“Neti, neti”, Not This, Not That, is a formula utilized by those following the path of knowledge to remind themselves not to get caught up in the outer forms and actions of the universal manifestation or the individual personality’s desires, goals, and focus. It is an essential part of the yoga of knowledge–as long as the individual is wrapped up in his own ego and the outer world, he cannot obtain any perspective or distance, or achieve a different state of consciousness that transcends the individual and the universal perspectives. It reminds the seeker that the Reality exceeds the capacity of the human mind, human speech and human understanding, and that the Reality exceeds all the manifested forms of the universal creation. In the day the brilliance of the sun makes the outer world seem like the sole reality; at night, we can see the stars and get a window to the larger universal creation. The texts refer to the “day” of the ordinary mind being the night of the mind of the seer; and vice versa.
Sri Aurobindo observes: “The traditional way of knowledge eliminates individual and universe. The Absolute it seeks after is featureless, indefinable, relationless, not this, not that, neti neti. And yet we can say of it that it is One, that it is Infinite, that it is Ineffable Bliss, Consciousness, Existence. Although unknowable to the mind, yet through our individual being and through the names and forms of the universe we can approach the realisation of the supreme Self that is Brahman, and by the realisation of the Self we come to a certain realisation also of this utter Absolute of which our true Self is the essential form in our consciousness (svarupa).”
“The system of negation is indispensable to it in order to get rid of its own definitions and limited experience; it is obliged to escape through a vague Indefinite into the Infinite. For it lives in a closed prison of constructions and representations that are necessary for its action but are not the self-existent truth either of Matter or Life or Mind or Spirit.”
However, the removal of all attributes and qualities, the “negative” emptying of all notions and ideation, is not the whole story. The Absolute is not solely transcendent, featureless and unconditioned. There is also a positive aspect to the Absolute, the aspect that creates and manifests the entire universe and its evolutionary process. “The Absolute is beyond personality and beyond impersonality, and yet it is both the Impersonal and the supreme Person and all persons. The Absolute is beyond the distinction of unity and multiplicity, and yet it is the One and the innumerable Many in all the universes. It is beyond all limitation by quality and yet it is not limited by a qualityless void but is too all infinite qualities. it is the individual soul and all souls and more of them; it is the formless Brahman and the universe.”
“These things are to the dimensional mind irreconcilable opposites, but to the constant vision and experience of the supramental Truth-Consciousness they are so simply and inevitably the intrinsic nature of each other that even to think of them as contraries is an unimaginable violence. The walls constructed by the measuring and separating Intellect have disappeared and the Truth in its simplicity and beauty appears and reduces all to terms of its harmony and unity and light. Dimensions and distinctions remain but as figures for use, not a separative prison for the self-forgetting Spirit.”
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 1, The Object of Knowledge, pp. 282-284