The highest realization was described by Bhagavan in terms of the Ajata doctrine of Advaita Vedanta: there is only pure Selfhood as a Totality, no creation, no being separate, no seeker, and no enlightenment. His life is testimony to the fact that it is not an unworldly abstraction.
We can only perceive objects and also the subject consists, as far as perceptible, only of objective components. The pure I is not objectifiable, in so far Neti is the giving away of the recognized objects, also those hidden in the subject.
But in order to cross the 'watershed', there must be a complete letting go. Samadhi is non-dual. For this, the intensive collection, which I brought into the discussion at the beginning, is the best option - although we cannot manufacture this. Only 'there'