When the mind starts to become profoundly still, and starts to shake off the notion ‘I am a body-mind, I am a person’, then not only does deep Bliss-Oneness-Love start to arise and the sense of individuality wane, but the intuition-seeing occurs that all of these things we perceive – such as body, mind and world – all of these are intuited-seen-perceived to be just a mere dancing of thought, a mere projection of mind-stuff, like a dream: empty, unreal, illusory, nothing more.
As thoughts markedly and profoundly slow down, all this comes to be seen directly.
From Shankara’s Vivekachudamani:
170. In dreams, when there is no actual contact with the external world, the mind alone creates the whole universe consisting of the experiencer etc. Similarly in the waking state also; there is no difference. Therefore all this (phenomenal universe) is the projection of the mind.
171. In dreamless sleep, when the mind is reduced to its causal state, there exists nothing (for the person asleep), as is evident from universal experience. Hence man’s relative existence is simply the creation of his mind, and has no objective reality.