 By embedding the discussion of reliable cognition within a general examination of mental episodes, Tibetan epistemologists were led to develop a typology of non-reliable cognitions. A fivefold typology is shared by the majority of scholars in the pre-classical period and is mostly adopted in later Gelukpa textbooks. Thinkers who adopt it frequently disagree, however, about the phrasing of the definition of each type and the specific cases they cover or not.