…On the other hand, we have norms that require us to act to help others, including by preventing aggressors from killing them, whether in abortion or otherwise. Norms requiring positive action, however, are not absolute but are always qualified as to circumstances. The reason is that an action is positively required only if, in the circumstances, it is uniquely well-ordered to the final end, i.e., there is no action available to the agent better ordered to that end than the action in question. Hence, the question as to whether there is an obligation to act—and if so, what that obligation is an obligation to do—always depends on the circumstances, for only by examining the circumstances can we determine which actions are available and how well-ordered to the final end various actions are…