Absolutely, 100% false.
I happened to be an atheist. I ALSO happen to be an agnostic.
These terms address two very different questions.
The former? Addresses the question: "is god real" with "show us proof"
The latter? Addresses the question "Can anyone know about gods?" "unlikely-- you have to define what you mean, first-- and nobody really has"
You have your definitions all mixed up-- no doubt from some theist who has never met an actual atheist.
Don't be silly.
'atheism - theism' isn't a dichotomy, with 'agnosticism' in the middle. It's a continuum, with something like 'strong' atheism on one end, and adamant theism on the other, and quite frankly, when one is looking at those two positions, they are really the SAME position; adamant conviction of a religious point of view regarding the existence of deity that is not, because it cannot be, based upon objective evidence.
One believes strongly that there is a God...so strongly that nothing could convince one that there isn't, OR...one believes strongly, so strongly that no possible evidence could convince one otherwise, that there isn't
Both positions are based upon unsubstantiated, non-objective beliefs. "Faith,' so to speak, and neither position is amenable to logic or argument.
MOST atheists do not occupy that far end, but more do than one would consider, given that those folks love 'logic' and the idea of accepting objective evidence, even when it messes with one's convictions. They don't, but they pay lip service.
The theists on the other end at least are more honest about their rejection of objective evidence.
ANYway....
I've always figured that we have, in a very loose set of folders, "strong' atheists who make the positive claim that 'There is no God," "weak" atheists, who say that they see no evidence that would make them believe in a God, but if there ever were any such evidence, they'd consider it, "ignostics" who claim that it is absolutely impossible to know whether there is a god or not and so the whole question is meaningless, "agnostics,' who don't know and don't think it's really possible to know, but hey, it's worth thinking about, "deists,' who think there probably is one but s/he pretty much abandoned the universe after creating it and certainly doesn't give a good hoot about us, ordinary theists who believe that there is a god, and He might even mess with us from time to time, and then there are the tried and true believers who are as convinced that there IS a God, and once more, God agrees with them and nothing will convince them otherwise.
It looks like a completed circle to me.
All I ask is that the atheist/ignostic/agnostic/theist involved figure out where on the spectrum s/he lies, and stop, when someone makes a point about where s/he is on THAT level, pretend that everybody is somewhere else.
My point is simple. I haven't ever spoken/debated with an atheist who did not end up letting me know that God appearing to him/her would not convince him/her of deity's existence, because the atheist involved would not be able to accept that evidence AS a personal appearance by God.
Why?
Because God doesn't exist. Therefore He can't appear, and any apparent appearance must be due to something else.