The ethics of impossible and possible changes to human nature

Some commentators speak freely about genetics being poised to change human nature. Contrary to such rhetoric, Norman Daniels believes no such thing is plausible since 'nature' describes characteristic traits of human beings as a whole. Genetic interventions that do their work one individual at a time are unlikely to change the traits of human beings as a class. Even so, one can speculate about ways in which human beings as a whole could be genetically altered, and there is nothing about that venture that could not be deliberated in the way other high-impact questions can be evaluated. There might well come a time when it would be defensible to use genetics to change human beings as a class, in order to protect people in the face of changed environmental circumstances or to enhance existing capacities. Moreover, if one understands human nature not in an empirically descriptive way but in a metaphysical way having implications about human behavior, it can make sense to talk about de-naturing individuals through genetic changes. Even under a metaphysical conception of human nature, however, one can still imagine that people in the future might want to alter their traits in pursuit of another normative idea of a good and valuable life, and genetic modifications might function as a pathway to that change.