I found this definition for 'deja vu' in 'Catch-22' which sounds quite scientific and convincing:
"Yossarian shook his head and explained that deja vu was just a momentary infinitesimal lag in the operation of two coactive sensory nerve centers that commonly functioned simultaneously."
Yossarian knows everything. Some more vus i found in the book:
"There were terrifying, sudden moments when objects, concepts and even people that the chaplain had lived with almost all his life inexplicably took on an unfamiliar and irregular aspect that he had never seen before and which made them totally strange: jamais vu".
"And there were other moments when he almost saw absolute truth in brilliant flashes of clarity that almost came to him: presque vu".
This book is increasing my knowledge by leaps and bounds!! And its quite alarming!