Leon R. Kass, M.D., is the Addie Clark Harding Professor Emeritus in the Committee on Social Thought and in the College at the University of Chicago and the Madden-Jewett Chair at the American Enterprise Institute. He was the chairman of the President’s Council on Bioethics from 2001 to 2005. He has been engaged for more than forty years with ethical and philosophical issues raised by biomedical advances and, more recently, with broader moral and cultural issues.

A More Natural Science

Born and raised in Chicago, Kass received his undergraduate and medical degrees at the University of Chicago and then pursued a Ph.D. in biochemistry at Harvard. His education and early professional life suggested a promising career in biomedical science, and offered few hints of the direction his thought and work would take.

But it was in confronting the human significance of biology and medicine that his priorities and interests started gradually to shift. His professional turn to the humanities began, as he recounted it, in a concern about the yawning gap “between all activities of life as lived and those activities as understood scientifically.” The reductionism of modern science, while surely productive in its own terms, seemed to him to close off some crucial paths to understanding human life in its fullness. The phenomena of life as they present themselves offer crucial insights into the nature of living things, and a natural science that ignores them is therefore grossly incomplete. As such a science grows more and more capable, moreover, it risks putting ever greater power into the hands of a populace ever more confused about its better and worse uses—a judgment, after all, that demands a sense of man’s nature and his proper purposes. Thus, he concluded, “a richer understanding and deeper appreciation of our humanity [was] necessary for facing the challenges confronting us in a biotechnological age.”

The desire to help society face those challenges led Kass into the burgeoning field of bioethics, in which he soon became a prominent and important figure. But his work in bioethics—both in the early stages of his career and in his later prominent public role leading the President’s Council on Bioethics—was always directed not to articulating cold and barren rules for action but to recovering a deep appreciation of the character and dignity of the human person. Such an appreciation, he argued, was necessary not only for limiting science, but for fully developing it.

Kass’s first book, a collection of essays called Toward a More Natural Science, sought to show how a science that took greater account of the phenomena of life could lead to a deeper understanding of the natural world, and especially of the human animal. “At the center of any philosophical anthropology will be an account of the human difference, of what is peculiarly human about human nature and the human animal,” he argued. Without such an account—without knowing what kind of beings we are—we can have little hope of understanding how we ought to live.

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Nature and Culture

Throughout the essays gathered in Toward a More Natural Science, however, Kass seemed clearly aware that recovering the kind of anthropology he was after would require more than reminding science of the price it had paid for its reductionism. A more natural science almost certainly cannot be recovered directly, and the fuller picture of man and his nature must be looked for simultaneously in other ways.

In his ambitious sequel, The Hungry Soul: Eating and the Perfecting of Our Nature, Kass sought to reinforce the effort by resort to our cultural practices and traditions, some of which, he argued, show clear evidence of having been custom-designed for precisely the kind of human being modern science now denies we are. The wisdom latent in our longstanding conventions is wisdom about human nature, and its teaching therefore is a more natural science.

The method of The Hungry Soul marked a turn—a turn which in his teaching and writing Kass had long since taken—to seek after wisdom in the cultural and intellectual inheritances of our civilization on the assumption that these were forged by students of human nature confronted with the same basic questions human beings must always confront, and that they have survived because they offer profound and in important ways also true answers to these questions.

The Hungry Soul, by taking up a subject at the nexus of the natural and the cultural, showed how this expanded search followed directly from Kass’s concern about the scientific turn away from human experience. It, too, was directed to addressing “the gap between the ethically sterile nature studied by science and the morally freighted life lived by human beings.” And it too sought to recover a mode of understanding open to a richer sense of what it is to be human.

In his continuing work on bioethics and in his increasing emphasis on the study of the great books, stories, and achievements of Western Civilization, Kass aimed always to paint a fuller picture of the human animal by seeking wisdom latent in the cultural practices and institutions that have best spoken to those aspects of ourselves ignored by our modern scientific outlook. When we consider the rituals, practices, stories, and traditions that mean the most to us and shape our lives, Kass wrote, we find that we are not just matter in motion. “Our souls still crave the drama of what Tolstoy called ‘real life’: immediately meaningful work, genuine love and intimacy, true ties to place and persons, kinship with nature, family, and community, dignity, understanding, and an openness to the divine. But real life has become nearly impossible as we have ceased to know and honor its forms.”

The ways that we do what we do, even when we are not explicitly alert to their sources or meanings, tell us an enormous amount about who and what we human beings are. And the best and highest artifacts of our cultural traditions are those that speak to these deepest questions of meaning, and that offer us some hints of how we may conform to those highest possibilities implicit in our nature.

The search after that nature and its highest possibilities in this way took Kass from the study of the human animal to the study of the cultural habitat that animal has constructed for itself—but always with an eye to the true and fullest nature of the human being himself.

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Human Being and Citizen

The cultural habitat we human beings have built for ourselves is of course also a civic, political, and religious habitat, and Kass’s work has frequently taken up the ways in which all of these can help us better grasp the nature of the human being, and of the life well lived.

Even in his study of political and moral matters, however, Kass’s work has always been fundamentally philosophical. He has championed the use of politics and law in the defense of crucial human goods, to be sure, most notably in some of his work in bioethics. But he has done so only in cases when he has judged that the essential prerequisites to human flourishing, and especially the family, were at risk. For the most part, even in bioethics, Kass’s efforts have been a search for understanding of the human creature, which might inform the efforts of his students and his readers to live well. He argues neither from nor for authority, even when expounding on the meaning of the Ten Commandments or arguing for laws that would prohibit human cloning.

This is actually most evident in the arena of Kass’s work that might be thought both most inclined to authoritative rulemaking and most reliant on the authority of origin, but which turns out to be neither: his study of the Hebrew Bible. His reading of the book of Genesis, developed over several decades and offered most fully in his book The Beginning of Wisdom, does not lean on the authority of the text’s claim to divine origin but on the premise that the text offers teachings which, once unpacked, will help show why the practices they enjoin contain latent but persuasive wisdom. Kass seeks for the roots of our traditions without seeking to uproot them. He believes that, properly understood, our traditions and the highest accomplishments of our culture speak to a fuller understanding of human nature that can help us see what we are, and therefore how we might make the most of ourselves.

His work on America’s civic and cultural heritage—conducted jointly with his wife and fellow scholar, the late Amy Kass—has similarly sought after the deepest roots of America’s character and soul, not just in our founding documents and political statements of purpose, but in (as suggested by the subtitle of What So Proudly We Hail, the book the Kasses edited with political scientist Diana Schaub) “story, speech, and song.”

Here, too, Kass’s work is grounded in the desire to understand more fully the nature of the human being and in the assumption that men and women have been pursuing such understanding for countless generations, so that the efforts they have undertaken—and especially those that have spoken most powerfully to generations of readers and followers—have something to say to us today, and will have something to say to human beings for as long as such beings exist. It is an attitude that approaches the past not with unswerving piety and not with arrogant doubt, but with openness and, above all, with gratitude: gratitude for our nature, and gratitude for what our predecessors have made of it.


An Ascent In Touch With Its Beginnings

Wisdom-seeking gratitude is the dominant flavor of every page of Kass’s work, and the importance of approaching great questions with such a disposition is the foremost lesson he has always imparted to his students.

In his ongoing study of biology and bioethics, teaching of great works of literature and philosophy, and inquiry into the depths of the Bible, Kass seeks the nature of man through his ways of being and acting. In the forms of human life—the arc of the individual lifespan and the ever-repeating intergenerational shape of family life, the rituals of birth and love and marriage and mourning, the public celebrations of important national occasions, the rules of courtship and worship—is the outline of the human flourishing that our modern natural science leaves out of view, but that we modern human beings desperately desire, even when we do not quite know it.

“Cultural memory still holds gingerly a tattered script” for such flourishing, Kass has written, “but many of its pages are missing and the guidance it provides us is barely audible and, even then, delivered in what appears to us to be a foreign tongue.” He has worked to learn and to teach that foreign tongue, the language of human flourishing in which the great cultural achievements of Western civilization are written. “An appreciation of what is given to us by nature could point us toward humanly instituted practices and beliefs that perfect our given nature,” he argues. “If true, this would imply that some practices really are just, noble, and holy, and that we can discern or discover what they are.”

In describing the structure of the argument of The Hungry Soulwhich traces the meaning of eating from its biological character through the limits and constraints human beings have placed upon it, to the ways we have beautified it and turned feeding into dining, through the roles it has played in our highest religious rituals—Kass put things this way: “The argument is thus an ascent—from nature to human nature to human nature culturally clothed by the just, then the noble, then the holy—but an ascent that remains in touch with its beginnings.” There in a nutshell is the arc of Kass’s interests over more than four decades and counting. In search of wisdom about how human beings may flourish, he has studied nature and man’s nature, and in pursuit of man’s nature he has delved deeply and broadly into our cultural wisdom about justice and ethics, nobility and excellence, and then sanctity and holiness.

—Essay by Yuval Levin