In the Taittiriya Upanishad, five successive sheaths are described that go from gross matter to the more subtle substances of being. The sheath of Matter is filled and informed with the more subtle sheath of the Life Energy, prana. The sheath of Mind fills and informs the sheath of Prana. And the Sheath of Knowledge, vijnana, more subtle yet, fills and informs the sheath of Mind. The Upanishad thereby distinuishes between the action of Mind and the action of Knowledge.
Sri Aurobindo provides a more comprehensive and detailed discussion of the differences between the two, which highlights the way that the Gita uses the term jnana, or Knowledge. “…it is the light by which we grow into our true being, not the knowledge by which we increase our information and our intellectual riches; it is not scientific or psychological or philosophic or ethical or aesthetic or worldly and practical knowledge. These too no doubt help us to grow, but only in the becoming, not in the being; they enter into the definition of Yogic knowledge only when we use them as aids to know the Supreme, the Self, the Divine,–scientific knowledge, when we can get through the veil of processes and phenomena and see the one Reality behind which explains them all; psychological knowledge, when we use it to know ourselves and to distinguish the lower from the higher, so that this we may renounce and into that we may grow; philosophical knowledge, when we turn it as a light upon the essential principles of existence so as to discover and live in that which is eternal; ethical knowledge, when by it having distinguished sin from virtue we put away the one and rise above the other into the pure innocence of the divine Nature; aesthetic knowledge, when we discover by it the beauty of the Divine; knowledge of the world, when we see through it the way of the Lord with his creatures and use it for the service of the Divine in man. Even then they are only aids; the real knowledge is that which is a secret to the mind, of which the mind only gets reflections, but which lives in the spirit.”
The Gita repeatedly uses the term jnana, so it is important to recognize that “knowledge” is not of these intellectual or mental forms, but that higher knowledge of the Divine that resides, in the Upanishads term, in that inner and more subtle sheath that fills and informs the sheath represented by the action of mind.
Sri Aurobindo, Essays on the Gita, First Series, Chapter 20, Equality and Knowledge, pp. 194-195