Friend of reason Steven Pinker plows into the mushy category of "human dignity"—routinely invoked to argue against advances in science and medicine that will enliven and lengthen our lives—like nobody's business here:
Many people are vaguely disquieted by developments (real or imagined) that could alter minds and bodies in novel ways. Romantics and Greens tend to idealize the natural and demonize technology. Traditionalists and conservatives by temperament distrust radical change. Egalitarians worry about an arms race in enhancement techniques. And anyone is likely to have a "yuck" response when contemplating unprecedented manipulations of our biology. The President's Council has become a forum for the airing of this disquiet, and the concept of "dignity" a rubric for expounding on it. This collection of essays is the culmination of a long effort by the Council to place dignity at the center of bioethics. The general feeling is that, even if a new technology would improve life and health and decrease suffering and waste, it might have to be rejected, or even outlawed, if it affronted human dignity.
Whatever that is. The problem is that "dignity" is a squishy, subjective notion, hardly up to the heavyweight moral demands assigned to it.
Read Pinker's reason interview here.