Hetu

Cause, motive, reason. In YS 2.3, the five kleśas are the hetu (root cause) of all vṛttis that disturb the mind. Identifying the hetu of an affliction is essential for its spiritual cure: without understanding the cause, practice addresses the symptom, not the origin. In nyāya logic, hetu is the middle term of the syllogism that establishes the connection between the proposition and its evidence. See klesha and vrtti.