CONFLICT OF RIGHTS AND DUTIES
The clash between one person's rights and another person's duties. Such conflict is only apparent, since all rights and duties are derived from law, and all just law is derived from the natural law based on the eternal law of God. And God cannot both command and forbid the same thing. The stringer right or duty prevails; the weaker simply ceases to be a right or duty at all.
In practice, however, it can be extremely difficult to determine which is the stronger right or duty. Certain general norms are commonly recognized in making such a determination. Thus, other things being equal, the stronger right or duty is the one that involves the nobler person, e.g., God before man, parents before children; higher law, e.g., natural law before positive law, inalienable rights before alienable rights; more common good, e.g., the country before the family, the family before the individual; graver matter, e.g., the soul before the body, life before property; clearer title, e.g., the certain before the doubtful, paying a debt before giving a gift; closer relationship, e.g., closer relatives before remote ones, friends before strangers; and greater urgency, e.g., fighting a fire before reading a book, saving the living before burying the dead.
What makes these norms hard to apply is that in any given situation other things are not equal. One right or duty may appear stronger according to one of these norms, and the opposite right or duty stronger for another reason. It is here especially that the virtue of prudence, both natural and supernatural, is indispensable.