According to Lewis, the dehumanization threatened by the mastery of nature has, at its deepest cause, less the emerging biotechnologies that might di… - Leon Kass

[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.

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.

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.