My initial interest in this area of study was stimulated by Erich Frauwallner's works. Frauwallner died before my work on this study began. It was Kar! Potter's insightful interpretation of philosophical matters which was a constant inspiration for the project. This study is arevision of my doctoral dissertation submitted at the University of Washington in Seattle.Although I completed this monograph in 1999, recent scholarship should at least be acknowledged, if not engaged in my arguments toward establishing the reconstruction of the Sankhya methods of knowing. Numerous contributions on Sankhya are collected in an issue of Asiatische Studien 53.3 (1999), edited by Johannes Bronkhorst. Some of these, such as E. Steinkellner's "The Sastitantra on Perception, a Collection of Fragments" and Eli Franco's "Avita and Avita" bear directly on this work, so I will address them at the appropriate places in endnotes. They are part of my new research on Sankhya, along with the critical edition of the Yuktidipika by Wezler and Motegi (1998).