Several modern commentators of Dignaga have puzzled over the 5th century Buddhist philosopher1s theory of the triple condition of the inferential sign. Th. Stcherbatsky (1932), Richard Hayes (1988) and Bimal K. Matilal (1986) have wondered at the reasons for Dignaga’s insistence on the inclusion of the secondcondition, which seems to be the logical equivalent of the third condition. Do the three criteria together furnish patterns of valid inference which differ from those patterns furnished by criteria one and three alone? In (...) this paper, I detail three types of cases which underline the importance of the inclusion of the second criterion. (shrink)