According to Osho, dreamless sleep is a third, deeper state beneath the dreaming unconscious where suppression ceases, disturbance ends, and thus the unconscious has nothing to project as dreams. In this utter stillness the body-mind rejuvenates, time disappears, and one rests in profound darkness—an invaluable pause and a threshold to real awakening, consciously accessible through meditative witnessing.
In very deep sleep, your mind gets so quiet it stops pushing up pictures, so nothing appears and you just rest.