Mental modifications

The five types of mental modifications are: correct cognition, based on direct perception, valid inference and verbal testimony; misconception, based upon something other than itself, namely the five kleshas or sources of sorrow — ignorance, egoism, attachment, hate and the fear of death, according to the Yogabhashya; fantasy, engendered by words and concepts, when and to the degree that they do not refer to reality; sleep, which occurs when other modifications cease and the mind is emptied of mental contents; and memory, which is the result of clinging to, or at least not letting go of, objects or images of subjective experiences.