To preface it, the definition atheists advance is "not believing that a god exists" (what I'll label the "weak definition" for purposes of this entry) whereas the definition theists advance is "believing that no gods exist" (what I'll label the "strong definition").
The argument I hear often is something along the lines of:
Atheists improperly argue etymology, historical use of the term, or dictionary definitions. While interesting, it bears no weight on the current meaning of the word; words change over time. The correct meaning of the word is that in which it is commonly used.This is the common usage argument. Overlooking the fact that dictionaries give usages of the words rather than definitions (thus rendering that point moot), one should take the time to ask: How is "atheist" commonly used? Imagine the following conversation (in which I have actually been the atheist):
Bob: What are your views about God?And a variant:
Bert: I don't believe God exists.
Bob: Oh. You're an atheist?
Bob: Do you believe that a god exists?Both of these support the weak definition. I imagine most people who pose Bob's first question and receive Bert's response would then call Bert an atheist. Such a response is inconsistent with the strong definition.
Bob: Oh. So you're an atheist?
Not Believing vs Believing Not
Another common argument goes that there is no difference between the two definitions. The weak definition centers on "not believing" whereas the strong definition centers on "believing not." Is there a difference? There's a difference because the former definition is about having no belief whereas the latter is necessarily having a belief.
To illustrate the difference, I'll pick a topic which most people probably won't be familiar with: semantics of programming languages. Consider:
A sentential form which is of a leftmost derivation is necessary for recursive-descent parsing.Do you believe the above is true or false? If you have don't have any idea about what a sentential form is or what recursive-descent parsing is, it is the ostensible truth that you have no belief. You neither believe that the above claim is true nor do you believe that the above claim is false. You neither believe for or against. You don't believe.
Now, consider the following conversation:
Me: Do you believe that recursive-descent parsing requires a sentential form which is of a leftmost derivation?Is it accurate for me to conclude that, since you do not believe that the claim is true, you necessarily believe that it is false? Of course not.
Me: Oh, so you believe that claim is false!
X: I believe the claim is true.If I ask you if you believe the claim is true, I'm asking "do you fall in the category X." Since you're in category Y, you would have to answer "no." That places you in the category "~X." It's a fallacy for me to conclude you are in category Z, though, because ~X = Y + Z. Since you fall in the category Y, it is valid for you to say "I do not fall in category X" -- "I don't believe the claim is true."
Y: I neither believe the claim is true nor do I believe the claim is false.
Z: I believe the claim is false.
There's a clear distinction between not believing a claim is true and believing a claim is false. So, similarly:
X: I believe a god exists. (theist)Now, if you ask me if I fall in category X, I would have to say no. I lie squarely in ~X.
Y: I neither believe god exists, nor do I believe that no gods exist. (non-theist)
Z: I believe that no gods exist. (anti-theist)
Do you believe a god exists? Yes = X; No = ~X.
Since I don't hold that belief -- since I don't believe a god exists -- I am in ~X. It's a fallacy for you to conclude that I must therefore be in category Z.
To tie this in to the weak and strong definitions, the weak definition is ~X while the strong definition is Z. Note that ~X = Y + Z. So, these two terms are not mutually exclusive; Z is a subset of ~X. All Z are also ~X but not all ~X are Z.
Conclusion: Redefining Atheism
So, to the point, theists often charge that we are trying to redefine atheism. That's clearly not the case. But even if it is... so what? "Gay" hasn't always meant homosexual -- at some point they began to redefine it by choosing it as a label for themselves. Even if it weren't the case that atheism is defined using the weak definition both in dictionaries and in common usage, what does it matter that we are trying to redefine it? It's simply the label we've chosen to identify ourselves as.
But this goes to a larger point. To often it's the case that the charge is leveled that we're trying to redefine atheism in a grand misdirection. What is the logic in the mind of the person who alleges this?
Dan: Do you believe a god exists?Ad nauseam. They seem to somehow shift the debate from the belief in a god to a debate about the label on beliefs in a god. What is the logic in Dan's mind? That Sal secretly believes there are no gods, calls himself an atheist, insists on atheism simply being a lack of belief to misdirect, but also claiming at the same time he doesn't believe gods exist?
Dan: Ah, so you're an atheist!
Sal: Yeah, I don't believe any gods exist.
Dan: Well, believing there are no gods requires just as much faith as my position.
Sal: I never said I believe there are no gods. I'm an atheist; I just lack the belief.
Dan: Oh, you're just trying to redefine the word to mean lacking a belief. It really means that you believe there are no gods.
Sal: But that's not what I believe. I don't have a belief about the existence of gods.
Dan: Quit trying to redefine the word.
Let's not forget that these are the labels we put on ideas; the labels themselves have no meaning. They are defined by the ideas which they label. Quit directing arguments against the label and start directing them towards the idea.