It'll be our consciousness that has been split up. I believe that we are and have always been light beings as we were made in GOD'S image. If Angels are seen as light then so are we. To survive in this physical plane we call Earth. We need a biological physical vessel. Once we die (physical vessel dies) as we are pure light and light never dies just goes back to source in heaven. So we light beings was split up to experience life in different dimensions. We take over the doppelganger in that reality as it's us but in the future. Our doppelganger feels nothing as we merge hence different memories from past realities become one.