I know this is a well-worn topic, but I think it is worth hashing over this old question one more time.

First, some obvious points that many ignorant, bible-thumping, knuckle-dragging bigots are unable to grasp:

1. ATHEISM is not the same as MATERIALISM (not all atheists are materialists).

2. ATHEISM is not the same as MARXISM (not all atheists are Marxists).

3. ATHEISM is not the same as HUMANISM (not all atheists are Humanists).

4. ATHEISM is not the same as AGNOSTICISM (not all atheists are agnostics).

5. ATHEISM is not the same as SKEPTICISM (not all atheists are skeptics).

6. ATHEISM is not the same as NATURALISM (not all atheists are naturalists).

7. ATHEISM is not the same as EXISTENTIALISM (not all atheists are Existentialists).

If you don’t understand these basic and obvious points, then please stop reading this post now, and go back to your cave or to your church’s para-military compound in Arkansas or Alabama.

Now for something a bit more sophisticated.   Consider the following initial, rough definition of “atheism”:

DEF1

Person P accepts ATHEISM if and only if P believes that “There is no God.”

There are a couple of problems with this definition.  First of all, (DEF1) is compatible with someone being a polytheist.  One can both believe that “There is no God” and at the same time (without any contradiction) believe that “There are many gods”.  To believe that “There is no God” is to believe that there is no god who is the one-and-only all-powerful, all-knowing, eternal creator of the universe.

But denying that there is a god who has infinite power, infinite knowledge, and infinite duration is NOT the same as denying that there is any god whatsoever.  One could deny the existence of an all-powerful, all-knowing, eternal god and yet believe that there are many gods who have finite power, and finite knowledge, and/or who are of finite duration.  In other words, one can reject traditional western theism (the belief in God found in the western religious traditions of Judaism, Christianity, and Islam) and yet be a polytheist and believe in the existence of many finite gods.

A second problem with (DEF1) is that it does not make room for atheists who claim that the concept of “God” is incoherent.  A.J. Ayer, Antony Flew, and Kai Nielsen were all atheist philosophers, but they all believe that the sentence “God exists” is incoherent.  They believe that the sentence “God exists” is neither true nor false.  So, they also believe that the negation or denial of this sentence is also incoherent.  Thus, none of these atheist philosophers believed that the sentence “There is no God” makes a true statement.  On the basis of (DEF1) none of these atheist philosophers would be categorized as being an “atheist”.

The best solution to the first problem, is to draw a distinction between strong and weak atheism.  Weak atheism is the denial of traditional western theism.  Strong atheism is the denial of the existence of any and all gods.

DEF2A

Person P accepts WEAK ATHEISM if and only if P believes that “There is no God.”

DEF2B

Person P accepts STRONG ATHEISM if and only if P believes that “There are no gods.”

On these definitions, strong atheism implies weak atheism, but weak atheism does not imply strong atheism.  Someone who believes that “There are no gods” must also believe (to be logically consistent) that “There is no God”.  But some one who believes “There is no God” could believe that “There are some gods” (i.e. gods who are finite in power, knowledge, or duration).

These definitions, however, do not get around the second objection, concening atheists who believe that the sentence “God exists” fails to make a coherent statement.  One way to get around the second objection would be to characterize atheism not as a belief, but as the absence of a belief:

DEF3A

Person P accepts WEAK ATHEISM if and only if P does NOT believe that “God exists.”

DEF3B

Person P accepts STRONG ATHEISM if and only if P does NOT believe that “One or more gods exist.”

But while these definitions might get around both the first and second objections, they are still problematic, because we think of atheism as being an intellectual position or stance.  The lack of a belief, however, is not an intellectual position.  Presumably, ALL BABIES lack the belief that “God exists”, but it is absurd and counterintuitive to say that ALL BABIES are atheists.  Babies simply don’t have any position on the question of the existence of God, and they certainly do not have a position on whether the sentence “God exists” expresses a coherent statement.

I propose an alternative way to deal with the second objection, a way that preserves the view that atheism is an intellectual position or stance, and that avoids the counterintuitive implication that ALL BABIES are atheists:

DEF4A

Person P accepts WEAK ATHEISM if and only if P believes that the sentence “God exists” does NOT express a true statement.

DEF4B

Person P accepts STRONG ATHEISM if and only if P believes that the sentence “One or more gods exist” does NOT express a true statement.

As far as I can see, these defintions get around the two main objections that we have been considering, and they do so while preserving the intuition that atheism is an intellectual position or stance, a belief that we cannot ascribe to ALL BABIES.

Some who accept weak atheism believe the sentence “God exists” expresses a statement that is false, while others who accept weak atheism believe the sentence “God exists” does not express a coherent statement at all.  Both sorts of atheists are encompased by (DEF4A).

Some who accept strong atheism believe the sentence “One or more gods exist” expresses a coherent statement that is false, while others who accept strong atheism believe the sentence “One or more gods exist” does not express a coherent statement at all.

One final point, which is probably the most controversial point I have to make on this topic.  Although atheism is an intellectual position or stance, it is NOT a point of view.  At least, it is NOT a worldview, and it is NOT an ideology, and it is NOT a philosophy, and it is NOT a religion.  In short, atheism is the rejection of a specific religious belief or a religious “assertion”.  Weak atheism is basically the rejection of traditional western theism.  Strong atheism is basically the rejection of any sort of theism, including belief in one or more finite gods.

That is why the first seven statements at the beginning of this article are true.  Atheism is the rejection of a particular religious belief or religious “assertion”.  Atheism is NOT the assertion of a general point of view or philosophy or worldview.  Furthermore, atheists do not necessarily agree on WHY we ought to reject a particular religious belief or assertion.

Some atheists reject the assertion that “God exists” because they think it is FALSE.  Other atheists reject the assertion “God exists” because they think it is INCOHERENT.  The atheists who think “God exists” makes a FALSE statement have different reasons and arguments for thinking this statement is false.  So, atheists do not necessarily agree with each other about WHY we ought to reject the assertion that “God exists” or that “One or more gods exist”.

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Update (10/5/15):

Angra Mainyu suggested a counterexample to my proposed definition 4A:

c. What if Alice is silent on whether God exists on your definition, but she believes that “there is an omnipotent, omniscient, morally perfect being” is not true …? 
The classification you propose does not cover a case like that.

I also came up with a similar objection to 4A.  What about a person who does not understand English?  A person who speaks French, German, Italian, Spanish, Chinese, or Japanese but does not understand English will in most cases NOT have an opinion about the truth or the coherence of the sentence “God exists.”  because he/she will not understand the meaning of this sentence.

I can get around my objection and perhaps Angra Mainyu’s objection as well by revising the proposed definition a bit:

5A. Person P accepts WEAK ATHEISM if and only if P believes that a sentence S does NOT express a true statement, and sentence S has the same meaning as the English sentence “God exists.”

There is a difficulty with this defintion, however. It appears to imply that the sentence “God exists” is a meaningful sentence, which begs an important question.

However, it does NOT assume that the sentence “God exists” expresses a coherent statement.  The sentence, “This is a four-sided triangle.” is a meaningful sentence, and it can be translated into other languages, but it is an incoherent sentence in that it contains a logical contradiction.  So, 5A leaves open the question as to whether the sentence “God exists” contains a logical contradiction, but does assume that this sentence has a meaning, at least enough meaning for it to be possible to translate the sentence into another language.

Personally, I don’t mind begging the question as to whether “God exists” is a meaningful sentence.  It seems obvious to me that it is a meaningful sentence, and one reason for thinking this is that it is obvious that this sentence can be translated into other languages.  How could a meaningless sentence be translated correctly into another language?  So, I’m OK with begging this particular question.