When we first meet Dr. Erin Gilbert (Kristen Wiig), she's teaching at Columbia University, but within seconds of her introduction, we find out that she once wrote a book about the existence of paranormal phenomena. When confronted with it, she initially tries to deny that she's the author but begrudgingly concedes the point, and upon finding out that the book has found its way back into print, promptly sets off to get her co-author, Dr. Abby Yates (Melissa McCarthy), to yank it from any further publication, fearing that her academic reputation might be damaged.
Setting aside the question of how quickly Erin did her 180-degree turn from "ghosts are real" to "just kidding," does this new Ghostbusters movie take place in a universe that doesn't have the internet? Even if the book had been out of print for awhile, it's not like its existence was completely erased, so it's hard to imagine no one had ever approached Erin—who clearly hadn't changed her name—about it at any point prior to when Ed Mulgrave (Ed Begley, Jr.) stops by to ask for her help. Similarly, what are the odds that Columbia wouldn't have done some sort of background check and found out about it? Pretty slim, we're thinking.