Earlier versions of this paper were prepared during my tenure of a Special Foreign Professorship at Chiba University, Japan, 1 Oct. to 31 Dec. 1991, sponsored by the Japanese Ministry of Education, Science and Culture, and presented in the seminars held at the Institute of Asian Culture, Sophia University, Tokyo; Institute of Middle Eastern Studies, International University of Japan, Urasa, Niigata Prefecture, and Centre of Southeast Asian Studies, Kyoto University. I would like to express my sincere appreciation to my colleagues at these institutions for their fruitful discussions.