Atheism and happiness

Recently I have read several blogs criticizing Atheists based on a common logical argument. I’ve literally been reading this (though worded differently) everywhere:

Draw a circle on a piece of paper, placing a single dot in the center that represents you. Everything you can possibly understand is illustrated by the circle. How can you claim to know about what is outside of the circle? In other words, how can Atheists know that there isn’t a god without being all-knowing themselves?

A lot of bloggers cite this as the reason that they are “agnostic rather than atheistic.” This results from a misunderstanding of the terms.

Agnostic (Greek: α- a-, without + γνώσις gnōsis, knowledge) is a statement of knowledge. If you claim to be agnostic, you claim to be unable to prove whether or not a god or gods exist. You can be an agnostic theist, one who believes in a god but cannot prove its existence, or you can be an agnostic atheist, one who cannot prove or disprove gods, but does not believe in them.

In the same way that being agnostic is a statement of knowledge, atheism is a statement of belief. In answer to the question above, the atheist does not believe that there is circle at all, or rather that the circle emcompasses all that exists. While the theist would ask, “How can you prove that what is outside the circle doesn’t exist?” The Atheist would ask, “How can you prove that it does?”