There is a qualitative change in the nature of consciousness active at the Vijnana or Gnosis level, which represents the sheath or plane of consciousness beyond the mental level. The mental level can rise to heights not ordinarily known in the normal human awareness, with states of intuition, inspiration and insight that make it appear to be highly evolved; however, these states still maintain the basic characteristic of the mental framework and the mental limitations. They still base the awareness in division and fragmentation, and still try to build up a picture of truth by piecing together separate elements and creating a picture from there.
The Knowledge-Self, however, is based in a consciousness of unity and oneness and experiences everything, not as divided and fragmented, but as unified and expressing the differences as incidents in a larger whole. Sri Aurobindo refers to this level as the “supramental”, implying that it is beyond the mind. This is the transitional state of consciousness that mediates between the upper hemisphere of Existence-Consciousness-Bliss, Sat-Chit-Ananda, and the lower hemisphere of Matter-Life-Mind. In the Taittiriya Upanishad it is referred to as the Vijnanamaya Atman, the Self consisting of Knowledge.
Sri Aurobindo observes: “But the transition from the mind-self to the knowledge-self is the great and the decisive transition in the Yoga. It is the shaking off of the last hold on us of the cosmic ignorance and our firm foundation in the Truth of things, in a consciousness infinite and eternal and inviolable by obscurity, falsehood, suffering or error.”
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 22, Vijnana or Gnosis, pg. 456