Well that's a mighty deep question you've posited to us here. First you have to separate the things that make you, well, you. Your mind, body, and theoretical soul are all separate things that only form an individual while they're connected. Matter can neither be created nor destroyed. When you die, the matter that makes up your body deteriorates and is recycled back into the universe to make way for other things. Energy as well cannot simply cease to exist, but can change form. Your mind and consciousness are the result of electrical impulses in the brain. The brain also creates an electromagnetic field while alive. That energy, upon dying, is lost as heat or conducted out of the body. If you believe in such things, it should be theoretically possible for your mind to leave an imprint on conductive materials if the electromagnetic field emitted at death is strong enough, which could account for ghosts and such. Finally the soul, which no one can prove exists or doesn't exist. We don't know what it is if it does exist, and thus can't apply the laws of science to it. That's where religion and faith typically come in. Personally I do not believe in a heaven or hell. The soul is most likely a form of as-of-yet undefined energy, and if all the energy of dead people was leaving earth to go to other realms where would the energy for new souls come from? I believe that, in the case of souls being real, reincarnation of some kind is the most likely result. The energy from dead souls is recycled back into the world to create new life. Chances are that soul gets mixed in with all the other dead souls before some of it is scooped out for a new life, and because the mind and body are separate it is highly unlikely that any memories or personality traits survive into the new life.