The only scientific approximation to the “soul” would be the energy coursing through a living body. When you die this energy is not destroyed, as that would violate the fundamental laws of physics. Instead that energy is incorporated back to the source of all things, the Universe/God. In fact research in the area of past life regression has find evidence of a reincarnation like phenomena. The most striking evidence comes from young children that remember intricate details of what they call their previous life. When investigated the facts are corroborated.