According to Osho, reality is eternally one and indivisible; our sense of separation is a projection of the conditioned mind that slices wholeness into parts. To become one with reality, become whole and aware—see through mental divisions. In awareness, the opposition of 'individual' and 'cosmic' disappears; all dissolves into the cosmic, which alone is.
We feel separate because our trained mind cuts life into pieces; when we become truly aware, the pieces vanish and we are simply the whole.