Science was once a child of the church.

[Cinjin]

Well, first of all, I'm a deist, not an atheist.
Secondly -
That's an odd response but hey, you're new here so I'll answer the question that I JUST asked of you.

The reason why atheism can easily exist without theism is because the default setting of all humans is lack of knowledge.
When you are born, you believe in nothing until some gullible halfwit attempts to imprint you with his own ideas of who created what.

However, not every person ever born on this planet has received such stupidity. There were and are still many who have never believed in a god - thus atheism. Now, if you're merely referencing the fact that the word theism is a part of atheism, than you're just arguing semantics and I have no time for such futile idiocy. I'm hoping that you're not just arguing semantics right?

Summation: The lack of knowledge of any god creates a person who does not believe in god. Therefore, atheism is completely possible to exist without theism.

Well you make a convincing argument, and I can see your point, and agree. I just find it hard to accept that there was a time in humanity, not counting early Neanderthals and Cromagnons, that humans were not being influenced by a belief in gods. Lets just say the last 40-50,000 years, what time in history did humans have the goddless experience you are suggesting?

There is a culture in the Amazon even today that is completely atheistic. The Pirahã people know of no god and even rejected the idea of Jesus when they found out that the missionaries had never heard or seen him. This is proof positive that atheism exists separate from theism, but even on a much greater scale, there are millions of atheists who have never believed in any god at any time in their life. Regardless of whether or not they heard of your god, they made the choice to reject theism often solely on the premise of my original point: lack of knowledge because of lack of evidence.