Since time is a physical quantity which can measured with fantastic accuracy, I've always taken it for granted. By chance I ran across the PTS and it has introduced me to the many paradoxes inherent in time. I have just read a book by Palle Yourgrau entitled "A World Without TIme: The Forgotten Legacy of Goedel and Einstein." Kurt Goedel was perhaps the greatest logician of the 20th century, if not of all time. Goedel and Einstein became close friends in 1942 at the Princeton Institute for Advanced Studies. Einstein taught Goedel general relativity. Goedel developed a cosmology based on a rotating universe which was consistent with general relativity. According to Yourgrau this consistency has never been dis-proven. In Goedel's universe time was cyclical, hence it was possible to travel into the past. Goedel concluded that the existence of time was inconsistent with general relativity. To this day, this conclusion is either disbelieved or ignored. Yourgrau states that "Rarely have so many understood so little about so much." If one has the time(?), this book is well written and is a fun read for anyone interested in mathematical logic, physics, and the characters that once inhabited these domains.
L J Swartzendruber
