Between the Big Bang and Big Crunch the universe goes thru cycles of expansion and contraction. During expansion, we remember a real past attending a variable and unseeable future. In contraction, because time is reversed, we remember a virtual past which, contrary to the entropic arrow of time, hasn't really happened yet. We percieve it as a normal, causal unfolding but accompanied by a crunchy noise and it just looks crinkly.
We don't remember the future in this direction either --backward from its beginning at the end of universal expansion-- for two reasons. Light is traveling backwards, out of our eyes and assembling all observables. Second reason is nobody liked the future very much and forgot it.
Because universe doesn't expand or contract quite evenly --less like a star-studded balloon than other stuff I shouldn't have machine-washed-- Bang and Crunch can coincide. Neither is time uniform --uniforms are dry-clean only. Time can constrict on an expanding field, which is how an acrylic sock can melt your turtleneck head hole shut in the dryer--creating an irreducible singularity. Thus do time and anti-time collide in brains and make deja vu.
Because the cycles throw us together from opposing ends of time, we get glimpses of ourselves coming back. Effect is more or less pronounced by what cycle predominates locally. My last planetarium visit suggests we are on spin. This also accounts for the disorienting experience of Jamais Vu.
Jamais Vu is the opposite of Deja Vu and consists of waking up in your pajamas --Jamais=french for jammies-- without knowing where or why. Sometimes Jamais Vu is inaccurately applied to waking up naked and painted jammy-like colors in the middle of a jungle with no clue where you are or how it happened. This is not Jamais Vu. It means you are a cultural anthropologist.