19890801, Joel Feinberg, Ron Milo, Keith Burgess-Jackson, and Allen Buchanan Twenty years ago today, on the campus of the University of Arizona in beautiful Tucson, I defended my Ph.D. dissertation, "Constitutional Interpretation." It was, and remains, one of the happiest days of my life. My dissertation was directed by Joel Feinberg (1926-2004). Allen Buchanan (on the far right in the picture) and Ronald Milo (second from left) served on my committee. You might say that I've been a doctor for 20 years. A rock-and-roll doctor.