Leon R. Kass (born February 12, 1939) is an American physician, scientist, educator, and public intellectual, best known as proponent of liberal education via the "Great Books," as an opponent of human cloning and euthanasia, as a critic of certain areas of technological progress and embryo research, and for his controversial tenure as chairman of the President's Council on Bioethics from 2001 to 2005.
The Problem of Technology (1993) 
- Included in Technology in the Western Political Tradition (1993)
- Ancient science had sought knowledge of what things are, to be contemplated as an end in itself satisfying to the knower. In contrast, modern science seeks knowledge of how things work, to be used as a means for the relief and comfort of all humanity, knowers and non-knowers alike.
- p. 7
- Even the modern word "concept" means "a grasping together," implying that the mind itself, in its act of knowing, functions like the intervening hand (in contrast to its ancient counterpart, “idea,” “that which can be beheld,” which implies that the mind functions like the receiving eye). And modern science rejects, as meaningless or useless, questions that cannot be answered by the application of method. Science becomes not the representation and demonstration of truth, but an art: the art of finding the truth—or, rather, that portion of truth that lends itself to be artfully found.
- p. 8
- The truths modern science finds—even about human beings—are value-neutral, in no way restraining, and indeed perfectly adapted for, technical application. In short, as Hans Jonas has put it, modern science contains manipulability at its theoretical core—and this remains true even for those great scientists who are themselves motivated by the desire for truth and who have no interest in that mastery over nature to which their discoveries nonetheless contribute and for which science is largely esteemed by the rest of us and mightily supported by the modern state.
- p. 8
- Could technology, understood as the disposition and activity of mastery, turn out to be a stumbling block in the path of the master himself?
- p. 9
Forbidding Science: Some Beginning Reflections (2006) 
- Francis Bacon, in his New Atlantis, could charge his elite scientists in Salomon’s House with practicing self-censorship to avoid publicizing dangerous knowledge. Here is how the Father of Salomon’s House describes their practice: “We have consultations, which of the inventions and experiences which we have discovered shall be published, and which not: and take all a oath of secrecy for the concealing of those which we think fit to keep secret: though some of those we do reveal sometime to the State, and some not.” Bacon, the first prophet of the new relation between science and society and of the “conquest of nature for the relief of man’s estate,” knew better than we that knowledge is dangerous, that publication is a public and politically relevant act, and that self-censorship on the part of scientists is necessary and desirable. The passage is also remarkable for its wonderful ambiguity regarding whether scientists or the State has ultimate authority over dangerous knowledge
- Many of our fellow citizens do not share the blind faith in the simple beneficence of all technological innovation. And because they do not share the corporealist, morally neutral, and in some cases atheistic world-view that they attribute (fairly or not) to science and scientists, they are reluctant to surrender the power of decision to the very people who they think are creating the problem.
Looking for an Honest Man (2009) 
- Grappling with real-life concerns — from cloning to courtship, from living authentically to dying with dignity — has made me a better reader. Reciprocally, reading in a wisdom-seeking spirit has helped me greatly in my worldly grapplings. Not being held to the usual dues expected of a licensed humanist — professing specialized knowledge or publishing learned papers — I have been able to wander freely and most profitably in all the humanistic fields. I have come to believe that looking honestly for the human being, following the path wherever it leads, may itself be an integral part of finding it. A real question, graced by a long life to pursue it among the great books, has been an unadulterated blessing.
- Fifty years ago, when Europeans and Americans still distinguished high culture from popular culture, and when classical learning was still highly esteemed in colleges and universities, C. P. Snow delivered his famous Rede Lecture at Cambridge University, "The Two Cultures and the Scientific Revolution." Snow did more than warn of the growing split between the old culture of the humanities and the rising culture of science. He took Britain's literary aristocracy to task for its dangerous dismissal of scientific and technological progress, which Snow believed offered the solutions to the world's deepest problems. In a vitriolic response to Snow, the literary critic F. R. Leavis defended the primacy of the humanities for a civilizing education, insisting that science must not be allowed to operate outside of the moral norms that a first-rate humanistic education alone could provide.
- In contrast to 50 years ago, few licensed humanists today embrace any view of the humanities that could in fact justify making them the centerpiece of a college curriculum.
- Diogenes ... refuses to be taken in by complacent popular belief that we already know human goodness from our daily experience, or by confident professorial claims that we can capture the mystery of our humanity in definitions. But mocking or not, and perhaps speaking better than he knew, Diogenes gave elegantly simple expression to the humanist quest for self-knowledge: I seek the human being — my human being, your human being, our humanity. In fact, the embellished version of Diogenes' question comes to the same thing: To seek an honest man is, at once, to seek a human being worthy of the name, an honest-to-goodness exemplar of the idea of humanity, a truthful and truth-speaking embodiment of the animal having the power of articulate speech.
- [Medical] science was indeed powerful, but its self-understanding left much to be desired. It knew the human parts in ever-finer detail, but it concerned itself little with the human whole. ... The art of healing does not inquire into what health is, or how to get and keep it: The word "health" does not occur in the index of the leading textbooks of medicine. To judge from the way we measure medical progress, largely in terms of mortality statistics and defeats of deadly diseases, one gets the unsettling impression that the tacit goal of medicine is not health but rather bodily immortality, with every death today regarded as a tragedy that future medical research will prevent.
- According to Lewis, the dehumanization threatened by the mastery of nature has, at its deepest cause, less the emerging biotechnologies that might directly denature bodies and flatten souls, and more the underlying value-neutral, soulless, and heartless accounts that science proffers of living nature and of man. By expunging from its account of life any notion of soul, aspiration, and purpose, and by setting itself against the evidence of our lived experience, modern biology ultimately undermines our self-understanding as creatures of freedom and dignity, as well as our inherited teachings regarding how to live — teachings linked to philosophical anthropologies that science has now seemingly dethroned.
- I turned to [Aristotle's] De Anima (On Soul), expecting to get help with understanding the difference between a living human being and its corpse, relevant for the difficult task of determining whether some persons on a respirator are alive or dead. I discovered to my amazement that Aristotle has almost no interest in the difference between the living and the dead. Instead, one learns most about life and soul not, as we moderns might suspect, from the boundary conditions when an organism comes into being or passes away, but rather when the organism is at its peak, its capacious body actively at work in energetic relation to—that is, in "souling"—the world: in the activities of sensing, imagining, desiring, moving, and thinking. Even more surprising, in place of our dualistic ideas of soul as either a "ghost in the machine," invoked by some in order to save the notion of free will, or as a separate immortal entity that departs the body at the time of death, invoked by others to address the disturbing fact of apparent personal extinction, Aristotle offers a powerful and still defensible holistic idea of soul as the empowered and empowering "form of a naturally organic body." "Soul" names the unified powers of aliveness, awareness, action, and appetite that living beings all manifest.
This is not mysticism or superstition, but biological fact, albeit one that, against current prejudice, recognizes the difference between mere material and its empowering form. Consider, for example, the eye. The eye's power of sight, though it "resides in" and is inseparable from material, is not itself material. Its light-absorbing chemicals do not see the light they absorb. Like any organ, the eye has extension, takes up space, can be touched and grasped by the hand. But neither the power of the eye — sight — nor sight's activity — seeing — is extended, touchable, corporeal. Sight and seeing are powers and activities of soul, relying on the underlying materials but not reducible to them. Moreover, sight and seeing are not knowable through our objectified science, but only through lived experience. A blind neuroscientist could give precise quantitative details regarding electrical discharges in the eye produced by the stimulus of light, and a blind craftsman could with instruction fashion a good material model of the eye; but sight and seeing can be known only by one who sees.
- For most Americans, ethical matters are usually discussed either in utilitarian terms of weighing competing goods or balancing benefits and harms, looking to the greatest good for the greatest number, or in moralist terms of rules, rights and duties, "thou shalts" and "thou shalt nots." Our public ethical discourse is largely negative and "other-directed": We focus on condemning and avoiding misconduct by, or on correcting and preventing injustice to, other people, not on elevating or improving ourselves. How liberating and encouraging, then, to encounter an ethics focused on the question, "How to live?" and that situates what we call the moral life in the larger context of human flourishing. How eye-opening are arguments that suggest that happiness is not a state of passive feeling but a life of fulfilling activity, and especially of the unimpeded and excellent activity of our specifically human powers—of acting and making, of thinking and learning, of loving and befriending. How illuminating it is to see the ethical life discussed not in terms of benefits and harms or rules of right and wrong, but in terms of character, and to understand that good character, formed through habituation, is more than holding right opinions or having "good values," but is a binding up of heart and mind that both frees us from enslaving passions and frees us for fine and beautiful deeds. How encouraging it is to read an account of human life—the only such account in our philosophical tradition—that speaks at length and profoundly about friendship, culminating in the claim that the most fulfilling form of friendship is the sharing of speeches and thoughts.
- Perhaps the most remarkable feature of Aristotle's teaching concerns the goals of ethical conduct. Unlike the moralists, Aristotle does not say that morality is a thing of absolute worth or that the virtuous person acts in order to adhere to a moral rule or universalizable maxim. And unlike the utilitarians, he does not say morality is good because it contributes to civic peace or to private gain and reputation. Instead, Aristotle says over and over again that the ethically excellent human being acts for the sake of the noble, for the sake of the beautiful.
The human being of fine character seeks to display his own fineness in word and in deed, to show the harmony of his soul in action and the rightness of his choice in the doing of graceful and gracious deeds. The beauty of his action has less to do with the cause that his action will serve or the additional benefits that will accrue to himself or another — though there usually will be such benefits. It has, rather, everything to do with showing forth in action the beautiful soul at work, exactly as a fine dancer dances for the sake of dancing finely. As the ballerina both exploits and resists the downward pull of gravity to rise freely and gracefully above it, so the person of ethical virtue exploits and elevates the necessities of our embodied existence to act freely and gracefully above them. Fine conduct is the beautiful and intrinsically fulfilling being-at-work of the harmonious or excellent soul.
- With his attractive picture of human flourishing, Aristotle offers lasting refuge against the seas of moral relativism. Taking us on a tour of the museum of the virtues — from courage and moderation, through liberality, magnificence, greatness of soul, ambition, and gentleness, to the social virtues of friendliness, truthfulness, and wit — and displaying each of their portraits as a mean between two corresponding vices, Aristotle gives us direct and immediate experience in seeing the humanly beautiful. Anyone who cannot see that courage is more beautiful than cowardice or rashness, or that liberality is more beautiful than miserliness or prodigality, suffers, one might say, from the moral equivalent of color-blindness.
- To act nobly, a noble heart is not enough. It needs help from a sharp mind. Though the beginnings of ethical virtue lie in habituation, starting in our youth, and though the core of moral virtue is the right-shaping of our loves and hates, by means of praise and blame, reward and punishment, the perfection of character finally requires a certain perfection of the mind.
- Prudence is ... more than mere shrewdness. If not tied down to the noble and just ends that one has been habituated to love, the soul's native power of cleverness can lead to the utmost knavery.
- I have discovered in the Hebrew Bible teachings of righteousness, humaneness, and human dignity—at the source of my parents' teachings of mentschlichkeit—undreamt of in my prior philosophizing. In the idea that human beings are equally God-like, equally created in the image of the divine, I have seen the core principle of a humanistic and democratic politics, respectful of each and every human being, and a necessary correction to the uninstructed human penchant for worshiping brute nature or venerating mighty or clever men. In the Sabbath injunction to desist regularly from work and the flux of getting and spending, I have discovered an invitation to each human being, no matter how lowly, to step outside of time, in imitatio Dei, to contemplate the beauty of the world and to feel gratitude for its—and our—existence. In the injunction to honor your father and your mother, I have seen the foundation of a dignified family life, for each of us the nursery of our humanization and the first vehicle of cultural transmission. I have satisfied myself that there is no conflict between the Bible, rightly read, and modern science, and that the account of creation in the first chapter of Genesis offers "not words of information but words of appreciation," as Abraham Joshua Heschel put it: "not a description of how the world came into being but a song about the glory of the world's having come into being"—the recognition of which glory, I would add, is ample proof of the text's claim that we human beings stand highest among the creatures. And thanks to my Biblical studies, I have been moved to new attitudes of gratitude, awe, and attention. For just as the world as created is a world summoned into existence under command, so to be a human being in that world—to be a mentsch—is to live in search of our summons. It is to recognize that we are here not by choice or on account of merit, but as an undeserved gift from powers not at our disposal. It is to feel the need to justify that gift, to make something out of our indebtedness for the opportunity of existence. It is to stand in the world not only in awe of its and our existence but under an obligation to answer a call to a worthy life, a life that does honor to the special powers and possibilities—the divine-likeness—with which our otherwise animal existence has been, no thanks to us, endowed.