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.