Despite the maxim that “ignorance of the law is no excuse,” ignorance of public and private law is pervasive and often sensible. Acquiring perfect information about the legal rules that might have an impact on their activities would leave many consumers (and others) with little time and few resources to pursue those activities. Holding individuals accountable for their failure to obtain costly legal information would be unfair in many circumstances, and would also create incentives to conduct inefficient legal investigation.

Legal doctrine has developed three distinct strategies to account for reasonable ignorance of law. First, where feasible, doctrine provides incentives for those with better access to legal information to transmit that information to otherwise ignorant parties. Second, when incentives are not feasible, doctrine often excuses reasonably ignorant actors – so long as their actions do not significantly interfere with the private rights of others. Third, in circumstances where excusing the reasonably ignorant actor would affect victims in ways that might generate unfairness or inefficiency, doctrine limits the remedies available to those victims in ways that reduce incentives for inefficient legal investigation.

These strategies ameliorate the unfairness and inefficiency associated with rigid adherence to the maxim. Although doctrine employs these strategies across a wide range of legal issues, the strategies are underutilized in some areas of law, most notably copyright law. Those areas remain ripe for reform.