Earlier quoted context omitted.
Sure, but nonexistence is the default. Has to be the default; most possible things do not exist. In this case we have no evidence for, so we stay with the default.
You're making the "if a tree falls in the woods and nobody hears it" pontification? If so, I disagree with you.
Absence of evidence isn't proof of existence. Ultimately it's all about probabilities based what is known. Unlikely there is a blue teacup within Saturn's rings or a flying spaghetti monster.