It can be confusing to define the object of an action because it may be unclear if there is a per se or a per accidens order to the end. Three common difficulties in distinguishing between these are that the per se ordering must be either in the nature of the end or in the act, that this ordering to an end is a real and not merely a logical one, and that technology has a tendency to ignore the teleology (...) of natures by breaking things down to their parts for manipulation. Having drawn these distinctions, craniotomy is then compared to lethal self-defense. National Catholic Bioethics Quarterly 13.4 : 611–616. (shrink)