Back when I was the moderator of the USENET newsgroup alt.atheism.moderated, I used to debate the definition of atheism and I used to defend the atheism as the lack of belief position. I’m persuaded, however, by Ted Drange that by default we should define our terms in a way which matches ordinary usage. Ordinary usage of the word “atheism” is that it means the belief that God does not exist. I see no benefit whatsoever to the proposal that nontheists should spend their limited time on trying to convince people both that (a) atheism is rational and (b) that they should use the word atheism in a different way, as opposed to merely focusing on (a).
Among professional philosophers, including self-identified atheist philosophers, probably the majority viewpoint is that atheism is the belief that there is no God and agnosticism is the lack of belief in God’s existence and God’s nonexistence. (Notable exceptions would be Michael Martin, Antony Flew, and Keith Parsons.) When professional philosophers want an umbrella term to group together people who believe God does not exist with the people who merely lack belief, probably the majority of them use the term “nontheist.”
For the record, I am fully aware of how condescending it can come across when person A says, “I’m an X,” and person B says, “No, you’re not. You’re a Y.” In other words, who am I to tell people how they should self-identify? In response, I would point out the following.
(1) I think people have the right to label themselves however they wish; I am not making a normative or ethical issue out of this. In other words, I’m not saying nontheists have an ethical requirement to use the word atheist consistently with ordinary usage.
(2) I am suggesting as a matter of strategy and “resource management” that there are much better uses of our time than an anal-retentive defense of etymological purism, i.e., the “but the greek roots of atheism, a + theism, mean literally without theism” defense. The meaning of words can and do change over time. If the meaning of “atheism” has changed from its Greek roots, then so be it.
Instead of focusing on etymology, I suggest a more pragmatic approach. With respect to the definition of atheism, I think we have a situation where two people who speak English and use the same words (e.g., belief, God, atheism, etc.) are effectively speaking two different languages. A self-identified ‘atheist’ and theist may even think they have a disagreement because superficially it seems they are speaking the same language, but they’re not. Because they’re not speaking the same language, we must distinguish the labels we assign to various positions from the positions themselves.
Imagine the following conversation:
Self-Identified ‘Atheist’: I’m an atheist.
Theist: Oh, so you believe that God does not exist. What’s your evidence for the nonexistence of God?
Self-Identified ‘Atheist’: No, I lack the belief that God exists. The lack of belief that God exists does not require any justification unless we first are given some reason to hold that belief.
Theist: No, you’re re-defining words. Atheism is the belief God does not exist.
Self-Identified ‘Atheist’: We’re using the same words in different ways. Based on how you define the word atheist, then I’m not an atheist; I’m an agnostic. Based on how I define the word atheist, however, I am an atheist. If we’re going to have real dialogue rather than just the illusion of communication, we’re going to have to agree on a set of terminology for the discussion.
Theist: [at this point the theist will either insist on his terminology or be willing to adopt yours; either way, the difference in terminology will be explicitly acknowledged by both sides and real communication will be possible.]
The point is that there is rarely much value in debating definitions, but real dialogue is possible if one of the parties is willing to state their position in terms of the definitions the other party accepts. As Andrew Kirk pointed out, “This is no different to learning a new language, or even a local dialect, and then using it rather than your own native dialect, to aid communication between yourself and a speaker of that dialect.”
I think the main obstacle to taking this sort of pragmatic approach is an unstated (and probably unconscious) assumption of what I will call “linguistic objectivism,” the idea that the truth of definitions of words does not depend upon the subject states (beliefs, desires, etc.) of persons. I cannot even imagine how linguistic objectivism could be true. If it even makes sense to talk about something being the ‘correct’ definition of a word, it seems to me that could only be the case in a relative sense. In other words, to borrow terminology from ethics and apply it to linguistics, I’m suggesting we should drop the pretense of ‘linguistic objectivism’ and instead be ‘linguistic relativists’: we should recognize that linguistics are relative to different cultures and different times.
Indeed, to press Kirk’s analogy all the way, what etymological purists about the “atheism is the lack of belief that God exists” definition are doing is equivalent to an American going deep into Mexico to a city that is not a tourist town, and then being hellbent on the fact that the Mexican locals must speak English, despite the fact that he is, quite literally, on their turf. The point is that, everything else held equal, it seems odd, if not presumptuous, for a group representing a minority linguistic tradition or culture, to insist that the majority linguistic tradition or culture submit to the minority group’s linguistic norms. (Here I am assuming that “atheism,” regardless of how it is defined, is the minority position.)