Buddhi is the faculty of discernment — the intelligence that judges, decides and understands, as distinct from mind (manas) and from the senses. In the Bhagavad-gītā the quality of one’s happiness is traced to the state of the buddhi: happiness born of the clarity of intelligence regarding the self (ātma-buddhi-prasāda-jam) is called sāttvika. Pages here that treat buddhi and its purification.
