The self which we have to perfect, is neither pure atman which is ever perfect nor the ego which is the cause of imperfection, but the divine self manifested in the shifting stream of Nature.
Existence is composed of Prakriti and Purusha, the consciousness that sees and the consciousness that executes and formalises what we see. The one we call Soul, the other Nature. These are the first double term from which our yoga has to start.
When we come to look into ourselves instead of out at the world and begin to analyse our subjective experience, we find that there are two parts of our being which can be, to all appearance, entirely separated from each other, one a consciousness which is still and passive and supports, and the other a consciousness which is busy, active and creative, and is supported. The passive and fundamental consciousness is the soul, the Purusha, Witness or Sakshi; the active and superstructural consciousness is nature, Prakriti, processive or creative energy of the Sakshi. But the two seem at first to stand apart and distinct, as if they had no share in each other.
The Purusha, still and silent witness of whatever Prakriti chooses to create, not interfering with her works, but reflecting only whatever forms, names and movements she cases on the pure mirror of his eternal existence and the Prakriti restlessly creating, acting, forming and effecting things for the delight of the Purusha, compose the double system of the Sankhyas. But as we continue analysing their relations and accumulate more and more experience of our subjective life, we find that this seeing of the Purusha is in effect a command. Whatever Prakriti perceives it to be the pleasure of the Purusha to see, she tends to preserve in his subjective experience or to establish; whatever she perceives it to be his pleasure to cease to see, she tends to renounce and abolish. Whatever he consents to in her, she forces on him and is glad of her mastery and his submission, but whenever he insists, she is bound eventually to obey. Easily found to be true in our subjective experience, this ultimate principle of things is eventually discovered by the yogin to determine even objective phenomena.
The Purusha and Prakriti are therefore not only the Witness and the Activity witnessed, but the Lord and his executive energy. The Purusha is Ishwara, the Prakriti is his shakti. Their play with each other is both the motive and the executive force of all existence in the universe.
The Divine is the eternal self and spirit; but nature too is everlasting power of the self, eternal conscious-Force of the spirit. Mind, life and matter are powers of that power, energies of that force, substance of that spirit; spirit and matter are not separate and contrary creations, but matter itself is a self-creation of the Spirit.
Being and becoming are the single one. The one does not become the many, but the one is forever the many even as the Many are forever the one.
This by a self-existent self-knowledge thou shalt know, through a supramental knowledge by identity - the problem, the opposition, the shifts of philosophy, the rifts of Science, the fragmentary upliftings of Religion are the devices of a still ignorant consciousness, a [...] seeking knowledge.
Excerpt from the book Essays Divine and Human by Sri Aurobindo