This paper focuses on the preliminary evaluation of expressions of moral sentiment under conditions of cultural pluralism. The advance of science and technology puts ever new power over nature in human hands, and if this new power is to more fully serve human ends, then it must become the means or material of human virtue. This prospect poses the question of the relationship between power and virtue, and equally, the question of how scientific advances may be understood to enter into (...) a pluralism of moral doctrines and deliberations. Taking a page from the philosophy of science, the present approach examines the relationship between scientific advances and moral evaluations of developing practices as mediated by contemporary accounts of the virtues of hypotheses. If we conceive of expressions of moral sentiment as hypotheses for the amendment or expansion of existing moral doctrines in the light of new possibilities for action, then this suggests that expressions of moral sentiment may be evaluated, in a preliminary way, by reference to standard lists of the virtues of hypotheses: refutability, conservatism, modesty or simplicity, precision, elegance, and generality. Expressions of moral sentiment are subject to preliminary evaluation, on cognitive grounds, by reference to their prospective integration and/or modification of on-going moral traditions. (shrink)