The conduct of adjudication is often influenced by motions—requests made by litigants to modify the course of adjudication. The question studied in this article is why adjudication should be designed so as to permit the use of motions. The answer developed is that litigants will naturally know a great deal about their specific matter, whereas a court will ordinarily know little except to the degree that the court has already invested effort to appreciate it. By giving litigants the right to bring motions, the judicial system leads litigants to efficiently provide information to courts that is relevant to the adjudicative process.