I consider myself an atheist as well as an agnostic. And whenever I mention that to someone, I get a puzzled or disapproving look. (See this comment on one of my previous posts: Religion, Culture and Mr Hitchens.)
Many perceive agnosticism as the middle way between atheism and theism. And people who consider themselves agnostics with that definition in mind seem to feel that both atheism and theism positions are dogmatic. “How can someone be 100% certain that God exists (or does not exist)?”, they ask. From this POV, atheists seem to be making the same mistake as theists (cocksure certitude about an un-provable hypothesis), and agnosticism sounds like a reasonable, open-minded and rational position to take.
This is a flawed understanding of what agnosticism (and atheism) is about. Let’s start with the etymology. The word agnostic comes from the Greek word ‘gnōsis’ which means knowledge. And atheism comes from ‘theo’ which means god. So while agnosticism is about the lack of knowledge about God’s existence, atheism is about the lack of belief in God. They both operate in different paradigms:
A = An agnostic theist who does not claim to know for sure whether God exists, but he choose to believe in God anyways.
B = An agnostic atheist who does not believe in God and also thinks that the existence of such entity cannot be known for sure. (This is where I belong. I think the absence of evidence does make God improbable, but not impossible. I do not claim to know for sure that God does not exist. But I think God’s existence is very unlikely.)
C = A gnostic atheist who claims to know for sure that such entity does not exist, and (hence) does not believe in God. This is an unreasonable position – and perhaps very few atheists belong to this category. Atheists usually believe in science and reason, and recognize that all scientific truths are provisional. (“I believe x.” does not mean “I can prove x.”, but “It would be unreasonable to doubt x.” See my earlier post Science Never Proves Anything for more details on this.)
D = A gnostic theist who claims to know that God exists, and (hence) believes in God. I think most theists probably belong in this category, because they are usually pretty sure that their belief is reasonable and justifiable with “evidence”.
So there. Atheism and agnosticism are not mutually exclusive. Also, while some of the above positions are logically more coherent (and hence more prevalent) than others, theoretically, one can belong to any of those four quadrants. I belong to the agnostic atheist quadrant. Where do you belong?