The paradox
He said that he could easily show proof that he is from the future. But there is something that is stopping him from doing it. If he shows something from the future, there is a great possibility that it will create a paradox. That is why he hasn’t done it so far. That’s why he has tried everything he can to not look different from the humans of 2017. What he was saying, was being accepted by the lie detector. All of it was marked as true.