What is Atheism?

[Nonpareil]

To quote myself from another thread, it seems rather odd when a proposition like "'God exists' is true" can be considered either true or not true because it is a belief, whereas its negation, "'God exists' is not true",  cannot be either true or not true because it isn't considered a belief.

No one says that the proposition "God does not exist" has no truth value. They say that it has an unknown truth value, as does "God exists", and that lack of belief is all that is required to be labeled an atheist.