Impossibility and Changed and Unforeseen Circumstances

Abstract

Suppose that the parties are agreed on what performance each is to make but some event makes this performance impossible, or more difficult, or its market price drastically changes. These problems have been handled by two doctrines drawn from two different sources. Roman law developed a doctrine of impossibility to deal with impossible performances. Canon law developed one of changed circumstances to deal with unexpected events that made a performance of greater or lesser value to each party. In the medieval and early modern period, jurists developed philosophical and moral explanations of these doctrines. With time, these explanations were forgotten or simplified. Today, to many modern jurists, both doctrines seem to defy rational explanation. Nevertheless, if we look at the history of these doctrines, we will find that there is a much to be learned, both negatively and positively. Negatively, we will see, the jurists were never able to develop a good explanation of the Roman texts governing impossibility. Their explanation was that no one could be bound to do the impossible which simply did not square with the texts. On the positive side, they did develop a good explanation of the effect of unexpected circumstances. It was so good that I believe that if it is properly understood, it can also explain why relief is sometimes given when a performance is impossible.