The Quest for Human Nature
What Philosophy andScience Have Learned
MARCO J. NATHAN
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Library of Congress Cataloging-in-Publication Data
Names: Nathan, Marco J., author.
Title: The quest for human nature : what philosophy and science have learned / Marco J. Nathan.
Description: New York, NY : Oxford University Press, [2024] | Includes bibliographical references and index.
Identifiers: LCCN 2023040357 (print) | LCCN 2023040358 (ebook) | ISBN 9780197699256 (paperback) | ISBN 9780197699249 (hardback) | ISBN 9780197699263 (epub)
Subjects: LCSH: Humanity. | Philosophy and science.
Classification: LCC BJ1533 .H9 N38 2024 (print) | LCC BJ1533 .H9 (ebook) | DDC 179.7—dc23/eng/20231031
LC record available at https://lccn.loc.gov/2023040357
LC ebook record available at https://lccn.loc.gov/2023040358
DOI: 10.1093/oso/9780197699249.001.0001
DedicatedwithlovetothenewgenerationoftheNathan family: Martina,Virginia,Alexander,Nicoló,Jacob,andLaila. Whateveryournatureturnsouttobe,mayitneverchange!
Many wonders there be, but naught more wondrous than man; Over the surging sea, with a whitening south wind wan, Through the foam of the firth, man makes his perilous way; And the eldest of deities Earth that knows not toil nor decay Ever he furrows and scores, as his team, year in year out, With breed of the yoked horse, the ploughshare turneth about. Sophocles, Antigone, translated by F. Storr (1912)
Contents
Preface
1. What’s at Stake?
2. A Science of Human Nature?
3. Is There a Human Nature?
4. What Makes a Trait Innate?
5. Are We Genetically Determined?
6. Oppression or Emancipation? Part (i): Human Races
7. Oppression or Emancipation? Part (ii): Sex and Gender
8. Normality: Facts or Politics?
9. Should We Be Concerned about Enhancing Our Nature?
10. Can Science Explain Human Nature?
References Index
Preface
Once upon a time, back when dirt was fresh, I was a newly minted Assistant Professor full of hopes and dreams. My (then) department chair asked me if I was willing to teach a First-Year Seminar—the question of course was rhetorical; I didn’t really have a choice. As part of the University of Denver’s common curriculum, the First-Year Seminar, or “FSEM,” is a course that every incoming student must take during their first quarter in college. Its main function is to provide a rigorous introduction to their life to-be, mentorship, and, some would say, a healthy dose of handholding. At the same time, it also presupposes a rigorous academic component, and I was free to choose the topic. “Teach your passion!” That was the advice offered. I called “B.S.”—and, No, not in the “Bachelor of Science” sense. My doctoral dissertation was titled “Causation and Explanation in Molecular Developmental Biology.” Most of my research focused on technical foundational issues in biology, neuropsychology, economics, and other special sciences. How was I supposed to teach this to beginning students fresh out of high school? That ain’t gonna happen, I told myself. I replaced what I considered an ill-posed convey-your-love request with a different, more cogent endeavor. What did I always want to learn but never had the time and energy to do? After a few soul-searching walks, the best answer I could come up with was human nature. I went online, ordered a few books, and brainstormed how to convey my newfound “passion” to incoming students.
I taught that course—Human Nature: Perspectives from Philosophy and Science—for eight consecutive years. It turned out that I was dead wrong. Not only is it possible after all to teach your research to enthusiastic students, making the material accessible without sacrificing rigor. Indeed, that is precisely what we should be
striving for. In addition, there are three issues regarding the general subject matter, human nature, that got my juices flowing. For starters, it embodies what, to my mind at least, philosophy was always meant to be: a broad, exciting, and applicable topic that nonspecialists, including non-academics, care about deeply. This felt like a breath of fresh air in a discipline that has occasionally been weirdly preoccupied with various forms of navel-gazing. Second, human nature provides a framework for posing and discussing substantial empirical questions on neutral grounds. Allow me to explain. Since the turn of the new millennium, philosophy of science has undergone a “naturalization” process, whereby its problems and methodology have been taken to be continuous with those of the natural and social sciences. While the renewed attention to actual scientific practice is surely an important and welcome step forward, philosophy, or so it seems to me, has been losing its terrain. The study of human nature reveals how foundational questions about who we are can be raised and discussed not as problems in the sciences, but in a sort of “no man’s land” where philosophy and science come together and work in unison, as a team. Third and finally, I realized not without surprise that there is an open niche in the editorial market. Now, human nature is a hallowed topic that digs its roots all the way down to the dawn of philosophy. Myriad essays and books have been written on the subject. At the same time, the relationship between scientific and philosophical studies of human nature is relatively under-explored. Sure, there is a handful of contemporary classics. Still, a rigorous and accessible treatise on the role of human nature in philosophy and the sciences, natural or social, appears not yet available. Furthermore, many key issues remain unsettled. That’s what brought me to write the work presently in your hands or on your screen.
The pressing question becomes: how should all this be packaged? As said, there is no shortage of literature on human nature, philosophical and scientific. What makes the present volume you are currently holding fresh, unique, worth a read? One goal I had was expository clarity, that is, striving to be rigorous but approachable by a non-specialist audience. Yet, the present work is not conceived
solely, or even primarily, as an introductory survey of extant views. The ensuing chapters attempt to bring in two strands of novelty. First, the breadth of the discussion. While several available texts focus on the scientific and philosophical aspects of human nature, few address both simultaneously, let alone try to bridge the gap dividing them. Second, and more important, I stress an aspect of human nature that has been surprisingly neglected. Scientists and empirically oriented philosophers have focused on human nature as a basic factual notion. Humanists have concentrated on the irreducible, non-testable dimensions of human nature. I try to carve an intermediate path. The bottom line of my exploration is that human nature lies at the conceptual heart of scientific inquiry. At the same time, human nature is not something that science can explain. How can these two tenets be maintained simultaneously? How can a scientific concept not be fully explainable by science? Answering this question will require setting the stage, by outlining some major episodes in the contemporary study of human nature. Accessible to an audience of readers with lots of intellectual curiosity but not much scientific background, this volume provides more than just an opinionated introduction. It constitutes a venture into unexplored terrain, a fresh take on a hallowed topic, and a critical examination of both the power and the limits of science.
Along the way, I have been blessed by the help and support of many colleagues, students, and friends. I am especially grateful to Bill Anderson, Andrea Borghini, Jeff Brown, Guie Del Pinal, Thomas Nail, Jared Nieft, Sarah Pessin, Naomi Reshotko, Maximiliana Rifkin, Mika Smith, Antonella Tramacere, and Marco Viola for their insightful comments on various drafts of this work. I am thankful to the production staff at Oxford University Press and, in particular, to Peter Ohlin for believing in the project from the get-go and providing constant support. Two anonymous reviewers have offered helpful feedback and much-needed pushback. The Department of Philosophy at the University of Denver has fostered a productive and stimulating environment where to develop my ideas. Many students, both from within and outside my Human Nature: Perspectives from Science and Philosophy First-Year Seminar, have contributed many
insights. While they are far too many to name, I truly hope that some of my own passion for the subject has rubbed off, so that they can take over soon and correct all the blunders and mistakes I have inevitably stumbled upon.
Finally, none of this would have been possible without the unfaltering help, patience, and support of my family, immediate and extended. A special thanks to the younger generations for brightening my days and providing a constant reminder of the moral encapsulated in the words of one of the greatest humanists to ever live, Giovanni Pico della Mirandola. The opening remarks of the seminal Oration on the Dignity of Man approvingly quote Hermes Trismegistus: “Magnum, o Asclepi, miraculum est homo.” Indeed, what a great miracle human beings are.
What’s at Stake?
Magnum, o Asclepi, miraculum est homo
What great miracle, Asclepius, is man Giovanni Pico della Mirandola, Oration on the Dignity ofMan, 1496
§1.1 Hallowed Questions
Let’s kick things off with a simple thought experiment. Picture a fancy cocktail party. Now, imagine being an alien from a distant galaxy quietly witnessing this mundane scene, secretly concealed in a corner of the ballroom. You have been saddled by your otherworldly boss with the task of providing a descriptive snapshot of what’s unfolding right before your own eyes. How would you portray the happening? Would you be more captivated by similarities or by differences between these wacky featherless bipeds?
Either perspective seems perfectly defensible. On the one hand, a perceptive extraterrestrial observer would be well advised to stress that humans have lots in common. Most of us share analogous features. We have two eyes, two kidneys, one heart, one nose. We tend to wear clothes, at least in public. We are remarkably effective at using sounds to effortlessly communicate with one another. On the other hand, we are all quite distinctly unique. We have different heights, postures, hair colors, and accents. Some of us wear glasses. Our sense of fashion is strikingly varied. We argue about sports, politics, and much else. Individual idiosyncrasies might seem so overwhelming as to rule out any reasonable talk of universality. And yet, we are all human, alltoohuman—to borrow Nietzsche’s elegant aphorism.
These casual observations raise a deceptively basic issue. What is it that, despite all our differences, you, I, and Peyton Manning have in common, setting us apart from my left shoe, your laptop, Lassie the dog, and Koko the gorilla? What makes us human? What’s our one true nature?
Before plunging into a substantial discussion of this topic, the remainder of this section tackles a preliminary skeptical rejoinder. Does answering these questions really matter? What hinges on shedding light on our shared humanity, our own very nature? Some authors get irritated when challenged to motivate the significance of their work. Personally, I encourage it. After all I’m inviting you to embark on a book-length voyage. This better be worth your precious time.
To get our juices flowing, I wish to point the spotlight on a passage from an interview with Noam Chomsky entitled “A Philosophy of Language.” In the course of his conversation with Mitsou Ronat, Chomsky proclaims:
Any serious social science or theory of social change must be founded on some concept ofhuman nature. A theorist of classical liberalism such as Adam Smith begins by affirming that human nature is defined by a propensity to truck and barter, to exchange goods: that assumption accords very well with the social order he defends. If you accept the premise (which is hardly credible), it turns out that human nature conforms to an idealized early capitalist society, without monopoly, without state intervention, and without social control of production. If, on the contrary, you believe with Marx or the French and German Romantics that only social cooperation permits the full development of human powers, you will then have a very different picture of a desirable society. There is always some conception ofhuman nature, implicit or explicit, underlying a doctrine ofsocialorder or social change. (Chomsky [1 976] 2006, p. 126, italics added)
This statement could hardly be starker or more explicit. It contends that some underlying conception of human nature is a necessary precondition for any informed, empirically grounded discussion of social issues. To appreciate why Chomsky ascribes such a central, foundational role to this notion, it will be instructive to briefly
illustrate how different conceptions of human nature underlie and influence the views of prominent thinkers.1
Consider, first, the depiction of humanity sketched by the English political philosopher Thomas Hobbes in his 1651 masterpiece: Leviathan. Simply put, Hobbes was a psychological egoist who viewed humans as fundamentally selfish beings. On the one hand, at a coarse level of description, nature has made us roughly equal in physical and psychological abilities. Hence, whereas some people may be marginally stronger or smarter than others, we all have the capacity—either alone or in cahoots with others—to harm or even kill fellow citizens. On the other hand, Hobbes continues, we all desire to attain the same broad goals. We strive to secure nourishment, health, shelter, and scarce resources. We seek power, fame, and glory, among other things.
The combination of our capacity to harm with a yearning for the same rewards gives people reason to fear one another, leading to a brute state of nature where there is no law, morality, or justice. It is a war of all against all, encapsulated well by the Latin maxim Homo hominilupus, “Man is wolf to man.” Since this ruthless competition works in no one’s favor, people soon realize that it is in their best interest to compromise. We agree to trade in part of our freedom to do as we please for a chance to live in relative peace. We sign a metaphorical social contract where the rules of the game are established and enforced by a mighty ruler, the eponymous “Leviathan,” which refers to the state, the central government of a country.
Now compare Hobbes’ moral, social, and political outlook with the portrait offered by the Swiss philosopher Jean-Jacques Rousseau. According to Rousseau, human beings are born innocent, fundamentally good and gentle creatures. We come to the world as “noble savages” living in a simple and blissful state of goodness and ignorance. It is culture and society—the loftiest arts and sciences being no exception—that wreak havoc, causing intellectual corruption and moral degeneracy. As Rousseau himself writes in his Letters to Beaumont: “The fundamental principle of all morality,
about which I have reasoned in all my works . . . is that man is a naturally good creature, who loves justice and order; that there is no original perversity in the human heart, and that the first movements of nature are always right.”2
In the state of nature, everyone is self-sufficient. But inequality and disparity grow out of greed, nurturing a desire for private property. Property fosters inequality which, in turns, triggers envy and resentment. We need state and government, along with the inevitable restrictions to individual freedom, to protect property rights against the violence of the angry mobs.
These rough and ready generalizations admittedly fail to do justice to the nuanced and detail-rich canvases painted by two of the most influential political thinkers of all time, or to the gargantuan scholarship spawned by their writings. My present goal is merely to illustrate Chomsky’s contention that deep and fundamental disagreements—descriptive and prescriptive ones alike—stem from radically divergent characterizations of human nature. On both accounts, we need government, which boils down to a social contract of sorts. Yet, on the one hand, for Hobbes, strong, powerful institutions enforcing law and order in a jungle “red in tooth and claw” elevate us from our ruthless state of nature. On the other hand, for Rousseau, the necessity of government arises from the incapacity to return to our primordial condition of inherent goodness: an idyll involving individuals in nature who were healthy and happy, living in peace and prosperity.
How should we follow with policy recommendations? Should our government be stern, vigilant, and inflexible? Or should the state adopt a more laissez-faire attitude, only intervening when strictly needed? A Hobbesian political conservative would presumably prescribe the former scenario, lest our wolfish state of nature overcome the fragile balance we struggle to maintain through much energy and sacrifice. A Rousseauian liberal, in contrast, might rejoin that such radical measures unduly shackle our freedom, which has already been compromised, and taint our natural virtue. They would
opt for the latter alternative, deeming it better conforming to who we truly are.
Economic theories and policies depend on an underlying conception of human nature no less than their political counterparts do. To elaborate on Chomsky’s passage, in his magnum opus, The Wealth of Nations, the classical economist Adam Smith notes that the division of labor originates in neither wisdom nor culture. Rather, as Smith himself eloquently puts it, this practice is brought about by “the necessary, though very slow and gradual, consequence of a certain propensity in human nature . . . the propensity to truck, barter, and exchange one thing for another” (1776 [2000], p. 14). If business and commerce, to paraphrase and extend Smith’s insight in more contemporary jargon, are an integral part of human nature, this provides a strong argument for developing and implementing economic policies that not only adhere to, but also nurture such defining qualities. With these considerations in mind, it is hardly surprising that Smith is widely considered to be the founding father of modern capitalism.3 The British thinker believed—without, however, the ability to demonstrate it—that the voluntary exchange of goods would result in an efficient organization of economic life, beneficial to all. This insight, combined with the assumption that free markets respect individual liberties more than any other sociopolitical arrangement, provides a compelling justification for a capitalist economy.
Now, compare this outlook with the perspective of Karl Marx, a staunch materialist, committed to a dialectic view of history. In major works, such as DasKapital(1867), Marx viewed capitalism as a mere phase in the unfolding of human economics. Just as capitalism overturned the feudal system, in time it too is to be supplanted by a communist society embodying the state of cooperation that permits our full development. From this standpoint, a free economy shackles as opposed to liberates. Again, setting aside nuances, such as Marx’s own stance on determinism, the point is that competing assumptions will evidently lead to very different ideals and normative recommendations for what constitutes a truly
just and desirable society. These prescriptions, in turn, imply a conception of who we are. In a nutshell, they presuppose some theory of human nature.
In short, assumptions about human nature pervade our sociopolitical outlook. If we are inherently individualistic, as Hobbes theorizes, full cooperation constrains freedom. If we are social creatures, as argued by Rousseau, personal liberty is subordinate to the benefit of the group. Are humans endowed with similar talents or does variation run amok? A deeply egalitarian society is much more “human” on the former scenario than the latter. Trade is genuinely “natural” for Smith, much less so for Marx.
I should stress how Chomsky is hardly alone in drawing these stark conclusions. Along the same lines, biologists Levins and Lewontin remark:
Discussions of human nature almost invariably arise from a political context, although the problem sometimes masquerades as a purely objective question about human evolution. No political theorist, not even the completely historicist Marx, has been able to dispense with the problem of human nature; on the contrary, all have found it fundamental to the construction of their worldview. After all, if we want to give a normative description of society, how can we say how society ought to be organized unless we claim to know what human beings are really like? (Levins and Lewontin 1985b, p. 254)
Similarly, Steven Pinker opens his incendiary defense of human nature, The Blank Slate, claiming that “[e]veryone has a theory of human nature. . . . A tacit theory of human nature . . . is embedded in the very way we think about people.” The point is reinforced a few sentences later:
Our theory of human nature is the wellspring of much in our lives. We consult it when we want to persuade or threaten, inform or deceive. It advises us on how to nurture our marriages, bring up our children, and control our own behavior. Its assumptions about learning drive our educational policy; its assumptions about motivation drive our policies on economics, law and crime. And because it delineates what people can achieve easily, what they can achieve only with sacrifice and pain, and what they cannot achieve at all, it affects our values: what we believe we can reasonably strive for as individuals and as a society. Rival theories of human nature are entwined in different ways of life and different political systems, and have been a source of much conflict over the course of history. (Pinker 2002, p. 1)
Time to connect a few dots. Our discussion kicked off by asking what makes us truly human. We motivated this issue by noting how some conception of human nature deeply informs any systematic reflection on who we are and ought to be. This point has been independently stressed by authors such as Chomsky, Lewontin, and Pinker, who have very different scientific backgrounds, sociopolitical agendas, and perspectives on humanity. Once we converge on the driving question and realize that human nature matters a lot, our next step is to ask: great, what is this human nature? How should we unveil it? Can a consensus be reached?
§1.2 The Gauntlet
The topic of human nature traditionally falls within the province of the humanities, broadly construed to encompass philosophy, poetry, theology, and embryonic ante-litteram precursors to the natural and social sciences. For thousands of years, philosophers of all traditions spanning the globe have theorized about the quintessential features of our species and their sociopolitical and moral implications. Let’s look into what it means to approach human nature “philosophically,” what methodology is presupposed, and whether it yield the desired fruits.
For much of the history of philosophy, the characterization of human nature and the human soul were indistinguishable projects. As an illustration, in the fourth century bce, Plato’s Republic
introduced a separation among three parts of the human soul: the intellect, the appetites, and the passions. Academic speculation on the subdivisions of the soul—or equivalently, the organization of the mind—has occupied a prominent place in the Western canon ever since. For Aristotle, Plato’s disciple and peer in terms of influence and intellectual stature, all living beings have souls, albeit souls of different kinds and combinations. Plants only have nutritive and reproductive souls. Non-human animals also have sentience and selfmotion. Humans further have a distinctive rational intellect. Centuries later, Descartes argued that the soul was a non-material substance, ontologically distinct from physical matter. It was this immaterial entity that contained the key to who we are, both as individuals and as a species.
In short, the portal to human nature was the human soul or mind, the most striking and distinctive attribute that sets us apart from the rest of the known universe. Nevertheless, the systematic study of the mind or soul presented formidable difficulties. Revealed scriptures provide metaphorical allusions, at best. And all these approaches were conducted at a time when accurate knowledge of biology and psychology was patchy, when not altogether absent. It remained murky how true understanding was to be obtained.
The challenge becomes especially clear in the context of Cartesian substance dualism, which views mind and body as distinct kinds of entities. From a contemporary standpoint, Descartes’ dualist ontology, and its associated methodology, may raise a few eyebrows. How do we study empirically an ethereal soul, an immaterial mind? How do we test any hypothesis we may have concerning its structure and character? The short answer is that we do not and cannot. If the soul—the alleged foundation of human nature—is to be mainly studied a priori, that is, from the proverbial armchair without any systematic feedback, there simply cannot be any empirical science of human nature. This left many scholars unsatisfied. In the aftermath of the scientific revolution, natural philosophers began exploring the prospects of developing a more experimental approach. Thus emerged the first proto-naturalistic analyses of what makes us who we are.
In the introduction to ATreatiseonHumanNature([1738] 2000), Hume called for the development of a “science of man” based on a careful observation of human life, as opposed to a priori arguments and armchair reasoning. Throughout his seminal work, Hume strived to determine what typical humans are like with respect to cognitive and other psychological traits. A few decades later, Kant took up where Hume left off, furthering the project of collecting observations about people around the globe. But, unlike Hume, Kant does not envision a systematic “science of man.” His target is more practical. The Anthropology ([1798] 2006) aims to delineate our animal tendencies and inclinations. Along the way, it picks out key differences between women and men and between the various peoples on Earth. What we see in Hume and Kant is the dawn of a pre-scientific anthropology and comparative psychology, though neither project is devoid of stipulative assumptions, ad hoc premises, and biased observations from more or less dubious sources. More importantly, an organizing principle was still missing. This was bound to change with the rise of the evolutionary framework. The evolutionary Weltanschauung, laid out in the nineteenth century by the independent work of Charles Darwin and Alfred Russel Wallace, provided a firmer foundation for studying human nature from a scientific perspective. Throughout his career, Wallace remained committed to a form of human exceptionalism that keeps our own species out of the reach of natural selection. In contrast, Darwin recognized the potential of his evolutionary theory as a foundation for the empirical study of human behavior and culture. He devoted much of The Descent of Man to a defense of the view that humans are a product of evolution. He also sketched his own theory of sexual selection and applied it to humans. Darwin was fascinated by how organisms, including human populations, vary across the globe. He compared his own reports with those of other anthropologists, explorers, naturalists, and philosophers. But Darwin employed these observations differently from Hume or Kant. By establishing the pervasiveness of variation throughout the biological kingdom, Darwin aimed to accomplish two notable feats. First, he argued against the idea of species as fixed, immutable types.
Second, he established that variation, coupled with differential reproduction, could be the main engine of evolutionary change.
It is worth noting that Darwin’s evolutionary theory falls short of a true science of human nature. Although Darwin provided the key insight that humans, too, are products of evolutionary forces, his work remains far from a full-fledged, bona fide experimental investigation of our own species. His observed differences across both sexes and populations, sprinkled with gendered and ethnocentric biases, do not constitute a significant advancement over his predecessors. Hence, one could legitimately wonder what makes Darwin’s work groundbreaking.
Darwin’s pioneering contribution to the study of human nature lies in providing the backbone for much subsequent discussion. Before the rise of evolutionary theory, the question of how we came to be who we are remained elusive—a principle without an explanation, so to speak. Divine creation was the only player on the field. Natural selection paved the way for a more rigorous, “naturalized” account of human nature, a foil to approach the study of people from an empirical perspective, a way to meet the demanding standards of scientific theorizing. In this sense, Darwin is rightfully considered the founding father of a science of who we are. Yet, none of this happened overnight. It was a hard-won accomplishment. In the late nineteenth century, many readers of On theOriginofSpecieswere left wondering whether humans really are the product of natural selection. Even Wallace, the co-founder of the modern theory of evolution, was not quite ready and willing to answer this question in the positive. A hundred years later, focus had shifted. By the second half of the twentieth century, no scholar worth their salt seriously questioned our shared ancestry with other species and the role of natural selection guiding our phylogenetic trajectory. By then, the key issues had become whether biology can unlock Charles Lyell’s “mystery of mysteries” and science unveil human nature.
Few contemporary humanists would deny that evolutionary theory is a precious ally in the quest for human nature. But some took a further step, suggesting it was high time for science to finally take
matters into its own hands. The zoologist G. G. Simpson (1969) argued that all attempts to answer questions about human nature and the meaning of life made before the publication of Darwin’s Origin are worthless. “We are better off,” he quipped, “if we ignore them completely.”4
The most systematic attempt to replace philosophical speculation with rigorous scientific theorizing came with the development of a field known as sociobiology. In the 1970s, a group of evolutionary theorists, led by E. O. Wilson, suggested that puzzles concerning human nature, traditionally addressed by philosophers, could be solved once and for all by a grand synthesis of biological knowledge. Half a century later, sociobiology is now all but dead and gone. Still, the seeds for the naturalization of human nature had been sown. The spirit of Wilson’s proposal lives on, repackaged in the guise of such fields as Darwinian anthropology, human behavioral ecology, cultural evolution, and evolutionary psychology. The gauntlet has been thrown down. There is no shortage of volunteers willing to pick it up.
The goal of this book is to outline and assess the state of this debate. Is science the key to fathoming the depths of human nature? If so, what has it discovered? Is there any room left for the humanities or are traditional philosophical approaches superseded? While comprehensive answers to these queries will require a longer discussion, let’s take a sneak peek at what’s coming our way.
§1.3 Mapping the Road Ahead
This book encompasses ten chapters, including the one you are currently reading. Each module poses and addresses a question concerning what science has discovered about human nature. While individual topics are self-contained, my own views unfold cumulatively, in a stepwise fashion.
This introduction, “What’s at Stake?,” sets the stage for pages to come. Specifically, we highlighted two broad themes, which will be developed in greater detail as we move along. First, sparked by
Chomsky’s insight, I motivated the centrality of the concept of human nature to our philosophical and sociopolitical agenda. Second, I pinpointed a popular sentiment seeking to replace traditional humanistic inquiries with empirical approaches. The ensuing four chapters survey what science has discovered over the past five decades. As we shall see, despite groundbreaking theoretical progress and staggering experimental findings, a firm grip on our nature still eludes us. The second half of the book ponders whether a robust notion of human nature is required to pursue our relevant scientific and philosophical projects. Spoiler alert: the answer is positive. Human nature constitutes the necessary backdrop for much discussion in both the humanities and the sciences, natural and social alike. The final chapter strives to reconcile these contrasting conclusions, suggesting that human nature is indeed an indispensable scientific construct. Nevertheless, it is a concept that science cannot explain.
Chapter 2, “A Science of Human Nature?,” outlines the most influential attempts to investigate human nature from an empirical standpoint. Our survey kicks off with a primer of Darwin’s theory of evolution by natural selection, before moving on to Wilson’s provocative proposal. What made Wilson’s project so incendiary? Sociobiologists advanced bold claims. Women, we are told, are born cautious and coy whereas men are naturally hasty, aggressive, and promiscuous. Hierarchical divisions are deeply rooted in our society. Xenophobia may well be part of our biological endowment. We are gullible and easy to indoctrinate. This gloomy portrait of humanity is grounded in a simplistic story about how our heritable psychological traits must be encoded in the genes no less than our physical characteristics. With these considerations in mind, it is perhaps unsurprising that human sociobiology was harshly criticized in the 1980s, resulting in public distancing from its excesses. Then, in the 1990s, some of these old stories came lurching back, repackaged as “Darwinian anthropology,” “human behavioral ecology,” and “evolutionary psychology.” The second part of the chapter sketches these revamped projects together with skeptical cautionary voices remarking on methodological hurdles. Regardless of whether we
view these research fields as a revolution or a red herring, one thing is clear. Science struggles no less than philosophy in providing a clear, cogent, and plausible account of human nature. No reason to throw in the towel—at least not yet—but we’ve got plenty of work cut out for us.
Providing a comprehensive methodological assessment of sociobiology and its intellectual progeny lies beyond the scope of this project. The sobering moral to be drawn from the discussion, from the present standpoint, is that our guiding question—can contemporary science shed light on human nature?—cannot even be raised, let alone answered, without providing an explicit definition of what it is that we are seeking. We thus need to take a step back. Framing our object of explanation is the task of Chapter 3, “Is There a Human Nature?” Specifically, we shall consider three influential proposals. First, according to a widespread stance, human nature coincides with the essence of being human, that is, a set of intrinsic conditions individually necessary and jointly sufficient for belonging to our species. Despite its intuitiveness, essentialism is no longer a popular view. Most contemporary scholars agree that there is no non-trivial set of intrinsic properties satisfied by all and only humans. Second, we’ll explore a strategy purporting to capture the idea that human nature is meant to describe only “normal” humans: the natural state model. Third, and finally, I outline a “field guide” conception of human nature encompassing an array of views aiming to capture and explain typical and characteristic human traits. Contrary to essentialist strategies, the field guide view drops the assumption that our nature should describe essential conditions for species membership. Unlike the natural state model, it disavows any prescriptive characterization of normality. Field guide conceptions are empirically kosher and methodologically viable. Nevertheless, these “thin,” toned-down definitions are unable to play the robust normative role that we demand from our hallowed concept. For human nature to have the regulative and organizing powers traditionally ascribed to it, something more is required. Where next? Perhaps the moral to be drawn is that “nature” is too broad and slippery a concept to be tackled head-on. It may be wise
to recalibrate on a different target. With this concern in mind, the following two chapters attempt to break down the overarching notion of human nature into smaller, better tractable proxies, more intimately connected to scientific research.
With this aim in mind, Chapter 4, “What Makes a Trait Innate?,” explores the issue of innateness, drawing some connections to human nature. Many readers will be familiar with both with the term “innate” and the intuitive idea of some human characteristics being “inborn.” The alleged innateness of socially significant features makes for especially enticing proclamations. Pop-science books and newspaper articles regularly report findings pertaining to traits such as violence, racism, and political or religious inclinations as being “innate,” “genetic,” or “hardwired.” These expressions are often treated as synonyms. But are they? And what exactly do they mean? After some brief stage-setting remarks, we move on to consider what innateness is not. We shall survey a handful of popular definitions and show why, despite shedding light on their target, they all fall short of an adequate and comprehensive analysis of innateness. Next, we’ll focus on arguments suggesting that we abandon the concept of innateness altogether. The final sections explore a different route. Instead of pursuing a definition of innateness directly, we’ll review some evidence about the inborn human cognitive endowment, a feat often referred to in developmental psychology as “core knowledge.” These findings are intriguing. Nevertheless, the central question from our present standpoint is whether innateness and cognate notions provide a surrogate for human nature, enabling an empirical analysis of who we are. Unfortunately, the answer seems negative. Debates about innateness and inborn cognitive endowment presuppose a notion of human nature rather than explain it. Our search therefore continues.
Chapter 5, “Are We Genetically Determined?,” focuses on the topic of genetic determinism. The core insight is intuitive enough. To label a certain trait as “genetically determined” is to treat it as the consequence of a specific genotype. But how exactly we should cash out the tenet that a feature, mental or physical, is produced, determined, or otherwise caused by genes and their properties calls
for elucidation. How should we parse the hypotheses that, say, eye color or height are genetically determined whereas religious affiliation and sport allegiances are not? And does answering these questions shed light on human nature? To make sure that all readers are on board, I begin with a primer of genes, genomes, and their role in the production of organisms. We then provide a preliminary definition of genetic determinism according to which a trait is genetically determined if and only if it has a flattish norm of reaction. Next, we connect genetic determinism with heritability, a technical concept purporting to quantify the degree of variation in a trait due to genetic differences within a population of reference. The remainder of the chapter discusses developmentalist challenges to determinism and outlines the prospects of bolstering a true interactionist model of how genes and environment jointly produce organisms like us. I conclude that, despite the important strides we’ve made in our understanding of the relation between genotypes and phenotypes, admittedly genetic determinism does not provide a suitable proxy for naturalizing the study of human nature or cognate notions. Switching from innateness to genetic determinism changes the subject but not the outcome. These pesky concepts presuppose a human nature and, as such, they cannot explain it.
Disheartened by all the roadblocks encountered on our path so far, some readers may start to wonder whether we may have taken a wrong turn. Spurred by Chomsky’s dictum that there is no social science without an underlying conception of human nature, we looked at the natural sciences to unlock the mystery. Still, convincing answers have proven more elusive than we may have initially surmised. This raises nagging concerns. What if Chomsky was wrong? What happens if we remove human nature from the equation? Do we really have no viable theory of social change as a result? The second half of the book addresses these questions. Rather than striving to define human nature directly, or via connected notions, we’ll focus on some of its modern-day implications: scientific, sociopolitical, and philosophical.
To begin, consider that the very idea of human nature has all too often been used or abused to justify the oppression of social groups.
