Cross-posted from Hemant Mehta's The Friendly Atheist conversation. Here's his Youtube video to which the following is addressed:
Morris is, of course, exactly right about the meaning of "atheist", which is literally "not" + "god" + "beleiver". It does not mean "without" or "lacking", though these are logical consequences of the prefix ~a, which is a privative, an affix which has the logical property of negating the root to which it is attached. Logically it is not NIL or NULL, it is NOT.
Now here's the thing: the word "god" ]is meaningless. There is no physical object to which the word "god" points. If there was, "god" would be as real as Pastor Morris, or the Prince of Denmark. No, not that Prince of Denmark - but Frederick, the actual human prince. The other prince, Hamlet, also has the characteristic of not having a physical object to point at. Like Hamlet, "god" is a work of fiction the meaning of which is entirely dependent on the text, which discloses the logical claim of "god's" identity.
This was in essence understood as far back as 500 BC, when Democritus described the gods as "eidola", or projections of human ideas. In fact atheists - those who believe god is not - have existed since then and likely earlier. Ancient Christians accused each other of being atheists since no two sects shared the same exact claim of "god" identity and nature, hence the one denied the reality of the other.
But that meaning no longer holds in popular "atheist" circles. They now come to claim that the word simply means "without" or "lacking" belief in god. Contrary to Mr. Mehta's claim, a shift in the meaning of the word "atheist" has happened, and relatively recently. We know precisely when, actually: when the philosopher Antony Flew published The Presumption of Atheism in 1976. I do not believe there are any dictionaries published prior to the popularization of Flew's argument that define "atheism" as the lack of belief in god - I've looked, and haven't found any. What is certain however is that Flew articulated the view many "atheists" now hold of themselves:
...Whereas nowadays the usual meaning of 'atheist' in English is 'someone who asserts that there is no such being as God, I want the word to be understood not positively but negatively... in this interpretation an atheist becomes: not someone who positively asserts the non-existence of God; but someone who is simply not a theist. The introduction of this new interpretation of the word 'atheism' may appear to be a piece of perverse Humpty-Dumptyism, going arbitrarily against established common usage...So Flew introduced the idea that an "atheist" was one who simply did not believe that "God" exists. He explicitly argued that term as it was widely understood then ought to be changed, and he was so successful that the present generation of "atheists" neither realize this meaning is new nor that Flew - who later rejected atheism - was its originator.
To deny Morris's claims of what "atheist" has traditionally meant and that it has recently changed is to assert a falsehood born of ignorance. What's worse, doing so leaves the atheist open to his charge that the reason for this change is because contemporary "atheists" are afraid to argue that "god" does not exist. He is in fact exactly right in my view.
Which is a pity because arguing that "god" does not exist is as easy and straightforward as allowing the theist to define it, this "god". And this is where the actual argument Morris presents in the video isn't just wrong, it's a lie. A lie so big we atheists often buy into it without realizing it. Any "god" is a proposition, a claim, made by the theist. Scientifically speaking we do not proceed uncritically from the claim to empirical proofs or disproofs of it - that would be folly which would commit the already strained resources of scientists to a flood of impossible claims. Impossible claims are simply claims which cannot be true, given their own premises. They are logically contradictory.
The Christian "god" is an example of this. As is the "god" of Islam. In fact any god-claim which asserts the existence of an omnipotent being is false on its face, given the paradox of the stone. There are many other problems with this, of course, from contradictions with other "omni-" properties to the Euthyphro Dilemma. No claim which contradicts itself can be true - or, if one prefers, if it is "true" then "truth" is meaningless, since it is both true and untrue simultanously.
So yes, "atheist" does mean one who denies the existence of "god", and no, "god" is not an open ended undefined set which can contain possible though undefined members. That's literally a nonsense, and one long employed by theists themselves to discredit atheism. We ought not aid them in this effort.
And yes, there are those of us who claim to know that a given god does not exist. What's more, we can prove it.