Advaita Vedanta Non Dual Vedanta. What is meant by non-duality? I think it means the dichotomy between the observer and the observed. The subject - object. But it seems to me that it is impossible to have any experience without an experiencer. The experience I am having is not had by someone else so clearly there is an experiencer. The experiencer is not the Ego. The Ego is just a thought construct that appropriates experiences as mine.
What non duality seems to point at (and also as I have experienced non duality) is the absence of the Ego in the equation. Then there is full experience and a sense of supreme connectedness with what is being experienced. It is a state we naturally arrive at with the diminishing of the Ego function. It is still dual though. Even if we say there is just experiencing it still implies an experiencer. There are just no thoughts in between the experiencer and the what is being experienced. A better word might be Non Plural. In my view it is nonsense to say that the Ego experiences. It only comments. It is just that we are so identified with the Ego that we imagine that the Ego experiences.
In advaita non duality refers to the equality of Atman and Brahman or that it is one continuous whole. That is a definition that we can accept and has nothing to do with observer and observed. Awareness of the totality can be in nirvikalpa samadhi in which no object is perceived but just consciousness. It is simply complete quietness of the mind, no excitation and Kastrup suggests it is akin to the carrier signal of radio. Obviously you cannot live in this world in that state.