@igm,
You can prove something exists. You can refuse to know anything (perfectly fine).
You cannot prove that something does
not exist.
I meet a unicorn, I snap a photo of it. Someone else may disbelieve anyway ("Yeah right, it looks doctored"), but I do have visual evidence of said unicorn.
On the other hand, I may say that no unicorn exists. But maybe the multiverse theory is right, and writers are basically channeling parallel dimensions (or an ancient memory of a unicorn-like beast).
The point is, if something is said not to exist, you have to exhaust any possibility that it never existed or doesn't exist elsewhere. Otherwise you are a liar, claiming to know all events. This upset me in another discussion on the Great Flood. This is an omniscience disproval fallacy. "I know there is no God." Are you God? Can you see everywhere and every time? "No?" Then how do you
know there is no God?
Now, can you prove that something invisible exists? Sure can! What about radiation? You often can't see it but it makes you sick. God being invisible doesn't
Agnosticism is more logical than atheism. You can not believe or not know that there is a God. You can believe or know there is a God. But to know there isn't a God is an act of hubris, placing your knowledge equal to God, by deciding that you are sure of his nonexistence. This assertion is a claim of omniscience.
Burden of proof for nonexistence > burden of proof for existence.
I only have to produce a photo, hoofprints, a horn, and a dead unicorn to convince people that I have killed a unicorn like the awful person I am. But in order to prove no unicorn exists, I either have to exhaust all locations and somehow prove that I have really looked everywhere.
Or I have to come up with a logical reason why unicorns cannot exist. But such reasons are often limited (circular square is not a logical impossibility) or the effective equivalent of a strawman changing parameters to discount the object in question. "Unicorns must be magical." Must they? Can not a horn with a horn be sufficient? "God must be omniscient, omnipotent, omnipresent, and omnibenevolent (I only heard this last one in the last twenty years)." Must he? Must he even be a "He"?