Abstract: This article was originally delivered as part of the Addison C. Harris Lecture Series at the Indiana University School of Law at Bloomington on October 22-23, 1986. Prior to Professor Bator’s death on February 24, 1989, he asked Professor Charles Fried of the Harvard Law School to oversee the publication of this article, indicating that he was generally satisfied with his most recent draft. Accordingly, apart from minor editorial changes, this article is substantially in the form in which Professor Bator left it.