It is through ignorance (avidya) imposed on the Self, that people suffer the sorrows arising from desire and work (karma). But that ignorance does not really inhere in one’s Self just as the snake, the silver, the water, and the dirt, superimposed on a rope, a mother of pearl, a desert, and the sky (respectively) do not in reality exist as the distortion of the rope etc.. But they appear as the defects of those things (rope etc.) because of the superimposition of false notions on the substances (rope etc.) that provide the basis for them. They (the substances) are not tainted by those faults, for they are outside the notions thus falsely superimposed. Similarly, people, after having superimposed on the Self the false notions of action, agent, and fruit, like the snake (on a rope) experience the misery of birth, death, etc. consequent on the superimposition; but the Self, though it is the Self of all, is not tainted by the sorrows of the world outside. For just like the rope etc. It is extraneous to the superimposition of false notion.(commentary of Sankara on Katha Up. II.ii.11)
This is an outline statement of the adhyasa (superimposition) thesis using all the standard examples. It is, in my view, best understood after the fashion of a Kantian transcendental postulate. It is not as though there is an act of superimposing as an act amongst other acts: adhyasa is a background, supervenient condition. Realising it as operative is a matter of understanding and knowledge rather than experience. Strictly speaking ecstatic experience such as samadhi does not banish ignorance in Sankara’s view. Others hold that it is certainly at the very least propaeduetic. They would be of the yogic persuasion.
Part of the realisation of the Self, contra the ego/self, is the dismissal of the narrative diachronic notion as Galen Strawson does. One then falls back into the pratibodha viditam concept of the Self as known with every state of awareness or the Self as immediate presence.
It (i.e. Brahman) is really known when it is known with (i.e. the Self of) each state of consciousness, because thereby one gets immortality. (Since) through one’s own Self is acquired strength, (therefore) through knowledge is attained immortality.(Kena Up. II.4)
(commentary) Pratibodha-viditam, known with reference to each state of intelligence. By the work bodha are meant the cognitions acquired through the intellect. The Self, that encompasses all ideas as Its objects, is known in relation to all these ideas. Being the witness of all cognitions, and by nature nothing but the power of consciousness, the Self is indicated by the cognitions themselves, in the midst of cognitions, as non-different from them. There is no other door to Its awareness.