Have you ever gone under general anaesthesia? The kind where you are up and talking one second, and then, ten hours later, you wake up somewhere else entirely? You know that space in-between, where there was nothing at all?
It’s about like that, except that you never wake up.
Your consciousness is inextricably entwined with your physical existence. Everything about you that makes you you is contained in your brain. When your brain chemistry is changed–by drugs, disease, or injury–who you are changes as well. When your brain dies, when it ceases to function, you cease to exist. There is no evidence that there is some supernatural force that inhabits your body and brain, but on the contrary, there is plenty of evidence that you are your body and brain.