Philosophically I call myself agnostic. But colloquially I call myself an atheist. Also while I'm agnostic about there existing _any_ powerful being (god), I'm pretty dang confident that the gods described in religious texts do not exist. So in that sense, I am atheist (towards human religions). And it is in this last sense that I could see someone going from agnostic-to-atheist by reading the Bible or in other ways learning more about religion/psychology/history.