The fifteenth chapter opens with the image of the cosmic tree, rooted above and branching below. Its leaves are the hymns and formulations of knowledge; its boughs spread upward and downward, nourished by the gunas; its secondary roots strike down into the world of men and the bondage of works (15·1). The tree cannot be understood by gazing only at its visible extension; it must be felled with the strong sword of non-attachment, and the soul must then seek the supreme status from which there is no return.
Sri Aurobindo reads this chapter as one of the Gita’s most concentrated metaphysical statements. The world-tree is the manifestation of the Eternal in mutable Nature, but the soul is not meant to remain lost among the branches; it must seek the original Person from whom the ancient creative movement streams forth. This is no hatred of the world but the need to find the root above rather than to dwell for ever among the lower extensions.
Krishna then declares the Jiva to be an eternal portion of the Divine himself, which, entering into Nature, draws to itself the mind and the senses and carries them from body to body as the wind carries fragrance from its source (15·7). The ignorant do not see the soul that departs and dwells and experiences through the gunas, but the eye of knowledge perceives it. This is vital for Sri Aurobindo: the individual soul is not an illusion or a passing ego but a real and eternal portion of the Divine, even though its surface personality is mutable and is bound only while it identifies itself with the lower nature.
The Divine is then shown sustaining the world from within its very functions: the light in sun and moon, the fire of life lodged in living bodies that digests the fourfold food, the force that enters the earth and upholds all creatures, the sap that nourishes the plants, and the presence seated in the heart from whom proceed memory and knowledge and their loss (15·15). He is no remote transcendence only but the secret upholder of the whole life-process.
The chapter rises at last to its crown, the distinction of the three Purushas. There are two spirits in the world, the Kshara and the Akshara: the mutable, which is the soul involved in the changing forms of all beings, and the immutable, the silent and unchanging Self above the flux. But beyond both is a third and highest, the supreme Purusha, the Purushottama, who pervades and upholds the three worlds and is greater than the perishable and higher even than the imperishable (15·17, 15·18). This is the key that lets the Gita reconcile action and silence, the world and liberation, the individual soul and the universal Divine. To know the Purushottama is to know the Divine integrally and to adore him with the whole being, and so the fifteenth chapter provides the metaphysical crown that the final teaching on nature, duty, works and surrender requires.
