Buddhi is the aspect of mind which is higher than the perceptive mind or it is the higher mind which shows the passage to inner wisdom. The word buddhi is originated from the root budh (to awaken). Buddhi enables us to decide, judge and make discriminations. It helps us in making right decisions. In our life we come across many ups and downs which we have to face or solve. The basic agency to resolve all these problems is buddhi.
According to the Upanishads, the human body is like a chariot, the sense organs are related to horses and the mind to the reins. The charioteer is comparable to Buddhi or knowledge. Without a charioteer the chariot is of no use, similarly, the body, mind and the senses are of little use without buddhi or knowledge.
Buddhi is the dimension of mind (chitta) and is associated with Brahman. The other dimension of mind (chitta) is manas that is associated with ego-construction or ahamkara (the changing ego). The manas through attraction with the matter and sensual pleasures (kama) causes the birth of Brahman into materialistic world as an individual soul. On the contrary, the buddhi attracts to Brahman and guides the incarnated soul how to detach itself from the materialistic world or all worldly desires to eventually attain liberation (moksha).
If buddhi works clearly, it can guide the manas. The decisions should be made by buddhi otherwise decisions made by manas will be colored by ego (ahamkara). Usually, our buddhi is clouded by various impressions of the mind (chitta) which can be unclouded by spiritual practice (sadhana). We have imposed a cover of ego on the buddhi which should be thrown off to realize the true power of buddhi.
The buddhi is considered close to our inner self (atma). It receives energy from the atma and delivers it to the mind. The mind then passes it to senses and activates the whole body. Only a pure and untained buddhi can transmit the full power of atma to the body. So, we must make efforts to keep it pure and holy.
This Picture has been contributed by Mr Arjun Naorem Singh who is a practising Yoga Teacher practicing in China and who is listed as a Yoga Teacher at Ajarya Yoga Academy.