A Journey Through the Anomalies of Mind, Memory, and Time. Deja vu is the eerie sensation of 'remembering' an experience or situation that never occured. Scientific research into deja vu has revealed intriguing theories, ranging from short-term memory misfires to neurophysiological disorders. Yet other theories suggest more paranormal causes for deja vu, such as glimpses into parallel realities. Perhaps the true explanation lies somewhere in between.