All atheist means is "not a theist." Anyone who lacks an affirmative belief in god is an atheist. That includes, for example, newborns. People are highly resistant to this definition, because if "atheist" is a dirty word, you hardly want to admit that you or your child started out as one.
I think the definition is more "regional" than that. Different communities tend to adapt their own specifics to the terms atheist and agnostic. The few communities I have been in that really used agnostic did use it as a placeholder between atheist and theist. It essentially was used for people who were on the fence and honestly did not know what to believe. They did not have an active belief for or against God; thus, they were agnostic.
I can see the use of that term, but I am guessing that the majority here do not fit that description.
Depending what you mean by God I fit that description. Specifically if you allow God to mean an agent that created the visible universe rather than a process, then I have no evidence for or against either hypothesis.
If you are restricting God to mean Judeo-Christian type Gods, then I am an atheist,
If you’re not sure:
Where I come from, if you don’t believe in God and you don’t have a proof that God doesn’t exist, you say you’re agnostic. A typical conversation in polite company would go like this:
Woman: What are your religious views?
Me: Oh, I’m an atheist. You?
Woman: Well, do you know for certain that God doesn’t exist?
Me: I’m pretty sure, that’s what I believe.
Woman: How do you know that God isn’t withholding all evidence that he exists to test your faith? How do you know that’s not the case?
Me: Well, it’s possible that everything is an illusion.
Woman (with finality): You’re agnostic.
Every community has its own set of definitions. Here on LW, you are an atheist, simply, if you don’t believe in God. You don’t have to be 100% certain – we understand that nothing is 100% certain and you believe in God’s non-existence if you believe it with the same conviction that you believe other things, such as the Earth is orbiting around the sun. For a fuller explanation, see this comment.
For the rest of us:
My favorite passage in the Bible is Exodus 4 because this is the part of the bible that made me suspect that it was written by men; men that were pretty unsophisticated in their sense of justice and reasonable deity behavior. God asks Moses to come be on His side, and Moses agrees. The next thing that happens is that God is trying to kill Moses because his son isn’t circumcised. I guess God already asked Moses to do that? They left that part out of the story. Nevertheless, God seems more peevish than rational here. Presumably, he chose Moses for a reason. So trying to kill him in the very next scene doesn’t make a lot of sense.
As someone who has had some trouble figuring out how things are thought about in atheist circles, I would like to suggest not being like God in Exodus 4 when people ask why we’re atheist even though we can’t prove there’s no God. It’s understandably annoying to repeat yourself, but they need to understand the context of atheism here. You can refer them to this comment again or "The Fallacy of Gray" or here.
And steel yourself for the inevitable argument that belief in God is a special case and deserves extra certainty. These are final steps…
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I would like this to be a reference for people coming onto the site that consider themselves agnostic. Any editing suggestions welcome.