This chapter argues that the weight of teachings in the ICJ varies between works. Some works are cited far more than others. The most-cited writers tend to men from Western countries. The judges frequently justify citations of teachings, by arguing that the teachings of high quality, that the writer is an expert, that the writer holds an official position, or that multiple writers agree. It is plausible to view this as factors that influence the weight of teachings. Explanations for why the judges distinguish between works is that they want to make their opinions authoritative, that they want to save time, and that they want to comply with the ICJ Statute Article 38(1). Finally it is argued that the variations between the weight of teachings shows that authority in international law is established through an informal, collective process.

This chapter analyses the ICJ Statute Article 38(1), interpreting each its component terms, with a particular emphasis on ‘teachings’. One overall conclusion is that the wording of Article 38(1) gives at best limited on guidance on the application of teachings, which supports the utility of the examination made in the rest of the book. When interpreting ‘teachings’ specifically, it is particularly difficult to classify works produced by the International Law Commission. They are not seen as ‘teachings’ in the book.