This article raises three challenges to Richard McCormick's proportionalism. First, adequately to judge proportionate reason requires the specification of a particular background moral content and metaphysical context. Absent such specification, evaluation of proportionate reason is inherently and deeply ambiguous. Second, to resolve such ambiguity and yet remain Christian, proportionalism must adopt a forthrightly Christian moral content set within a straightforwardly Christian metaphysics. This move will, however, set Christian bioethics off as sectarian—a conclusion McCormick wishes to avoid. Third, even if proportionalism (...) were to adopt a Christian moral content and metaphysics to avoid such ambiguity, its methodology sets aside a key aspect of the Christian life: repentance. Proportionalism does not account for the core reality that repentance plays in one's personal encounter with and knowledge of God. As I will argue, the challenge in part is that moral action cannot be adequately conceptualized, nor can moral theology be properly understood, outside of the authentic practice of the religious life, and repentance is central to that Christian reality. (shrink)