The atheist is quick to point out when a person asks him why he is an atheist that the questioner is an atheist as well. He points out that the questioner does not believe in Zeus, Apollo, Baal, and the Flying Spaghetti Monster. Since these and any number of deities which cannot be disproved are no longer taken seriously today, all people though they might believe in one God, are atheists in respect to those other deities.
But, atheism is not merely the denial of a certain dogma about God or gods, it is the reversal of a deep seated assumption in the soul; the sense that there is a meaning and a direction in the world it sees. This denial is the real root of atheism and is the reason for the rejection of God or gods. If there is one positive thing we can say about all those who believed in the mythological deities, it is that most of them held firmly to a purpose in what they saw. The same cannot be said of the atheist.