Agnosticism suggests that we do not have knowledge. We most definitely have knowledge. The only requirement to be atheist is to believe in (convinced of) zero gods. An archaic term, Gnostic in the past meant that someone was the authority on knowledge. This is thoroughly a misnomer. The most well read top minds in the world are not Gnostic. The opposite, Agnostic, is also terribly misleading. I like the way Aron Ra put it: Science doesn't know everything. Religion knows nothing.
I have those argument discussions frequently here.