We’ve all had it happen to us at least once in our lives: we sit down to eat in a restaurant where we’ve never been, and suddenly we get that feeling that we’ve been there before. Sometimes we even know where certain things are. How uncanny!
Of course, that feeling is called déjà vu, which translates from French into English as “already seen.”

Since this phenomenon is so widespread among the human population, scientists have tried (and failed) to determine its origins. Researchers have determined that some medical conditions, such as epilepsy, can create the feeling of déjà vu in some people. But this still doesn’t explain why the majority of healthy people have had this experience at least once in their lives.

Some research points toward dreams as being the culprit in some cases, while other studies suggest that some people build false memories based on new experiences. Illicit drug use has also been said to be a reason behind déjà vu.

Still, these scientific explanations don’t explain the majority of cases of déjà vu. So what are some other explanations?

Psychologists who are followers of Carl Jung argue that déjà vu is simply a case of the always present, but usually dormant, collective unconscious coming to surface. They argue that, though you personally may have never been in that restaurant before, we are all connected to the collective unconscious, and you are therefore experiencing a shared memory. Jungians further believe that the closer you are to other individuals the more connected you are. Therefore, if one of your living blood relatives sat in that restaurant, or even an ancestor, it could result in a stronger sense of déjà vu.

Yes, I know, pretty deep stuff. But there is still another potential explanation for déjà vu—the supernatural.

Some people believe that déjà vu comes from an experience you’ve actually had in a past life. Of course, this explanation is more popular in many Asian countries where beliefs in reincarnation are more popular than in the West. This may also explain why understanding déjà vu is much less of an obsession in Asia.

Finally, there are those who think déjà vu is the result of possession. Yes, that’s right, this theory holds that evil spirits who were once human have found a way to enter your body, which gives you that feeling that you’ve been somewhere before.

In the end, there are a few things that we can say definitively about déjà vu. One, its origins will probably never be known for certain. Two, if you’ve had that feeling before, chances are you’ll feel it again.

In fact, you may even feel like you’ve read this before. Have you?