Prana, the life-energy, supports the physical body as the physical prana, but it also supports the action of the mind as the psychic prana. The seeker, in order to overcome the limitations of the life-energy in its characteristic action, needs to appreciate and fully understand the action of the psychic prana.
Sri Aurobindo describes the three characteristics of the life-energy: “The characteristics of Life are action and movement, a reaching out to absorb and assimilate what is external to the individual and a principle of satisfaction or dissatisfaction in what it seizes upon or what comes to it, which is associated with the all-pervading phenomenon of attraction and repulsion. These three things are everywhere in Nature because Life is everywhere in Nature. But in us mental beings they are all given a mental value according to the mind which perceives and accepts them. They take the form of action, of desire and of liking and disliking, pleasure and pain.”
This vital action distorts to its own ends the understanding of the pure mental instrument, and leads to confusion and mis-direction. Desire plants a bias in our mental process. “As the universal Divine Being, all-embracing and all-possessing, acts, moves, enjoys purely for the satisfaction of divine Delight, so the individual life acts, moves, enjoys and suffers predominantly for the satisfaction of desire.”
The yogic process requires the seeker to leave behind the desire-mind and associate with the bliss or enjoyment of the Divine, in an equal and wide embrace of the entire existence. Understanding the way that the desire-mind embeds itself in the mental process and colors the thoughts and decisions is an important step in conquering the attachment to the life-energy which limits and retards the process of the yoga.
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 8, The Release from the Heart and the Mind, pg. 335