Originally Posted by McDuffie

Some do; some don't.

the prefix 'a' means 'without' (not 'denial of')
the word theism means belief in god(s)

Atheists are people who do not possess a belief in god(s). That is not the same as believing there is an absense of god(s).

I am a so-called 'weak' atheist. I don't possess any god belief. I cannot say there is no god(s), but I do not actively believe in any god(s).

My friend Don is a so-called 'strong' atheist. He will insist that there is no god(s).

Suffice it to say that atheism is not a belief system. It cannot possibly qualify as one.