Our mental "continuity" is really just an illusion. The brain develops a narrative that it feels best incorporates all of the sense clues at its' immediate disposal - and it looks for changes from moment to moment to narrate the passage of linear time. But, as others have pointed out here, sometimes that glitches. generally the brain draws from prior memories to develop its' narrative by comparing sense to sense and noting differences. deja vu happens when it calls on the last memory to develop the narrative - which it usually doesn't seem to do. we tend to search for historical patterns of the past vice immediate past. not sure why.

Check out Norman Doidge's canonical work "The Brain that Changes" and pay particular attention to the split brain studies. After the corpus callosum is split between the right and left hemispheres they are left to develop these narratives on their own based on the limited sensory information each has available to it. There is an amazing example that illustrates this effect. When the left side is told to perform an action without knowledge by the right and the right is asked to explain it will make up the most amazing story to include all the sensory input available to it and memories. This is the type of glitch where deva vu occurs.

From the Oracle of Delphi to modern game theories we have had nothing but futile attempts to predict the future or evolve a winning strategy.

I have experienced it. If it happened all the time, I would go see a neurologist. [sciencedaily.com]

I get deja vu feelings all the time, but so far it has never helped me predict the future or avoid danger or bad decisions, unfortunately.
So I really think it's just our mind glitching so that we feel like we are remembering something but really aren't.

yep, it's deja vu all over again.

Whenever I would get the feeling that I experienced something before I always thought that it was my brain misfiring. I logically knew I wasn't experiencing the same thing again. This is not the same as something feeling familiar. In that case I figure I was being reminded of something.

With a lousy sense of direction, I get that feeling often while hiking and driving.

"This trail junction looks familiar," I say.

"Yes, Kathleen, we have been here dozens of times. We passed it this morning."

It's maddening.

It’s a vague feeling of familiarity … nothing cosmic. It’s always given me a buzz though. Anymore, I’ve the time to consider ‘why,’ and generally figure it out ~

I think we have probably all experienced the feeling of deja vu at some time or another. I have no real knowledge of why it occurs, but understand that there are a lot of things beyond my comprehension and this is probably one of them. The brain is like a giant computer which has stored within it memories of everything we have ever experienced. We dream at night, and although I personally can never remember them, unless I’m awakened directly from one, these dreams are recalled memories jumbled up. Perhaps deja vu is a similar type of brain activity, a response to stimulus in the present which our brains identify with an experience from our past which we mistake for a memory. In fact this could just be a jumbled up recall of some other similar experience...a brain malfunction or false memory if you like.

I feel like i read this post before

it's an interesting phenomenon because so many of us experience it, and because so many believe what they experience actually foretells future occurrences, but in my opinion it's also a load of rubbish because it's impossible. i'd like to hear your interesting theories about it, though.

We talked a bit about it in my neurophysiology lecture. There is an area of the brain responsible for the feeling of familiarity. Deja vu can actually be triggered through trans cranial magnetic stimulation.