An Historical Analysis of the Principle of Double Effect

The principle of the double effect is one of the most practical in the study of moral theology. As a principle it is important not so much in purely theoretical matters as in the application of theory to practical cases. It is especially necessary in the subject matter of scandal, material cooperation, illicit pleasure and of injury done to oneself or to another. Although it is a fundamental principle, it is far from a simple one; and moralists readily admit its complexity. Moreover, it is not an inflexible rule or mathematical formula, but rather an efficient guide to prudent moral judgment in solving the more difficult cases. It is a subtle principle, and for this reason it is liable to misuse on the part of the untrained mind. Even moralists need to proceed cautiously in its practical application. Frequently, in making applications to identical cases, moralists arrive at opposite conclusions. Nevertheless, the principle is perfectly valid and justifiable by reason and Catholic tradition. Reasonably enough this principle has not always been as well understood and put in practice by scholars and others as it is today and as its worth merits. And the historical development of this principle presents an interesting study involving some controversy. In its application, the principle of the double effect may have been understood implicitly many centuries before it was actually formulated. Even as far back as the events of the Old Testament, we find examples of moral actions justifiable under this principle. That the persons who performed these actions were implicitly using this principle we are not certain; for there are other explanations to justify their ac-