Abstract

In defining supervening impossibility of performance, the South African law of contract recognises a “general rule”, which entails that performance is excused if impossibility is brought about by vis major or casus fortuitus. This rule is then made subject to a vague and broad list of qualifications. It is argued here that this approach is unhelpful, and that the general principles on supervening impossibility of performance may be restated in more concrete terms. The general rule may simply maintain that absolute impossibility excuses a debtor. The rule should then be subject to clear and specific qualifications. These qualifications entail that liability may nonetheless be imposed if: (i) the debtor actually foresaw or reasonably should have foreseen the event giving rise to impossibility; (ii) the debtor could have taken reasonable steps to avoid such an event or overcome its consequences; (iii) the debtor created the impossibility; or (iv) the debtor was in mora at the time of impossibility. It is argued that it may be unhelpful to include fault on the side of the debtor in this list, inasmuch as fault could actually obscure other qualifications to the general rule, rather than act as a qualification in its own right.