True Knowledge is Being devoid of knowledge as well as ignorance of objects. Knowledge of objects is not true knowledge.
~ Forty Verses on Reality, Verse 12, written by Sri Ramana Maharishi
In Self-Knowledge, neither the knower, the knowing, or the known remain. If any of these three remain, that is ego, that is duality, that is suffering.
So how can this even be called ‘knowledge’? Know that the word ‘knowledge’ is just used to signify that thoughtless non-dual intuition of Reality that is Self.
It, the Self, is indescribable, so various words and phrases, all insufficient, are used, such as ‘knowledge’, ‘know thyself’, ‘be thyself’, etc, etc. None of these are quite right, but these words and phrases can convey something nonetheless, for you ‘know’ this already. You already fully know yourself, so these words can seemingly awaken you to that which you already know.
To know the Self is just to, having severed the identity with body-mind-name-form-ego, it is just to BE the Self, that which you ARE.
Self-knowledge is an inherent quality of the Self. Self and Self-Knowledge are one and the same. The Self always fully knows itself. You always fully know what you are. Not that the ego or mind knows – that is maya – but the Self, that which you are, always knows itself non-conceptually, without words, without any mediation by the body or mind.
This can never be known by the mind-ego. That is why even brain-damage will not remove self-realisation – because self-realisation is not related to the body-mind! Realisation ‘takes’ one ‘beyond body-mind-world! If it didn’t, it would itself be temporary, and liberation is neither temporary nor is it affected by time!
The Self is Self-Knowledge. But because there is no other that the Self, it cannot be said to be knowledge really, for there is no knower/knowing/known!