Bhagavad Gita 15.16 (BG 15.16) | Puruṣottama-yoga: The Supreme Indweller

Suddenly Krishna brings in the triple concepts of perishable and imperishable purushas and the still superior one called Purushottama.

On looking at the world what strikes us first is the perishable nature of everything, big or small, on the earth and beyond it as well. Change is Nature’s characteristic, which denotes perishability.

For anything to be changeful, there should be a nonchanging base or substratum. Nature, with its three gunas constitutes this, which has been existing for an incalculable time. While the products of gunas change fast, ceaselessly, gunas remain as their substratum. On this basis, we can regard them as imperishable, compared to the perishable features.

But this is not the sole, singular adhishthāna (substratum), which evolves the changefulness and acts as the changeless base. It is like wakefulness, dream and sleep, the three states of ours. The three have their individual base.

If you probe further, the three states together with their immediate individual substratum (which is the fourth), are themselves creations of still something finer, greater and ultimate. That fifth factor, so to say, is the imperishable existence. All else is merely its display.

That ultimate is Paramātmā, which the ‘I’ denotes. Understood in its absolute nature, this ‘I’ is the Paramātmā. Perishable prakrti including our body has its substratum, the antahkarana (inner coordinate or jiva). Beyond this is the ultimate adhishthāna, the Purushottama, the supreme Purusha, called Paramātmā. Krishna identifies it as within oneself. With senses superior to objects (3.42), everything in us is superior as we go inward, with Paramātmā the most superior!