Like its sister terms, Buddhi consists of the root ‘budh’ - meaning to know or to be awake. It refers to wisdom and intellect, and to use the power of one's conscious and unconscious mind to understand and analyze the world around us, to discriminate and decide the best courses of action.
Buddhi yoga focuses on this consciousness and works to achieve self-development through uniting the mind with a higher awareness or energy. The overall aim is to attain an evenness within one's mind, overcoming weakness to refine and achieve a higher level of consciousness.
Developing the spiritual mind is as essential a part of the practice as developing the physical body, and Buddhi is just one of four functions, with the others being manas, citta, and ahamkara.
As the inner wisdom, the concept helps us to make wise and correct choices with confidence. It gives us knowledge of the world around us, helping us to define the impressions of the world provided by our mind and senses. It identifies encounters as a person, or a tree, and allocates the object a place in space and time by projecting attributes such as size, color, and relationship to other surrounding objects.
It is important always to remember the interconnected nature of all things, and the clarity offered by Buddhi does not detract from this fact. It does not reveal the true nature of reality, which is a unified whole in which all living things are connected.
Because of this, Buddhi has the ability to be aware of itself; judging the extent to which it can know true reality. It is by its very nature divisive - splitting impressions into recognizable shapes and objects - and is therefore limited to the perceptions of the physical world. This awareness of limitation is an essential aspect of the teachings.