Editor’s note: A transcript of Wilson’s conversation with Stoppard is available here. An abridged version with commentary by journalist Stuart Jeffries was published in the UK newspaper The Guardian on May 23 2015In February 2014 I received an email from my philosopher friend, Elliott Sober, to say that he had been contacted by the playwright Tom Stoppard to discuss the topic of altruism. I immediately asked Elliott to introduce me to Stoppard so that I could be part of the conversation.Altruism was a topic that Elliott and I had been discussing for over 25 years, resulting in numerous academic articles and our 1998 book Unto Others: The Evolution and Psychology of Unselfish Behavior. Our collaboration reflected a broader trend in the study of altruism. Traditionally the province of philosophers, it was increasingly becoming the province of scientists, including evolutionists such as myself.Tom Stoppard’s interest signaled another development. Widely regarded as one of the foremost playwrights of our time, he roamed outside the Ivory Tower. He had disdainfully walked away from college as a young man to make his own way, first as a journalist and then as a playwright with a genius for combining serious philosophical themes with storytelling skills that attracted a larger audience than Elliott or I would ever see. Tom contacting Elliott on the strength of our book Unto Others suggested to me that the philosophy-to-science transition was about to make a jail break, leaping over the walls of the Ivory Tower and into the madding crowd of everyday life.Prompted by Elliott, Tom duly emailed to say that he was writing a play titled The Hard Problem that dealt with the theme of altruism. Unto Others was part of his preparation. Somewhat star struck, I tried to make helpful suggestions on the topic of altruism and sent him a manuscript copy of my newest book, Does Altruism Exist? He thanked me and I heard nothing for about a year, when his wife Sabrina emailed to ask for my mailing address to send a copy of the script. The play would be opening at London’s National Theater that night. Sabrina cheerily ended her email with the words “Fingers crossed!”The script arrived a few days later as a thin paperback with an abstract blue and white cover that, after a bit of mental processing, resolved itself into a mother and child. The story within surprised me. It was about altruism but it was also about consciousness and the distinction between body and mind. Tom was combining several hard philosophical problems in a way that I couldn’t easily follow. Most unsettling, the play expressed doubt that science could solve the hard problems at all. It was as if Tom had examined our philosophy-to-science transition and wanted none of it. This was represented in the play by Hilary, the main protagonist, leaving the gleaming scientific institute where she had been working to become a graduate student in philosophy.My association with Tom might have ended there, but the publication of Does Altruism Exist? in January 2015 led to an invitation to appear on a BBC radio show in April, requiring a trip to London. A flurry of emails led not only to a ticket to see The Hard Problem, but also to a joint interview with Tom for one of Britain’s major newspapers, The Guardian. A scientist and a playwright would share their perspectives on the hard problem of altruism.Still a bit star struck, I did not think of imposing further on Tom until I received a call on my cell phone during a meeting a couple of weeks before my trip.“Hello, David. This is Tom Stoppard.”I bolted from my meeting to receive Tom’s call in the hallway. He said that he was reading Does Altruism Exist? a second time and was impelled to ask some questions. He hoped I didn’t mind being called out of the blue. His voice was as deferential as a novice asking a favor of an expert and it occurred to me for the first time that he might feel as tentative speaking with me as I did speaking with him. I was also surprised that Tom was still investing effort in thinking about altruism after his play had been written. One thing led to another and an invitation to dine with Tom and Sabrina after viewing the play the night before our interview was added to my itinerary.It was fascinating to see the play after closely reading the script, something I had never done before. I was beginning to understand why Tom felt that the hard problems couldn’t be solved by science and why I thought they could. When it was over I met up with two of Tom’s friends from the theater world who were also seeing the play for the first time and we took a cab to the restaurant where Tom and Sabrina were awaiting us. In the cab they discussed the play the way that wine connoisseurs discuss wine, pointing out nuances that my palate was much too crude to notice. We entered a restaurant with photographs of stage personalities lining the walls and were led to our table. Sabrina was a slim woman with a warm smile who quickly put me at my ease. Tom had tousled hair and a face that somehow managed to look boyish, even though he was in his late 70’s. The conversation bounced playfully from topic to topic. I could tell that Tom wanted to return to our serious conversation and we agreed to meet for coffee before our interview with the Guardian the next day.Interviews are supposed to be spontaneous and we didn’t know how the journalist for the Guardian might want to structure it, so we talked in general terms over coffee before entering the offices of Yale University Press and being shown up the stairs to an elegant conference room with tall windows overlooking Bedford Square. We were introduced to Stuart Jeffries, a feature writer for the Guardian, and decided that the interview should consist of an open-ended conversation between Tom and me, drawing upon my book and his play whenever possible, which would serve as a block of wood for Stuart to whittle into a piece of the appropriate length.Tom began by observing that a book with the title Does Altruism Exist? would have been picked up by a philosopher in years gone by but today would be more likely to be picked up by a scientist. In agreement, I replied that my book was actually located in the science section of a London bookstore I had visited. By this measure, the philosophy-to-science transition was complete.Then, like wading into a lake and encountering a sudden drop-off, our conversation plunged into deep water. Without a trace of malice, Tom made some points about my book and science in general that were uncomfortable to hear. The book’s answer to the title’s question might be “yes” for altruism as defined by a biologist, but “no” for altruism as defined by a philosopher and the kind of altruism that interested him. Moreover, he was struck by the tone certainty in my book, as if I couldn’t be wrong. He observed that the whole world of science exudes the same sense of certainty, as if the final word has just been said or at worst is just around the corner. As for the tone of my book, the last time he could recollect such certainty was The Selfish Gene, published by Richard Dawkins in 1976.Ouch! The Selfish Gene is the book that my book was overturning! Worse, I was on record for saying “humility is a religious virtue but it is also a secular virtue and a scientific virtue” in a recent interview with the evolutionary scientist Richard Lewontin. Did this make me a total hypocrite?I felt that I could explain how humility and certainty can go together in science, like a zen fusion of opposites. I also thought that Tom had Hilary walk away from science prematurely in his play, although I can appreciate why she wanted to leave. This was going to be a deep conversation indeed. It lasted 90minutes, 30 minutes longer than scheduled. The twists and turns can be followed by reading the full transcript along with Stuart’s whittled down version in the Guardian. For the rest of this essay I will attempt to describe three hard problems that Tom ponders in his play, why he thinks that the problems cannot be solved by science, and why he might be wrong. I say this without a trace of malice, just as Tom made cutting observations without a trace of malice toward me.The first hard problem is altruism and goodness in all of its forms. For Tom and his protagonist Hilary, science is a parched desert when it comes to explaining the nature of goodness. As Spike, the supremely confident scientist in the play puts it, “Above all, don’t use the word good as though it meant something in evolutionary science!”The second hard problem is that everything cannot be reduced to physical causes, but science pretends that it can. We don’t need a fictional character to express this opinion because we have Sir Francis Crick, the co-discoverer of DNA, who is quoted in the playbill of The Hard Problem as writing in his book The Astonishing Hypothesis: “You, your joys and your sorrows, your memories and your ambition, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules”.The third hard problem is that even if science can explain the kind of instinctive altruism found in bees and brainworms (an example that Tom lifted from Unto Others to use in his play!) it can’t or at least hasn’t explained the kind of consciously motivated altruism found in humans.In the play, Hilary challenges the scientists around her to address these hard problems. When they fail, she leaves the scientific institute where has been working to become a philosopher and in particular to explore dualism, the proposition that mind cannot be explained in terms of matter. She is leaving a sinking ship, because the institute is the toy of a billionaire hedge fund manager whose unethical trading practices are causing the entire economy to collapse.I can speak from experience that Tom is like a real-life Hilary, seeking out scientists and challenging them to address the hard problems. The reason that he continues to think about altruism after writing his play is because he has been thinking about it and the other hard problems all his life. The play is a progress report on an ongoing quest. I can also appreciate why Tom might conclude that science can’t address the hard problems, based on his journey so far. The scientific landscape does give the impression that altruism doesn’t exist, that everything can be reduced to physical causes, and that there is no free will. Nevertheless, I think I know where we might dig to find water. Before using my dousing rod, I need to explain how it is not hypocritical for a scientist to express certainty and humility at the same time.During our conversation, Tom somewhat guiltily dredged up Ronald Reagan’s retort “There you go again!” to Jimmy Carter during a 1980 presidential election debate. Tom’s point was that scientists confine themselves to a certain type of explanation and never stray outside its walls. I agree and the wall even has a name: methodological naturalism.Several centuries ago, the idea that organisms are animated by a divine spark and are fundamentally different than non-living matter (vitalism) was a respectable scientific theory. Gradually, evidence accumulated that organisms are animated entirely by physical processes following unchanging laws. The universe and geological features of the earth likewise came to be explained in terms of the same physical laws without requiring divine intervention such as the creation of the earth or a great flood caused by a superior being. One problem with supernatural explanations is that they are too permissive, since God can potentially will anything. The term naturalism refers to explanations based exclusively on natural causes. A position called metaphysical naturalism claims that supernatural causes do not exist. The position of methodological naturalism makes a more humble claim that supernatural causes might exist but will not be invoked to explain the phenomena at hand. Most scientists and scholars subscribe to methodological naturalism for a practical reason, because inquiry that confines itself to natural causes is likely to be more productive than indulging in supernatural explanations. Methodological naturalism is a wall and a very useful one indeed. I am proud to say “Here I go again!” every time I confine myself to its boundaries.As for certainty, some theories come and go but others are here to stay in all probability. The earth is very old and revolves around the sun. Continents drift. Evolution happens. We don’t need to remain tentative about everything. I stand by my certainty for two claims made in Does Altruism Exist? The first is that altruistic traits can and do evolve by group selection, as these terms are defined in multilevel selection theory. The second is that evolutionary theory is a vastly underutilized resource for understanding and improving the human condition.One reason that I chose to express certainty as a rhetorical strategy is because both group selection and evolutionary theory in relation to human affairs were widely rejected in the past and must overcome stigmatization to become respectable again. I know a thing or two about the fallibility of received scientific wisdom, which is why a 2x4 is needed to make some of my points in Does Altruism Exist?The wall created by methodological naturalism helps to clarify Hilary’s dilemma in the play and Tom’s dilemma in real life. The territory inside the wall appears unpromising for addressing the hard problems, but what are the conceptual tools for exploring outside the wall? Hilary and Tom are not trying to find God in any conventional sense. They are placing their faith in the philosophical tradition of dualism, with its concept of a mind that has no physical basis whatsoever. I wish them luck but I worry that they will go in circles. I also worry that we will lose a common vocabulary and will become unable to communicate at all. For my part, I prefer to continue prospecting for answers to Tom’s hard problems inside the wall of methodological naturalism. Here is where I would dig for each of the problems.I think that Does Altruism Exist? makes a solid start on the altruism problem. Tom’s dissatisfaction is that it doesn’t say enough about consciously motivated altruism in humans. Hold that thought…The distinction between ultimate and proximate causation is a promising place to dig for solutions to the second problem. I made this point during our conversation by imagining an art studio filled with clay sculptures. A person who claimed that everything about the sculptures could be explained by the properties of clay would be insane. The clay merely provides a malleable substance for the shaping influence of the artists, who could implement their ideas with a variety of other physical substances. Likewise, to the extent that the physical basis of life results in heritable variation, it becomes a kind of malleable clay that is shaped by environmental forces that result in differential survival and reproduction. The result of this shaping process (ultimate causation) cannot be explained by the physical basis of life (proximate causation) any more than a sculpture can be explained by the properties of clay.Thinking of the mind in terms of ultimate causation allows for explanations that have nothing to do with physical processes without denying that everything about the mind also has a physical basis. Intrigued, I emailed my philosopher friend Elliott Sober (who also traveled to England and met with Tom) and asked him if anyone had tried to think of the mind/body problem in philosophy in terms of the ultimate/proximate distinction in evolutionary theory. Elliott replied that no one had to his knowledge. There might be enough water to turn the desert green for anyone who wants to dig in that area!Tom was not entirely happy with my sculpture metaphor because the shapes of the sculptures only have meaning in the mind of the human observer, which has no counterpart for natural selection. Hold that thought….Cultural evolution is a promising place to dig for Tom’s third hard problem concerning conscious motivation. It’s not surprising that Tom associates evolution primarily with genetic evolution because that’s how almost everyone else thinks about it, including most evolutionary scientists. Nevertheless, evolution requires variation, selection, and heritability, not genes per se. Genes provide one mechanism of heredity, but there are others, including human meaning systems. An expansion of evolutionary theory to include other mechanisms of inheritance is in progress that could provide more fertile ground for solving Tom’s third problem than genetic evolution alone. Cultural evolution can also help to address the first two problems, by explaining what we mean by conscious motivation and symbolic systems that give meaning to such things as clay sculptures.This is not the place to elaborate on these prospects. I am merely pointing in their direction. I am decidedly uncertain about what will be found and will eagerly follow the adventures of anyone who decides to explore the mind/body problem on the other side of the wall of methodological naturalism. In the meantime, reflecting with Tom on his three hard problems was a peak experience and he has a standing invitation to consult with me again.