In sleep, in trance, in absent-mindedness there is no differentiation. What is that which was then but is absent now? The difference is due to mind.
The mind is sometimes present and at other times absent; there is no change in the Reality.
The same person who was in sleep is now too, in waking. The Self is the same all through.
Limitation is only in the mind.
The same Self is here and now, in the wakeful state, as in deep sleep when no limitation is felt. There was no mind in sleep whereas it is now active. The Self exists in the absence of mind also.
The above excerpt has been taken from Conscious Immortality, Chapter 13 (bold type added by me for emphasis).