Like the other poster said there's no cause known. All I can think of is something happened so close to an experience (something you can actually recall is a different matter) or perhaps something you've experienced peripherally such as a dream or media.

Or perhaps just something so close to one of those you feel like it's happening in front of you.

Or just a glitch in the brain?

Or perhaps it's the Matrix shrug unsure if that's better or worse.

Or....

[–] PoastRotato@lemmy.world 13 points 1 week ago* (last edited 1 week ago) (1 children)

I read somewhere once that one theory behind deja vu is that it's the result of a temporary de-sync between your left and right brain hemispheres. Usually signals reach each hemisphere at about the same time, but sometimes the signals can be de-synced by a few milliseconds and (theoretically) cause you to process the same thing twice in quick succession, giving you the vague impression of familiarity on the second signal process.

Edit: Messed up a bit. Each hemisphere sends a signal to the temporal lobe for processing, and that's where the de-sync can happen.

[–] LadyButterfly@piefed.blahaj.zone 5 points 1 week ago

That's interesting thanks