Leon Kass was born in 1939, on the twelfth of February, when we celebrate the birthdays of Abraham Lincoln and Charles Darwin. A mere coincidence, of course, but an interesting one. In celebrating Lincoln, we pay homage to human dignity; in celebrating Darwin, we pay homage to the progress of scientific knowledge. In celebrating Leon Kass, we honor a philosopher who has sought to understand and defend human dignity while remaining a man of science. From genotypes to the Book of Genesis, Kass has searched for truth in human nature, while heeding both the verities of moral philosophy and the facts of our biology.

The household into which Kass was born was Yiddish-speaking and charged with a fervor for social justice. Home was the South Side of Chicago, where Kass’s father owned and ran a clothing store. High school was a program for advanced students run by the University of Chicago, where he then enrolled as an undergraduate at the age of fifteen and subsequently pursued his medical degree. There he also met his wife and intellectual partner, the late Amy Kass, to whom he was married for over forty years and with whom he raised two daughters.

After a medical internship at Beth Israel hospital in Boston, Kass returned to academic study, this time at Harvard, where he received a Ph.D. in biochemistry. The young research scientist then moved on to the National Institutes of Health, where he studied problems in molecular biology in a highly collegial atmosphere and seemed primed to pursue a rewarding career in medical research.

Meanwhile, his avocational interests were giving shape to another type of career. In medical school Kass had shown an interest in medical ethics, and in studying biochemistry he found a host of moral questions that wanted answering. An urge to think philosophically about science was turning into a full-blown yearning for the examined life. As an anniversary gift in 1966, his friend Harvey Flaumenhaft gave Kass a copy of Rousseau’s Discourse on the Arts and Sciences. Kass credits Flaumenhaft, a longtime faculty member and former dean at St. John’s College in Annapolis, with instigating a number of his life-altering encounters with great books.

But prior to reading Rousseau’s famous argument that progress in the arts and sciences is inversely related to progress in morals, Kass had another kind of life-altering encounter. In the summer of 1965, he and Amy joined the civil rights movement and traveled south to register voters. Working and living in Holmes County, Mississippi, Kass says he found more honor and dignity in the county’s uneducated, churchgoing black community than he’d noticed among his fellow students at Harvard, who professed all the right opinions but whose greatest cause, it seemed to him, was their own personal advancement. If this was true, then perhaps Rousseau’s argument was correct.

While Kass continued working at NIH, his reading became considerably more specific to the direction he was taking, as when he made his way through The Phenomenon of Life by Hans Jonas, the German-born philosopher who taught for many years at the New School for Social Research. As Kass recently told Humanities magazine: “Here was a man who philosophized profoundly about the phenomena of life but in full acceptance of modern scientific findings, and who showed me how to begin to address a disquiet that I had . . . about the insufficiency of the reductionism of molecular biology.”

Soon, Kass addressed this disquiet publicly by entering the fray of early scientific debate over cloning and other hot science topics in the pages of the Washington Post. Amidst news that it was becoming possible for man to assert control over his own biological destiny, Kass began making the argument that the merely possible was not necessarily preferable. In 1970, he took a leave of absence from NIH to become, for two years, executive director of the Committee on the Life Sciences and Social Policy at the National Research Council. In 1973, he won a humanities fellowship from NEH to investigate the concept of organism in philosophical thought. Kass never returned to NIH, but during this period began a series of penetrating essays on important issues such as the Hippocratic Oath and the proper ends of medicine.

Having married well and befriended well, Kass made another fruitful decision by becoming a teacher. In 1972, he began teaching at St. John’s College, home to a well-known Great Books program. Along with Amy, he joined, in 1976, the faculty at the University of Chicago. The texts of the classroom became the next set of life-altering books, above all Aristotle’s Nicomachean Ethics and the book of Genesis, though the syllabi he taught (often with Amy as his teaching partner) would include classics as far afield as Kant’s Critique of Pure Reason and Tolstoy’s War and Peace.

The first of his own three books, published in 1985, Toward a More Natural Science, marshaled Kass’s essays on “Making Babies” and other questions of bioethics to call on science to study life as experienced beyond the laboratory, in everyday circumstances. Such a science, he hoped, could offer better guidance for ethical decisions in medicine. The distinguishing feature of Kass’s investigations was its philosophical spirit to discover what was true and right and then ask how it might be pursued.

The subtitle of his second book, The Hungry Soul, published in 1994, was especially telling: “Eating and the Perfecting of Our Nature.” The book’s discussion begins with the biology of consumption and continues on to the meaning of those customs that attend humans when dining. The breadth of his education allows Kass the freedom to go from what is known in science to what is thought, felt, and expressed about our noblest inclinations in history and literature.

In 2001, Kass was appointed chairman of the President’s Council on Bioethics. Famously, he asked all the members of the commission to begin their work by reading “The Birth-Mark,” a short story about scientific hubris by Nathaniel Hawthorne. In 2002 and 2003, the council issued two major reports: Human Cloning and Human Dignity and Beyond Therapy. In 2003, Kass also published The Beginning of Wisdom, his meditation on reading the book of Genesis, a text that he has taught many times.

Over the years, Kass has received many honors and awards and has been affiliated with many well-known institutions. He is a founding fellow of The Hastings Center, a think tank devoted to issues of bioethics. At the American Enterprise Institute, he is currently the the Madden-Jewett Chair. And from 1984 to 1991, he served as a member of the National Council on the Humanities, the advisory board of the National Endowment for the Humanities.

From the National Endowment for the Humanities