Many people have experienced deja vu, some thinking it's got something to do with past lives and rebirths. Deja vu is a kind of instant daydream playback. The restive brainwaves when you sleep cause dreams. You can't dream of people, places and things that you've never seen before. A person born blind cannot dream or experience deja vu. Deja vu occurs at a state when you're lax and not concentrating. Instant daydream playback means that the nano-second that you've seen the place for the first time, the next nano-second your brainwaves register it, you suddenly regain concentration. The lapse of a nano-second you'd feel as if long ago you've seen it before.