Dr Karan Raj posted a video on TikTok and racked up 825,000 views as he explained the science behind why we all feel déjà vu – saying it simply comes down to “sloppy admin by your brain”Dr Karan Raj posted a video on TikTok and racked up 825,000 views as he explained the science behind why we all feel déjà vu – saying it simply comes down to “sloppy admin by your brain”