Lol, yes. :-p Honestly, what would you accept as "proof" of existence? For example, if you're thinking about something, you have brought that "something" into existence merely by thinking about it. Having a conversation provides oral & audio proof, whether you believe it's illusory or real. Touching something provides physical proof that it's tangible, regardless of mental state; belief of physical interaction makes that interaction real, thus existence is proven. Does that make sense to you? Proof of existence is relatively simple with no constraints to the experiment. :-) Concerning your hashtag, definitely firm, since that means you have their attention. :-p