It is not about proof. It is about justification.

Human can not prove any thing real, so truth has to be revealed to you from above. But you have to justify the truth you accepted, using common sense, logic and reliable facts, because you don't want to believe something based on blind faith.

Our human activity is not based on proof, it is based on justification. Without justificatoin, things would be arbitrary, just like your illusion.

We cannot prove anything doesn't mean we cannot judge what is more plausible.That is the key point I am trying to make. your common sense or your illusion, which is more reliable?  That is no common ground between your illusion and my illusion, but there is a lot common ground between my common sense and your common sense, so clearly, it is justifiable to trust common sense than to trust your illusion. That doesn't mean common sense is always true, just that, if there is no exceptional reason, then you should trust your common sense than your illusion.