Force Majeure and Excuses in Smart Contracts

Abstract: A classic legal problem is whether breach of contract may give rise to a remedy. Under common law this is discussed under the doctrine of excuses. Its civil lawequivalent is the attributability of causes of non-performance of an obligation, and its converse, force majeure. Despite the variety of approaches in various jurisdictions, the general outlines are roughly equivalent as far as translation into smart contracts is concerned: the main issue is what is the cause of non-performance and whether this cause can be attributed. Smart contracts can deal with the general outline of this structure, but may in practice only approximate the refinement that contract law offers. Themain problems are: determining the actual cause of the non-performance by means of automated oracles or the smart contract on its own (without relying on human judgment), dealing with multiple causality and impediments due to the creditor, determining attributability of the cause of non-performance. Smart contracts may offer no more than an approximation of the detailed rules of contract law, by hard-and-fast rules. This may suffice for certain categories of contracts, but may need additional effort to obtain a closer approximation of contract law rules where larger interests are concerned. The related doctrine of withholding performance is similarly difficult to realize appropriately in smart contracts. As regards hardship or unforeseen circumstances, it is best to disallow this in smart contracts,which leaves open the questionwhether partiesmight go to court for relief. The reliance on oracles furthermore opens a weakness to the automatic performance of smart contracts, due to possible liability of oracles for perceived incorrect assessment.