Déja-vûs is a process that has been described by sciences often.

It is simply the process of reading and writing at the same time in your brain and thus producing a wrong cognition. It happens rarely and is something like a disfunction but does no harm.

In many discussions like this one you see that people guess and try to find supernatural explanations just like they did with religion. But often there are explanations available when people start reading literature instead of guessing.