Vijnanamaya, the Wisdom Sheath

Vijnanamaya kosha is the fourth of the five sheaths of Vedantic thought, the sheath made of wisdom or intellect, vijnana or buddhi, the faculty of discernment, judgement, discrimination and higher understanding, as distinct from the restless processing mind of the sheath outside it. It lies within the mental sheath and is subtler than it, the layer of the intellect that decides, discriminates the real from the unreal, and carries the sense of the individual "I" as a knower.

In the nested scheme of the Taittiriya Upanishad this sheath is the seat of the discerning intelligence and of the will, closer to the self than the ordinary mind, and it is by refining this faculty of discrimination that the seeker distinguishes the atman from all that merely covers it. Within it lies only the sheath of bliss and, beyond that, the self. The five koshas are the classical Vedantic model of the layered person, and the wisdom sheath is the innermost but one. The doctrine is ancient and Indian.