that respect, either.

One of the books I discussed in my chapter on free will is Sam Harris’s very short book of the same name. Harris, who has a background in neuroscience, makes a very well argued and persuasive case against any idea that there is some sort of spooky process going on in the brain that defies the laws of chemistry, physics, and the cell biology of connections of the brain. As a cell biologist myself, I completely agree with that. I don’t think there’s anything going on in the brain that requires some sort of ethereal spirit to explain it or that isn’t inherent in what the cells and the electrical potentials that run around the brain actually do so. First of all, I want to make that very clear.

However, it strikes me that to a very large extent Harris’ arguments against free will amount to a kind of determinism that argues not just against free will but also against independence and individuality. So in effect, if I were to swallow his arguments hook, line, and sinker, I would not be me. I would simply be a collection of atoms whose every action and every moment was simply determined by the pre-existing state of those atoms and molecules. There’s a wonderful quote by J. B. S. Haldane, the great evolutionary biologist, that basically says, “If my brain is wholly made up of atoms, and I see no reason to believe that it is not, then even my belief that atoms exist is determined by the atoms in my brain and therefore I have no reason for believing it to be true.”

My concern about an abnegation of free will is that it threatens science.

And that’s sort of the paradox that comes with this idea. I think Sam Harris sees free will as an essential component of Western Abrahamic religious faith, to which he is certainly hostile in a very reasoned way. Therefore, any hint that free will might be genuine somehow is an apologia for religious faith, which Harris would regard as nonproductive.

But my concern about an abnegation of free will is that it threatens science. The reason is that the very idea of science itself is predicated on the faith—if you want to call it that—that we human beings can be independent judges of empirical data in a properly designed and controlled experiment. When you get right down to it, if we truly lack free will, then we lack the independent judgment required to drive science forward.

There are several passages in his book that struck me as profoundly ironic. One of those is a passage where Harris basically says how much better our lives will be if only we realize that we lack free will. When you take up that particular pulpit, what you’re telling your readers, who presumably lack free will, to do is to make a value judgment that their lives would be better (and, of course, they have no free will to make their lives better) if they accept your argument (and again, they have no free will to accept it), which you make even though you don’t have free will, that free will does not exist.

There is a very curious set of passages towards the end of the book. I think as he concluded this short book, Dr. Harris realized that he had to explain why he wrote it, since he doesn’t have free will either. It’s a very strange passage at the end where he basically says, paraphrasing, My brain will tell me to do all sorts of things, like use the word elephant on this page, which I just did for no reason. He says, basically, I can’t tell you how I decided that this book is now finished because my brain decided for me, but maybe I’m hungry now. I’m going to go to have something to eat. And that’s the end of the book.

That’s a profoundly unsatisfying conclusion from the point of view of the scientist, to say that we make fundamental decisions for absolutely no reason. There’s a quote I use in my book from Stephen Hawking, who also is concerned about free will. Hawking says if we ever do arrive at a final theory that can explain not only the origin of the universe but the behavior of the universe at every moment since then, and we are truly deterministic beings, it would mean that theory itself would determine the way in which we arrive at the theory and how, therefore, would we know whether the theory were true? And to me that’s the great irony inherent in arguments against free will.

The last point—I brought this out in a book that’s fundamentally on human evolution—is that I think many people in the popular sense take evolution to mean that we do not have free will because we are “just animals.” The argument that I tried to make is that if we do have genuine free will, it was evolution that gave it to us. Therefore, evolution is not the enemy of free will. Evolution, if free will exists, is actually its creator.

DN: Relatedly, you argue, contra Thomas Nagel or Raymond Tallis, that the explanations of conscious thought can be explained by science, that consciousness itself could have evolved. Can you summarize why you think that’s the case?

KM: Consciousness is really an interesting question, and until I waded into it I had no idea how contentious the field was. But boy, I do now. I showed the draft of my book to a number of people and one of them told me, “I loved your book right up to the chapter on consciousness,” but he couldn’t endorse it because I conceded too much to the “physicalists.” Another manuscript reviewer said, “I loved your book right up to the chapter on consciousness,” but that reviewer took the exact opposite view, namely that I was too hesitant about physicalism and ascribed too much to emergent properties and the complexity of the brain and so forth.

One of the things that tells me is that consciousness is going to be argued about for a long time. And one of the most interesting things about consciousness—and it’s an obvious observation—is that literally everyone thinks they’re an expert in it because everyone is conscious!

When I was preparing the book, I read a highly influential book by NYU philosopher Thomas Nagel called Mind and Cosmos. The subtitle, as many of your readers may know, is Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False. And boy did that subtitle catch me. For an empirical scientist it’s a difficult book to read because it’s very deep into philosophy. But the effort is well worth it because Nagel does write clearly and he’s forceful in his conclusions. He basically argues that consciousness—or what David Chalmers might call “the hard problem of consciousness”—is inherently beyond what we today have, in terms of empirical science, to explain. And if consciousness is inexplicable, then the neo-Darwinian theory of nature is wrong, which has always struck me as a stretch.

Evolution is not the enemy of free will. Evolution, if free will exists, is actually its creator.

The reason for that is, Nagel says, that neo-Darwinism claims to be able to explain the evolution of everything about us, including consciousness. And if consciousness can’t be explained by science period, it means there’s something wrong with the neo-Darwinian theory of evolution. I would say what he’s really talking about is a problem in neuroscience. Neuroscience has not yet ultimately explained everything that goes on in the brain. Another way of putting that is the human brain so far has not succeeded in figuring itself out in every detail. And that’s absolutely true—that’s what keeps experimental neuroscientists in business.

But the issue of consciousness has always struck me—again, as a cell biologist—as a little strange. Often within Nagel’s reasoning is the idea that the physicalists are wrong because there is nothing about the properties of matter or the complex molecules, systems, and even cells built up from matter that would allow you to predict the existence of consciousness. If our lives are made up of matter—and surely they are—then how can atoms like carbon, phosphorous, nitrogen, and sulfur atoms be conscious? Consciousness must transcend the material.

My answer is I’m not sure that there’s anything about the basic properties of matter that would allow someone to conclude that life itself was possible. But nonetheless, life is a material phenomenon. If I have a candy with lots of carbon atoms and I eat it, some of those carbon atoms are going to become part of me: bone, muscle, fat, and possibly part of my nervous system. Is there a fundamental change in those carbon atoms when they’re incorporated into a living human cell? Talk to any chemist and the answer is “no.” Carbon is still carbon, whether it’s part of a living thing or not.

So I would say consciousness is not a “property” of matter. Consciousness is not something that matter is. Rather, consciousness, like life, is something that matter does. Many people seem to conclude that there has to be something more than matter to explain consciousness. I think, as do a number of other people who’ve written about this, that we are overestimating what we understand about the nature of matter. Many physicists, especially people working at CERN, the Large Hadron Collider, will tell you that the nature of matter is not just protons, neutrons, and electrons. It is far more complex than that. To think that this does not influence living systems, I think, is to be hopelessly naive.

So I think consciousness is real. I think consciousness is based in matter. And I think, ultimately, science will do what it always does, which is get closer and closer and closer to unraveling the ultimate nature of neural phenomena. And I think that includes consciousness.

DN: In your book you have several passages from literature or poetry that you use to illustrate your points. I want to bring up one I was reminded of when reading The Trial by Kafka. Near the end, the main character, K, is talking to a priest, and he’s trying to make sense of what this enigmatic “doorkeeper of the law” is telling him. The priest’s conclusion is that “it’s not necessary to accept everything is true. One must only accept it as necessary.”

That feeling might run through these debates a bit. It’s maybe common among religious people who are arguing against evolution or for the existence of God because without God they believe a society would be in shambles, so therefore they accept God as a priori necessary. With so much at stake on this topic, how do you avoid motivated reasoning, wherein your views on religion drive how you investigate or interpret evolutionary theory?

KM: In line with what you said about Kafka, there’s a wonderful quote from Dostoyevsky: “If God is dead, then everything is permitted.” I’ve heard that raised by Phillip Johnson, who was a law professor at Cal Berkeley and who’s a leading critic of evolution and quite prominent in the intelligent-design movement. He said it as if to say, “Well, you might not really believe in God, but you ought to because without that supposition society is going to collapse.”

My first book for a popular audience was called Finding Darwin’s God: A Scientist’s Search for Common Ground Between God and Evolution. It’s fair to say when I wrote that book I came out of the closet as a religious person. Even though I didn’t say so explicitly, people who read it immediately understood—because of the way in which I talked about religious faith—that I was a Roman Catholic. The line I always tell people, because I think it’s the best way to describe me, is that I’m a practicing Catholic—and I will keep practicing until I get it right. Because I certainly think I have to continue to work at it.

Consciousness is not something that matter is. Rather, consciousness, like life, is something that matter does.

In terms of religious imperatives, what I’m trying to do in this book is address both religious and non-religious people from the point of view of finding worth and value in the human spirit and in human nature. To be perfectly honest, two of the people I have found most inspirational in that respect were both atheists: Jacob Bronowski, who wrote The Ascent of Man, and most especially the late Carl Sagan. Sagan was an unabashed atheist, but he’s someone who has certainly appreciated religious sensibilities in terms of a sense of the sacredness of nature.

There are many people who might know me from my earlier books and say, “Well of course you believe in free will and you believe the reality of consciousness and so forth simply because that’s a religious imperative.” To me, that would be a lot like picking up Sam Harris’s very serious book on free will and saying, “Well, of course you don’t believe in free will—you’re an atheist, and therefore I’ve disposed of your ideas.” In this book I bring up religious faith very little. I’m trying to make a purely scientific argument. The real question is whether or not you find the human experiment to be exceptional and of value. I would argue, trying to paraphrase Carl Sagan, that we human beings—all living things on this planet—are literally made out of stardust. And the reason for that is that the heavier elements that make life possible were themselves forged in the fires of stars. So we are literally part of that, we are materially part of the cosmos.

But what makes us different is that we are a part of the cosmos that is conscious and aware. So in human beings, the universe has become conscious of itself. We are in effect the universe waking up. And that doesn’t exactly fit with anybody’s version of religious dogma, and I didn’t want it to fit.

DN: I want to ask you about another controversial topic: evolutionary psychology. In the book, you argue a bit against evolutionary psychology, how it can be overambitious or how applied evolutionary theory can sometimes create “just so” stories. In your view, is evolutionary psychology inherently flawed? Or is there a version of evolutionary psychology that can help us better understand human behavior or the evolution of the human mind?

KM: Evolutionary psychology is not an inherently flawed field, and it can tell us really important things. It’s a field in which it’s inherently tempting to speculate and overgeneralize. The most compelling example of this has to do with infanticide, which is the killing of young babies by their parents, typically by fathers or stepfathers.

G. C. Williams, the great evolutionary biologist, in a book called The Pony Fish’s Glow, talked about harem murders among certain species of monkeys (and the description I’m going to give you has actually been confirmed recently by scientists looking for DNA evidence to confirm the relatedness of male monkeys to the offspring and so forth).

G. C. Williams described a particular kind of monkey living in India where the social structure is harem based. There is a single male who is the harem master for a few less than a dozen females, and he impregnates all of them, and they all have these babies and so forth. Every now and then there’s a struggle among males and the harem master is defeated or killed. When a new male takes over the harem, he systematically kills the young children of all the females. As soon as he kills their babies, they go into estrus, he mates with them, and then he fathers his own children with them.

Now what G. C. Williams wrote about this—and this is pretty terrifying—I think his language was “he kills her children. They then display their love for their babies murderer by bearing new children for him.” And then G. C. Williams wrote, “Do you still think God is good?” Boy, that’s really scary stuff. Now here’s why that’s interesting. You might ask yourself, “Gee, I wonder if there’s any reflection of that in human behavior?” And the answer turns out to be a stunning yes. There have been several studies on infanticide (the killing of a child under 12 months of age within the family) and it’s almost always done by a male parent.

The studies have been done in several countries, including the U.S., but the best was done in Canada. When I tell my students about this I tell them to brace themselves for this because it sounds scary, but it’s not as scary as it seems at first. It turns out that a stepfather is a hundred and twenty times more likely to kill one of his stepchildren compared to a biological father’s likelihood of killing one of his own biological children. A hundred and twenty times. That’s terrifying. That fits with G. C. Williams’s analysis of harem behavior in monkeys.

But then I also tell my students, “Now, I know many of you come from families in which you have stepparents, and you’re all university age and you might wonder, ‘Oh, my God, how did I survive this?’” The key is to step back for a second and to look at the statistics. The actual number of infanticides in the Canadian study was 324 per one million stepchildren. That equals one in 2,500. More than 999 times out of 1,000, that stepfather is quite likely a loving, nurturing, and affectionate parent.

So in human beings, the universe has become conscious of itself. We are in effect the universe waking up.

So the interesting thing when you’re making arguments about evolutionary psychology is that it’s very easy to make an argument as to why a stepfather should have a biological imperative to kill stepchildren: There is no genetic relationship, and therefore in evolutionary terms it’s a waste of resources. But if you make that argument you then have to say, “Why is the evolutionary argument so weak as to vanish into insignificance: one in 2,500?”

I think the answer there is very simple. In terms of human behavior, we all do inherit certain biological predispositions to behavior that can be shaped by evolution. That’s what evolutionary psychology can tell us about. But the reason the rate of murder vanishes into almost insignificance is because we humans grow up in a culture, and culture is powerful. That culture is basically to raise young men—not always successfully, I will admit—with a reverence for life, for children, and with a necessity to respect the lives of other human beings. That’s part of all human cultures.

So evolutionary psychology can tell us a great deal about the inherent drives that natural selection has wired into us. But every now and then, evolutionary psychology pretends to be the only reason why we behave the way in which we do. To pretend that evolutionary psychology can give us a complete explanation of all of humanities and social sciences is, I think, an example of overreach.

DN: Along the same line, you call sexual selection through mate choice “highly speculative.” Specifically, there’s a theory that creating art, music, or literature is a way to signal our heritable mental fitness, and that our choice of mates is a selection mechanism driving that. Is this theory just over-weighted or do you think it’s a wholly inaccurate way to account for the evolution of our minds?

KM: What you’re specifically referring to is a book called The Art Instinct, by Denis Dutton. Dutton was an Australian art critic who argued that the making of art could be explained as an example of sexual selection. He noted that most artists historically have been male and argued that people make art in order to impress the girls and to increase their opportunities for mating. I’m married to a woman who is an artist, and I’m not sure that she would say that she created art in order to get a whole bunch of guys.

Sexual selection is a real thing. No biologist would argue otherwise. I certainly wouldn’t either. But to take—as some writers have—not just art but also music and literature and to try to use them as examples of sexual selection to explain why males dominate those professions? I’ve heard people argue that all the great comedians are male precisely because comedy is an art form that guys used to get lucky with the ladies. And that’s why women aren’t funny. I think women are funny and some of my favorite comedians are female.

When one makes those arguments, they try to concoct an evolutionary “just-so story” for why it’s wired in our genes without ever bothering to actually look for those genes. I think people overlook the fact that we all grow up in a society (this is the way I referred to the issue of infanticide as well). But those societies have been male dominated and have historically assigned gender roles. It’s hardly surprising that in such a society men have largely stepped into those roles.

Specifically, dealing with Dutton’s arguments in the art instinct, he cited psychological studies that show that people—particularly young people—prefer landscapes with trees, animals, and water. And indeed that’s true. But please try to explain to me why we regard Picasso as a great artist. He doesn’t have trees animals or water in most of his paintings.

As one critic of Dutton’s book wrote, while this sort of theory might explain mediocre art, it’s worth noting that when every piece of great art in a great museum violates your central tenet, maybe it’s a good idea to think again.

DN: Shifting to evolution and religion, you write, “Darwin clearly realized that a little polishing of the human ego would go a long way toward encouraging the acceptance of his ideas.” I think your argument in the book is similar. To convince people, is it necessary to polish the ego of certain religious believers in order to make evolution more palatable to them?

KM: I don’t think so. When I speak to religious audiences, particularly Christian audiences, the way I put it is very simple. I don’t want to polish evolution at all. I simply say, Look, the first duty of any Christian is to the truth. I think you understand that as a Christian. And therefore, your first question about evolution should not be Does it violate what my preacher told me about the book of Genesis? or Does it contradict the references to Adam in the letters of Paul? No, no, no. Your first question about evolution should be really simple: Is it true? And if it’s true then we should find a way to understand it.

We often are sorely lacking an essential skill: to always assume good will on the part of the person with whom you disagree, even if it’s not always true.

My authority for that—and I’m always glad to quote him—isn’t some new-age theologian. It’s Saint Augustine, Bishop of Hippo, writing at the beginning of the fifth century. He wrote a book called The Literal Meaning of Genesis. There’s a wonderful passage in there in which Saint Augustine writes even a non-believer can—and I’m modernizing his words—study astronomy, geology, and biology, and the worst thing that could happen would be for a religious believer, presumably telling the non-believer what the Bible means, talking nonsense on scientific topics; we have to do everything we can to prevent that from happening so that a non-believer won’t miss the message of salvation.

So what I tell religious audiences is not, “Hey, I’m going to give you a nice spin-doctored version of evolution,” but rather, “Evolution is scientific fact. Deal with it. And find a way—as Saint Augustine would find a way—to basically fit it in with your understanding of the world and God’s place in it.”

DN: You’ve just demonstrated you’re a fierce defender of evolution, but as you mentioned you’re also a practicing Roman Catholic. I’ve noticed you’re friends with Richard Dawkins, whose views on religion we can safely say are quite opposite yours.

KM: They are indeed, but let me interject by saying I do consider Richard a friend. He’s mentioned me very generously in his books, he’s promoted my books in Great Britain, and I’ve had some very good interactions with him.

DN: I’m sure you’re also friends with many Christians whose views on evolution are similarly at odds with yours in the way that Richard Dawkins’s views on religion are at odds with yours. In what feels like an especially polarized political or sometimes scientific climate, how do you maintain these relationships with people who vehemently disagree with you? Do you have any advice or secrets on that?

KM: You’re going to laugh at this: Become a sports official. I participated in several sports when I was a kid, and I was a baseball player in particular.

I thought that when I had children I’d be my son’s little league coach. But I only had girls, so I ended up as a softball coach. Then my girls grew up and moved on to the high school team and so forth. I loved fast-pitch softball, but I didn’t want to coach other people’s kids.

So I went over to the “dark side” and became an umpire. I’m in my twenty-first year, and I umpire fast-pitch softball all the way up to the NCAA level. If you want to acquire skills in dealing with people who vehemently disagree with you, become a sports official!

I’ve been asked by some of my colleagues, “When you’re debating a so-called scientific creationist, how do you keep your cool?” My answer is if you have any idea what people say to an umpire during a ballgame you would understand not only how to keep your cool but also why it’s important. That’s the first thing.

I think the second thing—I’m speaking very broadly now in terms of the current political climate the United States—is that we often are sorely lacking an essential skill: to always assume good will on the part of the person with whom you disagree, even if it’s not always true. But boy, it helps you psychologically, and it also helps you to fashion a more coherent argument if you assume that the other person is amenable to reason and if you try to see the motivation behind your own argument.

I have lots of experience with that, on the ball field and off the ball field. And I think that’s important. With respect to Richard, I honestly think that for many years Richard has been the clearest, the most incisive, and the most persuasive writer on evolutionary theory on this planet. Therefore, I value his prose and his insight and his ability to explain complex evolutionary ideas.

If you take a frankly nonscientific book of Richard’s, The God Delusion, his bestselling book of all time, even though he mentions me in the book very generously and he thanks me for my efforts against the intelligent design movement, I find a lot to criticize in that book. But I wouldn’t go after Richard personally, because I know that he’s a person of integrity and I know that he stands by his convictions. Those are different from mine, but that certainly doesn’t prevent us from interacting and actually from helping each other and making common cause.