My assumption
I had always assumed a distinct difference between agnostics and atheists. The agnostic admits a degree of ambiguity in belief, while the atheist denies the possibility that God(s) exists.
But, it would appear there are devout atheists that believe they will prove God(s) does not exist through science, as in the case of Carl Sagan, in his reliance upon the Big Bang theory to disprove creationism.
I was an Atheist for about 7 years in my youth. In retrospect, I see religion as the root of my disbelief. I had to overcome this huge obstacle of my distaste for religion to discern God from mankind. My faith in God did not survive. Afterall, there are many religions older than christianity, none of which seem to do any better or worse than teaching fundamental principles of proper behavior. In some cases, the behaviors we see from 'twisted' sects of any religion would be misanthropic--evil. From an entirely clinical perspective, Buddhism seems the most successful of all religions in terms of human interaction, i.e., not having a negative impact, but positive.
The transfer from one belief system to the next, from Atheism to belief in God or vice versa, is a completely personal journey of reasoning, or the complete lack thereof. I have always seen reliance upon my emotions for judgement as a poor attempt at autonomy. In my case, belief in God was a process of reasoning. I had to 'unlearn' religion, accept agnosticism, define my Atheism, and look deeply into what I consider the range of possibilities before making the final decision that there is a God.
In short, I see no ground for science being able to prove or disprove the existence of God. However, short-sighted religions that teach improper science leave their victims helplessly inept in a world of increasing knowledge. And, Atheists that 'attack' religion with science are as repulsive to me as any religious zealot.
I see no point in any of it. To be an Atheist is a personal choice that I deeply respect for the personal reasons stated above. To follow <B>Atheism</B> is as much a religion as Puritanistic Catholicism, and thereby just as useless--in my opinion. I see two mirrored religious sects standing across a tiny divide, pointing fingers and jeering at one another. Silly.